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hwmon: (ntc_thermistor) Add ntc thermistor to thermal subsystem as a sensor.

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To get more comprehensive and integrated thermal management, it adds ntc
thermistor to thermal framework as a thermal sensor. It's governed thermal
susbsystem only if it is described in DT node. Otherwise, it just notifies
temperature to userspace via sysfs as it used to be.

Signed-off-by: Jonghwa Lee <jonghwa3.lee@samsung.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
This commit is contained in:
Jonghwa Lee 2014-09-17 14:54:37 +09:00 committed by Guenter Roeck
parent 9b993e3661
commit c08860ffe5
3 changed files with 29 additions and 0 deletions
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3
Documentation/devicetree/bindings/hwmon/ntc_thermistor.txt
View File

@ -25,6 +25,9 @@ Requires node properties:
- "io-channels" Channel node of ADC to be used for
conversion.
Optional node properties:
- "#thermal-sensor-cells" Used to expose itself to thermal fw.
Read more about iio bindings at
Documentation/devicetree/bindings/iio/iio-bindings.txt

1
drivers/hwmon/Kconfig
View File

@ -1077,6 +1077,7 @@ config SENSORS_PC87427
config SENSORS_NTC_THERMISTOR
tristate "NTC thermistor support from Murata"
depends on !OF || IIO=n || IIO
depends on THERMAL || !THERMAL_OF
help
This driver supports NTC thermistors sensor reading and its
interpretation. The driver can also monitor the temperature and

25
drivers/hwmon/ntc_thermistor.c
View File

@ -38,6 +38,7 @@
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
#include <linux/thermal.h>
struct ntc_compensation {
int temp_c;
@ -182,6 +183,7 @@ struct ntc_data {
struct device *dev;
int n_comp;
char name[PLATFORM_NAME_SIZE];
struct thermal_zone_device *tz;
};
#if defined(CONFIG_OF) && IS_ENABLED(CONFIG_IIO)
@ -428,6 +430,20 @@ static int ntc_thermistor_get_ohm(struct ntc_data *data)
return -EINVAL;
}
static int ntc_read_temp(void *dev, long *temp)
{
struct ntc_data *data = dev_get_drvdata(dev);
int ohm;
ohm = ntc_thermistor_get_ohm(data);
if (ohm < 0)
return ohm;
*temp = get_temp_mc(data, ohm);
return 0;
}
static ssize_t ntc_show_name(struct device *dev,
struct device_attribute *attr, char *buf)
{
@ -562,6 +578,13 @@ static int ntc_thermistor_probe(struct platform_device *pdev)
dev_info(&pdev->dev, "Thermistor type: %s successfully probed.\n",
pdev_id->name);
data->tz = thermal_zone_of_sensor_register(data->dev, 0, data->dev,
ntc_read_temp, NULL);
if (IS_ERR(data->tz)) {
dev_dbg(&pdev->dev, "Failed to register to thermal fw.\n");
data->tz = NULL;
}
return 0;
err_after_sysfs:
sysfs_remove_group(&data->dev->kobj, &ntc_attr_group);
@ -578,6 +601,8 @@ static int ntc_thermistor_remove(struct platform_device *pdev)
sysfs_remove_group(&data->dev->kobj, &ntc_attr_group);
ntc_iio_channel_release(pdata);
thermal_zone_of_sensor_unregister(data->dev, data->tz);
return 0;
}