Hi Maxime, On Fri, Sep 10, 2021 at 03:09:39PM +0200, Maxime Ripard wrote:

Display drivers so far need to have a lot of boilerplate to first retrieve either the panel or bridge that they are connected to using drm_of_find_panel_or_bridge(), and then either deal with each with ad-hoc functions or create a drm panel bridge through drm_panel_bridge_add.

In order to reduce the boilerplate and hopefully create a path of least resistance towards using the DRM panel bridge layer, let's create the function devm_drm_of_get_next to reduce that boilerplate.

s/devm_drm_of_get_next/devm_drm_of_get_bridge/

Signed-off-by: Maxime Ripard maxime@cerno.tech

I like how this makes panels and bridges much more alike for the display drivers.

With the changelog fixed: Reviewed-by: Sam Ravnborg sam@ravnborg.org

(I assume you will apply yourself - otherwise tell me to do it).

---

drivers/gpu/drm/drm_bridge.c | 42 ++++++++++++++++++++++++++++++++---- drivers/gpu/drm/drm_of.c | 3 +++ include/drm/drm_bridge.h | 2 ++ 3 files changed, 43 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c index a8ed66751c2d..10ddca4638b0 100644 --- a/drivers/gpu/drm/drm_bridge.c +++ b/drivers/gpu/drm/drm_bridge.c @@ -28,6 +28,7 @@ #include <drm/drm_atomic_state_helper.h> #include <drm/drm_bridge.h> #include <drm/drm_encoder.h> +#include <drm/drm_of.h> #include <drm/drm_print.h>

#include "drm_crtc_internal.h" @@ -51,10 +52,8 @@

• Display drivers are responsible for linking encoders with the first bridge
• in the chains. This is done by acquiring the appropriate bridge with

• • of_drm_find_bridge() or drm_of_find_panel_or_bridge(), or creating it for a
• • panel with drm_panel_bridge_add_typed() (or the managed version
• • devm_drm_panel_bridge_add_typed()). Once acquired, the bridge shall be
• • attached to the encoder with a call to drm_bridge_attach().

• • devm_drm_of_get_bridge(). Once acquired, the bridge shall be attached to the
• • encoder with a call to drm_bridge_attach().
  • Bridges are responsible for linking themselves with the next bridge in the
  • chain, if any. This is done the same way as for encoders, with the call to

@@ -1233,6 +1232,41 @@ struct drm_bridge *of_drm_find_bridge(struct device_node *np) return NULL; } EXPORT_SYMBOL(of_drm_find_bridge);

+/**

• • devm_drm_of_get_bridge - Return next bridge in the chain
• • @dev: device to tie the bridge lifetime to
• • @np: device tree node containing encoder output ports
• • @port: port in the device tree node
• • @endpoint: endpoint in the device tree node
• • Given a DT node's port and endpoint number, finds the connected node
• • and returns the associated bridge if any, or creates and returns a
• • drm panel bridge instance if a panel is connected.
• • Returns a pointer to the bridge if successful, or an error pointer
• • otherwise.
• */

+struct drm_bridge *devm_drm_of_get_bridge(struct device *dev,

• 			  struct device_node *np,
  

• 			  unsigned int port,
  

• 			  unsigned int endpoint)
  

+{

• struct drm_bridge *bridge;
• struct drm_panel *panel;
• int ret;
• ret = drm_of_find_panel_or_bridge(np, port, endpoint,

• 			  &panel, &bridge);
  

• if (ret)

• return ERR_PTR(ret);
  

• if (panel)

• bridge = devm_drm_panel_bridge_add(dev, panel);
  

• return bridge;

+} +EXPORT_SYMBOL(devm_drm_of_get_bridge); #endif

MODULE_AUTHOR("Ajay Kumar ajaykumar.rs@samsung.com"); diff --git a/drivers/gpu/drm/drm_of.c b/drivers/gpu/drm/drm_of.c index 997b8827fed2..37c34146eea8 100644 --- a/drivers/gpu/drm/drm_of.c +++ b/drivers/gpu/drm/drm_of.c @@ -231,6 +231,9 @@ EXPORT_SYMBOL_GPL(drm_of_encoder_active_endpoint);

• return either the associated struct drm_panel or drm_bridge device. Either
• @panel or @bridge must not be NULL.

