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Commit c08860ff authored by Jonghwa Lee's avatar Jonghwa Lee Committed by Guenter Roeck
Browse files

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



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: default avatarJonghwa Lee <jonghwa3.lee@samsung.com>
Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
parent 9b993e36

Documentation/devicetree/bindings/hwmon/ntc_thermistor.txt

+3 −0
Original line number Diff line number Diff line
@@ -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

drivers/hwmon/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -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

drivers/hwmon/ntc_thermistor.c

+25 −0
Original line number Diff line number Diff line
@@ -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;

}