driver: leds: is31fl3196/99 dimmable dual/triple rgb driver

This is a driver for the Integrated Silicon Solution Inc. LED driver chips IS31FL3196 and IS31FL3199. They can drive up to 6 or 9 LEDs.

Each LED is individually controllable in brightness (through pwm) in 256 steps so that RGB LEDs can show any of ca. 16 Mio colors.

The maximum current of the LEDs can be programmed and limited to 5 .. 40mA through a device tree property.

The chip is connected through I2C and can have one of 4 addresses (0x64 .. 0x67) depending on how the AD pin is connected. The address is defined by the reg property as usual.

The chip also has a shutdown input which could be connected to a GPIO, but this driver uses software shutdown if all LEDs are inactivated.

The chip also has breathing and audio features which are not supported by this driver.

This driver was developed and tested on OMAP5 based Pyra handheld prototype.

Signed-off-by H. Nikolaus Schaller <[email protected]>

---
 .../devicetree/bindings/leds/is31fl319x.txt        |  41 +++
 drivers/leds/Kconfig                               |   8 +
 drivers/leds/Makefile                              |   1 +
 drivers/leds/leds-is31fl319x.c                     | 406 +++++++++++++++++++++
 include/linux/leds-is31fl319x.h                    |  24 ++
 5 files changed, 480 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/leds/is31fl319x.txt
 create mode 100644 drivers/leds/leds-is31fl319x.c
 create mode 100644 include/linux/leds-is31fl319x.h

Documentation/devicetree/bindings/leds/is31fl319x.txt new file +4 -0

new file mode 100644
index 0000000..d13c7ca
@@ -0,0 +1,41 @@
+LEDs connected to is31fl319x RGB LED controller chip
+
+Required properties:
+- compatible : should be : "issi,is31fl3196" or "issi,is31fl3199".

From a quick look at the datasheets, I believe the Si-En SN3199 [1]

Documentation/devicetree/bindings/leds/is31fl319x.txt new file +16 -0

+	#address-cells = <1>;
+	#size-cells = <0>;
+	reg = <0x65>;
+
+	led0: red-aux@0 {
+		label = "red:aux";
+		reg = <0>;
+	};
+
+	led1: green-power@4 {
+		label = "green:power";
+		reg = <4>;
+		linux,default-trigger = "default-on";
+	};
+};
+

drivers/leds/Kconfig +0 -0

index 2251478..f099bcb 100644

drivers/leds/Makefile +0 -0

 obj-$(CONFIG_LEDS_HP6XX)		+= leds-hp6xx.o
 obj-$(CONFIG_LEDS_OT200)		+= leds-ot200.o
 obj-$(CONFIG_LEDS_FSG)			+= leds-fsg.o

drivers/leds/leds-is31fl319x.c new file +2 -0

new file mode 100644
index 0000000..e211c46
@@ -0,0 +1,406 @@
+/*
+ * Copyright 2015 Golden Delcious Computers

drivers/leds/leds-is31fl319x.c new file +53 -0

+ *
+ */
+
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/leds.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/workqueue.h>
+#include <linux/leds-is31fl319x.h>
+#include <linux/of.h>
+
+/* register numbers */
+#define IS31FL319X_SHUTDOWN	0x00
+#define IS31FL319X_CTRL1	0x01
+#define IS31FL319X_CTRL2	0x02
+#define IS31FL319X_CONFIG1	0x03
+#define IS31FL319X_CONFIG2	0x04
+#define IS31FL319X_RAMP_MODE	0x05
+#define IS31FL319X_BREATH_MASK	0x06
+#define IS31FL319X_PWM1		0x07
+#define IS31FL319X_PWM2		0x08
+#define IS31FL319X_PWM3		0x09
+#define IS31FL319X_PWM4		0x0a
+#define IS31FL319X_PWM5		0x0b
+#define IS31FL319X_PWM6		0x0c
+#define IS31FL319X_PWM7		0x0d
+#define IS31FL319X_PWM8		0x0e
+#define IS31FL319X_PWM9		0x0f
+#define IS31FL319X_DATA_UPDATE	0x10
+#define IS31FL319X_T0_1		0x11
+#define IS31FL319X_T0_2		0x12
+#define IS31FL319X_T0_3		0x13
+#define IS31FL319X_T0_4		0x14
+#define IS31FL319X_T0_5		0x15
+#define IS31FL319X_T0_6		0x16
+#define IS31FL319X_T0_7		0x17
+#define IS31FL319X_T0_8		0x18
+#define IS31FL319X_T0_9		0x19
+#define IS31FL319X_T123_1	0x1a
+#define IS31FL319X_T123_2	0x1b
+#define IS31FL319X_T123_3	0x1c
+#define IS31FL319X_T4_1		0x1d
+#define IS31FL319X_T4_2		0x1e
+#define IS31FL319X_T4_3		0x1f
+#define IS31FL319X_T4_4		0x20
+#define IS31FL319X_T4_5		0x21
+#define IS31FL319X_T4_6		0x22
+#define IS31FL319X_T4_7		0x23
+#define IS31FL319X_T4_8		0x24
+#define IS31FL319X_T4_9		0x25
+#define IS31FL319X_TIME_UPDATE	0x26
+

drivers/leds/leds-is31fl319x.c new file +38 -0

+
+	struct is31fl319x_led {
+		struct is31fl319x_chip	*chip;
+		struct led_classdev	led_cdev;
+	} leds[NUM_LEDS];
+};
+
+static const struct i2c_device_id is31fl319x_id[] = {
+	{ "is31fl3196", 6 },
+	{ "is31fl3196", 9 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, is31fl319x_id);
+
+
+static int is31fl319x_write(struct is31fl319x_chip *is31, u8 reg, u8 byte)
+{
+	struct i2c_client *cl = is31->client;
+
+	if (reg >= IS31FL319X_REG_CNT)
+		return -EIO;
+	is31->reg_file[reg] = byte;	/* save in cache */
+	dev_dbg(&is31->client->dev, "write %02x to reg %02x\n", byte, reg);
+	return i2c_smbus_write_byte_data(cl, reg, byte);
+}
+
+static int is31fl319x_read(struct is31fl319x_chip *is31, u8 reg)
+{
+	if (reg >= IS31FL319X_REG_CNT)
+		return -EIO;
+	return is31->reg_file[reg];	/* read crom cache (can't read chip) */
+}
+
+static void is31fl319x_work(struct work_struct *work)
+{
+	struct is31fl319x_chip *is31 = container_of(work,
+						    struct is31fl319x_chip,
+						    work);

drivers/leds/leds-is31fl319x.c new file +18 -0

+
+	dev_dbg(&is31->client->dev, "write to chip\n");
+
+	ctrl1 = 0;
+	ctrl2 = 0;
+
+	for (i = 0; i < NUM_LEDS; i++) {
+		struct led_classdev *led = &is31->leds[i].led_cdev;
+		bool on;
+
+		if (!is31->leds[i].led_cdev.name)
+			continue;
+
+		dev_dbg(&is31->client->dev, "set brightness %u for led %u\n",
+					    led->brightness, i);
+
+		/* update brightness register */
+		is31fl319x_write(is31, IS31FL319X_PWM1 + i, led->brightness);

drivers/leds/leds-is31fl319x.c new file +22 -0

+
+	/* check if any PWM is enabled or all outputs are now off */
+	if (ctrl1 > 0 || ctrl2 > 0) {
+		dev_dbg(&is31->client->dev, "power up\n");
+		is31fl319x_write(is31, IS31FL319X_CTRL1, ctrl1);
+		is31fl319x_write(is31, IS31FL319X_CTRL2, ctrl2);
+		/* update PWMs */
+		is31fl319x_write(is31, IS31FL319X_DATA_UPDATE, 0x00);
+		/* enable chip from shut down */
+		is31fl319x_write(is31, IS31FL319X_SHUTDOWN, 0x01);
+	} else {
+		dev_dbg(&is31->client->dev, "power down\n");
+		/* shut down */
+		is31fl319x_write(is31, IS31FL319X_SHUTDOWN, 0x00);
+	}
+
+	dev_dbg(&is31->client->dev, "work done\n");
+
+}
+
+/* NOTE: this may be called from within irq context, e.g. led_trigger_event */
+

drivers/leds/leds-is31fl319x.c new file +18 -0

+
+static void is31fl319x_brightness_set(struct led_classdev *led_cdev,
+				   enum led_brightness brightness)
+{
+	struct is31fl319x_led *led = container_of(led_cdev,
+						  struct is31fl319x_led,
+						  led_cdev);
+	struct is31fl319x_chip *is31 = led->chip;
+	unsigned long flags;
+
+	spin_lock_irqsave(&is31->lock, flags);
+
+	if (brightness != is31fl319x_brightness_get(led_cdev)) {
+		if (!is31->work_scheduled) {
+			schedule_work(&is31->work);
+			is31->work_scheduled = true;
+		}
+	}

drivers/leds/leds-is31fl319x.c new file +20 -0

+}
+
+#ifdef CONFIG_OF
+static struct is31fl319x_platform_data *
+is31fl319x_led_dt_init(struct i2c_client *client, int num_leds)
+{
+	struct device_node *np = client->dev.of_node, *child;
+	struct is31fl319x_platform_data *pdata;
+	struct led_info *is31_leds;
+	int count;
+
+	count = of_get_child_count(np);
+	dev_dbg(&client->dev, "child count %d\n", count);
+	if (!count || count > NUM_LEDS)
+		return ERR_PTR(-ENODEV);
+
+	is31_leds = devm_kzalloc(&client->dev,
+			sizeof(struct led_info) * NUM_LEDS, GFP_KERNEL);
+	if (!is31_leds)
+		return ERR_PTR(-ENOMEM);

drivers/leds/leds-is31fl319x.c new file +72 -0

+		is31_leds[reg] = led;
+	}
+	pdata = devm_kzalloc(&client->dev,
+			sizeof(struct is31fl319x_platform_data), GFP_KERNEL);
+	if (!pdata)
+		return ERR_PTR(-ENOMEM);
+
+	pdata->leds.leds = is31_leds;
+	return pdata;
+}
+
+static const struct of_device_id of_is31fl319x_leds_match[] = {
+	{ .compatible = "issi,is31fl3196", (void *) 6 },
+	{ .compatible = "issi,is31fl3199", (void *) 9 },
+	{},
+};
+MODULE_DEVICE_TABLE(of, of_is31fl319x_leds_match);
+
+#else
+static struct is31fl319x_platform_data *
+is31fl319x_led_dt_init(struct i2c_client *client)
+{
+	return ERR_PTR(-ENODEV);
+}
+
+#endif
+
+static int is31fl319x_probe(struct i2c_client *client,
+		const struct i2c_device_id *id)
+{
+	struct is31fl319x_chip *is31;
+	struct i2c_adapter *adapter;
+	struct is31fl319x_platform_data *pdata;
+	int err;
+	int i = 0;
+
+	adapter = to_i2c_adapter(client->dev.parent);
+	pdata = dev_get_platdata(&client->dev);
+
+	dev_dbg(&client->dev, "probe\n");
+
+	dev_dbg(&client->dev, "NUM_LEDS = %d num_leds = %d\n",
+		NUM_LEDS, (int) id->driver_data);
+
+	if (!i2c_check_functionality(adapter, I2C_FUNC_I2C))
+		return -EIO;
+
+	if (!pdata) {
+		pdata = is31fl319x_led_dt_init(client, (int) id->driver_data);
+		if (IS_ERR(pdata)) {
+			dev_err(&client->dev, "DT led error %d\n",
+				(int) PTR_ERR(pdata));
+			return PTR_ERR(pdata);
+		}
+	}
+	is31 = devm_kzalloc(&client->dev, sizeof(*is31), GFP_KERNEL);
+	if (!is31)
+		return -ENOMEM;
+
+	is31->client = client;
+	INIT_WORK(&is31->work, is31fl319x_work);
+	spin_lock_init(&is31->lock);
+	i2c_set_clientdata(client, is31);
+
+	/* check for reply from chip (we can't read any registers) */
+	err = is31fl319x_write(is31, IS31FL319X_SHUTDOWN, 0x01);
+	if (err < 0) {
+		dev_err(&client->dev, "no response from chip write: err = %d\n",
+			err);
+		return -EPROBE_DEFER;	/* does not answer (yet) */
+	}
+

drivers/leds/leds-is31fl319x.c new file +72 -0

+			if (err < 0)
+				goto exit;
+		}
+	}
+
+	if (client->dev.of_node) {
+		u32 val;
+		u8 config2 = 0;
+
+		if (of_property_read_u32(client->dev.of_node, "max-current-ma",
+					 &val)) {
+			if (val > 40)
+				val = 40;
+			if (val < 5)
+				val = 5;
+			config2 |= (((64 - val) / 5) & 0x7) << 4; /* CS */
+		}
+		if (of_property_read_u32(client->dev.of_node, "audio-gain-db",
+					 &val)) {
+			if (val > 21)
+				val = 21;
+			config2 |= val / 3; /* AGS */
+		}
+		if (config2)
+			is31fl319x_write(is31, IS31FL319X_CONFIG2, config2);
+	}
+
+	schedule_work(&is31->work);	/* first update */
+
+	dev_dbg(&client->dev, "probed\n");
+	return 0;
+exit:
+	dev_err(&client->dev, "led error %d\n", err);
+
+	while (i--) {
+		if (is31->leds[i].led_cdev.name)
+			led_classdev_unregister(&is31->leds[i].led_cdev);
+	}
+	return err;
+}
+
+static int is31fl319x_remove(struct i2c_client *client)
+{
+	int i;
+	struct is31fl319x_chip *is31 = i2c_get_clientdata(client);
+	struct is31fl319x_led *is31_leds = is31->leds;
+
+	for (i = 0; i < NUM_LEDS; i++) {
+		if (is31_leds[i].led_cdev.name)
+			led_classdev_unregister(&is31_leds[i].led_cdev);
+	}
+
+	cancel_work_sync(&is31->work);
+
+	return 0;
+}
+
+static struct i2c_driver is31fl319x_driver = {
+	.driver   = {
+		.name    = "leds-is31fl319x",
+		.of_match_table = of_match_ptr(of_is31fl319x_leds_match),
+	},
+	.probe    = is31fl319x_probe,
+	.remove   = is31fl319x_remove,
+	.id_table = is31fl319x_id,
+};
+
+module_i2c_driver(is31fl319x_driver);
+
+MODULE_AUTHOR("H. Nikolaus Schaller <[email protected]>");
+MODULE_DESCRIPTION("IS31FL319X LED driver");
+MODULE_LICENSE("GPL v2");

include/linux/leds-is31fl319x.h new file +24 -0

new file mode 100644
index 0000000..5f55abf
@@ -0,0 +1,24 @@
+/*
+ * IS31FL3196 LED chip driver.
+ *
+ * Copyright (C) 2015 H. Nikolaus Schaller <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ */
+
+#ifndef __LINUX_IS31FL319X_H
+#define __LINUX_IS31FL319X_H
+#include <linux/leds.h>
+
+struct is31fl319x_platform_data {
+	struct led_platform_data leds;
+};
+
+#endif /* __LINUX_IS31FL319X_H */

Hi Nikolaus,

I recently submitted a driver for the IS31FL32xx family of devices, so this driver caught my eye. I have a few comments below.

