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>
---
Updates in v2
- Remove NULL pointer checking already done by thermal_zone_of_sensor_unregister().
.../devicetree/bindings/hwmon/ntc_thermistor.txt | 3 +++
drivers/hwmon/ntc_thermistor.c | 25 ++++++++++++++++++++
2 files changed, 28 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..4ff89b2 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 +601,8 @@ 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;
}
--
1.7.9.5
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