[PATCHv4 1/1] thermal: of: improve of-thermal sensor registration API

[Eduardo Valentin <edubezval@gmail.com>]

Different drivers request API extensions in of-thermal. For this reason,
additional callbacks are required to fit the new drivers needs.

The current API implementation expects the registering sensor driver
to provide a get_temp and get_trend callbacks as function parameters.
As the amount of callbacks is growing, this patch changes the existing
implementation to use a .ops field to hold all the of thermal callbacks
to sensor drivers.

This patch also changes the existing of-thermal users to fit the new
API design. No functional change is introduced in this patch.

Cc: Alexandre Courbot <gnurou@gmail.com>
Cc: devicetree@vger.kernel.org
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Jean Delvare <jdelvare@suse.de>
Cc: linux-kernel@vger.kernel.org
Cc: linux-pm@vger.kernel.org
Cc: linux-tegra@vger.kernel.org
Cc: lm-sensors@lm-sensors.org
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Stephen Warren <swarren@wwwdotorg.org>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Zhang Rui <rui.zhang@intel.com>
Reviewed-by: Lukasz Majewski <l.majewski@samsung.com>
Signed-off-by: Eduardo Valentin <edubezval@gmail.com>
---
 drivers/hwmon/lm75.c                               |  9 +++--
 drivers/hwmon/ntc_thermistor.c                     |  6 +++-
 drivers/hwmon/tmp102.c                             |  6 +++-
 drivers/thermal/of-thermal.c                       | 40 ++++++++++------------
 drivers/thermal/tegra_soctherm.c                   |  7 ++--
 drivers/thermal/ti-soc-thermal/ti-thermal-common.c |  8 +++--
 include/linux/thermal.h                            | 24 +++++++++----
 7 files changed, 63 insertions(+), 37 deletions(-)
---
Difference from V3:
  - Keep the same behavior regarding callback checks.
    Change in behavior may be sent in a separate patch.
Difference from V2:
  - Fix wrong assignment in tegra driver.
Difference from V1:
  - Fix error handling when .get_trend is not provided.

diff --git a/drivers/hwmon/lm75.c b/drivers/hwmon/lm75.c
index d16dbb3..e7c8bf9 100644
--- a/drivers/hwmon/lm75.c
+++ b/drivers/hwmon/lm75.c
@@ -176,6 +176,10 @@ static struct attribute *lm75_attrs[] = {
 };
 ATTRIBUTE_GROUPS(lm75);
 
+static const struct thermal_zone_of_device_ops lm75_of_thermal_ops = {
+	.get_temp = lm75_read_temp,
+};
+
 /*-----------------------------------------------------------------------*/
 
 /* device probe and removal */
@@ -291,10 +295,9 @@ lm75_probe(struct i2c_client *client, const struct i2c_device_id *id)
 	if (IS_ERR(data->hwmon_dev))
 		return PTR_ERR(data->hwmon_dev);
 
-	data->tz = thermal_zone_of_sensor_register(data->hwmon_dev,
-						   0,
+	data->tz = thermal_zone_of_sensor_register(data->hwmon_dev, 0,
 						   data->hwmon_dev,
-						   lm75_read_temp, NULL);
+						   &lm75_of_thermal_ops);
 	if (IS_ERR(data->tz))
 		data->tz = NULL;
 
diff --git a/drivers/hwmon/ntc_thermistor.c b/drivers/hwmon/ntc_thermistor.c
index 4ff89b2..bca8521c8 100644
--- a/drivers/hwmon/ntc_thermistor.c
+++ b/drivers/hwmon/ntc_thermistor.c
@@ -486,6 +486,10 @@ static const struct attribute_group ntc_attr_group = {
 	.attrs = ntc_attributes,
 };
 
