input: Add new sun4i-ts driver for Allwinner sunxi SoC's rtp controller

The sun4i resisitive touchscreen controller also comes with a built-in temperature sensor. This commit adds support for it.

This commit also introduces a new "ts-attached" device-tree property, when this is not set, the input part of the driver won't register. This way the internal temperature sensor can be used to measure the SoC temperature independent of there actually being a touchscreen attached to the controller.

Signed-off-by Hans de Goede <[email protected]>

Reviewed-by Guenter Roeck <[email protected]>

---
 .../bindings/input/touchscreen/sun4i.txt           |   5 +
 drivers/input/touchscreen/sun4i-ts.c               | 140 ++++++++++++++++-----
 2 files changed, 114 insertions(+), 31 deletions(-)

Documentation/devicetree/bindings/input/touchscreen/sun4i.txt +5 -0

index 881aea7..aef5779 100644
@@ -6,10 +6,15 @@ Required properties:
  - reg: mmio address range of the chip
  - interrupts: interrupt to which the chip is connected
 
+Optional properties:
+ - allwinner,ts-attached: boolean indicating that an actual touchscreen is
+                         attached to the controller
+
 Example:
 
        rtp: rtp at 01c25000 {
                compatible = "allwinner,sun4i-a10-ts";
                reg = <0x01c25000 0x100>;
                interrupts = <29>;
+               allwinner,ts-attached;
        };

drivers/input/touchscreen/sun4i-ts.c +80 -28

index c5acdfb..f366221 100644
@@ -3,6 +3,9 @@
  *
  * Copyright (C) 2013 - 2014 Hans de Goede <[email protected]>
  *
+ * The hwmon parts are based on work by Corentin LABBE which is:
+ * Copyright (C) 2013 Corentin LABBE <[email protected]>
+ *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation; either version 2 of the License, or

@@ -30,6 +33,7 @@
  */
 
 #include <linux/err.h>
+#include <linux/hwmon.h>
 #include <linux/init.h>
 #include <linux/input.h>
 #include <linux/interrupt.h>

@@ -106,14 +110,12 @@ struct sun4i_ts_data {
        void __iomem *base;
        unsigned int irq;
        bool ignore_fifo_data;
+       int temp_data;
 };
 
-static irqreturn_t sun4i_ts_irq(int irq, void *dev_id)
+static void sun4i_ts_irq_handle_input(struct sun4i_ts_data *ts, u32 reg_val)
 {
-       struct sun4i_ts_data *ts = dev_id;
-       u32 reg_val, x, y;
-
-       reg_val  = readl(ts->base + TP_INT_FIFOS);
+       u32 x, y;
 
        if (reg_val & FIFO_DATA_PENDING) {
                x = readl(ts->base + TP_DATA);

@@ -139,6 +141,20 @@ static irqreturn_t sun4i_ts_irq(int irq, void *dev_id)
                input_report_key(ts->input, BTN_TOUCH, 0);
                input_sync(ts->input);
        }
+}
+
+static irqreturn_t sun4i_ts_irq(int irq, void *dev_id)
+{
+       struct sun4i_ts_data *ts = dev_id;
+       u32 reg_val;
+
+       reg_val  = readl(ts->base + TP_INT_FIFOS);
+
+       if (reg_val & TEMP_DATA_PENDING)
+               ts->temp_data = readl(ts->base + TEMP_DATA);
+
+       if (ts->input)
+               sun4i_ts_irq_handle_input(ts, reg_val);
 
        writel(reg_val, ts->base + TP_INT_FIFOS);
 

@@ -149,9 +165,9 @@ static int sun4i_ts_open(struct input_dev *dev)
 {
        struct sun4i_ts_data *ts = input_get_drvdata(dev);
 
-       /* Flush, set trig level to 1, enable data and up irqs */
-       writel(DATA_IRQ_EN(1) | FIFO_TRIG(1) | FIFO_FLUSH(1) | TP_UP_IRQ_EN(1),
-              ts->base + TP_INT_FIFOC);
+       /* Flush, set trig level to 1, enable temp, data and up irqs */
+       writel(TEMP_IRQ_EN(1) | DATA_IRQ_EN(1) | FIFO_TRIG(1) | FIFO_FLUSH(1) |
+               TP_UP_IRQ_EN(1), ts->base + TP_INT_FIFOC);
 
        return 0;
 }

@@ -160,15 +176,48 @@ static void sun4i_ts_close(struct input_dev *dev)
 {
        struct sun4i_ts_data *ts = input_get_drvdata(dev);
 
-       /* Deactivate all IRQs */
-       writel(0, ts->base + TP_INT_FIFOC);
+       /* Deactivate all input IRQs */
+       writel(TEMP_IRQ_EN(1), ts->base + TP_INT_FIFOC);
+}
+
+static ssize_t show_temp(struct device *dev, struct device_attribute *devattr,
+                        char *buf)
+{
+       struct sun4i_ts_data *ts = dev_get_drvdata(dev);
+
+       /* No temp_data until the first irq */
+       if (ts->temp_data == -1)
+               return -EAGAIN;
+
+       return sprintf(buf, "%d\n", (ts->temp_data - 1447) * 100);
+}
+
+static ssize_t show_temp_label(struct device *dev,
+                             struct device_attribute *devattr, char *buf)
+{
+       return sprintf(buf, "SoC temperature\n");
 }
 
