media: subdev: add v4l2_subdev_get_fmt() helper function

Add v4l2_subdev_get_fmt() helper function which implements
v4l2_subdev_pad_ops.get_fmt using active state. Subdev drivers that
support active state and do not need to do anything special in their
get_fmt op can use this helper directly for v4l2_subdev_pad_ops.get_fmt.
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Reviewed-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

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

@@ -1041,6 +1041,28 @@ void v4l2_subdev_cleanup(struct v4l2_subdev *sd)
 }
 EXPORT_SYMBOL_GPL(v4l2_subdev_cleanup);
 
+#if defined(CONFIG_VIDEO_V4L2_SUBDEV_API)
+
+int v4l2_subdev_get_fmt(struct v4l2_subdev *sd, struct v4l2_subdev_state *state,
+			struct v4l2_subdev_format *format)
+{
+	struct v4l2_mbus_framefmt *fmt;
+
+	if (format->pad >= sd->entity.num_pads)
+		return -EINVAL;
+
+	fmt = v4l2_subdev_get_pad_format(sd, state, format->pad);
+	if (!fmt)
+		return -EINVAL;
+
+	format->format = *fmt;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(v4l2_subdev_get_fmt);
+
+#endif /* CONFIG_VIDEO_V4L2_SUBDEV_API */
+
 #endif /* CONFIG_MEDIA_CONTROLLER */
 
 void v4l2_subdev_init(struct v4l2_subdev *sd, const struct v4l2_subdev_ops *ops)

include/media/v4l2-subdev.h

@@ -1303,6 +1303,27 @@ v4l2_subdev_lock_and_get_active_state(struct v4l2_subdev *sd)
 	return sd->active_state;
 }
 
+#if defined(CONFIG_VIDEO_V4L2_SUBDEV_API)
+
+/**
+ * v4l2_subdev_get_fmt() - Fill format based on state
+ * @sd: subdevice
+ * @state: subdevice state
+ * @format: pointer to &struct v4l2_subdev_format
+ *
+ * Fill @format->format field based on the information in the @format struct.
+ *
+ * This function can be used by the subdev drivers which support active state to
+ * implement v4l2_subdev_pad_ops.get_fmt if the subdev driver does not need to
+ * do anything special in their get_fmt op.
+ *
+ * Returns 0 on success, error value otherwise.
+ */
+int v4l2_subdev_get_fmt(struct v4l2_subdev *sd, struct v4l2_subdev_state *state,
+			struct v4l2_subdev_format *format);
+
+#endif /* CONFIG_VIDEO_V4L2_SUBDEV_API */
+
 #endif /* CONFIG_MEDIA_CONTROLLER */
 
 /**