1 files changed, 50 insertions, 4 deletions

diff --git a/drivers/input/touchscreen/sun4i-ts.c b/drivers/input/touchscreen/sun4i-ts.c
index 28a06749ae42..9ae53d4289fb 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;
@@ -180,16 +182,48 @@ static void sun4i_ts_close(struct input_dev *dev)
         writel(TEMP_IRQ_EN(1), ts->base + TP_INT_FIFOC);
 }
 
+static int sun4i_get_temp(const struct sun4i_ts_data *ts, long *temp)
+{
+        /* No temp_data until the first irq */
+        if (ts->temp_data == -1)
+                return -EAGAIN;
+
+        /*
+         * The user manuals do not contain the formula for calculating
+         * the temperature. The formula used here is from the AXP209,
+         * which is designed by X-Powers, an affiliate of Allwinner:
+         *
+         *     temperature = -144.7 + (value * 0.1)
+         *
+         * This should be replaced with the correct one if such information
+         * becomes available.
+         */
+        *temp = (ts->temp_data - 1447) * 100;
+
+        return 0;
+}
+
+static int sun4i_get_tz_temp(void *data, long *temp)
+{
+        return sun4i_get_temp(data, temp);
+}
+
+static struct thermal_zone_of_device_ops sun4i_ts_tz_ops = {
+        .get_temp = sun4i_get_tz_temp,
+};
+
 static ssize_t show_temp(struct device *dev, struct device_attribute *devattr,
                          char *buf)
 {
         struct sun4i_ts_data *ts = dev_get_drvdata(dev);
+        long temp;
+        int error;
 
-        /* No temp_data until the first irq */
-        if (ts->temp_data == -1)
-                return -EAGAIN;
+        error = sun4i_get_temp(ts, &temp);
+        if (error)
+                return error;
 
-        return sprintf(buf, "%d\n", (ts->temp_data - 1447) * 100);
+        return sprintf(buf, "%ld\n", temp);
 }
 
 static ssize_t show_temp_label(struct device *dev,
@@ -283,17 +317,27 @@ 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);
 
+        /*
+         * The thermal core does not register hwmon devices for DT-based
+         * thermal zone sensors, such as this one.
+         */
         hwmon = devm_hwmon_device_register_with_groups(ts->dev, "sun4i_ts",
                                                        ts, sun4i_ts_groups);
         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) {
                 error = input_register_device(ts->input);
                 if (error) {
                         writel(0, ts->base + TP_INT_FIFOC);
+                        thermal_zone_of_sensor_unregister(ts->dev, ts->tz);
                         return error;
                 }
         }
@@ -310,6 +354,8 @@ static int sun4i_ts_remove(struct platform_device *pdev)
         if (ts->input)
                 input_unregister_device(ts->input);
 
+        thermal_zone_of_sensor_unregister(ts->dev, ts->tz);
+
         /* Deactivate all IRQs */
         writel(0, ts->base + TP_INT_FIFOC);