backlight: enable backlight in 88pm860x

From 8d2bc9826f758f113fde6f3fd01723111fbf2a91 Mon Sep 17 00:00:00 2001
From: Haojian Zhuang <[email protected]>
Date: Mon, 9 Nov 2009 12:41:07 -0500
Subject: [PATCH] backlight: enable backlight in 88pm860x

At most, three backlight device can be supported in 88pm860x driver.

Signed-off-by Haojian Zhuang <[email protected]>

---
 drivers/video/backlight/88pm860x_bl.c |  304 +++++++++++++++++++++++++++++++++
 drivers/video/backlight/Kconfig       |    6 +
 drivers/video/backlight/Makefile      |    1 +
 3 files changed, 311 insertions(+), 0 deletions(-)
 create mode 100644 drivers/video/backlight/88pm860x_bl.c

drivers/video/backlight/88pm860x_bl.c new file +304 -0

new file mode 100644
index 0000000..b8f705c
@@ -0,0 +1,304 @@
+/*
+ * Backlight driver for Marvell Semiconductor 88PM8606
+ *
+ * Copyright (C) 2009 Marvell International Ltd.
+ *	Haojian Zhuang <[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.
+ */
+
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/platform_device.h>
+#include <linux/fb.h>
+#include <linux/i2c.h>
+#include <linux/backlight.h>
+#include <linux/mfd/88pm860x.h>
+
+#define MAX_BRIGHTNESS		(0xFF)
+#define MIN_BRIGHTNESS		(0)
+
+#define CURRENT_MASK		(0x1F << 1)
+
+struct pm860x_backlight_data {
+	struct pm860x_chip *chip;
+	struct i2c_client *i2c;
+	int	current_brightness;
+	int	port;
+	int	pwm;
+	int	iset;
+};
+
+static inline int wled_a(int port)
+{
+	int ret;
+
+	ret = ((port - PM8606_BACKLIGHT1) << 1) + 2;
+	return ret;
+}
+
+static inline int wled_b(int port)
+{
+	int ret;
+
+	ret = ((port - PM8606_BACKLIGHT1) << 1) + 3;
+	return ret;
+}
+
+/* WLED2 & WLED3 share the same IDC */
+static inline int wled_idc(int port)
+{
+	int ret;
+
+	switch (port) {
+	case PM8606_BACKLIGHT1:
+	case PM8606_BACKLIGHT2:
+		ret = ((port - PM8606_BACKLIGHT1) << 1) + 3;
+		break;
+	case PM8606_BACKLIGHT3:
+	default:
+		ret = ((port - PM8606_BACKLIGHT2) << 1) + 3;
+		break;
+	}
+	return ret;
+}
+
+static int pm860x_backlight_set(struct backlight_device *bl, int brightness)
+{
+	struct pm860x_backlight_data *data = bl_get_data(bl);
+	struct pm860x_chip *chip = data->chip;
+	unsigned char value;
+	int ret;
+
+	if (brightness > MAX_BRIGHTNESS)
+		value = MAX_BRIGHTNESS;
+	else
+		value = brightness;
+
+	ret = pm860x_reg_write(data->i2c, wled_a(data->port), value);
+	if (ret < 0)
+		goto out;
+
+	if ((data->current_brightness == 0) && brightness) {
+		if (data->iset) {
+			ret = pm860x_set_bits(data->i2c, wled_idc(data->port),
+					      CURRENT_MASK, data->iset);
+			if (ret < 0)
+				goto out;
+		}
+		if (data->pwm) {
+			ret = pm860x_set_bits(data->i2c, PM8606_PWM,
+					      PM8606_PWM_FREQ_MASK, data->pwm);
+			if (ret < 0)
+				goto out;
+		}
+		if (brightness == MAX_BRIGHTNESS) {
+			/* set WLED_ON bit as 100% */
+			ret = pm860x_set_bits(data->i2c, wled_b(data->port),
+					      PM8606_WLED_ON, PM8606_WLED_ON);
+		}
+	} else {
+		if (brightness == MAX_BRIGHTNESS) {
+			/* set WLED_ON bit as 100% */
+			ret = pm860x_set_bits(data->i2c, wled_b(data->port),
+					      PM8606_WLED_ON, PM8606_WLED_ON);
+		} else {
+			/* clear WLED_ON bit since it's not 100% */
+			ret = pm860x_set_bits(data->i2c, wled_b(data->port),
+					      PM8606_WLED_ON, 0);
+		}
+	}
+	if (ret < 0)
+		goto out;
+
+	dev_dbg(chip->dev, "set brightness %d\n", value);
+	data->current_brightness = value;
+	return 0;
+out:
+	dev_dbg(chip->dev, "set brightness %d failure with return "
+		"value:%d\n", value, ret);
+	return ret;
+}
+
+static int pm860x_backlight_update_status(struct backlight_device *bl)
+{
+	int brightness = bl->props.brightness;
+
+	if (bl->props.power != FB_BLANK_UNBLANK)
+		brightness = 0;
+
+	if (bl->props.fb_blank != FB_BLANK_UNBLANK)
+		brightness = 0;
+
+	if (bl->props.state & BL_CORE_SUSPENDED)
+		brightness = 0;
+
+	return pm860x_backlight_set(bl, brightness);
+}
+
+static int pm860x_backlight_get_brightness(struct backlight_device *bl)
+{
+	struct pm860x_backlight_data *data = bl_get_data(bl);
+	struct pm860x_chip *chip = data->chip;
+	int ret;
+
+	ret = pm860x_reg_read(data->i2c, wled_a(data->port));