Quoted 45 lines · On Mon, 18 Apr 2016 20:43:16 +0200 "H. Nikolaus Schaller" <[email protected]>…

This is a driver for the Integrated Silicon Solution Inc. LED driver chips IS31FL3196 and IS31FL3199. They can drive up to 6 or 9 LEDs.

Each LED is individually controllable in brightness (through pwm) in 256 steps so that RGB LEDs can show any of ca. 16 Mio colors.

The maximum current of the LEDs can be programmed and limited to 5 .. 40mA through a device tree property.

The chip is connected through I2C and can have one of 4 addresses (0x64 .. 0x67) depending on how the AD pin is connected. The address is defined by the reg property as usual.

The chip also has a shutdown input which could be connected to a GPIO, but this driver uses software shutdown if all LEDs are inactivated.

The chip also has breathing and audio features which are not supported by this driver.

This driver was developed and tested on OMAP5 based Pyra handheld prototype.

Signed-off-by H. Nikolaus Schaller <[email protected]>

---
  .../devicetree/bindings/leds/is31fl319x.txt        |  41 +++
  drivers/leds/Kconfig                               |   8 +
  drivers/leds/Makefile                              |   1 +
  drivers/leds/leds-is31fl319x.c                     | 406 +++++++++++++++++++++
  include/linux/leds-is31fl319x.h                    |  24 ++
  5 files changed, 480 insertions(+)

create mode 100644 Documentation/devicetree/bindings/leds/is31fl319x.txt create mode 100644 drivers/leds/leds-is31fl319x.c
create mode 100644 include/linux/leds-is31fl319x.h

Documentation/devicetree/bindings/leds/is31fl319x.txt new file +4 -0

new file mode 100644
index 0000000..d13c7ca
@@ -0,0 +1,41 @@
+LEDs connected to is31fl319x RGB LED controller chip
+
+Required properties:
+- compatible : should be : "issi,is31fl3196" or "issi,is31fl3199".

Quoted 1 line

From a quick look at the datasheets, I believe the Si-En SN3199 [1]

is the same as the ISSI IS31FL3199. ISSI purchased Si-En in 2011, and looks to have rebranded Si-En's existing LED controllers. Assuming the SN3199 is indeed the same as the IS31FL3199, I would suggest adding a compatible string of "si-en,sn3199" both here and in the driver itself (and update the Kconfig text as well).

[1] http://www.si-en.com/product.asp?parentid=890

Documentation/devicetree/bindings/leds/is31fl319x.txt line 12

Quoted 8 lines

+- #address-cells: must be 1
+- #size-cells: must be 0
+- reg: 0x64, 0x65, 0x66, 0x67.

Documentation/devicetree/bindings/leds/is31fl319x.txt new file +5 -0

+
+Optional properties:
+- max-current-ma:	maximum led current (5..40 mA, default 20 mA)
+- audio-gain-db:	audio gain selection (0..21 dB. default 0 dB)
+- breathing & audio:	not implemented

I'm not certain, but that last line feels wrong to me. I would expect to see just defined properties in this section, while that is more commentary. I would just leave it out, myself.

Documentation/devicetree/bindings/leds/is31fl319x.txt line 18

Quoted 6 lines

Documentation/devicetree/bindings/leds/is31fl319x.txt new file +6 -0

+
+Each led is represented as a sub-node of the issi,is31fl319x device.
+
+LED sub-node properties:
+- label : (optional) see Documentation/devicetree/bindings/leds/common.txt
+- reg : number of LED line (0 to 5 or 0 to 8 - not all need to be present)

Since the datasheets for these devices name the outputs "OUT1" through "OUT6"/"OUT9", I believe the correct range for the 'reg' property should be 1-6 and 1-9. At least that was the result of a discussion with Rob Herring [2], and therefore how the IS31FL32xx binding/driver was done. It also makes devicetrees easier to write relative to schematics which likely use the OUT1-N naming.

[2] http://www.spinics.net/lists/devicetree/msg116019.html

Documentation/devicetree/bindings/leds/is31fl319x.txt line 24

Quoted 6 lines

+- linux,default-trigger : (optional)

Documentation/devicetree/bindings/leds/is31fl319x.txt new file +5 -0

+   see Documentation/devicetree/bindings/leds/common.txt
+
+Examples:
+
+fancy_leds: is31fl3196@65 {

I believe the current preference would be to name the node by its function, rather than the device. For example:

	fancy_leds: leds@65

Documentation/devicetree/bindings/leds/is31fl319x.txt line 25

Quoted 1 line

Documentation/devicetree/bindings/leds/is31fl319x.txt new file +1 -0

+	compatible = "issi,is31fl319x";

I believe this should be "issi,is31fl3196" here.

Quoted 21 lines

Documentation/devicetree/bindings/leds/is31fl319x.txt new file +16 -0

+	#address-cells = <1>;
+	#size-cells = <0>;
+	reg = <0x65>;
+
+	led0: red-aux@0 {
+		label = "red:aux";
+		reg = <0>;
+	};
+
+	led1: green-power@4 {
+		label = "green:power";
+		reg = <4>;
+		linux,default-trigger = "default-on";
+	};
+};
+

drivers/leds/Kconfig +0 -0

index 2251478..f099bcb 100644

drivers/leds/Kconfig config LEDS_ASIC3 · line 495

Quoted 5 lines

drivers/leds/Kconfig +2 -0

@@ -491,6 +491,14 @@ config LEDS_ASIC3
  	  cannot be used. This driver supports hardware blinking with an on+off
  	  period from 62ms to 125s. Say Y to enable LEDs on the HP iPAQ hx4700.
 
+config LEDS_IS31FL319X
+	tristate "LED Support for IS31FL319x I2C chip"

Pedantic: "chips" (plural) seems appropriate here.

drivers/leds/Kconfig config LEDS_ASIC3 · line 500

Quoted 5 lines

drivers/leds/Kconfig +5 -0

+	depends on LEDS_CLASS && I2C
+	help
+	  This option enables support for LEDs connected to IS31FL3196
+	  or IS31FL3199 LED driver chips accessed via the I2C bus.
+	  Driver support brightness control and hardware-assisted blinking.

Pedantic: "supports" seems appropriate here.

I don't think this matters much, but I'm curious: any reason why this entry is inserted in the middle of the list, rather than at the end? Or better, right before/after the IS31FL32XX entry?

drivers/leds/Makefile obj-$(CONFIG_LEDS_TCA6507) += leds-tca6507.o · line 40

Quoted 13 lines

drivers/leds/Kconfig +1 -0

+
  config LEDS_TCA6507
  	tristate "LED Support for TCA6507 I2C chip"
  	depends on LEDS_CLASS && I2C

drivers/leds/Makefile +1 -0

index cb2013d..eee3010 100644
@@ -37,6 +37,7 @@ obj-$(CONFIG_LEDS_TCA6507)		+= leds-tca6507.o
  obj-$(CONFIG_LEDS_TLC591XX)		+= leds-tlc591xx.o
  obj-$(CONFIG_LEDS_CLEVO_MAIL)		+= leds-clevo-mail.o
  obj-$(CONFIG_LEDS_IPAQ_MICRO)		+= leds-ipaq-micro.o
+obj-$(CONFIG_LEDS_IS31FL319X)		+= leds-is31fl319x.o

Ditto.

Quoted 11 lines

drivers/leds/Makefile +0 -0

  obj-$(CONFIG_LEDS_HP6XX)		+= leds-hp6xx.o
  obj-$(CONFIG_LEDS_OT200)		+= leds-ot200.o
  obj-$(CONFIG_LEDS_FSG)			+= leds-fsg.o

drivers/leds/leds-is31fl319x.c new file +2 -0

new file mode 100644
index 0000000..e211c46
@@ -0,0 +1,406 @@
+/*
+ * Copyright 2015 Golden Delcious Computers

drivers/leds/leds-is31fl319x.c line 12

Quoted 10 lines

drivers/leds/leds-is31fl319x.c new file +10 -0

+ *
+ * Author: Nikolaus Schaller <[email protected]>
+ *
+ * Based on leds-tca6507.c
+ *
+ * This file is subject to the terms and conditions of version 2 of
+ * the GNU General Public License.  See the file COPYING in the main
+ * directory of this archive for more details.
+ *
+ * LED driver for the IS31FL3196/99 to drive 6 or 9 light effect LEDs.

I see that there are also 3190, 3191, and 3193 devices. Is it reasonable to think that support for those devices could be added to this driver in the future? I'm merely thinking of it from the POV that it is named is31fl319x.c.

Quoted 53 lines

drivers/leds/leds-is31fl319x.c new file +53 -0

+ *
+ */
+
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/leds.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/workqueue.h>
+#include <linux/leds-is31fl319x.h>
+#include <linux/of.h>
+
+/* register numbers */
+#define IS31FL319X_SHUTDOWN	0x00
+#define IS31FL319X_CTRL1	0x01
+#define IS31FL319X_CTRL2	0x02
+#define IS31FL319X_CONFIG1	0x03
+#define IS31FL319X_CONFIG2	0x04
+#define IS31FL319X_RAMP_MODE	0x05
+#define IS31FL319X_BREATH_MASK	0x06
+#define IS31FL319X_PWM1		0x07
+#define IS31FL319X_PWM2		0x08
+#define IS31FL319X_PWM3		0x09
+#define IS31FL319X_PWM4		0x0a
+#define IS31FL319X_PWM5		0x0b
+#define IS31FL319X_PWM6		0x0c
+#define IS31FL319X_PWM7		0x0d
+#define IS31FL319X_PWM8		0x0e
+#define IS31FL319X_PWM9		0x0f
+#define IS31FL319X_DATA_UPDATE	0x10
+#define IS31FL319X_T0_1		0x11
+#define IS31FL319X_T0_2		0x12
+#define IS31FL319X_T0_3		0x13
+#define IS31FL319X_T0_4		0x14
+#define IS31FL319X_T0_5		0x15
+#define IS31FL319X_T0_6		0x16
+#define IS31FL319X_T0_7		0x17
+#define IS31FL319X_T0_8		0x18
+#define IS31FL319X_T0_9		0x19
+#define IS31FL319X_T123_1	0x1a
+#define IS31FL319X_T123_2	0x1b
+#define IS31FL319X_T123_3	0x1c
+#define IS31FL319X_T4_1		0x1d
+#define IS31FL319X_T4_2		0x1e
+#define IS31FL319X_T4_3		0x1f
+#define IS31FL319X_T4_4		0x20
+#define IS31FL319X_T4_5		0x21
+#define IS31FL319X_T4_6		0x22
+#define IS31FL319X_T4_7		0x23
+#define IS31FL319X_T4_8		0x24
+#define IS31FL319X_T4_9		0x25
+#define IS31FL319X_TIME_UPDATE	0x26
+

drivers/leds/leds-is31fl319x.c line 75

Quoted 10 lines

drivers/leds/leds-is31fl319x.c new file +10 -0

+#define	IS31FL319X_REG_CNT	(IS31FL319X_TIME_UPDATE + 1)
+
+#define NUM_LEDS 9	/* max for 3199 chip */
+
+struct is31fl319x_chip {
+	struct i2c_client	*client;
+	struct work_struct	work;
+	bool			work_scheduled;
+	spinlock_t		lock;
+	u8			reg_file[IS31FL319X_REG_CNT];

I would suggest using the regmap infrastructure if you need to cache the register values. It also helpfully exports a debugfs interface.

