media: v4l: subdev: Add a function to set an I²C sub-device's name

v4l2_i2c_subdev_set_name() can be used to assign a name to a sub-device.
This way uniform names can be formed easily without having to resort to
things such as snprintf in drivers.
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

drivers/media/v4l2-core/v4l2-common.c

@@ -109,6 +109,19 @@ EXPORT_SYMBOL(v4l2_ctrl_query_fill);
 
 #if IS_ENABLED(CONFIG_I2C)
 
+void v4l2_i2c_subdev_set_name(struct v4l2_subdev *sd, struct i2c_client *client,
+			      const char *devname, const char *postfix)
+{
+	if (!devname)
+		devname = client->dev.driver->name;
+	if (!postfix)
+		postfix = "";
+
+	snprintf(sd->name, sizeof(sd->name), "%s%s %d-%04x", devname, postfix,
+		 i2c_adapter_id(client->adapter), client->addr);
+}
+EXPORT_SYMBOL_GPL(v4l2_i2c_subdev_set_name);
+
 void v4l2_i2c_subdev_init(struct v4l2_subdev *sd, struct i2c_client *client,
 		const struct v4l2_subdev_ops *ops)
 {
@@ -120,10 +133,7 @@ void v4l2_i2c_subdev_init(struct v4l2_subdev *sd, struct i2c_client *client,
 	/* i2c_client and v4l2_subdev point to one another */
 	v4l2_set_subdevdata(sd, client);
 	i2c_set_clientdata(client, sd);
-	/* initialize name */
-	snprintf(sd->name, sizeof(sd->name), "%s %d-%04x",
-		client->dev.driver->name, i2c_adapter_id(client->adapter),
-		client->addr);
+	v4l2_i2c_subdev_set_name(sd, client, NULL, NULL);
 }
 EXPORT_SYMBOL_GPL(v4l2_i2c_subdev_init);
 

include/media/v4l2-common.h

@@ -154,6 +154,18 @@ struct v4l2_subdev *v4l2_i2c_new_subdev_board(struct v4l2_device *v4l2_dev,
 		struct i2c_adapter *adapter, struct i2c_board_info *info,
 		const unsigned short *probe_addrs);
 
+/**
+ * v4l2_i2c_subdev_set_name - Set name for an I²C sub-device
+ *
+ * @sd: pointer to &struct v4l2_subdev
+ * @client: pointer to struct i2c_client
+ * @devname: the name of the device; if NULL, the I²C device's name will be used
+ * @postfix: sub-device specific string to put right after the I²C device name;
+ *	     may be NULL
+ */
+void v4l2_i2c_subdev_set_name(struct v4l2_subdev *sd, struct i2c_client *client,
+			      const char *devname, const char *postfix);
+
 /**
  * v4l2_i2c_subdev_init - Initializes a &struct v4l2_subdev with data from
  *	an i2c_client struct.