On 09/15/2013 03:02 PM, Eduardo Valentin wrote:
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 <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/lm75.c | 46 +++++++++++++++++++++++++++++++++++++++++-----
1 file changed, 41 insertions(+), 5 deletions(-)
diff --git a/drivers/hwmon/lm75.c b/drivers/hwmon/lm75.c
index c03b490..2ba09ef 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 +93,42 @@ 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);
+ long temperature;
+
+ if (IS_ERR(data))
+ return PTR_ERR(data);
+
+ temperature = lm75_reg_to_mc(data->temp[0], data->resolution);
+ if (temperature < 0)
+ dev_warn(data->hwmon_dev,
+ "operating in negative temp: %ld\n", temperature);
Please drop this warning. It is not the responsibility of the chip driver
to declare valid operational conditions, much less an arbitrary one
like zero degrees C.
Guenter
+
+ *temp = temperature;
+
+ 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 +294,17 @@ 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)) {
+ dev_warn(&client->dev,
+ "Could not parse thermal data in device tree: %ld\n",
+ PTR_ERR(data->tz));
+ data->tz = NULL;
+ }
+
dev_info(&client->dev, "%s: sensor '%s'\n",
dev_name(data->hwmon_dev), client->name);
@@ -285,6 +319,8 @@ static int lm75_remove(struct i2c_client *client)
{
struct lm75_data *data = i2c_get_clientdata(client);
+ /* thermal zone life cycle is not our responsibility */
+ 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);
--
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