• • This function is deprecated and should not be used in new drivers. Use
• • devm_drm_of_get_bridge() instead.
• • Returns zero if successful, or one of the standard error codes if it fails.
  */

int drm_of_find_panel_or_bridge(const struct device_node *np, diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h index 46bdfa48c413..f70c88ca96ef 100644 --- a/include/drm/drm_bridge.h +++ b/include/drm/drm_bridge.h @@ -911,6 +911,8 @@ struct drm_bridge *devm_drm_panel_bridge_add(struct device *dev, struct drm_bridge *devm_drm_panel_bridge_add_typed(struct device *dev, struct drm_panel *panel, u32 connector_type); +struct drm_bridge *devm_drm_of_get_bridge(struct device *dev, struct device_node *node,

• 			unsigned int port, unsigned int endpoint);
  

struct drm_connector *drm_panel_bridge_connector(struct drm_bridge *bridge); #endif

-- 2.31.1

On Fri, Sep 10, 2021 at 3:10 PM Maxime Ripard maxime@cerno.tech wrote:

Display drivers so far need to have a lot of boilerplate to first retrieve either the panel or bridge that they are connected to using drm_of_find_panel_or_bridge(), and then either deal with each with ad-hoc functions or create a drm panel bridge through drm_panel_bridge_add.

In order to reduce the boilerplate and hopefully create a path of least resistance towards using the DRM panel bridge layer, let's create the function devm_drm_of_get_next to reduce that boilerplate.

Hi Maxime,

This patch creates a dependency error for me:

depmod: ERROR: Cycle detected: drm_kms_helper -> drm -> drm_kms_helper depmod: ERROR: Cycle detected: cec depmod: ERROR: Found 2 modules in dependency cycles!

Cheers Patrik

Signed-off-by: Maxime Ripard maxime@cerno.tech

drivers/gpu/drm/drm_bridge.c | 42 ++++++++++++++++++++++++++++++++---- drivers/gpu/drm/drm_of.c | 3 +++ include/drm/drm_bridge.h | 2 ++ 3 files changed, 43 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c index a8ed66751c2d..10ddca4638b0 100644 --- a/drivers/gpu/drm/drm_bridge.c +++ b/drivers/gpu/drm/drm_bridge.c @@ -28,6 +28,7 @@ #include <drm/drm_atomic_state_helper.h> #include <drm/drm_bridge.h> #include <drm/drm_encoder.h> +#include <drm/drm_of.h> #include <drm/drm_print.h>

#include "drm_crtc_internal.h" @@ -51,10 +52,8 @@

• Display drivers are responsible for linking encoders with the first bridge
• in the chains. This is done by acquiring the appropriate bridge with

• • of_drm_find_bridge() or drm_of_find_panel_or_bridge(), or creating it for a
• • panel with drm_panel_bridge_add_typed() (or the managed version
• • devm_drm_panel_bridge_add_typed()). Once acquired, the bridge shall be
• • attached to the encoder with a call to drm_bridge_attach().

• • devm_drm_of_get_bridge(). Once acquired, the bridge shall be attached to the
• • encoder with a call to drm_bridge_attach().
  • Bridges are responsible for linking themselves with the next bridge in the
  • chain, if any. This is done the same way as for encoders, with the call to

@@ -1233,6 +1232,41 @@ struct drm_bridge *of_drm_find_bridge(struct device_node *np) return NULL; } EXPORT_SYMBOL(of_drm_find_bridge);

+/**

• • devm_drm_of_get_bridge - Return next bridge in the chain
• • @dev: device to tie the bridge lifetime to
• • @np: device tree node containing encoder output ports
• • @port: port in the device tree node
• • @endpoint: endpoint in the device tree node
• • Given a DT node's port and endpoint number, finds the connected node
• • and returns the associated bridge if any, or creates and returns a
• • drm panel bridge instance if a panel is connected.
• • Returns a pointer to the bridge if successful, or an error pointer
• • otherwise.
• */

