[v3,4/5] drm: convert drivers to use drm_of_find_panel_or_bridge
diff mbox

Message ID 20170322132608.17353-5-robh@kernel.org
State New
Headers show

Commit Message

Rob Herring March 22, 2017, 1:26 p.m. UTC
Similar to the previous commit, convert drivers open coding OF graph
parsing to use drm_of_find_panel_or_bridge instead.

This changes some error messages to debug messages (in the graph core).
Graph connections are often "no connects" depending on the particular
board, so we want to avoid spurious messages. Plus the kernel is not a
DT validator.

Signed-off-by: Rob Herring <robh@kernel.org>
Reviewed-by: Archit Taneja <architt@codeaurora.org>
---
v3:
- rebase to v4.11-rc2
- rework atmel to support 1 to N connections

 drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_output.c | 73 ++++++-------------
 drivers/gpu/drm/bridge/nxp-ptn3460.c             | 16 ++---
 drivers/gpu/drm/bridge/parade-ps8622.c           | 16 ++---
 drivers/gpu/drm/bridge/tc358767.c                | 27 +------
 drivers/gpu/drm/exynos/exynos_dp.c               | 35 ++++-----
 drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_rgb.c        | 39 +++-------
 drivers/gpu/drm/hisilicon/kirin/dw_drm_dsi.c     | 27 ++-----
 drivers/gpu/drm/imx/imx-ldb.c                    | 27 ++-----
 drivers/gpu/drm/imx/parallel-display.c           | 36 ++--------
 drivers/gpu/drm/mediatek/mtk_dsi.c               | 23 ++----
 drivers/gpu/drm/mxsfb/mxsfb_out.c                | 40 ++---------
 drivers/gpu/drm/rockchip/analogix_dp-rockchip.c  | 26 ++-----
 drivers/gpu/drm/sun4i/sun4i_rgb.c                | 11 +--
 drivers/gpu/drm/sun4i/sun4i_tcon.c               | 90 ++----------------------
 14 files changed, 92 insertions(+), 394 deletions(-)

--
2.10.1

Comments

Maxime Ripard March 23, 2017, 8:03 a.m. UTC | #1
On Wed, Mar 22, 2017 at 08:26:07AM -0500, Rob Herring wrote:
> Similar to the previous commit, convert drivers open coding OF graph
> parsing to use drm_of_find_panel_or_bridge instead.
> 
> This changes some error messages to debug messages (in the graph core).
> Graph connections are often "no connects" depending on the particular
> board, so we want to avoid spurious messages. Plus the kernel is not a
> DT validator.
> 
> Signed-off-by: Rob Herring <robh@kernel.org>
> Reviewed-by: Archit Taneja <architt@codeaurora.org>
> ---
> v3:
> - rebase to v4.11-rc2
> - rework atmel to support 1 to N connections
> 
>  drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_output.c | 73 ++++++-------------
>  drivers/gpu/drm/bridge/nxp-ptn3460.c             | 16 ++---
>  drivers/gpu/drm/bridge/parade-ps8622.c           | 16 ++---
>  drivers/gpu/drm/bridge/tc358767.c                | 27 +------
>  drivers/gpu/drm/exynos/exynos_dp.c               | 35 ++++-----
>  drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_rgb.c        | 39 +++-------
>  drivers/gpu/drm/hisilicon/kirin/dw_drm_dsi.c     | 27 ++-----
>  drivers/gpu/drm/imx/imx-ldb.c                    | 27 ++-----
>  drivers/gpu/drm/imx/parallel-display.c           | 36 ++--------
>  drivers/gpu/drm/mediatek/mtk_dsi.c               | 23 ++----
>  drivers/gpu/drm/mxsfb/mxsfb_out.c                | 40 ++---------
>  drivers/gpu/drm/rockchip/analogix_dp-rockchip.c  | 26 ++-----
>  drivers/gpu/drm/sun4i/sun4i_rgb.c                | 11 +--
>  drivers/gpu/drm/sun4i/sun4i_tcon.c               | 90 ++----------------------

For sun4i,
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>

Maxime
Sean Paul March 24, 2017, 2:22 p.m. UTC | #2
On Wed, Mar 22, 2017 at 08:26:07AM -0500, Rob Herring wrote:
> Similar to the previous commit, convert drivers open coding OF graph
> parsing to use drm_of_find_panel_or_bridge instead.
> 
> This changes some error messages to debug messages (in the graph core).
> Graph connections are often "no connects" depending on the particular
> board, so we want to avoid spurious messages. Plus the kernel is not a
> DT validator.
> 
> Signed-off-by: Rob Herring <robh@kernel.org>
> Reviewed-by: Archit Taneja <architt@codeaurora.org>
> ---
> v3:
> - rebase to v4.11-rc2
> - rework atmel to support 1 to N connections
> 
>  drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_output.c | 73 ++++++-------------
>  drivers/gpu/drm/bridge/nxp-ptn3460.c             | 16 ++---
>  drivers/gpu/drm/bridge/parade-ps8622.c           | 16 ++---
>  drivers/gpu/drm/bridge/tc358767.c                | 27 +------
>  drivers/gpu/drm/exynos/exynos_dp.c               | 35 ++++-----
>  drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_rgb.c        | 39 +++-------
>  drivers/gpu/drm/hisilicon/kirin/dw_drm_dsi.c     | 27 ++-----
>  drivers/gpu/drm/imx/imx-ldb.c                    | 27 ++-----
>  drivers/gpu/drm/imx/parallel-display.c           | 36 ++--------
>  drivers/gpu/drm/mediatek/mtk_dsi.c               | 23 ++----
>  drivers/gpu/drm/mxsfb/mxsfb_out.c                | 40 ++---------
>  drivers/gpu/drm/rockchip/analogix_dp-rockchip.c  | 26 ++-----
>  drivers/gpu/drm/sun4i/sun4i_rgb.c                | 11 +--
>  drivers/gpu/drm/sun4i/sun4i_tcon.c               | 90 ++----------------------
>  14 files changed, 92 insertions(+), 394 deletions(-)
>
<snip>

