[PATCH v1 1/1] media: i2c: mt9m114: Add get_fwnode_pad operation for IFP

[Svyatoslav Ryhel <clamor95@gmail.com>]

Currently, the driver's binding exposes only one endpoint, which maps to
the IFP subdevice's SOURCE pad. This configuration causes failures for
many devices using this camera because both the DT binding and the
one-to-one pad mapping logic map the endpoint to the wrong pad. Fix this
by implementing the get_fwnode_pad operation for the IFP, which correctly
matches the endpoint to the corresponding IFP pad.

Signed-off-by: Svyatoslav Ryhel <clamor95@gmail.com>
---
 drivers/media/i2c/mt9m114.c | 44 ++++++++++++++++++++++++++++---------
 1 file changed, 34 insertions(+), 10 deletions(-)

diff --git a/drivers/media/i2c/mt9m114.c b/drivers/media/i2c/mt9m114.c
index e395e2d14e97..16c2582551d3 100644
--- a/drivers/media/i2c/mt9m114.c
+++ b/drivers/media/i2c/mt9m114.c
@@ -1020,14 +1020,6 @@ static int mt9m114_stop_streaming(struct mt9m114 *sensor)
 	return ret;
 }
 
-/* -----------------------------------------------------------------------------
- * Common Subdev Operations
- */
-
-static const struct media_entity_operations mt9m114_entity_ops = {
-	.link_validate = v4l2_subdev_link_validate,
-};
-
 /* -----------------------------------------------------------------------------
  * Pixel Array Control Operations
  */
@@ -1381,6 +1373,10 @@ static const struct v4l2_subdev_internal_ops mt9m114_pa_internal_ops = {
 	.init_state = mt9m114_pa_init_state,
 };
 
+static const struct media_entity_operations mt9m114_pa_entity_ops = {
+	.link_validate = v4l2_subdev_link_validate,
+};
+
 static int mt9m114_pa_init(struct mt9m114 *sensor)
 {
 	struct v4l2_ctrl_handler *hdl = &sensor->pa.hdl;
@@ -1403,7 +1399,7 @@ static int mt9m114_pa_init(struct mt9m114 *sensor)
 
 	/* Initialize the media entity. */
 	sd->entity.function = MEDIA_ENT_F_CAM_SENSOR;
-	sd->entity.ops = &mt9m114_entity_ops;
+	sd->entity.ops = &mt9m114_pa_entity_ops;
 	pads[0].flags = MEDIA_PAD_FL_SOURCE;
 	ret = media_entity_pads_init(&sd->entity, 1, pads);
 	if (ret < 0)
@@ -2092,6 +2088,29 @@ static int mt9m114_ifp_registered(struct v4l2_subdev *sd)
 	return 0;
 }
 
+/*
+ * The IFP has only one fwnode endpoint, which corresponds to the pad
+ * linked to the PA (PA SINK), while it should be the SOURCE for the
+ * next media device in the pipe.
+ */
+static int mt9m114_ifp_get_fwnode_pad(struct media_entity *entity,
+				      struct fwnode_endpoint *endpoint)
+{
+	struct v4l2_subdev *sd = media_entity_to_v4l2_subdev(entity);
+	struct mt9m114 *sensor = ifp_to_mt9m114(sd);
+	struct fwnode_handle *ifp_port = dev_fwnode(&sensor->client->dev);
+	struct fwnode_handle *ifp_ep;
+	int ret;
+
+	ifp_ep = fwnode_graph_get_next_endpoint(ifp_port, NULL);
+
+	ret = endpoint->local_fwnode == ifp_ep ? 1 : -ENXIO;
+
+	fwnode_handle_put(ifp_ep);
+
+	return ret;
+}
+
 static const struct v4l2_subdev_video_ops mt9m114_ifp_video_ops = {
 	.s_stream = mt9m114_ifp_s_stream,
 };
@@ -2119,6 +2138,11 @@ static const struct v4l2_subdev_internal_ops mt9m114_ifp_internal_ops = {
 	.unregistered = mt9m114_ifp_unregistered,
 };
 
+static const struct media_entity_operations mt9m114_ifp_entity_ops = {
+	.link_validate = v4l2_subdev_link_validate,
+	.get_fwnode_pad = mt9m114_ifp_get_fwnode_pad,
+};
+
 static int mt9m114_ifp_init(struct mt9m114 *sensor)
 {
 	struct v4l2_subdev *sd = &sensor->ifp.sd;
@@ -2136,7 +2160,7 @@ static int mt9m114_ifp_init(struct mt9m114 *sensor)
 
 	/* Initialize the media entity. */
 	sd->entity.function = MEDIA_ENT_F_PROC_VIDEO_ISP;
-	sd->entity.ops = &mt9m114_entity_ops;
+	sd->entity.ops = &mt9m114_ifp_entity_ops;
 	pads[0].flags = MEDIA_PAD_FL_SINK;
 	pads[1].flags = MEDIA_PAD_FL_SOURCE;
 	ret = media_entity_pads_init(&sd->entity, 2, pads);
-- 
2.51.0