+static const struct thermal_zone_of_device_ops ntc_of_thermal_ops = {
+	.get_temp = ntc_read_temp,
+};
+
 static int ntc_thermistor_probe(struct platform_device *pdev)
 {
 	const struct of_device_id *of_id =
@@ -579,7 +583,7 @@ static int ntc_thermistor_probe(struct platform_device *pdev)
 								pdev_id->name);
 
 	data->tz = thermal_zone_of_sensor_register(data->dev, 0, data->dev,
-						ntc_read_temp, NULL);
+						   &ntc_of_thermal_ops);
 	if (IS_ERR(data->tz)) {
 		dev_dbg(&pdev->dev, "Failed to register to thermal fw.\n");
 		data->tz = NULL;
diff --git a/drivers/hwmon/tmp102.c b/drivers/hwmon/tmp102.c
index 5171995..ba9f478 100644
--- a/drivers/hwmon/tmp102.c
+++ b/drivers/hwmon/tmp102.c
@@ -158,6 +158,10 @@ ATTRIBUTE_GROUPS(tmp102);
 #define TMP102_CONFIG  (TMP102_CONF_TM | TMP102_CONF_EM | TMP102_CONF_CR1)
 #define TMP102_CONFIG_RD_ONLY (TMP102_CONF_R0 | TMP102_CONF_R1 | TMP102_CONF_AL)
 
+static const struct thermal_zone_of_device_ops tmp102_of_thermal_ops = {
+	.get_temp = tmp102_read_temp,
+};
+
 static int tmp102_probe(struct i2c_client *client,
 				  const struct i2c_device_id *id)
 {
@@ -215,7 +219,7 @@ static int tmp102_probe(struct i2c_client *client,
 	}
 	tmp102->hwmon_dev = hwmon_dev;
 	tmp102->tz = thermal_zone_of_sensor_register(hwmon_dev, 0, hwmon_dev,
-						     tmp102_read_temp, NULL);
+						     &tmp102_of_thermal_ops);
 	if (IS_ERR(tmp102->tz))
 		tmp102->tz = NULL;
 
diff --git a/drivers/thermal/of-thermal.c b/drivers/thermal/of-thermal.c
index f8eb625..e87ccdb 100644
--- a/drivers/thermal/of-thermal.c
+++ b/drivers/thermal/of-thermal.c
@@ -30,6 +30,7 @@
 #include <linux/err.h>
 #include <linux/export.h>
 #include <linux/string.h>
+#include <linux/thermal.h>
 
 #include "thermal_core.h"
 
@@ -77,8 +78,7 @@ struct __thermal_bind_params {
  * @num_tbps: number of thermal bind params
  * @tbps: an array of thermal bind params (0..num_tbps - 1)
  * @sensor_data: sensor private data used while reading temperature and trend
- * @get_temp: sensor callback to read temperature
- * @get_trend: sensor callback to read temperature trend
+ * @ops: set of callbacks to handle the thermal zone based on DT
  */
 
 struct __thermal_zone {
@@ -96,8 +96,7 @@ struct __thermal_zone {
 
 	/* sensor interface */
 	void *sensor_data;
-	int (*get_temp)(void *, long *);
-	int (*get_trend)(void *, long *);
+	const struct thermal_zone_of_device_ops *ops;
 };
 
 /***   DT thermal zone device callbacks   ***/
@@ -107,10 +106,10 @@ static int of_thermal_get_temp(struct thermal_zone_device *tz,
 {
 	struct __thermal_zone *data = tz->devdata;
 
-	if (!data->get_temp)
+	if (!data->ops->get_temp)
 		return -EINVAL;
 
-	return data->get_temp(data->sensor_data, temp);
+	return data->ops->get_temp(data->sensor_data, temp);
 }
 
 static int of_thermal_get_trend(struct thermal_zone_device *tz, int trip,
@@ -120,10 +119,10 @@ static int of_thermal_get_trend(struct thermal_zone_device *tz, int trip,
 	long dev_trend;
 	int r;
 