+	if (ret < 0)
+		goto out;
+	data->current_brightness = ret;
+	dev_dbg(chip->dev, "get brightness %d\n", data->current_brightness);
+	return data->current_brightness;
+out:
+	return -EINVAL;
+}
+
+static struct backlight_ops pm860x_backlight_ops = {
+	.options	= BL_CORE_SUSPENDRESUME,
+	.update_status	= pm860x_backlight_update_status,
+	.get_brightness	= pm860x_backlight_get_brightness,
+};
+
+static int __check_device(struct pm860x_backlight_pdata *pdata, char *name)
+{
+	struct pm860x_backlight_pdata *p = pdata;
+	int ret = -EINVAL;
+
+	while (p && p->id) {
+		if ((p->id != PM8606_ID_BACKLIGHT) || (p->flags < 0))
+			break;
+
+		if (!strncmp(name, pm860x_backlight_name[p->flags],
+			MFD_NAME_SIZE)) {
+			ret = (int)p->flags;
+			break;
+		}
+		p++;
+	}
+	return ret;
+}
+
+static int pm860x_backlight_probe(struct platform_device *pdev)
+{
+	struct pm860x_chip *chip = dev_get_drvdata(pdev->dev.parent);
+	struct pm860x_platform_data *pm860x_pdata;
+	struct pm860x_backlight_pdata *pdata = NULL;
+	struct pm860x_backlight_data *data;
+	struct backlight_device *bl;
+	struct resource *res;
+	unsigned char value;
+	char name[MFD_NAME_SIZE];
+	int ret;
+
+	res = platform_get_resource(pdev, IORESOURCE_IO, 0);
+	if (res == NULL) {
+		dev_err(&pdev->dev, "No I/O resource!\n");
+		return -EINVAL;
+	}
+
+	if (pdev->dev.parent->platform_data) {
+		pm860x_pdata = pdev->dev.parent->platform_data;
+		pdata = pm860x_pdata->backlight;
+	}
+	if (pdata == NULL) {
+		dev_err(&pdev->dev, "platform data isn't assigned to "
+			"backlight\n");
+		return -EINVAL;
+	}
+
+	data = kzalloc(sizeof(struct pm860x_backlight_data), GFP_KERNEL);
+	if (data == NULL)
+		return -ENOMEM;
+	strncpy(name, res->name, MFD_NAME_SIZE);
+	data->chip = chip;
+	data->i2c = (chip->id == CHIP_PM8606) ? chip->client	\
+			: chip->companion;
+	data->current_brightness = MAX_BRIGHTNESS;
+	data->pwm = pdata->pwm;
+	data->iset = pdata->iset;
+	data->port = __check_device(pdata, name);
+	if (data->port < 0) {
+		dev_err(&pdev->dev, "wrong platform data is assigned");
+		return -EINVAL;
+	}
+
+	bl = backlight_device_register(name, &pdev->dev, data,
+					&pm860x_backlight_ops);
+	if (IS_ERR(bl)) {
+		dev_err(&pdev->dev, "failed to register backlight\n");
+		kfree(data);
+		return PTR_ERR(bl);
+	}
+	bl->props.max_brightness = MAX_BRIGHTNESS;
+	bl->props.brightness = MAX_BRIGHTNESS;
+
+	platform_set_drvdata(pdev, bl);
+
+	/* Enable reference VSYS */
+	ret = pm860x_reg_read(data->i2c, PM8606_VSYS);
+	if (ret < 0)
+		goto out;
+	if ((ret & PM8606_VSYS_EN) == 0) {
+		value = ret | PM8606_VSYS_EN;
+		ret = pm860x_reg_write(data->i2c, PM8606_VSYS, value);
+		if (ret < 0)
+			goto out;
+	}
+	/* Enable reference OSC */
+	ret = pm860x_reg_read(data->i2c, PM8606_MISC);
+	if (ret < 0)
+		goto out;
+	if ((ret & PM8606_MISC_OSC_EN) == 0) {
+		value = ret | PM8606_MISC_OSC_EN;
+		ret = pm860x_reg_write(data->i2c, PM8606_MISC, value);
+		if (ret < 0)
+			goto out;
+	}
+	/* read current backlight */
+	ret = pm860x_backlight_get_brightness(bl);
+	if (ret < 0)
+		goto out;
+
+	backlight_update_status(bl);
+	return 0;
+out:
+	kfree(data);
+	return ret;
+}
+
+static int pm860x_backlight_remove(struct platform_device *pdev)
+{
+	struct backlight_device *bl = platform_get_drvdata(pdev);
+	struct pm860x_backlight_data *data = bl_get_data(bl);
+
+	backlight_device_unregister(bl);
+	kfree(data);
+	return 0;
+}
+
+static struct platform_driver pm860x_backlight_driver = {
+	.driver		= {
+		.name	= "88pm860x-backlight",
+		.owner	= THIS_MODULE,
+	},
+	.probe		= pm860x_backlight_probe,
+	.remove		= pm860x_backlight_remove,
+};
+
+static int __init pm860x_backlight_init(void)
+{
+	return platform_driver_register(&pm860x_backlight_driver);
+}
+module_init(pm860x_backlight_init);
+
+static void __exit pm860x_backlight_exit(void)
+{
+	platform_driver_unregister(&pm860x_backlight_driver);
+}
+module_exit(pm860x_backlight_exit);
+
+MODULE_DESCRIPTION("Backlight Driver for Marvell Semiconductor 88PM8606");
+MODULE_AUTHOR("Haojian Zhuang <[email protected]>");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:88pm860x-backlight");

