[PATCH v4 2/4] media: v4l: Support obtaining link frequency via get_mbus_config

[Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>]

Add link_freq field to struct v4l2_mbus_config in order to pass the link
frequency to the reciving sub-device.

Signed-off-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
---
 drivers/media/v4l2-core/v4l2-common.c | 13 +++++++++----
 include/media/v4l2-mediabus.h         |  2 ++
 2 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/drivers/media/v4l2-core/v4l2-common.c b/drivers/media/v4l2-core/v4l2-common.c
index 7f69b5a025fa..09b26ce612e9 100644
--- a/drivers/media/v4l2-core/v4l2-common.c
+++ b/drivers/media/v4l2-core/v4l2-common.c
@@ -503,15 +503,20 @@ s64 __v4l2_get_link_freq_ctrl(struct v4l2_ctrl_handler *handler,
 EXPORT_SYMBOL_GPL(__v4l2_get_link_freq_ctrl);
 
 s64 __v4l2_get_link_freq_pad(struct media_pad *pad, unsigned int mul,
-			     unsigned int div)
+			      unsigned int div)
 {
+	struct v4l2_mbus_config mbus_config = {};
 	struct v4l2_subdev *sd;
+	int ret;
 
 	sd = media_entity_to_v4l2_subdev(pad->entity);
-	if (!sd)
-		return -ENODEV;
+	ret = v4l2_subdev_call(sd, pad, get_mbus_config, pad->index,
+			       &mbus_config);
+	if (ret < 0 && ret != -ENOIOCTLCMD)
+		return ret;
 
-	return __v4l2_get_link_freq_ctrl(sd->ctrl_handler, mul, div);
+	return mbus_config.link_freq ?:
+		__v4l2_get_link_freq_ctrl(sd->ctrl_handler, mul, div);
 }
 EXPORT_SYMBOL_GPL(__v4l2_get_link_freq_pad);
 
diff --git a/include/media/v4l2-mediabus.h b/include/media/v4l2-mediabus.h
index 5bce6e423e94..2f39b52bb4d4 100644
--- a/include/media/v4l2-mediabus.h
+++ b/include/media/v4l2-mediabus.h
@@ -159,6 +159,7 @@ enum v4l2_mbus_type {
  * @bus.mipi_csi2: embedded &struct v4l2_mbus_config_mipi_csi2.
  *		   Used if the bus is MIPI Alliance's Camera Serial
  *		   Interface version 2 (MIPI CSI2).
+ * @link_freq: The link frequency. See also V4L2_CID_LINK_FREQ control.
  */
 struct v4l2_mbus_config {
 	enum v4l2_mbus_type type;
@@ -167,6 +168,7 @@ struct v4l2_mbus_config {
 		struct v4l2_mbus_config_mipi_csi1 mipi_csi1;
 		struct v4l2_mbus_config_mipi_csi2 mipi_csi2;
 	} bus;
+	u64 link_freq;
 };
 
 /**
-- 
2.39.2