input: Add new sun4i-ts driver for Allwinner sunxi

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]>

---
  .../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 +0 -0

index e45927e..6bac67b 100644

Documentation/devicetree/bindings/input/touchscreen/sun4i.txt +1 -0

  Example:
 
  	rtp: rtp at 01c25000 {
  		compatible = "allwinner,sun4i-ts";
  		reg = <0x01c25000 0x100>;
  		interrupts = <29>;
+		allwinner,ts-attached;
  	};

drivers/input/touchscreen/sun4i-ts.c +39 -10

index 5945219..16cbb01 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);
+}

drivers/input/touchscreen/sun4i-ts.c +62 -21

+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));

@@ -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);
+	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-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);

Quoted 9 lines · Hans de Goede

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]>

Couple of minor comments below, though no need to resubmit unless someone else has comments.

Reviewed-by Guenter Roeck <[email protected]>

Quoted 13 lines

---
 .../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 +0 -0

index e45927e..6bac67b 100644
@@ -6,10 +6,15 @@ Required properties:
  - reg: mmio address range of the chip
  - interrupts: interrupt to which the chip is connected
 

Documentation/devicetree/bindings/input/touchscreen/sun4i.txt Required properties: · line 12

Quoted 4 lines

Documentation/devicetree/bindings/input/touchscreen/sun4i.txt +4 -0

+Optional properties:
+ - allwinner,ts-attached: boolean indicating that an actual touchscreen is
+			  attached to the controller
+

Brr. While I understand that you were asked to do this, I don't really see the benefit of another "allwinner" here. As if this wasn't implied by the "compatible" property.

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