[PATCH v5 03/13] HID: hid-sensor-hub: introduce device managed API

sensor_hub_register_callback() is common API used for the HID IIO drivers,
prepare devm API devm_sensor_hub_register_callback() to acquire resource
during setup and release using device managed framework during drivers
fail, unbind or remove path.

store the required callback removal context (hsdev and usage_id) in a
dedicated struct sensor_hub_cb_devres, and register a devres action to
handle to release resource with devres framework and helper API.

Signed-off-by: Sanjay Chitroda <[email protected]>
---
 drivers/hid/hid-sensor-hub.c   | 32 ++++++++++++++++++++++++++++++++
 include/linux/hid-sensor-hub.h | 24 ++++++++++++++++++++++++
 2 files changed, 56 insertions(+)

diff --git a/drivers/hid/hid-sensor-hub.c b/drivers/hid/hid-sensor-hub.c
index 90666ff629de..31dbdce27dc6 100644
--- a/drivers/hid/hid-sensor-hub.c
+++ b/drivers/hid/hid-sensor-hub.c
@@ -187,6 +187,38 @@ int sensor_hub_remove_callback(struct hid_sensor_hub_device *hsdev,
 }
 EXPORT_SYMBOL_GPL(sensor_hub_remove_callback);
 
+static void sensor_hub_remove_callback_helper(void *ptr)
+{
+	struct sensor_hub_cb_devres *res = ptr;
+
+	sensor_hub_remove_callback(res->hsdev, res->usage_id);
+}
+
+int devm_sensor_hub_register_callback(struct device *dev,
+				      struct hid_sensor_hub_device *hsdev,
+				      u32 usage_id,
+				      struct hid_sensor_hub_callbacks *usage_callback)
+{
+	struct sensor_hub_cb_devres *res;
+	int ret;
+
+	ret = sensor_hub_register_callback(hsdev, usage_id, usage_callback);
+	if (ret)
+		return ret;
+
+	res = devm_kmalloc(dev, sizeof(*res), GFP_KERNEL);
+	if (!res) {
+		sensor_hub_remove_callback(hsdev, usage_id);
+		return -ENOMEM;
+	}
+
+	res->hsdev = hsdev;
+	res->usage_id = usage_id;
+
+	return devm_add_action_or_reset(dev, sensor_hub_remove_callback_helper, res);
+}
+EXPORT_SYMBOL_GPL(devm_sensor_hub_register_callback);
+
 int sensor_hub_set_feature(struct hid_sensor_hub_device *hsdev, u32 report_id,
 			   u32 field_index, int buffer_size, void *buffer)
 {
diff --git a/include/linux/hid-sensor-hub.h b/include/linux/hid-sensor-hub.h
index e71056553108..c00347b15513 100644
--- a/include/linux/hid-sensor-hub.h
+++ b/include/linux/hid-sensor-hub.h
@@ -75,6 +75,16 @@ struct hid_sensor_hub_device {
 	struct sensor_hub_pending pending;
 };
 
+/**
+ * struct sensor_hub_cb_devres - devres data for sensor hub callbacks
+ * @hsdev:	Hub device instance.
+ * @usage_id:	Usage ID associated with registered callback
+ */
+struct sensor_hub_cb_devres {
+	struct hid_sensor_hub_device *hsdev;
+	u32 usage_id;
+};
+
 /**
  * struct hid_sensor_hub_callbacks - Client callback functions
  * @pdev:		Platform device instance of the client driver.
@@ -139,6 +149,20 @@ int sensor_hub_register_callback(struct hid_sensor_hub_device *hsdev,
 int sensor_hub_remove_callback(struct hid_sensor_hub_device *hsdev,
 			u32 usage_id);
 
+/**
+ * devm_sensor_hub_register_callback() - Managed register client callbacks
+ * @dev: Device for resource management
+ * @hsdev: Hub device instance
+ * @usage_id: Usage id of the client (e.g. 0x200076 for Gyro)
+ * @usage_callback: Callback function storage
+ *
+ * This is the devres (managed) version of sensor_hub_register_callback().
+ * The callback will be automatically unregistered when the device is detached.
+ */
+int devm_sensor_hub_register_callback(struct device *dev,
+				      struct hid_sensor_hub_device *hsdev,
+				      u32 usage_id,
+				      struct hid_sensor_hub_callbacks *usage_callback);
 
 /* Hid sensor hub core interfaces */
 

-- 
2.34.1