media: v4l2-subdev: Introduce [get|set]_mbus_config pad ops

Introduce two new pad operations to allow retrieving and configuring the
media bus parameters on a subdevice pad.

The newly introduced operations aims to replace the s/g_mbus_config video
operations, which have been on their way for deprecation since a long
time.
Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

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

@@ -309,6 +309,20 @@ static int call_enum_dv_timings(struct v4l2_subdev *sd,
 	       sd->ops->pad->enum_dv_timings(sd, dvt);
 }
 
+static int call_get_mbus_config(struct v4l2_subdev *sd, unsigned int pad,
+				struct v4l2_mbus_config *config)
+{
+	return check_pad(sd, pad) ? :
+	       sd->ops->pad->get_mbus_config(sd, pad, config);
+}
+
+static int call_set_mbus_config(struct v4l2_subdev *sd, unsigned int pad,
+				struct v4l2_mbus_config *config)
+{
+	return check_pad(sd, pad) ? :
+	       sd->ops->pad->get_mbus_config(sd, pad, config);
+}
+
 static const struct v4l2_subdev_pad_ops v4l2_subdev_call_pad_wrappers = {
 	.get_fmt		= call_get_fmt,
 	.set_fmt		= call_set_fmt,
@@ -321,6 +335,8 @@ static const struct v4l2_subdev_pad_ops v4l2_subdev_call_pad_wrappers = {
 	.set_edid		= call_set_edid,
 	.dv_timings_cap		= call_dv_timings_cap,
 	.enum_dv_timings	= call_enum_dv_timings,
+	.get_mbus_config	= call_get_mbus_config,
+	.set_mbus_config	= call_set_mbus_config,
 };
 
 static const struct v4l2_subdev_video_ops v4l2_subdev_call_video_wrappers = {

include/media/v4l2-subdev.h

@@ -670,6 +670,30 @@ struct v4l2_subdev_pad_config {
  *
  * @set_frame_desc: set the low level media bus frame parameters, @fd array
  *                  may be adjusted by the subdev driver to device capabilities.
+ *
+ * @get_mbus_config: get the media bus configuration of a remote sub-device.
+ *		     The media bus configuration is usually retrieved from the
+ *		     firmware interface at sub-device probe time, immediately
+ *		     applied to the hardware and eventually adjusted by the
+ *		     driver. Remote sub-devices (usually video receivers) shall
+ *		     use this operation to query the transmitting end bus
+ *		     configuration in order to adjust their own one accordingly.
+ *		     Callers should make sure they get the most up-to-date as
+ *		     possible configuration from the remote end, likely calling
+ *		     this operation as close as possible to stream on time. The
+ *		     operation shall fail if the pad index it has been called on
+ *		     is not valid or in case of unrecoverable failures.
+ *
+ * @set_mbus_config: set the media bus configuration of a remote sub-device.
+ *		     This operations is intended to allow, in combination with
+ *		     the get_mbus_config operation, the negotiation of media bus
+ *		     configuration parameters between media sub-devices. The
+ *		     operation shall not fail if the requested configuration is
+ *		     not supported, but the driver shall update the content of
+ *		     the %config argument to reflect what has been actually
+ *		     applied to the hardware. The operation shall fail if the
+ *		     pad index it has been called on is not valid or in case of
+ *		     unrecoverable failures.
  */
 struct v4l2_subdev_pad_ops {
 	int (*init_cfg)(struct v4l2_subdev *sd,
@@ -710,6 +734,10 @@ struct v4l2_subdev_pad_ops {
 			      struct v4l2_mbus_frame_desc *fd);
 	int (*set_frame_desc)(struct v4l2_subdev *sd, unsigned int pad,
 			      struct v4l2_mbus_frame_desc *fd);
+	int (*get_mbus_config)(struct v4l2_subdev *sd, unsigned int pad,
+			       struct v4l2_mbus_config *config);
+	int (*set_mbus_config)(struct v4l2_subdev *sd, unsigned int pad,
+			       struct v4l2_mbus_config *config);
 };
 
 /**