This patch adds to lm75 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 lm75 DT node. Otherwise, the driver behavior
will be the same.

Cc: Jean Delvare <kh...@linux-fr.org>
Cc: Guenter Roeck <li...@roeck-us.net>
Cc: lm-sens...@lm-sensors.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Eduardo Valentin <eduardo.valen...@ti.com>
---
 drivers/hwmon/lm75.c | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/drivers/hwmon/lm75.c b/drivers/hwmon/lm75.c
index c03b490..0aa5e28 100644
--- a/drivers/hwmon/lm75.c
+++ b/drivers/hwmon/lm75.c
@@ -27,6 +27,8 @@
 #include <linux/hwmon-sysfs.h>
 #include <linux/err.h>
 #include <linux/mutex.h>
+#include <linux/thermal.h>
+#include <linux/of.h>
 #include "lm75.h"
 
 
@@ -70,6 +72,7 @@ static const u8 LM75_REG_TEMP[3] = {
 /* Each client has this additional data */
 struct lm75_data {
        struct device           *hwmon_dev;
+       struct thermal_zone_device      *tz;
        struct mutex            update_lock;
        u8                      orig_conf;
        u8                      resolution;     /* In bits, between 9 and 12 */
@@ -92,6 +95,19 @@ static struct lm75_data *lm75_update_device(struct device 
*dev);
 
 /* sysfs attributes for hwmon */
 
+static int lm75_read_temp(void *dev, unsigned long *temp)
+{
+       struct lm75_data *data = lm75_update_device(dev);
+
+       if (IS_ERR(data))
+               return PTR_ERR(data);
+
+       *temp = ((data->temp[0] >> (16 - data->resolution)) * 1000) >>
+                       (data->resolution - 8);
+
+       return 0;
+}
+
 static ssize_t show_temp(struct device *dev, struct device_attribute *da,
                         char *buf)
 {
@@ -271,11 +287,23 @@ lm75_probe(struct i2c_client *client, const struct 
i2c_device_id *id)
                goto exit_remove;
        }
 
+       if (of_find_node_by_name(client->dev.of_node, "thermal_zone")) {
+               data->tz = thermal_zone_of_device_register(&client->dev,
+                                                          &client->dev,
+                                                          lm75_read_temp);
+               if (IS_ERR(data->tz)) {
+                       status = PTR_ERR(data->tz);
+                       goto exit_hwmon;
+               }
+       }
+
        dev_info(&client->dev, "%s: sensor '%s'\n",
                 dev_name(data->hwmon_dev), client->name);
 
        return 0;
 
+exit_hwmon:
+       hwmon_device_unregister(data->hwmon_dev);
 exit_remove:
        sysfs_remove_group(&client->dev.kobj, &lm75_group);
        return status;
@@ -285,6 +313,7 @@ static int lm75_remove(struct i2c_client *client)
 {
        struct lm75_data *data = i2c_get_clientdata(client);
 
+       thermal_zone_device_unregister(data->tz);
        hwmon_device_unregister(data->hwmon_dev);
        sysfs_remove_group(&client->dev.kobj, &lm75_group);
        lm75_write_value(client, LM75_REG_CONF, data->orig_conf);
-- 
1.8.2.1.342.gfa7285d

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