[PATCH 03/17] Input: sun4i-ts: Add thermal zone sensor support

[Chen-Yu Tsai <wens@csie.org>]

The touchscreen controller has a temperature sensor embedded in the SoC,
which already has hwmon support in the driver.

Add DT thermal zone support so we can use it with cpufreq for thermal
throttling.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
---
 .../bindings/input/touchscreen/sun4i.txt           |  1 +
 drivers/input/touchscreen/sun4i-ts.c               | 27 ++++++++++++++++++++++
 2 files changed, 28 insertions(+)

diff --git a/Documentation/devicetree/bindings/input/touchscreen/sun4i.txt b/Documentation/devicetree/bindings/input/touchscreen/sun4i.txt
index aef57791f40b..7f1110adbd24 100644
--- a/Documentation/devicetree/bindings/input/touchscreen/sun4i.txt
+++ b/Documentation/devicetree/bindings/input/touchscreen/sun4i.txt
@@ -5,6 +5,7 @@ Required properties:
  - compatible: "allwinner,sun4i-a10-ts"
  - reg: mmio address range of the chip
  - interrupts: interrupt to which the chip is connected
+ - #thermal-sensor-cells: shall be 0
 
 Optional properties:
  - allwinner,ts-attached: boolean indicating that an actual touchscreen is
diff --git a/drivers/input/touchscreen/sun4i-ts.c b/drivers/input/touchscreen/sun4i-ts.c
index 28a06749ae42..b6e9043446d6 100644
--- a/drivers/input/touchscreen/sun4i-ts.c
+++ b/drivers/input/touchscreen/sun4i-ts.c
@@ -34,6 +34,7 @@
 
 #include <linux/err.h>
 #include <linux/hwmon.h>
+#include <linux/thermal.h>
 #include <linux/init.h>
 #include <linux/input.h>
 #include <linux/interrupt.h>
@@ -107,6 +108,7 @@
 struct sun4i_ts_data {
 	struct device *dev;
 	struct input_dev *input;
+	struct thermal_zone_device *tz;
 	void __iomem *base;
 	unsigned int irq;
 	bool ignore_fifo_data;
@@ -180,6 +182,23 @@ static void sun4i_ts_close(struct input_dev *dev)
 	writel(TEMP_IRQ_EN(1), ts->base + TP_INT_FIFOC);
 }
 
+static int get_temp(void *data, long *temp)
+{
+	struct sun4i_ts_data *ts = data;
+
+	/* No temp_data until the first irq */
+	if (ts->temp_data == -1)
+		return -EAGAIN;
+
+	*temp = (ts->temp_data - 1447) * 100;
+
+	return 0;
+}
+
+static struct thermal_zone_of_device_ops sun4i_ts_tz_ops = {
+	.get_temp = get_temp,
+};
+
 static ssize_t show_temp(struct device *dev, struct device_attribute *devattr,
 			 char *buf)
 {
@@ -288,6 +307,11 @@ static int sun4i_ts_probe(struct platform_device *pdev)
 	if (IS_ERR(hwmon))
 		return PTR_ERR(hwmon);
 
+	ts->tz = thermal_zone_of_sensor_register(ts->dev, 0, ts,
+						 &sun4i_ts_tz_ops);
+	if (IS_ERR(ts->tz))
+		ts->tz = NULL;
+
 	writel(TEMP_IRQ_EN(1), ts->base + TP_INT_FIFOC);
 
 	if (ts_attached) {
@@ -310,6 +334,9 @@ static int sun4i_ts_remove(struct platform_device *pdev)
 	if (ts->input)
 		input_unregister_device(ts->input);
 
+	if (ts->tz)
+		thermal_zone_of_sensor_unregister(ts->dev, ts->tz);
+
 	/* Deactivate all IRQs */
 	writel(0, ts->base + TP_INT_FIFOC);
 
-- 
2.1.4