+struct drm_bridge *devm_drm_of_get_bridge(struct device *dev,

•                                     struct device_node *np,
  

•                                     unsigned int port,
  

•                                     unsigned int endpoint)
  

+{

•   struct drm_bridge *bridge;
  

•   struct drm_panel *panel;
  

•   int ret;
  

•   ret = drm_of_find_panel_or_bridge(np, port, endpoint,
  

•                                     &panel, &bridge);
  

•   if (ret)
  

•           return ERR_PTR(ret);
  

•   if (panel)
  

•           bridge = devm_drm_panel_bridge_add(dev, panel);
  

•   return bridge;
  

+} +EXPORT_SYMBOL(devm_drm_of_get_bridge); #endif

MODULE_AUTHOR("Ajay Kumar ajaykumar.rs@samsung.com"); diff --git a/drivers/gpu/drm/drm_of.c b/drivers/gpu/drm/drm_of.c index 997b8827fed2..37c34146eea8 100644 --- a/drivers/gpu/drm/drm_of.c +++ b/drivers/gpu/drm/drm_of.c @@ -231,6 +231,9 @@ EXPORT_SYMBOL_GPL(drm_of_encoder_active_endpoint);

• return either the associated struct drm_panel or drm_bridge device. Either
• @panel or @bridge must not be NULL.

• • This function is deprecated and should not be used in new drivers. Use
• • devm_drm_of_get_bridge() instead.
• • Returns zero if successful, or one of the standard error codes if it fails.
  */

int drm_of_find_panel_or_bridge(const struct device_node *np, diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h index 46bdfa48c413..f70c88ca96ef 100644 --- a/include/drm/drm_bridge.h +++ b/include/drm/drm_bridge.h @@ -911,6 +911,8 @@ struct drm_bridge *devm_drm_panel_bridge_add(struct device *dev, struct drm_bridge *devm_drm_panel_bridge_add_typed(struct device *dev, struct drm_panel *panel, u32 connector_type); +struct drm_bridge *devm_drm_of_get_bridge(struct device *dev, struct device_node *node,

•                                   unsigned int port, unsigned int endpoint);
  

struct drm_connector *drm_panel_bridge_connector(struct drm_bridge *bridge); #endif

-- 2.31.1

On Thu, Sep 23, 2021 at 03:29:37AM +0300, Laurent Pinchart wrote:

Hi Maxime,

Thank you for the patch.

I know this has already been merged, but I have a question.

On Fri, Sep 10, 2021 at 03:09:39PM +0200, Maxime Ripard wrote:

...

Display drivers so far need to have a lot of boilerplate to first retrieve either the panel or bridge that they are connected to using drm_of_find_panel_or_bridge(), and then either deal with each with ad-hoc functions or create a drm panel bridge through drm_panel_bridge_add.

In order to reduce the boilerplate and hopefully create a path of least resistance towards using the DRM panel bridge layer, let's create the function devm_drm_of_get_next to reduce that boilerplate.

Signed-off-by: Maxime Ripard maxime@cerno.tech

drivers/gpu/drm/drm_bridge.c | 42 ++++++++++++++++++++++++++++++++---- drivers/gpu/drm/drm_of.c | 3 +++ include/drm/drm_bridge.h | 2 ++ 3 files changed, 43 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c index a8ed66751c2d..10ddca4638b0 100644 --- a/drivers/gpu/drm/drm_bridge.c +++ b/drivers/gpu/drm/drm_bridge.c @@ -28,6 +28,7 @@ #include <drm/drm_atomic_state_helper.h> #include <drm/drm_bridge.h> #include <drm/drm_encoder.h> +#include <drm/drm_of.h> #include <drm/drm_print.h>

#include "drm_crtc_internal.h" @@ -51,10 +52,8 @@

• Display drivers are responsible for linking encoders with the first bridge
• in the chains. This is done by acquiring the appropriate bridge with

• • of_drm_find_bridge() or drm_of_find_panel_or_bridge(), or creating it for a
• • panel with drm_panel_bridge_add_typed() (or the managed version
• • devm_drm_panel_bridge_add_typed()). Once acquired, the bridge shall be
• • attached to the encoder with a call to drm_bridge_attach().