Quoted 38 lines

drivers/leds/leds-is31fl319x.c new file +38 -0

+
+	struct is31fl319x_led {
+		struct is31fl319x_chip	*chip;
+		struct led_classdev	led_cdev;
+	} leds[NUM_LEDS];
+};
+
+static const struct i2c_device_id is31fl319x_id[] = {
+	{ "is31fl3196", 6 },
+	{ "is31fl3196", 9 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, is31fl319x_id);
+
+
+static int is31fl319x_write(struct is31fl319x_chip *is31, u8 reg, u8 byte)
+{
+	struct i2c_client *cl = is31->client;
+
+	if (reg >= IS31FL319X_REG_CNT)
+		return -EIO;
+	is31->reg_file[reg] = byte;	/* save in cache */
+	dev_dbg(&is31->client->dev, "write %02x to reg %02x\n", byte, reg);
+	return i2c_smbus_write_byte_data(cl, reg, byte);
+}
+
+static int is31fl319x_read(struct is31fl319x_chip *is31, u8 reg)
+{
+	if (reg >= IS31FL319X_REG_CNT)
+		return -EIO;
+	return is31->reg_file[reg];	/* read crom cache (can't read chip) */
+}
+
+static void is31fl319x_work(struct work_struct *work)
+{
+	struct is31fl319x_chip *is31 = container_of(work,
+						    struct is31fl319x_chip,
+						    work);

drivers/leds/leds-is31fl319x.c line 123

Quoted 10 lines

drivers/leds/leds-is31fl319x.c new file +10 -0

+	unsigned long flags;
+	int i;
+	u8 ctrl1, ctrl2;
+
+	dev_dbg(&is31->client->dev, "work called\n");
+
+	spin_lock_irqsave(&is31->lock, flags);
+	/* make subsequent changes run another schedule_work */
+	is31->work_scheduled = false;
+	spin_unlock_irqrestore(&is31->lock, flags);

I believe the LEDS core now handles the workqueues generically for blocking operations, so it's no longer needed in the individual drivers.

Quoted 18 lines

drivers/leds/leds-is31fl319x.c new file +18 -0

+
+	dev_dbg(&is31->client->dev, "write to chip\n");
+
+	ctrl1 = 0;
+	ctrl2 = 0;
+
+	for (i = 0; i < NUM_LEDS; i++) {
+		struct led_classdev *led = &is31->leds[i].led_cdev;
+		bool on;
+
+		if (!is31->leds[i].led_cdev.name)
+			continue;
+
+		dev_dbg(&is31->client->dev, "set brightness %u for led %u\n",
+					    led->brightness, i);
+
+		/* update brightness register */
+		is31fl319x_write(is31, IS31FL319X_PWM1 + i, led->brightness);

drivers/leds/leds-is31fl319x.c line 151

Quoted 10 lines

drivers/leds/leds-is31fl319x.c new file +10 -0

+
+		/* update output enable bits */
+		on = led->brightness > LED_OFF;
+		if (i < 3)
+			ctrl1 |= on << i;	/* 0..2 => bit 0..2 */
+		else if (i < 6)
+			ctrl1 |= on << (i+1);	/* 3..5 => bit 4..6 */
+		else
+			ctrl2 |= on << (i-6);	/* 6..8 => bit 0..2 */
+	}

Is any locking needed while iterating over is31->leds[]? Is there any opportunity for a race?

Quoted 22 lines

drivers/leds/leds-is31fl319x.c new file +22 -0

+
+	/* check if any PWM is enabled or all outputs are now off */
+	if (ctrl1 > 0 || ctrl2 > 0) {
+		dev_dbg(&is31->client->dev, "power up\n");
+		is31fl319x_write(is31, IS31FL319X_CTRL1, ctrl1);
+		is31fl319x_write(is31, IS31FL319X_CTRL2, ctrl2);
+		/* update PWMs */
+		is31fl319x_write(is31, IS31FL319X_DATA_UPDATE, 0x00);
+		/* enable chip from shut down */
+		is31fl319x_write(is31, IS31FL319X_SHUTDOWN, 0x01);
+	} else {
+		dev_dbg(&is31->client->dev, "power down\n");
+		/* shut down */
+		is31fl319x_write(is31, IS31FL319X_SHUTDOWN, 0x00);
+	}
+
+	dev_dbg(&is31->client->dev, "work done\n");
+
+}
+
+/* NOTE: this may be called from within irq context, e.g. led_trigger_event */
+

drivers/leds/leds-is31fl319x.c line 183

Quoted 10 lines

drivers/leds/leds-is31fl319x.c new file +10 -0

+static int is31fl319x_brightness_get(struct led_classdev *led_cdev)
+{
+	struct is31fl319x_led *led = container_of(led_cdev,
+						  struct is31fl319x_led,
+						  led_cdev);
+	struct is31fl319x_chip *is31 = led->chip;
+
+	/* read PWM register */
+	return is31fl319x_read(is31, IS31FL319X_PWM1 + (led - is31->leds));
+}

I believe that the LEDS core remembers the last set brightness for each LED,
and will use it if no brightness_get function is implemented. Since all is31fl319x_brightness_get() does is retrieve the saved value from your cache, I think you can just eliminate is31fl319x_brightness_get() altogether.

Quoted 18 lines

drivers/leds/leds-is31fl319x.c new file +18 -0

+
+static void is31fl319x_brightness_set(struct led_classdev *led_cdev,
+				   enum led_brightness brightness)
+{
+	struct is31fl319x_led *led = container_of(led_cdev,
+						  struct is31fl319x_led,
+						  led_cdev);
+	struct is31fl319x_chip *is31 = led->chip;
+	unsigned long flags;
+
+	spin_lock_irqsave(&is31->lock, flags);
+
+	if (brightness != is31fl319x_brightness_get(led_cdev)) {
+		if (!is31->work_scheduled) {
+			schedule_work(&is31->work);
+			is31->work_scheduled = true;
+		}
+	}

drivers/leds/leds-is31fl319x.c line 211

Quoted 10 lines

drivers/leds/leds-is31fl319x.c new file +10 -0

+
+	spin_unlock_irqrestore(&is31->lock, flags);
+}
+
+static int is31fl319x_blink_set(struct led_classdev *led_cdev,
+			     unsigned long *delay_on,
+			     unsigned long *delay_off)
+{
+	/* use software blink */
+	return 1;

The Kconfig entry claims hardware blink support. The comment here says the opposite. I believe this current implementation will result in the LEDS core falling back to software blink, but the same result would be achieved by just not setting the blink_set callback.

Quoted 20 lines

drivers/leds/leds-is31fl319x.c new file +20 -0

+}
+
+#ifdef CONFIG_OF
+static struct is31fl319x_platform_data *
+is31fl319x_led_dt_init(struct i2c_client *client, int num_leds)
+{
+	struct device_node *np = client->dev.of_node, *child;
+	struct is31fl319x_platform_data *pdata;
+	struct led_info *is31_leds;
+	int count;
+
+	count = of_get_child_count(np);
+	dev_dbg(&client->dev, "child count %d\n", count);
+	if (!count || count > NUM_LEDS)
+		return ERR_PTR(-ENODEV);
+
+	is31_leds = devm_kzalloc(&client->dev,
+			sizeof(struct led_info) * NUM_LEDS, GFP_KERNEL);
+	if (!is31_leds)
+		return ERR_PTR(-ENOMEM);

drivers/leds/leds-is31fl319x.c line 241

Quoted 10 lines

drivers/leds/leds-is31fl319x.c new file +10 -0

+
+	for_each_child_of_node(np, child) {
+		struct led_info led;
+		u32 reg;
+		int ret;
+
+		led.name =
+			of_get_property(child, "label", NULL) ? : child->name;
+		led.default_trigger =
+			of_get_property(child, "linux,default-trigger", NULL);

I believe it is better to use of_property_read_string() for these.

drivers/leds/leds-is31fl319x.c line 250

Quoted 9 lines

drivers/leds/leds-is31fl319x.c new file +9 -0

+		led.flags = 0;
+		ret = of_property_read_u32(child, "reg", &reg);
+		dev_dbg(&client->dev, "name = %s reg = %d\n", led.name, reg);
+		if (ret != 0 || reg < 0 || reg >= num_leds)
+			continue;
+
+		if (is31_leds[reg].name)
+			dev_err(&client->dev, "duplicate led line %d for %s -> %s\n",
+				reg, is31_leds[reg].name, led.name);

There are two errors (invalid DT) detected here, but the driver continues to load. I believe the preference is for errors like this to result in the probe failing outright.

Quoted 72 lines

drivers/leds/leds-is31fl319x.c new file +72 -0

+		is31_leds[reg] = led;
+	}
+	pdata = devm_kzalloc(&client->dev,
+			sizeof(struct is31fl319x_platform_data), GFP_KERNEL);
+	if (!pdata)
+		return ERR_PTR(-ENOMEM);
+
+	pdata->leds.leds = is31_leds;
+	return pdata;
+}
+
+static const struct of_device_id of_is31fl319x_leds_match[] = {
+	{ .compatible = "issi,is31fl3196", (void *) 6 },
+	{ .compatible = "issi,is31fl3199", (void *) 9 },
+	{},
+};
+MODULE_DEVICE_TABLE(of, of_is31fl319x_leds_match);
+
+#else
+static struct is31fl319x_platform_data *
+is31fl319x_led_dt_init(struct i2c_client *client)
+{
+	return ERR_PTR(-ENODEV);
+}
+
+#endif
+
+static int is31fl319x_probe(struct i2c_client *client,
+		const struct i2c_device_id *id)
+{
+	struct is31fl319x_chip *is31;
+	struct i2c_adapter *adapter;
+	struct is31fl319x_platform_data *pdata;
+	int err;
+	int i = 0;
+
+	adapter = to_i2c_adapter(client->dev.parent);
+	pdata = dev_get_platdata(&client->dev);
+
+	dev_dbg(&client->dev, "probe\n");
+
+	dev_dbg(&client->dev, "NUM_LEDS = %d num_leds = %d\n",
+		NUM_LEDS, (int) id->driver_data);
+
+	if (!i2c_check_functionality(adapter, I2C_FUNC_I2C))
+		return -EIO;
+
+	if (!pdata) {
+		pdata = is31fl319x_led_dt_init(client, (int) id->driver_data);
+		if (IS_ERR(pdata)) {
+			dev_err(&client->dev, "DT led error %d\n",
+				(int) PTR_ERR(pdata));
+			return PTR_ERR(pdata);
+		}
+	}
+	is31 = devm_kzalloc(&client->dev, sizeof(*is31), GFP_KERNEL);
+	if (!is31)
+		return -ENOMEM;
+
+	is31->client = client;
+	INIT_WORK(&is31->work, is31fl319x_work);
+	spin_lock_init(&is31->lock);
+	i2c_set_clientdata(client, is31);
+
+	/* check for reply from chip (we can't read any registers) */
+	err = is31fl319x_write(is31, IS31FL319X_SHUTDOWN, 0x01);
+	if (err < 0) {
+		dev_err(&client->dev, "no response from chip write: err = %d\n",
+			err);
+		return -EPROBE_DEFER;	/* does not answer (yet) */
+	}
+

drivers/leds/leds-is31fl319x.c line 332

Quoted 10 lines

drivers/leds/leds-is31fl319x.c new file +10 -0

+	for (i = 0; i < NUM_LEDS; i++) {
+		struct is31fl319x_led *l = is31->leds + i;
+
+		l->chip = is31;
+		if (pdata->leds.leds[i].name && !pdata->leds.leds[i].flags) {
+			l->led_cdev.name = pdata->leds.leds[i].name;
+			l->led_cdev.default_trigger
+				= pdata->leds.leds[i].default_trigger;
+			l->led_cdev.brightness_set = is31fl319x_brightness_set;
+			l->led_cdev.blink_set = is31fl319x_blink_set;

I don't see led_cdev.brightness_get being set here. Although if you do remove is31fl319x_brightness_get(), it obviously won't need to be set.

drivers/leds/leds-is31fl319x.c line 334

Quoted 2 lines

drivers/leds/leds-is31fl319x.c new file +2 -0

+			err = led_classdev_register(&client->dev,
+						    &l->led_cdev);

I would suggest using devm_led_classdev_register(). Then you can remove all the calls to led_classdev_unregister() in error and cleanup paths.

Quoted 92 lines

drivers/leds/leds-is31fl319x.c new file +72 -0

+			if (err < 0)
+				goto exit;
+		}
+	}
+
+	if (client->dev.of_node) {
+		u32 val;
+		u8 config2 = 0;
+
+		if (of_property_read_u32(client->dev.of_node, "max-current-ma",
+					 &val)) {
+			if (val > 40)
+				val = 40;
+			if (val < 5)
+				val = 5;
+			config2 |= (((64 - val) / 5) & 0x7) << 4; /* CS */
+		}
+		if (of_property_read_u32(client->dev.of_node, "audio-gain-db",
+					 &val)) {
+			if (val > 21)
+				val = 21;
+			config2 |= val / 3; /* AGS */
+		}
+		if (config2)
+			is31fl319x_write(is31, IS31FL319X_CONFIG2, config2);
+	}
+
+	schedule_work(&is31->work);	/* first update */
+
+	dev_dbg(&client->dev, "probed\n");
+	return 0;
+exit:
+	dev_err(&client->dev, "led error %d\n", err);
+
+	while (i--) {
+		if (is31->leds[i].led_cdev.name)
+			led_classdev_unregister(&is31->leds[i].led_cdev);
+	}
+	return err;
+}
+
+static int is31fl319x_remove(struct i2c_client *client)
+{
+	int i;
+	struct is31fl319x_chip *is31 = i2c_get_clientdata(client);
+	struct is31fl319x_led *is31_leds = is31->leds;
+
+	for (i = 0; i < NUM_LEDS; i++) {
+		if (is31_leds[i].led_cdev.name)
+			led_classdev_unregister(&is31_leds[i].led_cdev);
+	}
+
+	cancel_work_sync(&is31->work);
+
+	return 0;
+}
+
+static struct i2c_driver is31fl319x_driver = {
+	.driver   = {
+		.name    = "leds-is31fl319x",
+		.of_match_table = of_match_ptr(of_is31fl319x_leds_match),
+	},
+	.probe    = is31fl319x_probe,
+	.remove   = is31fl319x_remove,
+	.id_table = is31fl319x_id,
+};
+
+module_i2c_driver(is31fl319x_driver);
+
+MODULE_AUTHOR("H. Nikolaus Schaller <[email protected]>");
+MODULE_DESCRIPTION("IS31FL319X LED driver");
+MODULE_LICENSE("GPL v2");

include/linux/leds-is31fl319x.h new file +14 -0

new file mode 100644
index 0000000..5f55abf
@@ -0,0 +1,24 @@
+/*
+ * IS31FL3196 LED chip driver.
+ *
+ * Copyright (C) 2015 H. Nikolaus Schaller <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ */

include/linux/leds-is31fl319x.h line 24

Quoted 10 lines

include/linux/leds-is31fl319x.h new file +10 -0

+
+#ifndef __LINUX_IS31FL319X_H
+#define __LINUX_IS31FL319X_H
+#include <linux/leds.h>
+
+struct is31fl319x_platform_data {
+	struct led_platform_data leds;
+};
+
+#endif /* __LINUX_IS31FL319X_H */

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Am 19.04.2016 um 03:25 schrieb David Rivshin (Allworx) <[email protected]>:

Hi Nikolaus,

I recently submitted a driver for the IS31FL32xx family of devices, so this driver caught my eye. I have a few comments below.