-	if (!data->get_trend)
+	if (!data->ops->get_trend)
 		return -EINVAL;
 
-	r = data->get_trend(data->sensor_data, &dev_trend);
+	r = data->ops->get_trend(data->sensor_data, &dev_trend);
 	if (r)
 		return r;
 
@@ -324,8 +323,7 @@ static struct thermal_zone_device_ops of_thermal_ops = {
 static struct thermal_zone_device *
 thermal_zone_of_add_sensor(struct device_node *zone,
 			   struct device_node *sensor, void *data,
-			   int (*get_temp)(void *, long *),
-			   int (*get_trend)(void *, long *))
+			   const struct thermal_zone_of_device_ops *ops)
 {
 	struct thermal_zone_device *tzd;
 	struct __thermal_zone *tz;
@@ -336,9 +334,11 @@ thermal_zone_of_add_sensor(struct device_node *zone,
 
 	tz = tzd->devdata;
 
+	if (!ops)
+		return ERR_PTR(-EINVAL);
+
 	mutex_lock(&tzd->lock);
-	tz->get_temp = get_temp;
-	tz->get_trend = get_trend;
+	tz->ops = ops;
 	tz->sensor_data = data;
 
 	tzd->ops->get_temp = of_thermal_get_temp;
@@ -356,8 +356,8 @@ thermal_zone_of_add_sensor(struct device_node *zone,
  *             than one sensors
  * @data: a private pointer (owned by the caller) that will be passed
  *        back, when a temperature reading is needed.
- * @get_temp: a pointer to a function that reads the sensor temperature.
- * @get_trend: a pointer to a function that reads the sensor temperature trend.
+ * @ops: struct thermal_zone_of_device *. Must contain at least .get_trend and
+ *       .get_temp.
  *
  * This function will search the list of thermal zones described in device
  * tree and look for the zone that refer to the sensor device pointed by
@@ -382,9 +382,8 @@ thermal_zone_of_add_sensor(struct device_node *zone,
  * check the return value with help of IS_ERR() helper.
  */
 struct thermal_zone_device *
-thermal_zone_of_sensor_register(struct device *dev, int sensor_id,
-				void *data, int (*get_temp)(void *, long *),
-				int (*get_trend)(void *, long *))
+thermal_zone_of_sensor_register(struct device *dev, int sensor_id, void *data,
+				const struct thermal_zone_of_device_ops *ops)
 {
 	struct device_node *np, *child, *sensor_np;
 
@@ -424,9 +423,7 @@ thermal_zone_of_sensor_register(struct device *dev, int sensor_id,
 		if (sensor_specs.np == sensor_np && id == sensor_id) {
 			of_node_put(np);
 			return thermal_zone_of_add_sensor(child, sensor_np,
-							  data,
-							  get_temp,
-							  get_trend);
+							  data, ops);
 		}
 	}
 	of_node_put(np);
@@ -468,8 +465,7 @@ void thermal_zone_of_sensor_unregister(struct device *dev,
 	tzd->ops->get_temp = NULL;
 	tzd->ops->get_trend = NULL;
 
-	tz->get_temp = NULL;
-	tz->get_trend = NULL;
+	tz->ops = NULL;
 	tz->sensor_data = NULL;
 	mutex_unlock(&tzd->lock);
 }
diff --git a/drivers/thermal/tegra_soctherm.c b/drivers/thermal/tegra_soctherm.c
index 70f7e9e..9197fc0 100644
--- a/drivers/thermal/tegra_soctherm.c
+++ b/drivers/thermal/tegra_soctherm.c
@@ -317,6 +317,10 @@ static int tegra_thermctl_get_temp(void *data, long *out_temp)
 	return 0;
 }
 