drivers/video/backlight/Kconfig +6 -0

index 09bfa96..96a6b30 100644
@@ -262,3 +262,9 @@ config BACKLIGHT_ADP5520
 	  To compile this driver as a module, choose M here: the module will
 	  be called adp5520_bl.
 
+config BACKLIGHT_88PM860X
+	tristate "Backlight Driver for 88PM8606 using WLED"
+	depends on BACKLIGHT_CLASS_DEVICE && MFD_88PM860X
+	help
+	  Say Y to enable the backlight driver for Marvell 88PM8606.
+

drivers/video/backlight/Makefile +1 -0

index 9a40554..802d467 100644
@@ -28,4 +28,5 @@ obj-$(CONFIG_BACKLIGHT_SAHARA)	+= kb3886_bl.o
 obj-$(CONFIG_BACKLIGHT_WM831X)	+= wm831x_bl.o
 obj-$(CONFIG_BACKLIGHT_ADX)    += adx_bl.o
 obj-$(CONFIG_BACKLIGHT_ADP5520)	+= adp5520_bl.o
+obj-$(CONFIG_BACKLIGHT_88PM860X) += 88pm860x_bl.o
 

Signature · 1 line

1.5.6.5

Hi Haojian, Richard,

Quoted 5 lines · Haojian Zhuang

From 8d2bc9826f758f113fde6f3fd01723111fbf2a91 Mon Sep 17 00:00:00 2001
From: Haojian Zhuang <[email protected]>
Date: Mon, 9 Nov 2009 12:41:07 -0500
Subject: [PATCH] backlight: enable backlight in 88pm860x

Quoted 1 line

At most, three backlight device can be supported in 88pm860x driver.

I applied this patch and the LED one to my for-next branch. Richard, whenever you have time for that, could you please quickly check if they oook ok to you ? They're 2.6.34 material, so no rush here.

Quoted 8 lines · Samuel Ortiz

Hi Haojian, Richard,

Quoted 5 lines · Haojian Zhuang

From 8d2bc9826f758f113fde6f3fd01723111fbf2a91 Mon Sep 17 00:00:00 2001
From: Haojian Zhuang <[email protected]>
Date: Mon, 9 Nov 2009 12:41:07 -0500
Subject: [PATCH] backlight: enable backlight in 88pm860x

Quoted 4 lines

Quoted 1 line

At most, three backlight device can be supported in 88pm860x driver.

I applied this patch and the LED one to my for-next branch. Richard, whenever you have time for that, could you please quickly check if they oook ok to you ? They're 2.6.34 material, so no rush here.

I had a look through, they look basically ok.

In the LED patch I'm not sure I like the SET_BRIGHTNESS and SET_BLINK sharing of a workqueue though. Its not going to crash, I can just see values potentially getting lost as the code has a race condition. It would be easier if it just compared led->current_brightness to led->brightness acting if needed and something similar for LED blinking.

Cheers,

Richard

On Fri, Jan 8, 2010 at 7:27 AM, Richard Purdie <[email protected]> > In the LED patch I'm not sure I like the SET_BRIGHTNESS and SET_BLINK

Quoted 4 lines

sharing of a workqueue though. Its not going to crash, I can just see values potentially getting lost as the code has a race condition. It would be easier if it just compared led->current_brightness to led->brightness acting if needed and something similar for LED blinking.

Excuse me that there's a mutex lock in __led_set(). Both SET_BRIGHTNESS & SET_BLINK calls __led_set(). There shouldn't be race condition on set led. What's your opinion?