+static DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL);
+static DEVICE_ATTR(temp1_label, S_IRUGO, show_temp_label, NULL);
+
+static struct attribute *sun4i_ts_attrs[] = {
+       &dev_attr_temp1_input.attr,
+       &dev_attr_temp1_label.attr,
+       NULL
+};
+ATTRIBUTE_GROUPS(sun4i_ts);
+
 static int sun4i_ts_probe(struct platform_device *pdev)
 {
        struct sun4i_ts_data *ts;
        struct device *dev = &pdev->dev;
+       struct device_node *np = dev->of_node;
+       struct device *hwmon;
        int ret;
+       bool ts_attached;
+
+       ts_attached = of_property_read_bool(np, "allwinner,ts-attached");
 
        ts = devm_kzalloc(dev, sizeof(struct sun4i_ts_data), GFP_KERNEL);
        if (!ts)

@@ -176,24 +225,27 @@ static int sun4i_ts_probe(struct platform_device *pdev)
 
        ts->dev = dev;
        ts->ignore_fifo_data = true;
-
-       ts->input = devm_input_allocate_device(dev);
-       if (!ts->input)
-               return -ENOMEM;
-
-       ts->input->name = pdev->name;
-       ts->input->phys = "sun4i_ts/input0";
-       ts->input->open = sun4i_ts_open;
-       ts->input->close = sun4i_ts_close;
-       ts->input->id.bustype = BUS_HOST;
-       ts->input->id.vendor = 0x0001;
-       ts->input->id.product = 0x0001;
-       ts->input->id.version = 0x0100;
-       ts->input->evbit[0] =  BIT(EV_SYN) | BIT(EV_KEY) | BIT(EV_ABS);
-       set_bit(BTN_TOUCH, ts->input->keybit);
-       input_set_abs_params(ts->input, ABS_X, 0, 4095, 0, 0);
-       input_set_abs_params(ts->input, ABS_Y, 0, 4095, 0, 0);
-       input_set_drvdata(ts->input, ts);
+       ts->temp_data = -1;
+
+       if (ts_attached) {
+               ts->input = devm_input_allocate_device(dev);
+               if (!ts->input)
+                       return -ENOMEM;
+
+               ts->input->name = pdev->name;
+               ts->input->phys = "sun4i_ts/input0";
+               ts->input->open = sun4i_ts_open;
+               ts->input->close = sun4i_ts_close;
+               ts->input->id.bustype = BUS_HOST;
+               ts->input->id.vendor = 0x0001;
+               ts->input->id.product = 0x0001;
+               ts->input->id.version = 0x0100;
+               ts->input->evbit[0] =  BIT(EV_SYN) | BIT(EV_KEY) | BIT(EV_ABS);
+               set_bit(BTN_TOUCH, ts->input->keybit);
+               input_set_abs_params(ts->input, ABS_X, 0, 4095, 0, 0);
+               input_set_abs_params(ts->input, ABS_Y, 0, 4095, 0, 0);
+               input_set_drvdata(ts->input, ts);
+       }
 
        ts->base = devm_ioremap_resource(dev,
                              platform_get_resource(pdev, IORESOURCE_MEM, 0));

drivers/input/touchscreen/sun4i-ts.c +27 -1

+       if (IS_ERR(hwmon))
+               return PTR_ERR(hwmon);
+
+       writel(TEMP_IRQ_EN(1), ts->base + TP_INT_FIFOC);
+
+       if (ts_attached) {
+               ret = input_register_device(ts->input);
+               if (ret) {
+                       writel(0, ts->base + TP_INT_FIFOC);
+                       return ret;
+               }
+       }
 
        platform_set_drvdata(pdev, ts);
        return 0;
 }
 
+static int sun4i_ts_remove(struct platform_device *pdev)
+{
+       struct sun4i_ts_data *ts = platform_get_drvdata(pdev);
+
+       /* Explicit unregister to avoid open/close changing the imask later */
+       if (ts->input)
+               input_unregister_device(ts->input);
+
+       /* Deactivate all IRQs */
+       writel(0, ts->base + TP_INT_FIFOC);
+
+       return 0;
+}
+
 static const struct of_device_id sun4i_ts_of_match[] = {
        { .compatible = "allwinner,sun4i-a10-ts", },
        { /* sentinel */ }

@@ -253,6 +330,7 @@ static struct platform_driver sun4i_ts_driver = {
                .of_match_table = of_match_ptr(sun4i_ts_of_match),
        },
        .probe  = sun4i_ts_probe,
+       .remove = sun4i_ts_remove,
 };
 
 module_platform_driver(sun4i_ts_driver);
--

1.9.0

Hi,

drivers/input/touchscreen/sun4i-ts.c static int sun4i_ts_probe(struct platform_device *pdev) · line 288

Quoted 9 lines · Hans de Goede

drivers/input/touchscreen/sun4i-ts.c +2 -3

@@ -232,14 +284,39 @@ static int sun4i_ts_probe(struct platform_device *pdev)
        writel(STYLUS_UP_DEBOUN(5) | STYLUS_UP_DEBOUN_EN(1) | TP_MODE_EN(1),
               ts->base + TP_CTRL1);
 
-       ret = input_register_device(ts->input);
-       if (ret)
-               return ret;
+       hwmon = devm_hwmon_device_register_with_groups(ts->dev, "sun4i_ts",
+                                                      ts, sun4i_ts_groups);

This fails to compile when HWMON is not selected:

drivers/built-in.o: In function `sun4i_ts_probe':
/home/wens/cubieboard/linux/drivers/input/touchscreen/sun4i-ts.c:287:
undefined reference to `devm_hwmon_device_register_with_groups'

Best do a wrapper around the hwmon related code. drivers/input/touchscreen/ads7846.c has something similar, albeit for voltage.

Hi All,

Since Maxime rightfully pointed out an error in my resend of v3, here is v4 with that fixed.

Note the second patch which adds hwmon functionality has been reviewed by the hwon subsystem maintainer, and the sun?i*.dts changes to enable this have already been upstreamed.