+static const struct thermal_zone_of_device_ops tegra_of_thermal_ops = {
+	.get_temp = tegra_thermctl_get_temp,
+};
+
 static const struct of_device_id tegra_soctherm_of_match[] = {
 	{ .compatible = "nvidia,tegra124-soctherm" },
 	{ },
@@ -416,8 +420,7 @@ static int tegra_soctherm_probe(struct platform_device *pdev)
 		zone->shift = t124_thermctl_temp_zones[i].shift;
 
 		tz = thermal_zone_of_sensor_register(&pdev->dev, i, zone,
-						     tegra_thermctl_get_temp,
-						     NULL);
+						     &tegra_of_thermal_ops);
 		if (IS_ERR(tz)) {
 			err = PTR_ERR(tz);
 			dev_err(&pdev->dev, "failed to register sensor: %d\n",
diff --git a/drivers/thermal/ti-soc-thermal/ti-thermal-common.c b/drivers/thermal/ti-soc-thermal/ti-thermal-common.c
index 9eec26d..5fd0386 100644
--- a/drivers/thermal/ti-soc-thermal/ti-thermal-common.c
+++ b/drivers/thermal/ti-soc-thermal/ti-thermal-common.c
@@ -286,6 +286,11 @@ static int ti_thermal_get_crit_temp(struct thermal_zone_device *thermal,
 	return ti_thermal_get_trip_temp(thermal, OMAP_TRIP_NUMBER - 1, temp);
 }
 
+static const struct thermal_zone_of_device_ops ti_of_thermal_ops = {
+	.get_temp = __ti_thermal_get_temp,
+	.get_trend = __ti_thermal_get_trend,
+};
+
 static struct thermal_zone_device_ops ti_thermal_ops = {
 	.get_temp = ti_thermal_get_temp,
 	.get_trend = ti_thermal_get_trend,
@@ -333,8 +338,7 @@ int ti_thermal_expose_sensor(struct ti_bandgap *bgp, int id,
 
 	/* in case this is specified by DT */
 	data->ti_thermal = thermal_zone_of_sensor_register(bgp->dev, id,
-					data, __ti_thermal_get_temp,
-					__ti_thermal_get_trend);
+					data, &ti_of_thermal_ops);
 	if (IS_ERR(data->ti_thermal)) {
 		/* Create thermal zone */
 		data->ti_thermal = thermal_zone_device_register(domain,
diff --git a/include/linux/thermal.h b/include/linux/thermal.h
index ef90838..b565964 100644
--- a/include/linux/thermal.h
+++ b/include/linux/thermal.h
@@ -289,19 +289,31 @@ struct thermal_genl_event {
 	enum events event;
 };
 
+/**
+ * struct thermal_zone_of_device_ops - scallbacks for handling DT based zones
+ *
+ * Mandatory:
+ * @get_temp: a pointer to a function that reads the sensor temperature.
+ *
+ * Optional:
+ * @get_trend: a pointer to a function that reads the sensor temperature trend.
+ */
+struct thermal_zone_of_device_ops {
+	int (*get_temp)(void *, long *);
+	int (*get_trend)(void *, long *);
+};
+
 /* Function declarations */
 #ifdef CONFIG_THERMAL_OF
 struct thermal_zone_device *
-thermal_zone_of_sensor_register(struct device *dev, int id,
-				void *data, int (*get_temp)(void *, long *),
-				int (*get_trend)(void *, long *));
+thermal_zone_of_sensor_register(struct device *dev, int id, void *data,
+				const struct thermal_zone_of_device_ops *);
 void thermal_zone_of_sensor_unregister(struct device *dev,
 				       struct thermal_zone_device *tz);
 #else
 static inline struct thermal_zone_device *
-thermal_zone_of_sensor_register(struct device *dev, int id,
-				void *data, int (*get_temp)(void *, long *),
-				int (*get_trend)(void *, long *))
+thermal_zone_of_sensor_register(struct device *dev, int id, void *data,
+				const struct thermal_zone_of_device_ops *)
 {
 	return NULL;
 }
-- 
2.1.3