From DT point of view, in general, drivers should be asking for a
specific port number because their function is fixed in the binding.

of_graph_get_next_endpoint() doesn't match to this concept.

Simply replace

	- of_graph_get_next_endpoint(xxx, NULL);
	+ of_graph_get_endpoint_by_regs(xxx, 0, -1);

Link: https://lore.kernel.org/r/20240202174941.GA310089-robh@kernel.org
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
---
v5 ->v6
	- based on latest kernel branch

 drivers/gpu/drm/drm_of.c                              | 4 +++-
 drivers/gpu/drm/panel/panel-raspberrypi-touchscreen.c | 2 +-
 drivers/gpu/drm/tiny/arcpgu.c                         | 2 +-
 3 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/drm_of.c b/drivers/gpu/drm/drm_of.c
index 177b600895d3c..b6b2cade69aeb 100644
--- a/drivers/gpu/drm/drm_of.c
+++ b/drivers/gpu/drm/drm_of.c
@@ -504,6 +504,8 @@ EXPORT_SYMBOL_GPL(drm_of_get_data_lanes_count_ep);
  * Gets parent DSI bus for a DSI device controlled through a bus other
  * than MIPI-DCS (SPI, I2C, etc.) using the Device Tree.
  *
+ * This function assumes that the device's port@0 is the DSI input.
+ *
  * Returns pointer to mipi_dsi_host if successful, -EINVAL if the
  * request is unsupported, -EPROBE_DEFER if the DSI host is found but
  * not available, or -ENODEV otherwise.
@@ -516,7 +518,7 @@ struct mipi_dsi_host *drm_of_get_dsi_bus(struct device *dev)
 	/*
 	 * Get first endpoint child from device.
 	 */
-	endpoint = of_graph_get_next_endpoint(dev->of_node, NULL);
+	endpoint = of_graph_get_endpoint_by_regs(dev->of_node, 0, -1);
 	if (!endpoint)
 		return ERR_PTR(-ENODEV);
 
diff --git a/drivers/gpu/drm/panel/panel-raspberrypi-touchscreen.c b/drivers/gpu/drm/panel/panel-raspberrypi-touchscreen.c
index 4618c892cdd65..e10e469aa7a6c 100644
--- a/drivers/gpu/drm/panel/panel-raspberrypi-touchscreen.c
+++ b/drivers/gpu/drm/panel/panel-raspberrypi-touchscreen.c
@@ -400,7 +400,7 @@ static int rpi_touchscreen_probe(struct i2c_client *i2c)
 	rpi_touchscreen_i2c_write(ts, REG_POWERON, 0);
 
 	/* Look up the DSI host.  It needs to probe before we do. */
-	endpoint = of_graph_get_next_endpoint(dev->of_node, NULL);
+	endpoint = of_graph_get_endpoint_by_regs(dev->of_node, 0, -1);
 	if (!endpoint)
 		return -ENODEV;
 
diff --git a/drivers/gpu/drm/tiny/arcpgu.c b/drivers/gpu/drm/tiny/arcpgu.c
index 4f8f3172379e3..8c29b719ea626 100644
--- a/drivers/gpu/drm/tiny/arcpgu.c
+++ b/drivers/gpu/drm/tiny/arcpgu.c
@@ -288,7 +288,7 @@ static int arcpgu_load(struct arcpgu_drm_private *arcpgu)
 	 * There is only one output port inside each device. It is linked with
 	 * encoder endpoint.
 	 */
-	endpoint_node = of_graph_get_next_endpoint(pdev->dev.of_node, NULL);
+	endpoint_node = of_graph_get_endpoint_by_regs(pdev->dev.of_node, 0, -1);
 	if (endpoint_node) {
 		encoder_node = of_graph_get_remote_port_parent(endpoint_node);
 		of_node_put(endpoint_node);
-- 
2.43.0

Hi DRM Maintainers

> From DT point of view, in general, drivers should be asking for a
> specific port number because their function is fixed in the binding.
> 
> of_graph_get_next_endpoint() doesn't match to this concept.
> 
> Simply replace
> 
> 	- of_graph_get_next_endpoint(xxx, NULL);
> 	+ of_graph_get_endpoint_by_regs(xxx, 0, -1);
> 
> Link: https://lore.kernel.org/r/20240202174941.GA310089-robh@kernel.org
> Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
> Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
> Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> ---
(snip)
>  drivers/gpu/drm/drm_of.c                              | 4 +++-
>  drivers/gpu/drm/panel/panel-raspberrypi-touchscreen.c | 2 +-
>  drivers/gpu/drm/tiny/arcpgu.c                         | 2 +-

Who can be a MAINTAINER of this patch/file/dir ?
I'm keeping posting this patch but nothing happen during almost this
half year...

Thank you for your help !!

Best regards
---
Kuninori Morimoto