Quoted 40 lines · On Mon, 18 Apr 2016 20:43:16 +0200 "H. Nikolaus Schaller" <[email protected]>…

This is a driver for the Integrated Silicon Solution Inc. LED driver chips IS31FL3196 and IS31FL3199. They can drive up to 6 or 9 LEDs.

Each LED is individually controllable in brightness (through pwm) in 256 steps so that RGB LEDs can show any of ca. 16 Mio colors.

The maximum current of the LEDs can be programmed and limited to 5 .. 40mA through a device tree property.

The chip is connected through I2C and can have one of 4 addresses (0x64 .. 0x67) depending on how the AD pin is connected. The address is defined by the reg property as usual.

The chip also has a shutdown input which could be connected to a GPIO, but this driver uses software shutdown if all LEDs are inactivated.

The chip also has breathing and audio features which are not supported by this driver.

This driver was developed and tested on OMAP5 based Pyra handheld prototype.

Signed-off-by H. Nikolaus Schaller <[email protected]>

---

.../devicetree/bindings/leds/is31fl319x.txt        |  41 +++
drivers/leds/Kconfig                               |   8 +
drivers/leds/Makefile                              |   1 +
drivers/leds/leds-is31fl319x.c                     | 406 +++++++++++++++++++++
include/linux/leds-is31fl319x.h                    |  24 ++
5 files changed, 480 insertions(+)

create mode 100644 Documentation/devicetree/bindings/leds/is31fl319x.txt create mode 100644 drivers/leds/leds-is31fl319x.c
create mode 100644 include/linux/leds-is31fl319x.h

Documentation/devicetree/bindings/leds/is31fl319x.txt new file +0 -0

new file mode 100644
index 0000000..d13c7ca

Documentation/devicetree/bindings/leds/is31fl319x.txt line 4

Quoted 4 lines

Documentation/devicetree/bindings/leds/is31fl319x.txt new file +4 -0

@@ -0,0 +1,41 @@
+LEDs connected to is31fl319x RGB LED controller chip
+
+Required properties:
+- compatible : should be : "issi,is31fl3196" or "issi,is31fl3199".

From a quick look at the datasheets, I believe the Si-En SN3199 [1] is the same as the ISSI IS31FL3199. ISSI purchased Si-En in 2011, and looks to have rebranded Si-En's existing LED controllers. Assuming the SN3199 is indeed the same as the IS31FL3199, I would suggest adding a compatible string of "si-en,sn3199" both here and in the driver itself (and update the Kconfig text as well).

[1] http://www.si-en.com/product.asp?parentid=890

Documentation/devicetree/bindings/leds/is31fl319x.txt line 12

Quoted 9 lines

Documentation/devicetree/bindings/leds/is31fl319x.txt new file +8 -0

+- #address-cells: must be 1
+- #size-cells: must be 0
+- reg: 0x64, 0x65, 0x66, 0x67.
+
+Optional properties:
+- max-current-ma:	maximum led current (5..40 mA, default 20 mA)
+- audio-gain-db:	audio gain selection (0..21 dB. default 0 dB)
+- breathing & audio:	not implemented

I'm not certain, but that last line feels wrong to me. I would expect to see just defined properties in this section, while that is more commentary. I would just leave it out, myself.

Documentation/devicetree/bindings/leds/is31fl319x.txt line 18

Quoted 7 lines

Documentation/devicetree/bindings/leds/is31fl319x.txt new file +6 -0

+
+Each led is represented as a sub-node of the issi,is31fl319x device.
+
+LED sub-node properties:
+- label : (optional) see Documentation/devicetree/bindings/leds/common.txt
+- reg : number of LED line (0 to 5 or 0 to 8 - not all need to be present)

Since the datasheets for these devices name the outputs "OUT1" through "OUT6"/"OUT9", I believe the correct range for the 'reg' property should be 1-6 and 1-9. At least that was the result of a discussion with Rob Herring [2], and therefore how the IS31FL32xx binding/driver was done. It also makes devicetrees easier to write relative to schematics which likely use the OUT1-N naming.

[2] http://www.spinics.net/lists/devicetree/msg116019.html

Documentation/devicetree/bindings/leds/is31fl319x.txt line 24

Quoted 8 lines

Documentation/devicetree/bindings/leds/is31fl319x.txt new file +6 -0

+- linux,default-trigger : (optional)
+   see Documentation/devicetree/bindings/leds/common.txt
+
+Examples:
+
+fancy_leds: is31fl3196@65 {

I believe the current preference would be to name the node by its function, rather than the device. For example:

	fancy_leds: leds@65

Documentation/devicetree/bindings/leds/is31fl319x.txt line 25

Quoted 2 lines

Documentation/devicetree/bindings/leds/is31fl319x.txt new file +1 -0

+	compatible = "issi,is31fl319x";

I believe this should be "issi,is31fl3196" here.

Quoted 25 lines

Documentation/devicetree/bindings/leds/is31fl319x.txt new file +16 -0

+	#address-cells = <1>;
+	#size-cells = <0>;
+	reg = <0x65>;
+
+	led0: red-aux@0 {
+		label = "red:aux";
+		reg = <0>;
+	};
+
+	led1: green-power@4 {
+		label = "green:power";
+		reg = <4>;
+		linux,default-trigger = "default-on";
+	};
+};
+

drivers/leds/Kconfig +0 -0

index 2251478..f099bcb 100644
@@ -491,6 +491,14 @@ config LEDS_ASIC3
 	  cannot be used. This driver supports hardware blinking with an on+off
 	  period from 62ms to 125s. Say Y to enable LEDs on the HP iPAQ hx4700.
 

drivers/leds/Kconfig config LEDS_ASIC3 · line 495

Quoted 2 lines

drivers/leds/Kconfig +2 -0

+config LEDS_IS31FL319X
+	tristate "LED Support for IS31FL319x I2C chip"

Pedantic: "chips" (plural) seems appropriate here.

drivers/leds/Kconfig config LEDS_ASIC3 · line 500

Quoted 6 lines

drivers/leds/Kconfig +5 -0

+	depends on LEDS_CLASS && I2C
+	help
+	  This option enables support for LEDs connected to IS31FL3196
+	  or IS31FL3199 LED driver chips accessed via the I2C bus.
+	  Driver support brightness control and hardware-assisted blinking.

Pedantic: "supports" seems appropriate here.

I don't think this matters much, but I'm curious: any reason why this entry is inserted in the middle of the list, rather than at the end?

Or better,
right before/after the IS31FL32XX entry?

Quoted 10 lines

drivers/leds/Kconfig +1 -0

+

config LEDS_TCA6507

	tristate "LED Support for TCA6507 I2C chip"
	depends on LEDS_CLASS && I2C

drivers/leds/Makefile +0 -0

index cb2013d..eee3010 100644
@@ -37,6 +37,7 @@ obj-$(CONFIG_LEDS_TCA6507)		+= leds-tca6507.o

Quoted 4 lines

obj-$(CONFIG_LEDS_TLC591XX) += leds-tlc591xx.o
obj-$(CONFIG_LEDS_CLEVO_MAIL) += leds-clevo-mail.o
obj-$(CONFIG_LEDS_IPAQ_MICRO) += leds-ipaq-micro.o
+obj-$(CONFIG_LEDS_IS31FL319X) += leds-is31fl319x.o

Ditto.

Quoted 18 lines

obj-$(CONFIG_LEDS_HP6XX) += leds-hp6xx.o
obj-$(CONFIG_LEDS_OT200) += leds-ot200.o
obj-$(CONFIG_LEDS_FSG) += leds-fsg.o

drivers/leds/leds-is31fl319x.c new file +9 -0

new file mode 100644
index 0000000..e211c46
@@ -0,0 +1,406 @@
+/*
+ * Copyright 2015 Golden Delcious Computers
+ *
+ * Author: Nikolaus Schaller <[email protected]>
+ *
+ * Based on leds-tca6507.c
+ *
+ * This file is subject to the terms and conditions of version 2 of
+ * the GNU General Public License.  See the file COPYING in the main

drivers/leds/leds-is31fl319x.c line 12

Quoted 3 lines

drivers/leds/leds-is31fl319x.c new file +3 -0

+ * directory of this archive for more details.
+ *
+ * LED driver for the IS31FL3196/99 to drive 6 or 9 light effect LEDs.

I see that there are also 3190, 3191, and 3193 devices. Is it reasonable to think that support for those devices could be added to this driver in the future? I'm merely thinking of it from the POV that it is named is31fl319x.c.

Quoted 60 lines

drivers/leds/leds-is31fl319x.c new file +59 -0

+ *
+ */
+
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/leds.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/workqueue.h>
+#include <linux/leds-is31fl319x.h>
+#include <linux/of.h>
+
+/* register numbers */
+#define IS31FL319X_SHUTDOWN	0x00
+#define IS31FL319X_CTRL1	0x01
+#define IS31FL319X_CTRL2	0x02
+#define IS31FL319X_CONFIG1	0x03
+#define IS31FL319X_CONFIG2	0x04
+#define IS31FL319X_RAMP_MODE	0x05
+#define IS31FL319X_BREATH_MASK	0x06
+#define IS31FL319X_PWM1		0x07
+#define IS31FL319X_PWM2		0x08
+#define IS31FL319X_PWM3		0x09
+#define IS31FL319X_PWM4		0x0a
+#define IS31FL319X_PWM5		0x0b
+#define IS31FL319X_PWM6		0x0c
+#define IS31FL319X_PWM7		0x0d
+#define IS31FL319X_PWM8		0x0e
+#define IS31FL319X_PWM9		0x0f
+#define IS31FL319X_DATA_UPDATE	0x10
+#define IS31FL319X_T0_1		0x11
+#define IS31FL319X_T0_2		0x12
+#define IS31FL319X_T0_3		0x13
+#define IS31FL319X_T0_4		0x14
+#define IS31FL319X_T0_5		0x15
+#define IS31FL319X_T0_6		0x16
+#define IS31FL319X_T0_7		0x17
+#define IS31FL319X_T0_8		0x18
+#define IS31FL319X_T0_9		0x19
+#define IS31FL319X_T123_1	0x1a
+#define IS31FL319X_T123_2	0x1b
+#define IS31FL319X_T123_3	0x1c
+#define IS31FL319X_T4_1		0x1d
+#define IS31FL319X_T4_2		0x1e
+#define IS31FL319X_T4_3		0x1f
+#define IS31FL319X_T4_4		0x20
+#define IS31FL319X_T4_5		0x21
+#define IS31FL319X_T4_6		0x22
+#define IS31FL319X_T4_7		0x23
+#define IS31FL319X_T4_8		0x24
+#define IS31FL319X_T4_9		0x25
+#define IS31FL319X_TIME_UPDATE	0x26
+
+#define	IS31FL319X_REG_CNT	(IS31FL319X_TIME_UPDATE + 1)
+
+#define NUM_LEDS 9	/* max for 3199 chip */
+
+struct is31fl319x_chip {
+	struct i2c_client	*client;

drivers/leds/leds-is31fl319x.c line 75

Quoted 4 lines

drivers/leds/leds-is31fl319x.c new file +4 -0

+	struct work_struct	work;
+	bool			work_scheduled;
+	spinlock_t		lock;
+	u8			reg_file[IS31FL319X_REG_CNT];

I would suggest using the regmap infrastructure if you need to cache the register values. It also helpfully exports a debugfs interface.

drivers/leds/leds-is31fl319x.c line 85

Quoted 11 lines

drivers/leds/leds-is31fl319x.c new file +10 -0

+
+	struct is31fl319x_led {
+		struct is31fl319x_chip	*chip;
+		struct led_classdev	led_cdev;
+	} leds[NUM_LEDS];
+};
+
+static const struct i2c_device_id is31fl319x_id[] = {
+	{ "is31fl3196", 6 },
+	{ "is31fl3196", 9 },

Quoted 33 lines

drivers/leds/leds-is31fl319x.c new file +33 -0

+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, is31fl319x_id);
+
+
+static int is31fl319x_write(struct is31fl319x_chip *is31, u8 reg, u8 byte)
+{
+	struct i2c_client *cl = is31->client;
+
+	if (reg >= IS31FL319X_REG_CNT)
+		return -EIO;
+	is31->reg_file[reg] = byte;	/* save in cache */
+	dev_dbg(&is31->client->dev, "write %02x to reg %02x\n", byte, reg);
+	return i2c_smbus_write_byte_data(cl, reg, byte);
+}
+
+static int is31fl319x_read(struct is31fl319x_chip *is31, u8 reg)
+{
+	if (reg >= IS31FL319X_REG_CNT)
+		return -EIO;
+	return is31->reg_file[reg];	/* read crom cache (can't read chip) */
+}
+
+static void is31fl319x_work(struct work_struct *work)
+{
+	struct is31fl319x_chip *is31 = container_of(work,
+						    struct is31fl319x_chip,
+						    work);
+	unsigned long flags;
+	int i;
+	u8 ctrl1, ctrl2;
+
+	dev_dbg(&is31->client->dev, "work called\n");

drivers/leds/leds-is31fl319x.c line 123

Quoted 5 lines

drivers/leds/leds-is31fl319x.c new file +5 -0

+
+	spin_lock_irqsave(&is31->lock, flags);
+	/* make subsequent changes run another schedule_work */
+	is31->work_scheduled = false;
+	spin_unlock_irqrestore(&is31->lock, flags);

I believe the LEDS core now handles the workqueues generically for blocking operations, so it's no longer needed in the individual drivers.