> diff --git a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_rgb.c b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_rgb.c
> index c3651456c963..511d68e22452 100644
> --- a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_rgb.c
> +++ b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_rgb.c
> @@ -15,6 +15,7 @@
>  #include <drm/drmP.h>
>  #include <drm/drm_atomic_helper.h>
>  #include <drm/drm_crtc_helper.h>
> +#include <drm/drm_of.h>
>  #include <drm/drm_panel.h>
> 
>  #include "fsl_dcu_drm_drv.h"
> @@ -141,28 +142,6 @@ static int fsl_dcu_attach_panel(struct fsl_dcu_drm_device *fsl_dev,
>  	return ret;
>  }
> 
> -static int fsl_dcu_attach_endpoint(struct fsl_dcu_drm_device *fsl_dev,
> -				   const struct of_endpoint *ep)
> -{
> -	struct drm_bridge *bridge;
> -	struct device_node *np;
> -
> -	np = of_graph_get_remote_port_parent(ep->local_node);
> -
> -	fsl_dev->connector.panel = of_drm_find_panel(np);
> -	if (fsl_dev->connector.panel) {
> -		of_node_put(np);
> -		return fsl_dcu_attach_panel(fsl_dev, fsl_dev->connector.panel);
> -	}
> -
> -	bridge = of_drm_find_bridge(np);
> -	of_node_put(np);
> -	if (!bridge)
> -		return -ENODEV;
> -
> -	return drm_bridge_attach(&fsl_dev->encoder, bridge, NULL);
> -}
> -
>  int fsl_dcu_create_outputs(struct fsl_dcu_drm_device *fsl_dev)
>  {
>  	struct of_endpoint ep;
> @@ -179,14 +158,14 @@ int fsl_dcu_create_outputs(struct fsl_dcu_drm_device *fsl_dev)
>  		return fsl_dcu_attach_panel(fsl_dev, fsl_dev->connector.panel);
>  	}
> 
> -	ep_node = of_graph_get_next_endpoint(fsl_dev->np, NULL);
> -	if (!ep_node)
> -		return -ENODEV;
> -
> -	ret = of_graph_parse_endpoint(ep_node, &ep);
> -	of_node_put(ep_node);
> +	ret = drm_of_find_panel_or_bridge(fsl_dev->np, 0, 0, &panel, &bridge);

Hi Rob,
Apologies for the delay, I've been dealing with overhead the past few days. I ran across
this compile error when build testing your set.


../drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_rgb.c: In function
‘fsl_dcu_create_outputs’:
../drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_rgb.c:161:56: error: ‘panel’ undeclared
(first use in this function)
../drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_rgb.c:161:56: note: each undeclared
identifier is reported only once for each function it appears in
../drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_rgb.c:161:64: error: ‘bridge’ undeclared
(first use in this function)
../drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_rgb.c:148:22: warning: unused variable
‘ep_node’ [-Wunused-variable]
../drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_rgb.c:147:21: warning: unused variable
‘ep’ [-Wunused-variable]
../drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_rgb.c:171:1: warning: control reaches end
of non-void function [-Wreturn-type]
make[5]: *** [drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_rgb.o] Error 1
make[4]: *** [drivers/gpu/drm/fsl-dcu] Error 2
make[4]: *** Waiting for unfinished jobs....


The defconfigs we use can be found here:
https://cgit.freedesktop.org/drm/drm-tip/tree/?h=rerere-cache

Sean


>  	if (ret)
> -		return -ENODEV;
> +		return ret;
> 
> -	return fsl_dcu_attach_endpoint(fsl_dev, &ep);
> +	if (panel) {
> +		fsl_dev->connector.panel = panel;
> +		return fsl_dcu_attach_panel(fsl_dev, panel);
> +	}
> +
> +	return drm_bridge_attach(&fsl_dev->encoder, bridge, NULL);

<snip>

> --
> 2.10.1
>
Rob Herring May 9, 2017, 10:43 p.m. UTC | #3
On Tue, May 9, 2017 at 9:28 AM, Leonard Crestez <leonard.crestez@nxp.com> wrote:
> On Wed, Mar 22, 2017 at 5:01 PM, Philipp Zabel <p.zabel@pengutronix.de> wrote:
>> On Wed, 2017-03-22 at 08:26 -0500, Rob Herring wrote:
>> >
>> > Similar to the previous commit, convert drivers open coding OF graph
>> > parsing to use drm_of_find_panel_or_bridge instead.
>> >
>> > This changes some error messages to debug messages (in the graph core).
>> > Graph connections are often "no connects" depending on the particular
>> > board, so we want to avoid spurious messages. Plus the kernel is not a
>> > DT validator.
>> >
>> > Signed-off-by: Rob Herring <robh@kernel.org>
>> > Reviewed-by: Archit Taneja <architt@codeaurora.org>
>> Tested-by: Philipp Zabel <p.zabel@pengutronix.de>
>> (imx-ldb on i.MX6)
>
> It seems that this breaks on (at least) imx6qdl-sabreauto. The relevant
> section of the boot log looks like this:
>
> imx-drm display-subsystem: bound imx-ipuv3-crtc.2 (ops ipu_crtc_ops)
> imx-drm display-subsystem: bound imx-ipuv3-crtc.3 (ops ipu_crtc_ops)
> dwhdmi-imx 120000.hdmi: Detected HDMI TX controller v1.31a with HDCP
> (DWC HDMI 3D TX PHY)
> dwhdmi-imx 120000.hdmi: registered DesignWare HDMI I2C bus driver
> imx-drm display-subsystem: bound 120000.hdmi (ops dw_hdmi_imx_ops)
> imx-drm display-subsystem: failed to bind 2000000.aips-bus:ldb (ops
> imx_ldb_ops): -19
> imx-drm display-subsystem: master bind failed: -19
>
> It seems that imx6qdl-sabreauto does not have any panel defined in dts.
> This used to be ignored when of_graph_get_endpoint_by_regs returned
> NULL but now drm_of_find_panel_or_bridge returns -ENODEV and this
> causes imx_ldb_bind to fail altogether. Defining a panel works
> (including showing stuff on a LVDS panel). Ignoring -ENODEV also fixes
> this:
>
> --- drivers/gpu/drm/imx/imx-ldb.c
> +++ drivers/gpu/drm/imx/imx-ldb.c
> @@ -673,7 +673,7 @@ static int imx_ldb_bind(struct device *dev, struct device *master, void *data)
>                 ret = drm_of_find_panel_or_bridge(child,
>                                                   imx_ldb->lvds_mux ? 4 : 2, 0,
>                                                   &channel->panel, &channel->bridge);
> -               if (ret)
> +               if (ret != -ENODEV)
>                         return ret;
>
>                 /* panel ddc only if there is no bridge */
>
> I don't know much about drm and it's not clear if failing to find a
> panel should be an error here or not and the hack above is likely the
> wrong way to handle it anyway.

