[PATCH 06/16] hwmon: tmp102: expose to thermal fw via DT nodes

[Eduardo Valentin]

This patch adds to tmp102 temperature sensor the possibility
to expose itself as thermal zone device, registered on the
thermal framework.

The thermal zone is built only if a device tree node
describing a thermal zone for this sensor is present
inside the tmp102 DT node. Otherwise, the driver behavior
will be the same.

Cc: Jean Delvare <khali@xxxxxxxxxxxx>
Cc: Guenter Roeck <linux@xxxxxxxxxxxx>
Cc: lm-sensors@xxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Signed-off-by: Eduardo Valentin <eduardo.valentin@xxxxxx>
---
 drivers/hwmon/tmp102.c | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/drivers/hwmon/tmp102.c b/drivers/hwmon/tmp102.c
index d7b47ab..e432444 100644
--- a/drivers/hwmon/tmp102.c
+++ b/drivers/hwmon/tmp102.c
@@ -27,6 +27,8 @@
 #include <linux/mutex.h>
 #include <linux/device.h>
 #include <linux/jiffies.h>
+#include <linux/thermal.h>
+#include <linux/of.h>
 
 #define	DRIVER_NAME "tmp102"
 
@@ -50,6 +52,7 @@
 
 struct tmp102 {
 	struct device *hwmon_dev;
+	struct thermal_zone_device *tz;
 	struct mutex lock;
 	u16 config_orig;
 	unsigned long last_update;
@@ -93,6 +96,19 @@ static struct tmp102 *tmp102_update_device(struct i2c_client *client)
 	return tmp102;
 }
 
+static int tmp102_read_temp(void *dev, long *temp)
+{
+	struct tmp102 *tmp102 = tmp102_update_device(to_i2c_client(dev));
+
+	if (tmp102->temp[0] < 0)
+		dev_warn(tmp102->hwmon_dev,
+			 "operating in negative temp: %d\n", tmp102->temp[0]);
+
+	*temp = tmp102->temp[0];
+
+	return 0;
+}
+
 static ssize_t tmp102_show_temp(struct device *dev,
 				struct device_attribute *attr,
 				char *buf)
@@ -204,6 +220,16 @@ static int tmp102_probe(struct i2c_client *client,
 		goto fail_remove_sysfs;
 	}
 
+	tmp102->tz = thermal_zone_of_sensor_register(&client->dev, 0,
+						     &client->dev,
+						     tmp102_read_temp, NULL);
+	if (IS_ERR(tmp102->tz)) {
+		dev_warn(&client->dev,
+			 "Could not parse thermal data in device tree: %ld\n",
+			 PTR_ERR(tmp102->tz));
+		tmp102->tz = NULL;
+	}
+
 	dev_info(&client->dev, "initialized\n");
 
 	return 0;
@@ -220,6 +246,8 @@ static int tmp102_remove(struct i2c_client *client)
 {
 	struct tmp102 *tmp102 = i2c_get_clientdata(client);
 
+	/* thermal zone life cycle is not our responsibility */
+	thermal_zone_of_sensor_unregister(&client->dev, tmp102->tz);
 	hwmon_device_unregister(tmp102->hwmon_dev);
 	sysfs_remove_group(&client->dev.kobj, &tmp102_attr_group);
 
-- 
1.8.2.1.342.gfa7285d

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