Quoted 24 lines

drivers/leds/leds-is31fl319x.c new file +23 -0

+
+	dev_dbg(&is31->client->dev, "write to chip\n");
+
+	ctrl1 = 0;
+	ctrl2 = 0;
+
+	for (i = 0; i < NUM_LEDS; i++) {
+		struct led_classdev *led = &is31->leds[i].led_cdev;
+		bool on;
+
+		if (!is31->leds[i].led_cdev.name)
+			continue;
+
+		dev_dbg(&is31->client->dev, "set brightness %u for led %u\n",
+					    led->brightness, i);
+
+		/* update brightness register */
+		is31fl319x_write(is31, IS31FL319X_PWM1 + i, led->brightness);
+
+		/* update output enable bits */
+		on = led->brightness > LED_OFF;
+		if (i < 3)
+			ctrl1 |= on << i;	/* 0..2 => bit 0..2 */

drivers/leds/leds-is31fl319x.c line 151

Quoted 5 lines

drivers/leds/leds-is31fl319x.c new file +5 -0

+		else if (i < 6)
+			ctrl1 |= on << (i+1);	/* 3..5 => bit 4..6 */
+		else
+			ctrl2 |= on << (i-6);	/* 6..8 => bit 0..2 */
+	}

Is any locking needed while iterating over is31->leds[]? Is there any opportunity for a race?

Quoted 29 lines

drivers/leds/leds-is31fl319x.c new file +28 -0

+
+	/* check if any PWM is enabled or all outputs are now off */
+	if (ctrl1 > 0 || ctrl2 > 0) {
+		dev_dbg(&is31->client->dev, "power up\n");
+		is31fl319x_write(is31, IS31FL319X_CTRL1, ctrl1);
+		is31fl319x_write(is31, IS31FL319X_CTRL2, ctrl2);
+		/* update PWMs */
+		is31fl319x_write(is31, IS31FL319X_DATA_UPDATE, 0x00);
+		/* enable chip from shut down */
+		is31fl319x_write(is31, IS31FL319X_SHUTDOWN, 0x01);
+	} else {
+		dev_dbg(&is31->client->dev, "power down\n");
+		/* shut down */
+		is31fl319x_write(is31, IS31FL319X_SHUTDOWN, 0x00);
+	}
+
+	dev_dbg(&is31->client->dev, "work done\n");
+
+}
+
+/* NOTE: this may be called from within irq context, e.g. led_trigger_event */
+
+static int is31fl319x_brightness_get(struct led_classdev *led_cdev)
+{
+	struct is31fl319x_led *led = container_of(led_cdev,
+						  struct is31fl319x_led,
+						  led_cdev);
+	struct is31fl319x_chip *is31 = led->chip;

drivers/leds/leds-is31fl319x.c line 183

Quoted 4 lines

drivers/leds/leds-is31fl319x.c new file +4 -0

+
+	/* read PWM register */
+	return is31fl319x_read(is31, IS31FL319X_PWM1 + (led - is31->leds));
+}

I believe that the LEDS core remembers the last set brightness for each LED,
and will use it if no brightness_get function is implemented. Since all is31fl319x_brightness_get() does is retrieve the saved value from your cache, I think you can just eliminate is31fl319x_brightness_get() altogether.

Quoted 4 lines

drivers/leds/leds-is31fl319x.c new file +3 -0

+
+static void is31fl319x_brightness_set(struct led_classdev *led_cdev,
+				   enum led_brightness brightness)

drivers/leds/leds-is31fl319x.c line 196

Quoted 10 lines

drivers/leds/leds-is31fl319x.c new file +10 -0

+{
+	struct is31fl319x_led *led = container_of(led_cdev,
+						  struct is31fl319x_led,
+						  led_cdev);
+	struct is31fl319x_chip *is31 = led->chip;
+	unsigned long flags;
+
+	spin_lock_irqsave(&is31->lock, flags);
+
+	if (brightness != is31fl319x_brightness_get(led_cdev)) {

Quoted 12 lines

drivers/leds/leds-is31fl319x.c new file +12 -0

+		if (!is31->work_scheduled) {
+			schedule_work(&is31->work);
+			is31->work_scheduled = true;
+		}
+	}
+
+	spin_unlock_irqrestore(&is31->lock, flags);
+}
+
+static int is31fl319x_blink_set(struct led_classdev *led_cdev,
+			     unsigned long *delay_on,
+			     unsigned long *delay_off)

drivers/leds/leds-is31fl319x.c line 211

Quoted 3 lines

drivers/leds/leds-is31fl319x.c new file +3 -0

+{
+	/* use software blink */
+	return 1;

The Kconfig entry claims hardware blink support. The comment here says the opposite. I believe this current implementation will result in the LEDS core falling back to software blink, but the same result would be achieved by just not setting the blink_set callback.

Quoted 24 lines

drivers/leds/leds-is31fl319x.c new file +24 -0

+}
+
+#ifdef CONFIG_OF
+static struct is31fl319x_platform_data *
+is31fl319x_led_dt_init(struct i2c_client *client, int num_leds)
+{
+	struct device_node *np = client->dev.of_node, *child;
+	struct is31fl319x_platform_data *pdata;
+	struct led_info *is31_leds;
+	int count;
+
+	count = of_get_child_count(np);
+	dev_dbg(&client->dev, "child count %d\n", count);
+	if (!count || count > NUM_LEDS)
+		return ERR_PTR(-ENODEV);
+
+	is31_leds = devm_kzalloc(&client->dev,
+			sizeof(struct led_info) * NUM_LEDS, GFP_KERNEL);
+	if (!is31_leds)
+		return ERR_PTR(-ENOMEM);
+
+	for_each_child_of_node(np, child) {
+		struct led_info led;
+		u32 reg;

drivers/leds/leds-is31fl319x.c line 241

Quoted 6 lines

drivers/leds/leds-is31fl319x.c new file +6 -0

+		int ret;
+
+		led.name =
+			of_get_property(child, "label", NULL) ? : child->name;
+		led.default_trigger =
+			of_get_property(child, "linux,default-trigger", NULL);

I believe it is better to use of_property_read_string() for these.

drivers/leds/leds-is31fl319x.c line 250

Quoted 10 lines

drivers/leds/leds-is31fl319x.c new file +9 -0

+		led.flags = 0;
+		ret = of_property_read_u32(child, "reg", &reg);
+		dev_dbg(&client->dev, "name = %s reg = %d\n", led.name, reg);
+		if (ret != 0 || reg < 0 || reg >= num_leds)
+			continue;
+
+		if (is31_leds[reg].name)
+			dev_err(&client->dev, "duplicate led line %d for %s -> %s\n",
+				reg, is31_leds[reg].name, led.name);

There are two errors (invalid DT) detected here, but the driver continues to load. I believe the preference is for errors like this to result in the probe failing outright.

Quoted 79 lines

drivers/leds/leds-is31fl319x.c new file +77 -0

+		is31_leds[reg] = led;
+	}
+	pdata = devm_kzalloc(&client->dev,
+			sizeof(struct is31fl319x_platform_data), GFP_KERNEL);
+	if (!pdata)
+		return ERR_PTR(-ENOMEM);
+
+	pdata->leds.leds = is31_leds;
+	return pdata;
+}
+
+static const struct of_device_id of_is31fl319x_leds_match[] = {
+	{ .compatible = "issi,is31fl3196", (void *) 6 },
+	{ .compatible = "issi,is31fl3199", (void *) 9 },
+	{},
+};
+MODULE_DEVICE_TABLE(of, of_is31fl319x_leds_match);
+
+#else
+static struct is31fl319x_platform_data *
+is31fl319x_led_dt_init(struct i2c_client *client)
+{
+	return ERR_PTR(-ENODEV);
+}
+
+#endif
+
+static int is31fl319x_probe(struct i2c_client *client,
+		const struct i2c_device_id *id)
+{
+	struct is31fl319x_chip *is31;
+	struct i2c_adapter *adapter;
+	struct is31fl319x_platform_data *pdata;
+	int err;
+	int i = 0;
+
+	adapter = to_i2c_adapter(client->dev.parent);
+	pdata = dev_get_platdata(&client->dev);
+
+	dev_dbg(&client->dev, "probe\n");
+
+	dev_dbg(&client->dev, "NUM_LEDS = %d num_leds = %d\n",
+		NUM_LEDS, (int) id->driver_data);
+
+	if (!i2c_check_functionality(adapter, I2C_FUNC_I2C))
+		return -EIO;
+
+	if (!pdata) {
+		pdata = is31fl319x_led_dt_init(client, (int) id->driver_data);
+		if (IS_ERR(pdata)) {
+			dev_err(&client->dev, "DT led error %d\n",
+				(int) PTR_ERR(pdata));
+			return PTR_ERR(pdata);
+		}
+	}
+	is31 = devm_kzalloc(&client->dev, sizeof(*is31), GFP_KERNEL);
+	if (!is31)
+		return -ENOMEM;
+
+	is31->client = client;
+	INIT_WORK(&is31->work, is31fl319x_work);
+	spin_lock_init(&is31->lock);
+	i2c_set_clientdata(client, is31);
+
+	/* check for reply from chip (we can't read any registers) */
+	err = is31fl319x_write(is31, IS31FL319X_SHUTDOWN, 0x01);
+	if (err < 0) {
+		dev_err(&client->dev, "no response from chip write: err = %d\n",
+			err);
+		return -EPROBE_DEFER;	/* does not answer (yet) */
+	}
+
+	for (i = 0; i < NUM_LEDS; i++) {
+		struct is31fl319x_led *l = is31->leds + i;
+
+		l->chip = is31;
+		if (pdata->leds.leds[i].name && !pdata->leds.leds[i].flags) {

drivers/leds/leds-is31fl319x.c line 332

Quoted 5 lines

drivers/leds/leds-is31fl319x.c new file +5 -0

+			l->led_cdev.name = pdata->leds.leds[i].name;
+			l->led_cdev.default_trigger
+				= pdata->leds.leds[i].default_trigger;
+			l->led_cdev.brightness_set = is31fl319x_brightness_set;
+			l->led_cdev.blink_set = is31fl319x_blink_set;

I don't see led_cdev.brightness_get being set here. Although if you do remove is31fl319x_brightness_get(), it obviously won't need to be set.

drivers/leds/leds-is31fl319x.c line 334

Quoted 3 lines

drivers/leds/leds-is31fl319x.c new file +2 -0

+			err = led_classdev_register(&client->dev,
+						    &l->led_cdev);

I would suggest using devm_led_classdev_register(). Then you can remove all the calls to led_classdev_unregister() in error and cleanup paths.

Quoted 95 lines

drivers/leds/leds-is31fl319x.c new file +72 -0

+			if (err < 0)
+				goto exit;
+		}
+	}
+
+	if (client->dev.of_node) {
+		u32 val;
+		u8 config2 = 0;
+
+		if (of_property_read_u32(client->dev.of_node, "max-current-ma",
+					 &val)) {
+			if (val > 40)
+				val = 40;
+			if (val < 5)
+				val = 5;
+			config2 |= (((64 - val) / 5) & 0x7) << 4; /* CS */
+		}
+		if (of_property_read_u32(client->dev.of_node, "audio-gain-db",
+					 &val)) {
+			if (val > 21)
+				val = 21;
+			config2 |= val / 3; /* AGS */
+		}
+		if (config2)
+			is31fl319x_write(is31, IS31FL319X_CONFIG2, config2);
+	}
+
+	schedule_work(&is31->work);	/* first update */
+
+	dev_dbg(&client->dev, "probed\n");
+	return 0;
+exit:
+	dev_err(&client->dev, "led error %d\n", err);
+
+	while (i--) {
+		if (is31->leds[i].led_cdev.name)
+			led_classdev_unregister(&is31->leds[i].led_cdev);
+	}
+	return err;
+}
+
+static int is31fl319x_remove(struct i2c_client *client)
+{
+	int i;
+	struct is31fl319x_chip *is31 = i2c_get_clientdata(client);
+	struct is31fl319x_led *is31_leds = is31->leds;
+
+	for (i = 0; i < NUM_LEDS; i++) {
+		if (is31_leds[i].led_cdev.name)
+			led_classdev_unregister(&is31_leds[i].led_cdev);
+	}
+
+	cancel_work_sync(&is31->work);
+
+	return 0;
+}
+
+static struct i2c_driver is31fl319x_driver = {
+	.driver   = {
+		.name    = "leds-is31fl319x",
+		.of_match_table = of_match_ptr(of_is31fl319x_leds_match),
+	},
+	.probe    = is31fl319x_probe,
+	.remove   = is31fl319x_remove,
+	.id_table = is31fl319x_id,
+};
+
+module_i2c_driver(is31fl319x_driver);
+
+MODULE_AUTHOR("H. Nikolaus Schaller <[email protected]>");
+MODULE_DESCRIPTION("IS31FL319X LED driver");
+MODULE_LICENSE("GPL v2");

include/linux/leds-is31fl319x.h new file +16 -0

new file mode 100644
index 0000000..5f55abf
@@ -0,0 +1,24 @@
+/*
+ * IS31FL3196 LED chip driver.
+ *
+ * Copyright (C) 2015 H. Nikolaus Schaller <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ */
+
+#ifndef __LINUX_IS31FL319X_H

include/linux/leds-is31fl319x.h line 24

Quoted 8 lines

include/linux/leds-is31fl319x.h new file +8 -0

+#define __LINUX_IS31FL319X_H
+#include <linux/leds.h>
+
+struct is31fl319x_platform_data {
+	struct led_platform_data leds;
+};
+
+#endif /* __LINUX_IS31FL319X_H */

Hi David,

Quoted 1 line

Am 19.04.2016 um 03:25 schrieb David Rivshin (Allworx) <[email protected]>:

Quoted 10 lines

drivers/leds/leds-is31fl319x.c line 75

Quoted 6 lines

drivers/leds/leds-is31fl319x.c new file +6 -0

+struct is31fl319x_chip {
+	struct i2c_client	*client;
+	struct work_struct	work;
+	bool			work_scheduled;
+	spinlock_t		lock;
+	u8			reg_file[IS31FL319X_REG_CNT];

I would suggest using the regmap infrastructure if you need to cache the register values. It also helpfully exports a debugfs interface.