That looks like the right fix to me. Ideally, the DT should probably
define an LVDS connector node (if not a panel) in this case like we do
for other cases with DDC, but more importantly we shouldn't require a
DT update to fix things. If you needed power or gpio controls of the
panel you would also need some node in DT.

Do you mind sending a proper patch?

Rob

Patch
diff mbox

diff --git a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_output.c b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_output.c
index e7799b6ee829..f987b4572d4a 100644
--- a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_output.c
+++ b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_output.c
@@ -22,7 +22,7 @@ 
 #include <linux/of_graph.h>

 #include <drm/drmP.h>
-#include <drm/drm_panel.h>
+#include <drm/drm_of.h>

 #include "atmel_hlcdc_dc.h"

@@ -152,29 +152,11 @@  static const struct drm_connector_funcs atmel_hlcdc_panel_connector_funcs = {
 	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
 };

-static int atmel_hlcdc_check_endpoint(struct drm_device *dev,
-				      const struct of_endpoint *ep)
-{
-	struct device_node *np;
-	void *obj;
-
-	np = of_graph_get_remote_port_parent(ep->local_node);
-
-	obj = of_drm_find_panel(np);
-	if (!obj)
-		obj = of_drm_find_bridge(np);
-
-	of_node_put(np);
-
-	return obj ? 0 : -EPROBE_DEFER;
-}
-
 static int atmel_hlcdc_attach_endpoint(struct drm_device *dev,
-				       const struct of_endpoint *ep)
+				       const struct device_node *np)
 {
 	struct atmel_hlcdc_dc *dc = dev->dev_private;
 	struct atmel_hlcdc_rgb_output *output;
-	struct device_node *np;
 	struct drm_panel *panel;
 	struct drm_bridge *bridge;
 	int ret;
@@ -195,13 +177,11 @@  static int atmel_hlcdc_attach_endpoint(struct drm_device *dev,

 	output->encoder.possible_crtcs = 0x1;

-	np = of_graph_get_remote_port_parent(ep->local_node);
-
-	ret = -EPROBE_DEFER;
+	ret = drm_of_find_panel_or_bridge(np, 0, 0, &panel, &bridge);
+	if (ret)
+		return ret;

-	panel = of_drm_find_panel(np);
 	if (panel) {
-		of_node_put(np);
 		output->connector.dpms = DRM_MODE_DPMS_OFF;
 		output->connector.polled = DRM_CONNECTOR_POLL_CONNECT;
 		drm_connector_helper_add(&output->connector,
@@ -226,9 +206,6 @@  static int atmel_hlcdc_attach_endpoint(struct drm_device *dev,
 		return 0;
 	}

-	bridge = of_drm_find_bridge(np);
-	of_node_put(np);
-
 	if (bridge) {
 		ret = drm_bridge_attach(&output->encoder, bridge, NULL);
 		if (!ret)
@@ -243,31 +220,23 @@  static int atmel_hlcdc_attach_endpoint(struct drm_device *dev,

 int atmel_hlcdc_create_outputs(struct drm_device *dev)
 {
-	struct device_node *ep_np = NULL;
-	struct of_endpoint ep;
-	int ret;
-
-	for_each_endpoint_of_node(dev->dev->of_node, ep_np) {
-		ret = of_graph_parse_endpoint(ep_np, &ep);
-		if (!ret)
-			ret = atmel_hlcdc_check_endpoint(dev, &ep);
-
-		if (ret) {
-			of_node_put(ep_np);
-			return ret;
-		}
-	}
-
-	for_each_endpoint_of_node(dev->dev->of_node, ep_np) {
-		ret = of_graph_parse_endpoint(ep_np, &ep);
-		if (!ret)
-			ret = atmel_hlcdc_attach_endpoint(dev, &ep);
-
-		if (ret) {
-			of_node_put(ep_np);
+	struct device_node *remote;
+	int ret, endpoint = 0;
+
+	while (true) {
+		/* Loop thru possible multiple connections to the output */
+		remote = of_graph_get_remote_node(dev->dev->of_node, 0,
+						  endpoint++);
+		if (!remote)
+			break;
+
+		ret = atmel_hlcdc_attach_endpoint(dev, remote);
+		of_node_put(remote);
+		if (ret)
 			return ret;
-		}
 	}

-	return 0;
+	if (!endpoint)
+		return -ENODEV;
+	return ret;
 }
diff --git a/drivers/gpu/drm/bridge/nxp-ptn3460.c b/drivers/gpu/drm/bridge/nxp-ptn3460.c
index 27f98c518dde..351704390d02 100644
--- a/drivers/gpu/drm/bridge/nxp-ptn3460.c
+++ b/drivers/gpu/drm/bridge/nxp-ptn3460.c
@@ -20,8 +20,8 @@ 
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_gpio.h>
-#include <linux/of_graph.h>

