[PATCH V2 2/6] thermal: of-thermal: Add devm version of thermal_zone_of_sensor_register

[Laxman Dewangan]

Add resource managed version of thermal_zone_of_sensor_register() and
thermal_zone_of_sensor_unregister().

This helps in reducing the code size in error path, remove of
driver remove callbacks and making proper sequence for deallocations.

Signed-off-by: Laxman Dewangan <ldewangan@xxxxxxxxxx>

---
Changes from V1:
- Run checkpatch --strict and fix the issue.

 drivers/thermal/of-thermal.c | 81 ++++++++++++++++++++++++++++++++++++++++++++
 include/linux/thermal.h      | 18 ++++++++++
 2 files changed, 99 insertions(+)

diff --git a/drivers/thermal/of-thermal.c b/drivers/thermal/of-thermal.c
index 9043f8f..49ac23d 100644
--- a/drivers/thermal/of-thermal.c
+++ b/drivers/thermal/of-thermal.c
@@ -555,6 +555,87 @@ void thermal_zone_of_sensor_unregister(struct device *dev,
 }
 EXPORT_SYMBOL_GPL(thermal_zone_of_sensor_unregister);
 
+static void devm_thermal_zone_of_sensor_release(struct device *dev, void *res)
+{
+	thermal_zone_of_sensor_unregister(dev,
+					  *(struct thermal_zone_device **)res);
+}
+
+static int devm_thermal_zone_of_sensor_match(struct device *dev, void *res,
+					     void *data)
+{
+	struct thermal_zone_device **r = res;
+
+	if (WARN_ON(!r || !*r))
+		return 0;
+
+	return *r == data;
+}
+
+/**
+ * devm_thermal_zone_of_sensor_register - Resource managed version of
+ *				thermal_zone_of_sensor_register()
+ * @dev: a valid struct device pointer of a sensor device. Must contain
+ *       a valid .of_node, for the sensor node.
+ * @sensor_id: a sensor identifier, in case the sensor IP has more
+ *	       than one sensors
+ * @data: a private pointer (owned by the caller) that will be passed
+ *	  back, when a temperature reading is needed.
+ * @ops: struct thermal_zone_of_device_ops *. Must contain at least .get_temp.
+ *
+ * Refer thermal_zone_of_sensor_register() for more details.
+ *
+ * Return: On success returns a valid struct thermal_zone_device,
+ * otherwise, it returns a corresponding ERR_PTR(). Caller must
+ * check the return value with help of IS_ERR() helper.
+ * Registered hermal_zone_device device will automatically be
+ * released when device is unbounded.
+ */
+struct thermal_zone_device *devm_thermal_zone_of_sensor_register(
+	struct device *dev, int sensor_id,
+	void *data, const struct thermal_zone_of_device_ops *ops)
+{
+	struct thermal_zone_device **ptr, *tzd;
+
+	ptr = devres_alloc(devm_thermal_zone_of_sensor_release, sizeof(*ptr),
+			   GFP_KERNEL);
+	if (!ptr)
+		return ERR_PTR(-ENOMEM);
+
+	tzd = thermal_zone_of_sensor_register(dev, sensor_id, data, ops);
+	if (IS_ERR(tzd)) {
+		devres_free(ptr);
+		return tzd;
+	}
+
+	*ptr = tzd;
+	devres_add(dev, ptr);
+
+	return tzd;
+}
+EXPORT_SYMBOL_GPL(devm_thermal_zone_of_sensor_register);
+
+/**
+ * devm_thermal_zone_of_sensor_unregister - Resource managed version of
+ *				thermal_zone_of_sensor_unregister().
+ * @dev: Device for which which resource was allocated.
+ * @tzd: a pointer to struct thermal_zone_device where the sensor is registered.
+ *
+ * This function removes the sensor callbacks and private data from the
+ * thermal zone device registered with devm_thermal_zone_of_sensor_register()
+ * API. It will also silent the zone by remove the .get_temp() and .get_trend()
+ * thermal zone device callbacks.
+ * Normally this function will not need to be called and the resource
+ * management code will ensure that the resource is freed.
+ */
+void devm_thermal_zone_of_sensor_unregister(struct device *dev,
+					    struct thermal_zone_device *tzd)
+{
+	WARN_ON(devres_release(dev, devm_thermal_zone_of_sensor_release,
+			       devm_thermal_zone_of_sensor_match, tzd));
+}
+EXPORT_SYMBOL_GPL(devm_thermal_zone_of_sensor_unregister);
+
 /***   functions parsing device tree nodes   ***/
 
 /**
diff --git a/include/linux/thermal.h b/include/linux/thermal.h
index e13a1ac..9c48199 100644
--- a/include/linux/thermal.h
+++ b/include/linux/thermal.h
@@ -362,6 +362,11 @@ thermal_zone_of_sensor_register(struct device *dev, int id, void *data,
 				const struct thermal_zone_of_device_ops *ops);
 void thermal_zone_of_sensor_unregister(struct device *dev,
 				       struct thermal_zone_device *tz);
+struct thermal_zone_device *devm_thermal_zone_of_sensor_register(
+		struct device *dev, int id, void *data,
+		const struct thermal_zone_of_device_ops *ops);
+void devm_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,
@@ -376,6 +381,19 @@ void thermal_zone_of_sensor_unregister(struct device *dev,
 {
 }
 
+static inline struct thermal_zone_device *devm_thermal_zone_of_sensor_register(
+		struct device *dev, int id, void *data,
+		const struct thermal_zone_of_device_ops *ops)
+{
+	return ERR_PTR(-ENODEV);
+}
+
+static inline
+void devm_thermal_zone_of_sensor_unregister(struct device *dev,
+					    struct thermal_zone_device *tz)
+{
+}
+
 #endif
 
 #if IS_ENABLED(CONFIG_THERMAL)
-- 
2.1.4