There was an issue with regmap I don't exactly remember.

Maybe it was because it is impossible to read (initial) values from the chip.

Only write new ones. And check for chip presence can also only be done by checking if it responds or fails to a write command. So we would have to use tricks to make regmap work as intended.

And it may introduce overhead in initialization and does not save memory.

Quoted 11 lines

drivers/leds/leds-is31fl319x.c line 85

Quoted 11 lines

drivers/leds/leds-is31fl319x.c new file +10 -0

+
+	struct is31fl319x_led {
+		struct is31fl319x_chip	*chip;
+		struct led_classdev	led_cdev;
+	} leds[NUM_LEDS];
+};
+
+static const struct i2c_device_id is31fl319x_id[] = {
+	{ "is31fl3196", 6 },
+	{ "is31fl3196", 9 },

^^^there is also a bug using is31fl3196 twice

Quoted 33 lines

Quoted 33 lines

drivers/leds/leds-is31fl319x.c new file +33 -0

+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, is31fl319x_id);
+
+
+static int is31fl319x_write(struct is31fl319x_chip *is31, u8 reg, u8 byte)
+{
+	struct i2c_client *cl = is31->client;
+
+	if (reg >= IS31FL319X_REG_CNT)
+		return -EIO;
+	is31->reg_file[reg] = byte;	/* save in cache */
+	dev_dbg(&is31->client->dev, "write %02x to reg %02x\n", byte, reg);
+	return i2c_smbus_write_byte_data(cl, reg, byte);
+}
+
+static int is31fl319x_read(struct is31fl319x_chip *is31, u8 reg)
+{
+	if (reg >= IS31FL319X_REG_CNT)
+		return -EIO;
+	return is31->reg_file[reg];	/* read crom cache (can't read chip) */
+}
+
+static void is31fl319x_work(struct work_struct *work)
+{
+	struct is31fl319x_chip *is31 = container_of(work,
+						    struct is31fl319x_chip,
+						    work);
+	unsigned long flags;
+	int i;
+	u8 ctrl1, ctrl2;
+
+	dev_dbg(&is31->client->dev, "work called\n");

Quoted 8 lines

drivers/leds/leds-is31fl319x.c line 123

Quoted 5 lines

drivers/leds/leds-is31fl319x.c new file +5 -0

+
+	spin_lock_irqsave(&is31->lock, flags);
+	/* make subsequent changes run another schedule_work */
+	is31->work_scheduled = false;
+	spin_unlock_irqrestore(&is31->lock, flags);

I believe the LEDS core now handles the workqueues generically for blocking operations, so it's no longer needed in the individual drivers.

We had a lot of trouble with locking and blocking especially if we want to indicate CPU or (root) disk activity.

So it is implemented in a way that changes can be requested faster than the I2C bus can write new values to the chip.

Only after one sequence of I2C writes is done, another work function can be scheduled. And each group of writes updates as many LEDs in parallel if necessary.

Quoted 24 lines

Quoted 24 lines

drivers/leds/leds-is31fl319x.c new file +23 -0

+
+	dev_dbg(&is31->client->dev, "write to chip\n");
+
+	ctrl1 = 0;
+	ctrl2 = 0;
+
+	for (i = 0; i < NUM_LEDS; i++) {
+		struct led_classdev *led = &is31->leds[i].led_cdev;
+		bool on;
+
+		if (!is31->leds[i].led_cdev.name)
+			continue;
+
+		dev_dbg(&is31->client->dev, "set brightness %u for led %u\n",
+					    led->brightness, i);
+
+		/* update brightness register */
+		is31fl319x_write(is31, IS31FL319X_PWM1 + i, led->brightness);
+
+		/* update output enable bits */
+		on = led->brightness > LED_OFF;
+		if (i < 3)
+			ctrl1 |= on << i;	/* 0..2 => bit 0..2 */

Quoted 8 lines

drivers/leds/leds-is31fl319x.c line 151

Quoted 5 lines

drivers/leds/leds-is31fl319x.c new file +5 -0

+		else if (i < 6)
+			ctrl1 |= on << (i+1);	/* 3..5 => bit 4..6 */
+		else
+			ctrl2 |= on << (i-6);	/* 6..8 => bit 0..2 */
+	}

Is any locking needed while iterating over is31->leds[]? Is there any opportunity for a race?

No, because our locking mechanism ensures that only one work function is running at a time.

Yes there is a small race if a brightness value is updated by an interrupt.

But since the worker is already running, another one will be scheduled that will fix the value. So for an invisibly short moment there might be the wrong value.

Quoted 29 lines

Quoted 29 lines

drivers/leds/leds-is31fl319x.c new file +28 -0

+
+	/* check if any PWM is enabled or all outputs are now off */
+	if (ctrl1 > 0 || ctrl2 > 0) {
+		dev_dbg(&is31->client->dev, "power up\n");
+		is31fl319x_write(is31, IS31FL319X_CTRL1, ctrl1);
+		is31fl319x_write(is31, IS31FL319X_CTRL2, ctrl2);
+		/* update PWMs */
+		is31fl319x_write(is31, IS31FL319X_DATA_UPDATE, 0x00);
+		/* enable chip from shut down */
+		is31fl319x_write(is31, IS31FL319X_SHUTDOWN, 0x01);
+	} else {
+		dev_dbg(&is31->client->dev, "power down\n");
+		/* shut down */
+		is31fl319x_write(is31, IS31FL319X_SHUTDOWN, 0x00);
+	}
+
+	dev_dbg(&is31->client->dev, "work done\n");
+
+}
+
+/* NOTE: this may be called from within irq context, e.g. led_trigger_event */
+
+static int is31fl319x_brightness_get(struct led_classdev *led_cdev)
+{
+	struct is31fl319x_led *led = container_of(led_cdev,
+						  struct is31fl319x_led,
+						  led_cdev);
+	struct is31fl319x_chip *is31 = led->chip;

Quoted 8 lines

drivers/leds/leds-is31fl319x.c line 183

Quoted 4 lines

drivers/leds/leds-is31fl319x.c new file +4 -0

+
+	/* read PWM register */
+	return is31fl319x_read(is31, IS31FL319X_PWM1 + (led - is31->leds));
+}

I believe that the LEDS core remembers the last set brightness for each LED,
and will use it if no brightness_get function is implemented. Since all is31fl319x_brightness_get() does is retrieve the saved value from your cache, I think you can just eliminate is31fl319x_brightness_get() altogether.

Well, we do not use it as a real getter because as you say the LEDS core remembers it.

But we call it in the setter to determine if there is a change.

Quoted 14 lines

Quoted 4 lines

drivers/leds/leds-is31fl319x.c new file +3 -0

+
+static void is31fl319x_brightness_set(struct led_classdev *led_cdev,
+				   enum led_brightness brightness)

drivers/leds/leds-is31fl319x.c line 196

Quoted 10 lines

drivers/leds/leds-is31fl319x.c new file +10 -0

+{
+	struct is31fl319x_led *led = container_of(led_cdev,
+						  struct is31fl319x_led,
+						  led_cdev);
+	struct is31fl319x_chip *is31 = led->chip;
+	unsigned long flags;
+
+	spin_lock_irqsave(&is31->lock, flags);
+
+	if (brightness != is31fl319x_brightness_get(led_cdev)) {

Here.

Maybe we could inline the call to is31fl319x_read() and even inline is31fl319x_read because that is also the only location where it is used.

But it removes some inherent layering of the code (lowest level = read/write chip, get = know which registers to read, set = schedule work only if needed).

I have left it as is for the next version. Let's see if there are more comments.

Quoted 12 lines

Quoted 12 lines

drivers/leds/leds-is31fl319x.c new file +12 -0

+		if (!is31->work_scheduled) {
+			schedule_work(&is31->work);
+			is31->work_scheduled = true;
+		}
+	}
+
+	spin_unlock_irqrestore(&is31->lock, flags);
+}
+
+static int is31fl319x_blink_set(struct led_classdev *led_cdev,
+			     unsigned long *delay_on,
+			     unsigned long *delay_off)

Quoted 9 lines

drivers/leds/leds-is31fl319x.c line 211

Quoted 3 lines

drivers/leds/leds-is31fl319x.c new file +3 -0

+{
+	/* use software blink */
+	return 1;

The Kconfig entry claims hardware blink support. The comment here says the opposite. I believe this current implementation will result in the LEDS core falling back to software blink, but the same result would be achieved by just not setting the blink_set callback.

Yes, you are right. We wanted to implement HW blinking later. So let's remove it here and from Kconfig.

Quoted 24 lines

Quoted 24 lines

drivers/leds/leds-is31fl319x.c new file +24 -0

+}
+
+#ifdef CONFIG_OF
+static struct is31fl319x_platform_data *
+is31fl319x_led_dt_init(struct i2c_client *client, int num_leds)
+{
+	struct device_node *np = client->dev.of_node, *child;
+	struct is31fl319x_platform_data *pdata;
+	struct led_info *is31_leds;
+	int count;
+
+	count = of_get_child_count(np);
+	dev_dbg(&client->dev, "child count %d\n", count);
+	if (!count || count > NUM_LEDS)
+		return ERR_PTR(-ENODEV);
+
+	is31_leds = devm_kzalloc(&client->dev,
+			sizeof(struct led_info) * NUM_LEDS, GFP_KERNEL);
+	if (!is31_leds)
+		return ERR_PTR(-ENOMEM);
+
+	for_each_child_of_node(np, child) {
+		struct led_info led;
+		u32 reg;

Quoted 8 lines

drivers/leds/leds-is31fl319x.c line 241

Quoted 6 lines

drivers/leds/leds-is31fl319x.c new file +6 -0

+		int ret;
+
+		led.name =
+			of_get_property(child, "label", NULL) ? : child->name;
+		led.default_trigger =
+			of_get_property(child, "linux,default-trigger", NULL);

I believe it is better to use of_property_read_string() for these.

Sounds good, because it does some error checks but makes error handling a little more complex (since it is an optional property).

Quoted 14 lines

drivers/leds/leds-is31fl319x.c line 250

Quoted 10 lines

drivers/leds/leds-is31fl319x.c new file +9 -0

+		led.flags = 0;
+		ret = of_property_read_u32(child, "reg", &reg);
+		dev_dbg(&client->dev, "name = %s reg = %d\n", led.name, reg);
+		if (ret != 0 || reg < 0 || reg >= num_leds)
+			continue;
+
+		if (is31_leds[reg].name)
+			dev_err(&client->dev, "duplicate led line %d for %s -> %s\n",
+				reg, is31_leds[reg].name, led.name);

There are two errors (invalid DT) detected here, but the driver continues to load. I believe the preference is for errors like this to result in the probe failing outright.

I regard this type of error as a flaw that does not require the driver to probe completely. It simply uses the last of the duplicate definitions. By looking into the kernel log the error in DT can be easily seen and fixed (instead of wondering why all LEDs remain off).