+#include <drm/drm_of.h>
 #include <drm/drm_panel.h>

 #include "drm_crtc.h"
@@ -292,7 +292,6 @@  static int ptn3460_probe(struct i2c_client *client,
 {
 	struct device *dev = &client->dev;
 	struct ptn3460_bridge *ptn_bridge;
-	struct device_node *endpoint, *panel_node;
 	int ret;

 	ptn_bridge = devm_kzalloc(dev, sizeof(*ptn_bridge), GFP_KERNEL);
@@ -300,16 +299,9 @@  static int ptn3460_probe(struct i2c_client *client,
 		return -ENOMEM;
 	}

-	endpoint = of_graph_get_next_endpoint(dev->of_node, NULL);
-	if (endpoint) {
-		panel_node = of_graph_get_remote_port_parent(endpoint);
-		if (panel_node) {
-			ptn_bridge->panel = of_drm_find_panel(panel_node);
-			of_node_put(panel_node);
-			if (!ptn_bridge->panel)
-				return -EPROBE_DEFER;
-		}
-	}
+	ret = drm_of_find_panel_or_bridge(dev->of_node, 0, 0, &ptn_bridge->panel, NULL);
+	if (ret)
+		return ret;

 	ptn_bridge->client = client;

diff --git a/drivers/gpu/drm/bridge/parade-ps8622.c b/drivers/gpu/drm/bridge/parade-ps8622.c
index ac8cc5b50d9f..1dcec3b97e67 100644
--- a/drivers/gpu/drm/bridge/parade-ps8622.c
+++ b/drivers/gpu/drm/bridge/parade-ps8622.c
@@ -22,10 +22,10 @@ 
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
-#include <linux/of_graph.h>
 #include <linux/pm.h>
 #include <linux/regulator/consumer.h>

+#include <drm/drm_of.h>
 #include <drm/drm_panel.h>

 #include "drmP.h"
@@ -536,7 +536,6 @@  static int ps8622_probe(struct i2c_client *client,
 					const struct i2c_device_id *id)
 {
 	struct device *dev = &client->dev;
-	struct device_node *endpoint, *panel_node;
 	struct ps8622_bridge *ps8622;
 	int ret;

@@ -544,16 +543,9 @@  static int ps8622_probe(struct i2c_client *client,
 	if (!ps8622)
 		return -ENOMEM;

-	endpoint = of_graph_get_next_endpoint(dev->of_node, NULL);
-	if (endpoint) {
-		panel_node = of_graph_get_remote_port_parent(endpoint);
-		if (panel_node) {
-			ps8622->panel = of_drm_find_panel(panel_node);
-			of_node_put(panel_node);
-			if (!ps8622->panel)
-				return -EPROBE_DEFER;
-		}
-	}
+	ret = drm_of_find_panel_or_bridge(dev->of_node, 0, 0, &ps8622->panel, NULL);
+	if (ret)
+		return ret;

 	ps8622->client = client;

diff --git a/drivers/gpu/drm/bridge/tc358767.c b/drivers/gpu/drm/bridge/tc358767.c
index de9ffb49e9f6..5c26488e7a2d 100644
--- a/drivers/gpu/drm/bridge/tc358767.c
+++ b/drivers/gpu/drm/bridge/tc358767.c
@@ -1244,7 +1244,6 @@  static const struct regmap_config tc_regmap_config = {
 static int tc_probe(struct i2c_client *client, const struct i2c_device_id *id)
 {
 	struct device *dev = &client->dev;
-	struct device_node *ep;
 	struct tc_data *tc;
 	int ret;

@@ -1255,29 +1254,9 @@  static int tc_probe(struct i2c_client *client, const struct i2c_device_id *id)
 	tc->dev = dev;

 	/* port@2 is the output port */
-	ep = of_graph_get_endpoint_by_regs(dev->of_node, 2, -1);
-	if (ep) {
-		struct device_node *remote;
-
-		remote = of_graph_get_remote_port_parent(ep);
-		if (!remote) {
-			dev_warn(dev, "endpoint %s not connected\n",
-				 ep->full_name);
-			of_node_put(ep);
-			return -ENODEV;
-		}
-		of_node_put(ep);
-		tc->panel = of_drm_find_panel(remote);
-		if (tc->panel) {
-			dev_dbg(dev, "found panel %s\n", remote->full_name);
-		} else {
-			dev_dbg(dev, "waiting for panel %s\n",
-				remote->full_name);
-			of_node_put(remote);
-			return -EPROBE_DEFER;
-		}
-		of_node_put(remote);
-	}
+	ret = drm_of_find_panel_or_bridge(dev->of_node, 2, 0, &tc->panel, NULL);
+	if (ret)
+		return ret;

 	/* Shut down GPIO is optional */
 	tc->sd_gpio = devm_gpiod_get_optional(dev, "shutdown", GPIOD_OUT_HIGH);
diff --git a/drivers/gpu/drm/exynos/exynos_dp.c b/drivers/gpu/drm/exynos/exynos_dp.c
index 1ef0be338b85..a269f439e742 100644
--- a/drivers/gpu/drm/exynos/exynos_dp.c
+++ b/drivers/gpu/drm/exynos/exynos_dp.c
@@ -23,6 +23,7 @@ 
 #include <drm/drmP.h>
 #include <drm/drm_crtc.h>
 #include <drm/drm_crtc_helper.h>
+#include <drm/drm_of.h>
 #include <drm/drm_panel.h>

