V4L/DVB (11673): v4l2-device: unregister i2c_clients when unregistering the v4l2_device.

Until now I relied on i2c_del_adapter to unregister the i2c_clients for
me, however, if the i2c bus is a platform bus then it is never deleted.

So instead I need to unregister i2c clients when unregistering the
v4l2_device.
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/video/v4l2-common.c

@@ -746,6 +746,7 @@ void v4l2_i2c_subdev_init(struct v4l2_subdev *sd, struct i2c_client *client,
 		const struct v4l2_subdev_ops *ops)
 {
 	v4l2_subdev_init(sd, ops);
+	sd->flags |= V4L2_SUBDEV_FL_IS_I2C;
 	/* the owner is the same as the i2c_client's driver owner */
 	sd->owner = client->driver->driver.owner;
 	/* i2c_client and v4l2_subdev point to one another */

drivers/media/video/v4l2-device.c

@@ -83,8 +83,19 @@ void v4l2_device_unregister(struct v4l2_device *v4l2_dev)
 	v4l2_device_disconnect(v4l2_dev);
 
 	/* Unregister subdevs */
-	list_for_each_entry_safe(sd, next, &v4l2_dev->subdevs, list)
+	list_for_each_entry_safe(sd, next, &v4l2_dev->subdevs, list) {
 		v4l2_device_unregister_subdev(sd);
+		if (sd->flags & V4L2_SUBDEV_FL_IS_I2C) {
+			struct i2c_client *client = v4l2_get_subdevdata(sd);
+
+			/* We need to unregister the i2c client explicitly.
+			   We cannot rely on i2c_del_adapter to always
+			   unregister clients for us, since if the i2c bus
+			   is a platform bus, then it is never deleted. */
+			if (client)
+				i2c_unregister_device(client);
+		}
+	}
 }
 EXPORT_SYMBOL_GPL(v4l2_device_unregister);
 

include/media/v4l2-subdev.h

@@ -230,12 +230,16 @@ struct v4l2_subdev_ops {
 
 #define V4L2_SUBDEV_NAME_SIZE 32
 
+/* Set this flag if this subdev is a i2c device. */
+#define V4L2_SUBDEV_FL_IS_I2C (1U << 0)
+
 /* Each instance of a subdev driver should create this struct, either
    stand-alone or embedded in a larger struct.
  */
 struct v4l2_subdev {
 	struct list_head list;
 	struct module *owner;
+	u32 flags;
 	struct v4l2_device *v4l2_dev;
 	const struct v4l2_subdev_ops *ops;
 	/* name must be unique */
@@ -264,6 +268,7 @@ static inline void v4l2_subdev_init(struct v4l2_subdev *sd,
 	BUG_ON(!ops || !ops->core);
 	sd->ops = ops;
 	sd->v4l2_dev = NULL;
+	sd->flags = 0;
 	sd->name[0] = '\0';
 	sd->grp_id = 0;
 	sd->priv = NULL;