Quoted 80 lines

Quoted 80 lines

drivers/leds/leds-is31fl319x.c new file +77 -0

+		is31_leds[reg] = led;
+	}
+	pdata = devm_kzalloc(&client->dev,
+			sizeof(struct is31fl319x_platform_data), GFP_KERNEL);
+	if (!pdata)
+		return ERR_PTR(-ENOMEM);
+
+	pdata->leds.leds = is31_leds;
+	return pdata;
+}
+
+static const struct of_device_id of_is31fl319x_leds_match[] = {
+	{ .compatible = "issi,is31fl3196", (void *) 6 },
+	{ .compatible = "issi,is31fl3199", (void *) 9 },
+	{},
+};
+MODULE_DEVICE_TABLE(of, of_is31fl319x_leds_match);
+
+#else
+static struct is31fl319x_platform_data *
+is31fl319x_led_dt_init(struct i2c_client *client)
+{
+	return ERR_PTR(-ENODEV);
+}
+
+#endif
+
+static int is31fl319x_probe(struct i2c_client *client,
+		const struct i2c_device_id *id)
+{
+	struct is31fl319x_chip *is31;
+	struct i2c_adapter *adapter;
+	struct is31fl319x_platform_data *pdata;
+	int err;
+	int i = 0;
+
+	adapter = to_i2c_adapter(client->dev.parent);
+	pdata = dev_get_platdata(&client->dev);
+
+	dev_dbg(&client->dev, "probe\n");
+
+	dev_dbg(&client->dev, "NUM_LEDS = %d num_leds = %d\n",
+		NUM_LEDS, (int) id->driver_data);
+
+	if (!i2c_check_functionality(adapter, I2C_FUNC_I2C))
+		return -EIO;
+
+	if (!pdata) {
+		pdata = is31fl319x_led_dt_init(client, (int) id->driver_data);
+		if (IS_ERR(pdata)) {
+			dev_err(&client->dev, "DT led error %d\n",
+				(int) PTR_ERR(pdata));
+			return PTR_ERR(pdata);
+		}
+	}
+	is31 = devm_kzalloc(&client->dev, sizeof(*is31), GFP_KERNEL);
+	if (!is31)
+		return -ENOMEM;
+
+	is31->client = client;
+	INIT_WORK(&is31->work, is31fl319x_work);
+	spin_lock_init(&is31->lock);
+	i2c_set_clientdata(client, is31);
+
+	/* check for reply from chip (we can't read any registers) */
+	err = is31fl319x_write(is31, IS31FL319X_SHUTDOWN, 0x01);
+	if (err < 0) {
+		dev_err(&client->dev, "no response from chip write: err = %d\n",
+			err);
+		return -EPROBE_DEFER;	/* does not answer (yet) */
+	}
+
+	for (i = 0; i < NUM_LEDS; i++) {
+		struct is31fl319x_led *l = is31->leds + i;
+
+		l->chip = is31;
+		if (pdata->leds.leds[i].name && !pdata->leds.leds[i].flags) {

Quoted 8 lines

drivers/leds/leds-is31fl319x.c line 332

Quoted 5 lines

drivers/leds/leds-is31fl319x.c new file +5 -0

+			l->led_cdev.name = pdata->leds.leds[i].name;
+			l->led_cdev.default_trigger
+				= pdata->leds.leds[i].default_trigger;
+			l->led_cdev.brightness_set = is31fl319x_brightness_set;
+			l->led_cdev.blink_set = is31fl319x_blink_set;

I don't see led_cdev.brightness_get being set here. Although if you do remove is31fl319x_brightness_get(), it obviously won't need to be set.

Well, it is used in our is31fl319x_brightness_set function so we can't remove it completely.

Quoted 6 lines

drivers/leds/leds-is31fl319x.c line 334

Quoted 3 lines

drivers/leds/leds-is31fl319x.c new file +2 -0

+			err = led_classdev_register(&client->dev,
+						    &l->led_cdev);

I would suggest using devm_led_classdev_register(). Then you can remove all the calls to led_classdev_unregister() in error and cleanup paths.

Ok.

Quoted 95 lines

Quoted 95 lines

drivers/leds/leds-is31fl319x.c new file +72 -0

+			if (err < 0)
+				goto exit;
+		}
+	}
+
+	if (client->dev.of_node) {
+		u32 val;
+		u8 config2 = 0;
+
+		if (of_property_read_u32(client->dev.of_node, "max-current-ma",
+					 &val)) {
+			if (val > 40)
+				val = 40;
+			if (val < 5)
+				val = 5;
+			config2 |= (((64 - val) / 5) & 0x7) << 4; /* CS */
+		}
+		if (of_property_read_u32(client->dev.of_node, "audio-gain-db",
+					 &val)) {
+			if (val > 21)
+				val = 21;
+			config2 |= val / 3; /* AGS */
+		}
+		if (config2)
+			is31fl319x_write(is31, IS31FL319X_CONFIG2, config2);
+	}
+
+	schedule_work(&is31->work);	/* first update */
+
+	dev_dbg(&client->dev, "probed\n");
+	return 0;
+exit:
+	dev_err(&client->dev, "led error %d\n", err);
+
+	while (i--) {
+		if (is31->leds[i].led_cdev.name)
+			led_classdev_unregister(&is31->leds[i].led_cdev);
+	}
+	return err;
+}
+
+static int is31fl319x_remove(struct i2c_client *client)
+{
+	int i;
+	struct is31fl319x_chip *is31 = i2c_get_clientdata(client);
+	struct is31fl319x_led *is31_leds = is31->leds;
+
+	for (i = 0; i < NUM_LEDS; i++) {
+		if (is31_leds[i].led_cdev.name)
+			led_classdev_unregister(&is31_leds[i].led_cdev);
+	}
+
+	cancel_work_sync(&is31->work);
+
+	return 0;
+}
+
+static struct i2c_driver is31fl319x_driver = {
+	.driver   = {
+		.name    = "leds-is31fl319x",
+		.of_match_table = of_match_ptr(of_is31fl319x_leds_match),
+	},
+	.probe    = is31fl319x_probe,
+	.remove   = is31fl319x_remove,
+	.id_table = is31fl319x_id,
+};
+
+module_i2c_driver(is31fl319x_driver);
+
+MODULE_AUTHOR("H. Nikolaus Schaller <[email protected]>");
+MODULE_DESCRIPTION("IS31FL319X LED driver");
+MODULE_LICENSE("GPL v2");

include/linux/leds-is31fl319x.h new file +16 -0

new file mode 100644
index 0000000..5f55abf
@@ -0,0 +1,24 @@
+/*
+ * IS31FL3196 LED chip driver.
+ *
+ * Copyright (C) 2015 H. Nikolaus Schaller <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ */
+
+#ifndef __LINUX_IS31FL319X_H

Quoted 9 lines

include/linux/leds-is31fl319x.h line 24

Quoted 8 lines

include/linux/leds-is31fl319x.h new file +8 -0

+#define __LINUX_IS31FL319X_H
+#include <linux/leds.h>
+
+struct is31fl319x_platform_data {
+	struct led_platform_data leds;
+};
+
+#endif /* __LINUX_IS31FL319X_H */

In the next days I will debug and test the fixes...

BR and thanks,
Nikolaus

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Am 20.04.2016 um 23:04 schrieb Jacek Anaszewski <[email protected]>:

Quoted 3 lines · H. Nikolaus Schaller

Quoted 2 lines

I believe the LEDS core now handles the workqueues generically for blocking operations, so it's no longer needed in the individual drivers.

Quoted 2 lines

We had a lot of trouble with locking and blocking especially if we want to indicate CPU or (root) disk activity.

What kind of troubles you had? Could you share more details? Does it mean that current LED core design doesn't fit for your use cases?

Quoted 7 lines

So it is implemented in a way that changes can be requested faster than the I2C bus can write new values to the chip.

Only after one sequence of I2C writes is done, another work function can be scheduled. And each group of writes updates as many LEDs in parallel if necessary.

You can serialize the operations in brightness_set_blocking with a mutex.

Hi,
finally, I found the time to update the driver according to the many comments received a while ago.

Most of them have been worked in, including the regmap idea and brightness_set_blocking().

The driver works on our system, so that I will mail [PATCH v2] as a followup.

There is only one aspect of the new solution I am not sure if it is really better than our old proposal (see below).

Quoted 6 lines

Am 20.04.2016 um 23:04 schrieb Jacek Anaszewski <[email protected]>:

Quoted 3 lines · H. Nikolaus Schaller

Quoted 2 lines

I believe the LEDS core now handles the workqueues generically for blocking operations, so it's no longer needed in the individual drivers.

Quoted 6 lines

Quoted 2 lines

We had a lot of trouble with locking and blocking especially if we want to indicate CPU or (root) disk activity.

What kind of troubles you had? Could you share more details? Does it mean that current LED core design doesn't fit for your use cases?

The system started to flicker the LEDs irregularily and sometimes the whole kernel stalled.

Quoted 10 lines

Quoted 7 lines

So it is implemented in a way that changes can be requested faster than the I2C bus can write new values to the chip.

Only after one sequence of I2C writes is done, another work function can be scheduled. And each group of writes updates as many LEDs in parallel if necessary.

You can serialize the operations in brightness_set_blocking with a mutex.

Yes, that works fine in our (incomplete) test setup.

But I think it assumes that the i2c bus is never congested by other i2c traffic.

I have not found code that obviously takes care of the situation if led trigger events (e.g. mmc or cpu triggers) are coming in faster than the i2c (even using regmap) can write out over i2c.

If I understand the led core code correctly, it will just do another schedule_work for every single change of led brightness.

So I wonder if Is there some guarantee that this work queue will not fill up memory and is really processed faster than being filled? I.e. can the queue overflow?

To reduce this risk, my original implementation strategy was different. The update speed was limited by i2c writing. A new register update batch job was only scheduled if the previous one is finished. If i2c was blocked/congested, the writing worker thread would come to a halt.

All incoming led brightness changes were simply accumulated until a new batch job is started, because LEDs would anyways flicker invisibly fast.

Tests with the new driver have shown that it seems not to run into this situation on our system but it might depend on factors we have not yet tested (slow i2c, other i2c traffic on the same bus, CPU speed, event types choosen).

So I am a little in doubt about this risk. But I may have simply missed the reason why the standard approach works and can never overflow.

BR,
Nikolaus

Am 07.07.2016 um 10:46 schrieb Jacek Anaszewski <[email protected]>:

Hi Nikolaus,

Quoted 42 lines · H. Nikolaus Schaller

Hi,
finally, I found the time to update the driver according to the many comments received a while ago.

Most of them have been worked in, including the regmap idea and brightness_set_blocking().

The driver works on our system, so that I will mail [PATCH v2] as a followup.

There is only one aspect of the new solution I am not sure if it is really better than our old proposal (see below).

Quoted 6 lines

Am 20.04.2016 um 23:04 schrieb Jacek Anaszewski <[email protected]>:

Quoted 3 lines · H. Nikolaus Schaller

Quoted 2 lines

I believe the LEDS core now handles the workqueues generically for blocking operations, so it's no longer needed in the individual drivers.

Quoted 6 lines

Quoted 2 lines

We had a lot of trouble with locking and blocking especially if we want to indicate CPU or (root) disk activity.

What kind of troubles you had? Could you share more details? Does it mean that current LED core design doesn't fit for your use cases?

The system started to flicker the LEDs irregularily and sometimes the whole kernel stalled.

Quoted 10 lines

Quoted 7 lines

So it is implemented in a way that changes can be requested faster than the I2C bus can write new values to the chip.

Only after one sequence of I2C writes is done, another work function can be scheduled. And each group of writes updates as many LEDs in parallel if necessary.

You can serialize the operations in brightness_set_blocking with a mutex.

Yes, that works fine in our (incomplete) test setup.

Quoted 8 lines

But I think it assumes that the i2c bus is never congested by other i2c traffic.

I have not found code that obviously takes care of the situation if led trigger events (e.g. mmc or cpu triggers) are coming in faster than the i2c (even using regmap) can write out over i2c.

If I understand the led core code correctly, it will just do another schedule_work for every single change of led brightness.

Please look at schedule_work documentation in include/linux/workqueue.h:

/**
* schedule_work - put work task in global workqueue
* @work: job to be done
*
* Returns %false if @work was already on the kernel-global workqueue and
* %true otherwise.
*
* This puts a job in the kernel-global workqueue if it was not already

* queued and leaves it in the same position on the kernel-global
* workqueue otherwise.
*/
static inline bool schedule_work(struct work_struct *work)

{
       return queue_work(system_wq, work);
}

Quoted 25 lines

So I wonder if Is there some guarantee that this work queue will not fill up memory and is really processed faster than being filled? I.e. can the queue overflow?

To reduce this risk, my original implementation strategy was different. The update speed was limited by i2c writing. A new register update batch job was only scheduled if the previous one is finished. If i2c was blocked/congested, the writing worker thread would come to a halt.

All incoming led brightness changes were simply accumulated until a new batch job is started, because LEDs would anyways flicker invisibly fast.

Tests with the new driver have shown that it seems not to run into this situation on our system but it might depend on factors we have not yet tested (slow i2c, other i2c traffic on the same bus, CPU speed, event types choosen).

So I am a little in doubt about this risk. But I may have simply missed the reason why the standard approach works and can never overflow.

BR,
Nikolaus

Signature · 2 lines

Best regards,
Jacek Anaszewski

Am 20.04.2016 um 23:04 schrieb Jacek Anaszewski <[email protected]>:

Quoted 3 lines · H. Nikolaus Schaller

Quoted 2 lines

I believe the LEDS core now handles the workqueues generically for blocking operations, so it's no longer needed in the individual drivers.

Quoted 2 lines

We had a lot of trouble with locking and blocking especially if we want to indicate CPU or (root) disk activity.

What kind of troubles you had? Could you share more details? Does it mean that current LED core design doesn't fit for your use cases?

Quoted 7 lines

So it is implemented in a way that changes can be requested faster than the I2C bus can write new values to the chip.

Only after one sequence of I2C writes is done, another work function can be scheduled. And each group of writes updates as many LEDs in parallel if necessary.

You can serialize the operations in brightness_set_blocking with a mutex.

This is a driver for the Integrated Silicon Solution Inc. LED driver chips IS31FL3196 and IS31FL3199. They can drive up to 6 or 9 LEDs.

Each LED is individually controllable in brightness (through pwm) in 256 steps so that RGB LEDs can show any of ca. 16 Mio colors.

The maximum current of the LEDs can be programmed and limited to 5 .. 40mA through a device tree property.

The chip is connected through I2C and can have one of 4 addresses (0x64 .. 0x67) depending on how the AD pin is connected. The address is defined by the reg property as usual.

The chip also has a shutdown input which could be connected to a GPIO, but this driver uses software shutdown if all LEDs are inactivated.

The chip also has breathing and audio features which are not supported by this driver.

This driver was developed and tested on OMAP5 based Pyra handheld prototype.