 #include <drm/bridge/analogix_dp.h>
@@ -212,8 +213,11 @@  static const struct component_ops exynos_dp_ops = {
 static int exynos_dp_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
-	struct device_node *np = NULL, *endpoint = NULL;
+	struct device_node *np;
 	struct exynos_dp_device *dp;
+	struct drm_panel *panel;
+	struct drm_bridge *bridge;
+	int ret;

 	dp = devm_kzalloc(&pdev->dev, sizeof(struct exynos_dp_device),
 			  GFP_KERNEL);
@@ -237,28 +241,13 @@  static int exynos_dp_probe(struct platform_device *pdev)
 		goto out;
 	}

-	endpoint = of_graph_get_next_endpoint(dev->of_node, NULL);
-	if (endpoint) {
-		np = of_graph_get_remote_port_parent(endpoint);
-		if (np) {
-			/* The remote port can be either a panel or a bridge */
-			dp->plat_data.panel = of_drm_find_panel(np);
-			if (!dp->plat_data.panel) {
-				dp->ptn_bridge = of_drm_find_bridge(np);
-				if (!dp->ptn_bridge) {
-					of_node_put(np);
-					return -EPROBE_DEFER;
-				}
-			}
-			of_node_put(np);
-		} else {
-			DRM_ERROR("no remote endpoint device node found.\n");
-			return -EINVAL;
-		}
-	} else {
-		DRM_ERROR("no port endpoint subnode found.\n");
-		return -EINVAL;
-	}
+	ret = drm_of_find_panel_or_bridge(dev->of_node, 0, 0, &panel, &bridge);
+	if (ret)
+		return ret;
+
+	/* The remote port can be either a panel or a bridge */
+	dp->plat_data.panel = panel;
+	dp->ptn_bridge = bridge;

 out:
 	return component_add(&pdev->dev, &exynos_dp_ops);
diff --git a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_rgb.c b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_rgb.c
index c3651456c963..511d68e22452 100644
--- a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_rgb.c
+++ b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_rgb.c
@@ -15,6 +15,7 @@ 
 #include <drm/drmP.h>
 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_crtc_helper.h>
+#include <drm/drm_of.h>
 #include <drm/drm_panel.h>

 #include "fsl_dcu_drm_drv.h"
@@ -141,28 +142,6 @@  static int fsl_dcu_attach_panel(struct fsl_dcu_drm_device *fsl_dev,
 	return ret;
 }

-static int fsl_dcu_attach_endpoint(struct fsl_dcu_drm_device *fsl_dev,
-				   const struct of_endpoint *ep)
-{
-	struct drm_bridge *bridge;
-	struct device_node *np;
-
-	np = of_graph_get_remote_port_parent(ep->local_node);
-
-	fsl_dev->connector.panel = of_drm_find_panel(np);
-	if (fsl_dev->connector.panel) {
-		of_node_put(np);
-		return fsl_dcu_attach_panel(fsl_dev, fsl_dev->connector.panel);
-	}
-
-	bridge = of_drm_find_bridge(np);
-	of_node_put(np);
-	if (!bridge)
-		return -ENODEV;
-
-	return drm_bridge_attach(&fsl_dev->encoder, bridge, NULL);
-}
-
 int fsl_dcu_create_outputs(struct fsl_dcu_drm_device *fsl_dev)
 {
 	struct of_endpoint ep;
@@ -179,14 +158,14 @@  int fsl_dcu_create_outputs(struct fsl_dcu_drm_device *fsl_dev)
 		return fsl_dcu_attach_panel(fsl_dev, fsl_dev->connector.panel);
 	}

-	ep_node = of_graph_get_next_endpoint(fsl_dev->np, NULL);
-	if (!ep_node)
-		return -ENODEV;
-
-	ret = of_graph_parse_endpoint(ep_node, &ep);
-	of_node_put(ep_node);
+	ret = drm_of_find_panel_or_bridge(fsl_dev->np, 0, 0, &panel, &bridge);
 	if (ret)
-		return -ENODEV;
+		return ret;

-	return fsl_dcu_attach_endpoint(fsl_dev, &ep);
+	if (panel) {
+		fsl_dev->connector.panel = panel;
+		return fsl_dcu_attach_panel(fsl_dev, panel);
+	}
+
+	return drm_bridge_attach(&fsl_dev->encoder, bridge, NULL);
 }
diff --git a/drivers/gpu/drm/hisilicon/kirin/dw_drm_dsi.c b/drivers/gpu/drm/hisilicon/kirin/dw_drm_dsi.c
index 1737e98bc10a..5abc69c9630f 100644
--- a/drivers/gpu/drm/hisilicon/kirin/dw_drm_dsi.c
+++ b/drivers/gpu/drm/hisilicon/kirin/dw_drm_dsi.c
@@ -17,7 +17,6 @@ 

 #include <linux/clk.h>
 #include <linux/component.h>
-#include <linux/of_graph.h>

 #include <drm/drm_of.h>
 #include <drm/drm_crtc_helper.h>
@@ -754,34 +753,16 @@  static int dsi_parse_dt(struct platform_device *pdev, struct dw_dsi *dsi)
 {
 	struct dsi_hw_ctx *ctx = dsi->ctx;
 	struct device_node *np = pdev->dev.of_node;
-	struct device_node *endpoint, *bridge_node;
-	struct drm_bridge *bridge;
 	struct resource *res;
+	int ret;

