Re: [PATCH] hwmon: ntc_thermistor: Add ntc thermistor to thermal subsystem as a sensor.

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On 08/26/2014 03:12 AM, Chanwoo Choi wrote:
Hi Jonghwa,

On 08/26/2014 02:33 PM, Jonghwa Lee wrote:
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@xxxxxxxxxxx>
---
  .../devicetree/bindings/hwmon/ntc_thermistor.txt   |    3 +++
  drivers/hwmon/ntc_thermistor.c                     |   26 ++++++++++++++++++++
  2 files changed, 29 insertions(+)

diff --git a/Documentation/devicetree/bindings/hwmon/ntc_thermistor.txt b/Documentation/devicetree/bindings/hwmon/ntc_thermistor.txt
index 2391e5c..fcca8e7 100644
--- a/Documentation/devicetree/bindings/hwmon/ntc_thermistor.txt
+++ b/Documentation/devicetree/bindings/hwmon/ntc_thermistor.txt
@@ -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

diff --git a/drivers/hwmon/ntc_thermistor.c b/drivers/hwmon/ntc_thermistor.c
index bd41072..369dc8c 100644
--- a/drivers/hwmon/ntc_thermistor.c
+++ b/drivers/hwmon/ntc_thermistor.c
@@ -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 +601,9 @@ static int ntc_thermistor_remove(struct platform_device *pdev)
  	sysfs_remove_group(&data->dev->kobj, &ntc_attr_group);
  	ntc_iio_channel_release(pdata);

+	if (data->tz)
+		thermal_zone_of_sensor_unregister(data->dev, data->tz);

thermal_zone_of_sensor_unregister just return without operation if data->tz is NULL.
So, don't need to check the value of data->tz with if statement.


On a side note, devm_thermal_zone_of_sensor_register would be quite useful to have.

Guenter


_______________________________________________
lm-sensors mailing list
lm-sensors@xxxxxxxxxxxxxx
http://lists.lm-sensors.org/mailman/listinfo/lm-sensors




[Index of Archives]     [Linux Kernel]     [Linux Hardware Monitoring]     [Linux USB Devel]     [Linux Audio Users]     [Linux Kernel]     [Linux SCSI]     [Yosemite Backpacking]

  Powered by Linux