Signed-off-by H. Nikolaus Schaller <[email protected]>

---
  .../devicetree/bindings/leds/is31fl319x.txt        |  41 +++
  drivers/leds/Kconfig                               |   8 +
  drivers/leds/Makefile                              |   1 +
  drivers/leds/leds-is31fl319x.c                     | 406 +++++++++++++++++++++
  include/linux/leds-is31fl319x.h                    |  24 ++
  5 files changed, 480 insertions(+)

create mode 100644 Documentation/devicetree/bindings/leds/is31fl319x.txt create mode 100644 drivers/leds/leds-is31fl319x.c
create mode 100644 include/linux/leds-is31fl319x.h

Documentation/devicetree/bindings/leds/is31fl319x.txt new file +0 -0

new file mode 100644
index 0000000..d13c7ca

Documentation/devicetree/bindings/leds/is31fl319x.txt new file +18 -0

+
+Each led is represented as a sub-node of the issi,is31fl319x device.
+
+LED sub-node properties:
+- label : (optional) see Documentation/devicetree/bindings/leds/common.txt
+- reg : number of LED line (0 to 5 or 0 to 8 - not all need to be present)
+- linux,default-trigger : (optional)
+   see Documentation/devicetree/bindings/leds/common.txt
+
+Examples:
+
+fancy_leds: is31fl3196@65 {
+	compatible = "issi,is31fl319x";
+	#address-cells = <1>;
+	#size-cells = <0>;
+	reg = <0x65>;
+
+	led0: red-aux@0 {

drivers/leds/Kconfig +8 -0

index 2251478..f099bcb 100644
@@ -491,6 +491,14 @@ config LEDS_ASIC3
  	  cannot be used. This driver supports hardware blinking with an on+off
  	  period from 62ms to 125s. Say Y to enable LEDs on the HP iPAQ hx4700.
 
+config LEDS_IS31FL319X
+	tristate "LED Support for IS31FL319x I2C chip"
+	depends on LEDS_CLASS && I2C
+	help
+	  This option enables support for LEDs connected to IS31FL3196
+	  or IS31FL3199 LED driver chips accessed via the I2C bus.
+	  Driver support brightness control and hardware-assisted blinking.
+
  config LEDS_TCA6507
  	tristate "LED Support for TCA6507 I2C chip"
  	depends on LEDS_CLASS && I2C

drivers/leds/Makefile +1 -0

index cb2013d..eee3010 100644
@@ -37,6 +37,7 @@ obj-$(CONFIG_LEDS_TCA6507)		+= leds-tca6507.o
  obj-$(CONFIG_LEDS_TLC591XX)		+= leds-tlc591xx.o
  obj-$(CONFIG_LEDS_CLEVO_MAIL)		+= leds-clevo-mail.o
  obj-$(CONFIG_LEDS_IPAQ_MICRO)		+= leds-ipaq-micro.o
+obj-$(CONFIG_LEDS_IS31FL319X)		+= leds-is31fl319x.o
  obj-$(CONFIG_LEDS_HP6XX)		+= leds-hp6xx.o
  obj-$(CONFIG_LEDS_OT200)		+= leds-ot200.o
  obj-$(CONFIG_LEDS_FSG)			+= leds-fsg.o

drivers/leds/leds-is31fl319x.c new file +13 -0

new file mode 100644
index 0000000..e211c46
@@ -0,0 +1,406 @@
+/*
+ * Copyright 2015 Golden Delcious Computers
+ *
+ * Author: Nikolaus Schaller <[email protected]>
+ *
+ * Based on leds-tca6507.c
+ *
+ * This file is subject to the terms and conditions of version 2 of
+ * the GNU General Public License.  See the file COPYING in the main
+ * directory of this archive for more details.
+ *
+ * LED driver for the IS31FL3196/99 to drive 6 or 9 light effect LEDs.
+ *

drivers/leds/leds-is31fl319x.c new file +111 -0

+
+/* register numbers */
+#define IS31FL319X_SHUTDOWN	0x00
+#define IS31FL319X_CTRL1	0x01
+#define IS31FL319X_CTRL2	0x02
+#define IS31FL319X_CONFIG1	0x03
+#define IS31FL319X_CONFIG2	0x04
+#define IS31FL319X_RAMP_MODE	0x05
+#define IS31FL319X_BREATH_MASK	0x06
+#define IS31FL319X_PWM1		0x07
+#define IS31FL319X_PWM2		0x08
+#define IS31FL319X_PWM3		0x09
+#define IS31FL319X_PWM4		0x0a
+#define IS31FL319X_PWM5		0x0b
+#define IS31FL319X_PWM6		0x0c
+#define IS31FL319X_PWM7		0x0d
+#define IS31FL319X_PWM8		0x0e
+#define IS31FL319X_PWM9		0x0f
+#define IS31FL319X_DATA_UPDATE	0x10
+#define IS31FL319X_T0_1		0x11
+#define IS31FL319X_T0_2		0x12
+#define IS31FL319X_T0_3		0x13
+#define IS31FL319X_T0_4		0x14
+#define IS31FL319X_T0_5		0x15
+#define IS31FL319X_T0_6		0x16
+#define IS31FL319X_T0_7		0x17
+#define IS31FL319X_T0_8		0x18
+#define IS31FL319X_T0_9		0x19
+#define IS31FL319X_T123_1	0x1a
+#define IS31FL319X_T123_2	0x1b
+#define IS31FL319X_T123_3	0x1c
+#define IS31FL319X_T4_1		0x1d
+#define IS31FL319X_T4_2		0x1e
+#define IS31FL319X_T4_3		0x1f
+#define IS31FL319X_T4_4		0x20
+#define IS31FL319X_T4_5		0x21
+#define IS31FL319X_T4_6		0x22
+#define IS31FL319X_T4_7		0x23
+#define IS31FL319X_T4_8		0x24
+#define IS31FL319X_T4_9		0x25
+#define IS31FL319X_TIME_UPDATE	0x26
+
+#define	IS31FL319X_REG_CNT	(IS31FL319X_TIME_UPDATE + 1)
+
+#define NUM_LEDS 9	/* max for 3199 chip */
+
+struct is31fl319x_chip {
+	struct i2c_client	*client;
+	struct work_struct	work;
+	bool			work_scheduled;
+	spinlock_t		lock;
+	u8			reg_file[IS31FL319X_REG_CNT];
+
+	struct is31fl319x_led {
+		struct is31fl319x_chip	*chip;
+		struct led_classdev	led_cdev;
+	} leds[NUM_LEDS];
+};
+
+static const struct i2c_device_id is31fl319x_id[] = {
+	{ "is31fl3196", 6 },
+	{ "is31fl3196", 9 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, is31fl319x_id);
+
+
+static int is31fl319x_write(struct is31fl319x_chip *is31, u8 reg, u8 byte)
+{
+	struct i2c_client *cl = is31->client;
+
+	if (reg >= IS31FL319X_REG_CNT)
+		return -EIO;
+	is31->reg_file[reg] = byte;	/* save in cache */
+	dev_dbg(&is31->client->dev, "write %02x to reg %02x\n", byte, reg);
+	return i2c_smbus_write_byte_data(cl, reg, byte);
+}
+
+static int is31fl319x_read(struct is31fl319x_chip *is31, u8 reg)
+{
+	if (reg >= IS31FL319X_REG_CNT)
+		return -EIO;
+	return is31->reg_file[reg];	/* read crom cache (can't read chip) */
+}
+
+static void is31fl319x_work(struct work_struct *work)
+{
+	struct is31fl319x_chip *is31 = container_of(work,
+						    struct is31fl319x_chip,
+						    work);
+	unsigned long flags;
+	int i;
+	u8 ctrl1, ctrl2;
+
+	dev_dbg(&is31->client->dev, "work called\n");
+
+	spin_lock_irqsave(&is31->lock, flags);
+	/* make subsequent changes run another schedule_work */
+	is31->work_scheduled = false;
+	spin_unlock_irqrestore(&is31->lock, flags);
+
+	dev_dbg(&is31->client->dev, "write to chip\n");
+
+	ctrl1 = 0;
+	ctrl2 = 0;
+
+	for (i = 0; i < NUM_LEDS; i++) {
+		struct led_classdev *led = &is31->leds[i].led_cdev;
+		bool on;
+
+		if (!is31->leds[i].led_cdev.name)

drivers/leds/leds-is31fl319x.c new file +35 -0

+
+	/* check if any PWM is enabled or all outputs are now off */
+	if (ctrl1 > 0 || ctrl2 > 0) {
+		dev_dbg(&is31->client->dev, "power up\n");
+		is31fl319x_write(is31, IS31FL319X_CTRL1, ctrl1);
+		is31fl319x_write(is31, IS31FL319X_CTRL2, ctrl2);
+		/* update PWMs */
+		is31fl319x_write(is31, IS31FL319X_DATA_UPDATE, 0x00);
+		/* enable chip from shut down */
+		is31fl319x_write(is31, IS31FL319X_SHUTDOWN, 0x01);
+	} else {
+		dev_dbg(&is31->client->dev, "power down\n");
+		/* shut down */
+		is31fl319x_write(is31, IS31FL319X_SHUTDOWN, 0x00);
+	}
+
+	dev_dbg(&is31->client->dev, "work done\n");
+
+}
+
+/* NOTE: this may be called from within irq context, e.g. led_trigger_event */
+
+static int is31fl319x_brightness_get(struct led_classdev *led_cdev)
+{
+	struct is31fl319x_led *led = container_of(led_cdev,
+						  struct is31fl319x_led,
+						  led_cdev);
+	struct is31fl319x_chip *is31 = led->chip;
+
+	/* read PWM register */
+	return is31fl319x_read(is31, IS31FL319X_PWM1 + (led - is31->leds));
+}
+
+static void is31fl319x_brightness_set(struct led_classdev *led_cdev,
+				   enum led_brightness brightness)

drivers/leds/leds-is31fl319x.c new file +6 -0

+		if (!is31->work_scheduled) {
+			schedule_work(&is31->work);
+			is31->work_scheduled = true;
+		}
+	}
+

drivers/leds/leds-is31fl319x.c new file +67 -0

+{
+	struct device_node *np = client->dev.of_node, *child;
+	struct is31fl319x_platform_data *pdata;
+	struct led_info *is31_leds;
+	int count;
+
+	count = of_get_child_count(np);
+	dev_dbg(&client->dev, "child count %d\n", count);
+	if (!count || count > NUM_LEDS)
+		return ERR_PTR(-ENODEV);
+
+	is31_leds = devm_kzalloc(&client->dev,
+			sizeof(struct led_info) * NUM_LEDS, GFP_KERNEL);
+	if (!is31_leds)
+		return ERR_PTR(-ENOMEM);
+
+	for_each_child_of_node(np, child) {
+		struct led_info led;
+		u32 reg;
+		int ret;
+
+		led.name =
+			of_get_property(child, "label", NULL) ? : child->name;
+		led.default_trigger =
+			of_get_property(child, "linux,default-trigger", NULL);
+		led.flags = 0;
+		ret = of_property_read_u32(child, "reg", &reg);
+		dev_dbg(&client->dev, "name = %s reg = %d\n", led.name, reg);
+		if (ret != 0 || reg < 0 || reg >= num_leds)
+			continue;
+
+		if (is31_leds[reg].name)
+			dev_err(&client->dev, "duplicate led line %d for %s -> %s\n",
+				reg, is31_leds[reg].name, led.name);
+		is31_leds[reg] = led;
+	}
+	pdata = devm_kzalloc(&client->dev,
+			sizeof(struct is31fl319x_platform_data), GFP_KERNEL);
+	if (!pdata)
+		return ERR_PTR(-ENOMEM);
+
+	pdata->leds.leds = is31_leds;
+	return pdata;
+}
+
+static const struct of_device_id of_is31fl319x_leds_match[] = {
+	{ .compatible = "issi,is31fl3196", (void *) 6 },
+	{ .compatible = "issi,is31fl3199", (void *) 9 },
+	{},
+};
+MODULE_DEVICE_TABLE(of, of_is31fl319x_leds_match);
+
+#else
+static struct is31fl319x_platform_data *
+is31fl319x_led_dt_init(struct i2c_client *client)
+{
+	return ERR_PTR(-ENODEV);
+}
+
+#endif
+
+static int is31fl319x_probe(struct i2c_client *client,
+		const struct i2c_device_id *id)
+{
+	struct is31fl319x_chip *is31;
+	struct i2c_adapter *adapter;
+	struct is31fl319x_platform_data *pdata;

drivers/leds/leds-is31fl319x.c new file +9 -0

+				(int) PTR_ERR(pdata));
+			return PTR_ERR(pdata);
+		}
+	}
+	is31 = devm_kzalloc(&client->dev, sizeof(*is31), GFP_KERNEL);
+	if (!is31)
+		return -ENOMEM;
+
+	is31->client = client;

drivers/leds/leds-is31fl319x.c new file +30 -0

+	}
+
+	for (i = 0; i < NUM_LEDS; i++) {
+		struct is31fl319x_led *l = is31->leds + i;
+
+		l->chip = is31;
+		if (pdata->leds.leds[i].name && !pdata->leds.leds[i].flags) {
+			l->led_cdev.name = pdata->leds.leds[i].name;
+			l->led_cdev.default_trigger
+				= pdata->leds.leds[i].default_trigger;
+			l->led_cdev.brightness_set = is31fl319x_brightness_set;
+			l->led_cdev.blink_set = is31fl319x_blink_set;
+			err = led_classdev_register(&client->dev,
+						    &l->led_cdev);
+			if (err < 0)
+				goto exit;
+		}
+	}
+
+	if (client->dev.of_node) {
+		u32 val;
+		u8 config2 = 0;
+
+		if (of_property_read_u32(client->dev.of_node, "max-current-ma",
+					 &val)) {
+			if (val > 40)
+				val = 40;
+			if (val < 5)
+				val = 5;
+			config2 |= (((64 - val) / 5) & 0x7) << 4; /* CS */