 	/*
 	 * Get the endpoint node. In our case, dsi has one output port1
 	 * to which the external HDMI bridge is connected.
 	 */
-	endpoint = of_graph_get_endpoint_by_regs(np, 1, -1);
-	if (!endpoint) {
-		DRM_ERROR("no valid endpoint node\n");
-		return -ENODEV;
-	}
-	of_node_put(endpoint);
-
-	bridge_node = of_graph_get_remote_port_parent(endpoint);
-	if (!bridge_node) {
-		DRM_ERROR("no valid bridge node\n");
-		return -ENODEV;
-	}
-	of_node_put(bridge_node);
-
-	bridge = of_drm_find_bridge(bridge_node);
-	if (!bridge) {
-		DRM_INFO("wait for external HDMI bridge driver.\n");
-		return -EPROBE_DEFER;
-	}
-	dsi->bridge = bridge;
+	ret = drm_of_find_panel_or_bridge(np, 0, 0, NULL, &dsi->bridge);
+	if (ret)
+		return ret;

 	ctx->pclk = devm_clk_get(&pdev->dev, "pclk");
 	if (IS_ERR(ctx->pclk)) {
diff --git a/drivers/gpu/drm/imx/imx-ldb.c b/drivers/gpu/drm/imx/imx-ldb.c
index 88cd11d30134..8fb801fab039 100644
--- a/drivers/gpu/drm/imx/imx-ldb.c
+++ b/drivers/gpu/drm/imx/imx-ldb.c
@@ -647,7 +647,6 @@  static int imx_ldb_bind(struct device *dev, struct device *master, void *data)

 	for_each_child_of_node(np, child) {
 		struct imx_ldb_channel *channel;
-		struct device_node *ep;
 		int bus_format;

 		ret = of_property_read_u32(child, "reg", &i);
@@ -671,27 +670,11 @@  static int imx_ldb_bind(struct device *dev, struct device *master, void *data)
 		 * The output port is port@4 with an external 4-port mux or
 		 * port@2 with the internal 2-port mux.
 		 */
-		ep = of_graph_get_endpoint_by_regs(child,
-						   imx_ldb->lvds_mux ? 4 : 2,
-						   -1);
-		if (ep) {
-			struct device_node *remote;
-
-			remote = of_graph_get_remote_port_parent(ep);
-			of_node_put(ep);
-			if (remote) {
-				channel->panel = of_drm_find_panel(remote);
-				channel->bridge = of_drm_find_bridge(remote);
-			} else
-				return -EPROBE_DEFER;
-			of_node_put(remote);
-
-			if (!channel->panel && !channel->bridge) {
-				dev_err(dev, "panel/bridge not found: %s\n",
-					remote->full_name);
-				return -EPROBE_DEFER;
-			}
-		}
+		ret = drm_of_find_panel_or_bridge(child,
+						  imx_ldb->lvds_mux ? 4 : 2, 0,
+						  &channel->panel, &channel->bridge);
+		if (ret)
+			return ret;

 		/* panel ddc only if there is no bridge */
 		if (!channel->bridge) {
diff --git a/drivers/gpu/drm/imx/parallel-display.c b/drivers/gpu/drm/imx/parallel-display.c
index d5c06fd89f90..636031a30e17 100644
--- a/drivers/gpu/drm/imx/parallel-display.c
+++ b/drivers/gpu/drm/imx/parallel-display.c
@@ -19,10 +19,10 @@ 
 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_fb_helper.h>
 #include <drm/drm_crtc_helper.h>
+#include <drm/drm_of.h>
 #include <drm/drm_panel.h>
 #include <linux/videodev2.h>
 #include <video/of_display_timing.h>
-#include <linux/of_graph.h>

 #include "imx-drm.h"

@@ -208,7 +208,6 @@  static int imx_pd_bind(struct device *dev, struct device *master, void *data)
 {
 	struct drm_device *drm = data;
 	struct device_node *np = dev->of_node;
-	struct device_node *ep;
 	const u8 *edidp;
 	struct imx_parallel_display *imxpd;
 	int ret;
@@ -237,36 +236,9 @@  static int imx_pd_bind(struct device *dev, struct device *master, void *data)
 	imxpd->bus_format = bus_format;

 	/* port@1 is the output port */
-	ep = of_graph_get_endpoint_by_regs(np, 1, -1);
-	if (ep) {
-		struct device_node *remote;
-
-		remote = of_graph_get_remote_port_parent(ep);
-		if (!remote) {
-			dev_warn(dev, "endpoint %s not connected\n",
-				 ep->full_name);
-			of_node_put(ep);
-			return -ENODEV;
-		}
-		of_node_put(ep);
-
-		imxpd->panel = of_drm_find_panel(remote);
-		if (imxpd->panel) {
-			dev_dbg(dev, "found panel %s\n", remote->full_name);
-		} else {
-			imxpd->bridge = of_drm_find_bridge(remote);
-			if (imxpd->bridge)
-				dev_dbg(dev, "found bridge %s\n",
-					remote->full_name);
-		}
-		if (!imxpd->panel && !imxpd->bridge) {
-			dev_dbg(dev, "waiting for panel or bridge %s\n",
-				remote->full_name);
-			of_node_put(remote);
-			return -EPROBE_DEFER;
-		}
-		of_node_put(remote);
-	}
+	ret = drm_of_find_panel_or_bridge(np, 1, 0, &imxpd->panel, &imxpd->bridge);
+	if (ret)
+		return ret;

 	imxpd->dev = dev;

diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
index dd71cbb1a622..4d837b29ee9e 100644
--- a/drivers/gpu/drm/mediatek/mtk_dsi.c
+++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
@@ -16,11 +16,11 @@ 
 #include <drm/drm_crtc_helper.h>
 #include <drm/drm_mipi_dsi.h>
 #include <drm/drm_panel.h>
+#include <drm/drm_of.h>
 #include <linux/clk.h>
 #include <linux/component.h>
 #include <linux/of.h>
 #include <linux/of_platform.h>
-#include <linux/of_graph.h>
 #include <linux/phy/phy.h>
 #include <linux/platform_device.h>
 #include <video/videomode.h>
@@ -801,7 +801,6 @@  static int mtk_dsi_probe(struct platform_device *pdev)
 {
 	struct mtk_dsi *dsi;
 	struct device *dev = &pdev->dev;
-	struct device_node *remote_node, *endpoint;
 	struct resource *regs;
 	int comp_id;
 	int ret;
@@ -813,22 +812,10 @@  static int mtk_dsi_probe(struct platform_device *pdev)
 	dsi->host.ops = &mtk_dsi_ops;
 	dsi->host.dev = dev;

