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Subject[PATCH 07/19] hwmon: lm75: expose to thermal fw via DT nodes
Date
From: Eduardo Valentin <eduardo.valentin@ti.com>

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.

Note: This patch has also been reviewed by Jean D. He has
requested to perform a wider inspection of possible
users of thermal and hwmon interaction API. On the other
hand, the change on this patch is acceptable on first
step of overall code change.

Cc: Jean Delvare <khali@linux-fr.org>
Cc: lm-sensors@lm-sensors.org
Cc: linux-kernel@vger.kernel.org
Acked-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Eduardo Valentin <eduardo.valentin@ti.com>
(cherry picked from commit 22e731838b0e337fed5f16c67aa0b954028dfe93)

Signed-off-by: Alex Shi <alex.shi@linaro.org>
---
drivers/hwmon/lm75.c | 35 ++++++++++++++++++++++++++++++-----
1 file changed, 30 insertions(+), 5 deletions(-)

diff --git a/drivers/hwmon/lm75.c b/drivers/hwmon/lm75.c
index c03b490..1d3600a 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/of.h>
+#include <linux/thermal.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 */
@@ -90,22 +93,36 @@ static struct lm75_data *lm75_update_device(struct device *dev);

/*-----------------------------------------------------------------------*/

+static inline long lm75_reg_to_mc(s16 temp, u8 resolution)
+{
+ return ((temp >> (16 - resolution)) * 1000) >> (resolution - 8);
+}
+
/* sysfs attributes for hwmon */

+static int lm75_read_temp(void *dev, long *temp)
+{
+ struct lm75_data *data = lm75_update_device(dev);
+
+ if (IS_ERR(data))
+ return PTR_ERR(data);
+
+ *temp = lm75_reg_to_mc(data->temp[0], data->resolution);
+
+ return 0;
+}
+
static ssize_t show_temp(struct device *dev, struct device_attribute *da,
char *buf)
{
struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
struct lm75_data *data = lm75_update_device(dev);
- long temp;

if (IS_ERR(data))
return PTR_ERR(data);

- temp = ((data->temp[attr->index] >> (16 - data->resolution)) * 1000)
- >> (data->resolution - 8);
-
- return sprintf(buf, "%ld\n", temp);
+ return sprintf(buf, "%ld\n", lm75_reg_to_mc(data->temp[attr->index],
+ data->resolution));
}

static ssize_t set_temp(struct device *dev, struct device_attribute *da,
@@ -271,6 +288,13 @@ lm75_probe(struct i2c_client *client, const struct i2c_device_id *id)
goto exit_remove;
}

+ data->tz = thermal_zone_of_sensor_register(&client->dev,
+ 0,
+ &client->dev,
+ lm75_read_temp, NULL);
+ if (IS_ERR(data->tz))
+ data->tz = NULL;
+
dev_info(&client->dev, "%s: sensor '%s'\n",
dev_name(data->hwmon_dev), client->name);

@@ -285,6 +309,7 @@ static int lm75_remove(struct i2c_client *client)
{
struct lm75_data *data = i2c_get_clientdata(client);

+ thermal_zone_of_sensor_unregister(&client->dev, 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);
--
1.8.1.2


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