-	endpoint = of_graph_get_next_endpoint(dev->of_node, NULL);
-	if (endpoint) {
-		remote_node = of_graph_get_remote_port_parent(endpoint);
-		if (!remote_node) {
-			dev_err(dev, "No panel connected\n");
-			return -ENODEV;
-		}
-
-		dsi->bridge = of_drm_find_bridge(remote_node);
-		dsi->panel = of_drm_find_panel(remote_node);
-		of_node_put(remote_node);
-		if (!dsi->bridge && !dsi->panel) {
-			dev_info(dev, "Waiting for bridge or panel driver\n");
-			return -EPROBE_DEFER;
-		}
-	}
+	ret = drm_of_find_panel_or_bridge(dev->of_node, 0, 0,
+					  &dsi->panel, &dsi->bridge);
+	if (ret)
+		return ret;

 	dsi->engine_clk = devm_clk_get(dev, "engine");
 	if (IS_ERR(dsi->engine_clk)) {
diff --git a/drivers/gpu/drm/mxsfb/mxsfb_out.c b/drivers/gpu/drm/mxsfb/mxsfb_out.c
index b8e81422d4e2..f7d729aa09bd 100644
--- a/drivers/gpu/drm/mxsfb/mxsfb_out.c
+++ b/drivers/gpu/drm/mxsfb/mxsfb_out.c
@@ -19,6 +19,7 @@ 
 #include <drm/drm_crtc_helper.h>
 #include <drm/drm_fb_cma_helper.h>
 #include <drm/drm_gem_cma_helper.h>
+#include <drm/drm_of.h>
 #include <drm/drm_panel.h>
 #include <drm/drm_plane_helper.h>
 #include <drm/drm_simple_kms_helper.h>
@@ -82,20 +83,15 @@  static const struct drm_connector_funcs mxsfb_panel_connector_funcs = {
 	.atomic_destroy_state	= drm_atomic_helper_connector_destroy_state,
 };

-static int mxsfb_attach_endpoint(struct drm_device *drm,
-				 const struct of_endpoint *ep)
+int mxsfb_create_output(struct drm_device *drm)
 {
 	struct mxsfb_drm_private *mxsfb = drm->dev_private;
-	struct device_node *np;
 	struct drm_panel *panel;
-	int ret = -EPROBE_DEFER;
-
-	np = of_graph_get_remote_port_parent(ep->local_node);
-	panel = of_drm_find_panel(np);
-	of_node_put(np);
+	int ret;

-	if (!panel)
-		return -EPROBE_DEFER;
+	ret = drm_of_find_panel_or_bridge(drm->dev->of_node, 0, 0, &panel, NULL);
+	if (ret)
+		return ret;

 	mxsfb->connector.dpms = DRM_MODE_DPMS_OFF;
 	mxsfb->connector.polled = 0;
@@ -109,27 +105,3 @@  static int mxsfb_attach_endpoint(struct drm_device *drm,

 	return ret;
 }
-
-int mxsfb_create_output(struct drm_device *drm)
-{
-	struct mxsfb_drm_private *mxsfb = drm->dev_private;
-	struct device_node *ep_np = NULL;
-	struct of_endpoint ep;
-	int ret;
-
-	for_each_endpoint_of_node(drm->dev->of_node, ep_np) {
-		ret = of_graph_parse_endpoint(ep_np, &ep);
-		if (!ret)
-			ret = mxsfb_attach_endpoint(drm, &ep);
-
-		if (ret) {
-			of_node_put(ep_np);
-			return ret;
-		}
-	}
-
-	if (!mxsfb->panel)
-		return -EPROBE_DEFER;
-
-	return 0;
-}
diff --git a/drivers/gpu/drm/rockchip/analogix_dp-rockchip.c b/drivers/gpu/drm/rockchip/analogix_dp-rockchip.c
index 8548e8271639..615afad280a8 100644
--- a/drivers/gpu/drm/rockchip/analogix_dp-rockchip.c
+++ b/drivers/gpu/drm/rockchip/analogix_dp-rockchip.c
@@ -428,31 +428,13 @@  static const struct component_ops rockchip_dp_component_ops = {
 static int rockchip_dp_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
-	struct device_node *panel_node, *port, *endpoint;
 	struct drm_panel *panel = NULL;
 	struct rockchip_dp_device *dp;
+	int ret;

-	port = of_graph_get_port_by_id(dev->of_node, 1);
-	if (port) {
-		endpoint = of_get_child_by_name(port, "endpoint");
-		of_node_put(port);
-		if (!endpoint) {
-			dev_err(dev, "no output endpoint found\n");
-			return -EINVAL;
-		}
-
-		panel_node = of_graph_get_remote_port_parent(endpoint);
-		of_node_put(endpoint);
-		if (!panel_node) {
-			dev_err(dev, "no output node found\n");
-			return -EINVAL;
-		}
-
-		panel = of_drm_find_panel(panel_node);
-		of_node_put(panel_node);
-		if (!panel)
-			return -EPROBE_DEFER;
-	}
+	ret = drm_of_find_panel_or_bridge(dev->of_node, 1, 0, &panel, NULL);
+	if (ret)
+		return ret;

 	dp = devm_kzalloc(dev, sizeof(*dp), GFP_KERNEL);
 	if (!dp)
diff --git a/drivers/gpu/drm/sun4i/sun4i_rgb.c b/drivers/gpu/drm/sun4i/sun4i_rgb.c
index 757208f51731..46280dd70c9e 100644
--- a/drivers/gpu/drm/sun4i/sun4i_rgb.c
+++ b/drivers/gpu/drm/sun4i/sun4i_rgb.c
@@ -15,6 +15,7 @@ 
 #include <drm/drmP.h>
 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_crtc_helper.h>
+#include <drm/drm_of.h>
 #include <drm/drm_panel.h>

 #include "sun4i_drv.h"
@@ -218,9 +219,9 @@  int sun4i_rgb_init(struct drm_device *drm)
 	rgb->drv = drv;
 	encoder = &rgb->encoder;

-	tcon->panel = sun4i_tcon_find_panel(tcon->dev->of_node);
-	bridge = sun4i_tcon_find_bridge(tcon->dev->of_node);
-	if (IS_ERR(tcon->panel) && IS_ERR(bridge)) {
+	ret = drm_of_find_panel_or_bridge(tcon->dev->of_node, 1, 0,
+					  &tcon->panel, &bridge);
+	if (ret) {
 		dev_info(drm->dev, "No panel or bridge found... RGB output disabled\n");
 		return 0;
 	}
@@ -240,7 +241,7 @@  int sun4i_rgb_init(struct drm_device *drm)
 	/* The RGB encoder can only work with the TCON channel 0 */
 	rgb->encoder.possible_crtcs = BIT(0);

-	if (!IS_ERR(tcon->panel)) {
+	if (tcon->panel) {
 		drm_connector_helper_add(&rgb->connector,
 					 &sun4i_rgb_con_helper_funcs);
 		ret = drm_connector_init(drm, &rgb->connector,
@@ -261,7 +262,7 @@  int sun4i_rgb_init(struct drm_device *drm)
 		}
 	}

-	if (!IS_ERR(bridge)) {
+	if (bridge) {
 		ret = drm_bridge_attach(encoder, bridge, NULL);
 		if (ret) {
 			dev_err(drm->dev, "Couldn't attach our bridge\n");
diff --git a/drivers/gpu/drm/sun4i/sun4i_tcon.c b/drivers/gpu/drm/sun4i/sun4i_tcon.c
index ea2906f87cb9..2e4e365cecf9 100644
--- a/drivers/gpu/drm/sun4i/sun4i_tcon.c
+++ b/drivers/gpu/drm/sun4i/sun4i_tcon.c
@@ -15,13 +15,12 @@ 
 #include <drm/drm_crtc.h>
 #include <drm/drm_crtc_helper.h>
 #include <drm/drm_modes.h>
-#include <drm/drm_panel.h>
+#include <drm/drm_of.h>

 #include <linux/component.h>
 #include <linux/ioport.h>
 #include <linux/of_address.h>
 #include <linux/of_device.h>
-#include <linux/of_graph.h>
 #include <linux/of_irq.h>
 #include <linux/regmap.h>
 #include <linux/reset.h>
@@ -405,74 +404,6 @@  static int sun4i_tcon_init_regmap(struct device *dev,
 	return 0;
 }

-struct drm_panel *sun4i_tcon_find_panel(struct device_node *node)
-{
-	struct device_node *port, *remote, *child;
-	struct device_node *end_node = NULL;
-
-	/* Inputs are listed first, then outputs */
-	port = of_graph_get_port_by_id(node, 1);
-
-	/*
-	 * Our first output is the RGB interface where the panel will
-	 * be connected.
-	 */
-	for_each_child_of_node(port, child) {
-		u32 reg;
-
-		of_property_read_u32(child, "reg", &reg);
-		if (reg == 0)
-			end_node = child;
-	}
-
-	if (!end_node) {
-		DRM_DEBUG_DRIVER("Missing panel endpoint\n");
-		return ERR_PTR(-ENODEV);
-	}
-
-	remote = of_graph_get_remote_port_parent(end_node);
-	if (!remote) {
-		DRM_DEBUG_DRIVER("Unable to parse remote node\n");
-		return ERR_PTR(-EINVAL);
-	}
-
-	return of_drm_find_panel(remote) ?: ERR_PTR(-EPROBE_DEFER);
-}
-
-struct drm_bridge *sun4i_tcon_find_bridge(struct device_node *node)
-{
-	struct device_node *port, *remote, *child;
-	struct device_node *end_node = NULL;
-
-	/* Inputs are listed first, then outputs */
-	port = of_graph_get_port_by_id(node, 1);
-
-	/*
-	 * Our first output is the RGB interface where the panel will
-	 * be connected.
-	 */
-	for_each_child_of_node(port, child) {
-		u32 reg;
-
-		of_property_read_u32(child, "reg", &reg);
-		if (reg == 0)
-			end_node = child;
-	}
-
-	if (!end_node) {
-		DRM_DEBUG_DRIVER("Missing bridge endpoint\n");
-		return ERR_PTR(-ENODEV);
-	}
-
-	remote = of_graph_get_remote_port_parent(end_node);
-	if (!remote) {
-		DRM_DEBUG_DRIVER("Enable to parse remote node\n");
-		return ERR_PTR(-EINVAL);
-	}
-
-	return of_drm_find_bridge(remote) ?: ERR_PTR(-EPROBE_DEFER);
-}
-
 static int sun4i_tcon_bind(struct device *dev, struct device *master,
 			   void *data)
 {
@@ -555,22 +486,11 @@  static int sun4i_tcon_probe(struct platform_device *pdev)
 	struct device_node *node = pdev->dev.of_node;
 	struct drm_bridge *bridge;
 	struct drm_panel *panel;
+	int ret;

-	/*
-	 * Neither the bridge or the panel is ready.
-	 * Defer the probe.
-	 */
-	panel = sun4i_tcon_find_panel(node);
-	bridge = sun4i_tcon_find_bridge(node);
-
-	/*
-	 * If we don't have a panel endpoint, just go on
-	 */
-	if ((PTR_ERR(panel) == -EPROBE_DEFER) &&
-	    (PTR_ERR(bridge) == -EPROBE_DEFER)) {
-		DRM_DEBUG_DRIVER("Still waiting for our panel/bridge. Deferring...\n");
-		return -EPROBE_DEFER;
-	}
+	ret = drm_of_find_panel_or_bridge(node, 1, 0, &panel, &bridge);
+	if (ret == -EPROBE_DEFER)
+		return ret;

 	return component_add(&pdev->dev, &sun4i_tcon_ops);
 }