• • devm_drm_of_get_bridge(). Once acquired, the bridge shall be attached to the
• • encoder with a call to drm_bridge_attach().
  • Bridges are responsible for linking themselves with the next bridge in the
  • chain, if any. This is done the same way as for encoders, with the call to

@@ -1233,6 +1232,41 @@ struct drm_bridge *of_drm_find_bridge(struct device_node *np) return NULL; } EXPORT_SYMBOL(of_drm_find_bridge);

+/**

• • devm_drm_of_get_bridge - Return next bridge in the chain
• • @dev: device to tie the bridge lifetime to
• • @np: device tree node containing encoder output ports
• • @port: port in the device tree node
• • @endpoint: endpoint in the device tree node
• • Given a DT node's port and endpoint number, finds the connected node
• • and returns the associated bridge if any, or creates and returns a
• • drm panel bridge instance if a panel is connected.
• • Returns a pointer to the bridge if successful, or an error pointer
• • otherwise.
• */

+struct drm_bridge *devm_drm_of_get_bridge(struct device *dev,

• 			  struct device_node *np,
  

• 			  unsigned int port,
  

• 			  unsigned int endpoint)
  

+{

• struct drm_bridge *bridge;
• struct drm_panel *panel;
• int ret;
• ret = drm_of_find_panel_or_bridge(np, port, endpoint,

• 			  &panel, &bridge);
  

• if (ret)

• return ERR_PTR(ret);
  

• if (panel)

• bridge = devm_drm_panel_bridge_add(dev, panel);
  

• return bridge;

I really like the idea, I've wanted to do something like this for a long time. I however wonder if this is the best approach, or if we could get the panel core to register the bridge itself. The part that bothers me here is the assymetry in the lifetime of the bridges, the returned pointer is either looked up or allocated.

Bridge lifetime is such a mess that it may not make a big difference, but eventually we'll have to address that problem globally.

We can't have Rust soon enough :)

Does it really matter though? I thought the bridges couldn't be unloaded from a DRM device anyway, so for all practical purposes this will be removed at around the same time: when the whole DRM device is going to be teared down?

Maxime

W dniu 23.09.2021 o 02:29, Laurent Pinchart pisze:

Hi Maxime,

Thank you for the patch.

I know this has already been merged, but I have a question.

On Fri, Sep 10, 2021 at 03:09:39PM +0200, Maxime Ripard wrote:

...

Display drivers so far need to have a lot of boilerplate to first retrieve either the panel or bridge that they are connected to using drm_of_find_panel_or_bridge(), and then either deal with each with ad-hoc functions or create a drm panel bridge through drm_panel_bridge_add.

In order to reduce the boilerplate and hopefully create a path of least resistance towards using the DRM panel bridge layer, let's create the function devm_drm_of_get_next to reduce that boilerplate.

Signed-off-by: Maxime Ripard maxime@cerno.tech

drivers/gpu/drm/drm_bridge.c | 42 ++++++++++++++++++++++++++++++++---- drivers/gpu/drm/drm_of.c | 3 +++ include/drm/drm_bridge.h | 2 ++ 3 files changed, 43 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c index a8ed66751c2d..10ddca4638b0 100644 --- a/drivers/gpu/drm/drm_bridge.c +++ b/drivers/gpu/drm/drm_bridge.c @@ -28,6 +28,7 @@ #include <drm/drm_atomic_state_helper.h> #include <drm/drm_bridge.h> #include <drm/drm_encoder.h> +#include <drm/drm_of.h> #include <drm/drm_print.h>

#include "drm_crtc_internal.h" @@ -51,10 +52,8 @@

• Display drivers are responsible for linking encoders with the first bridge
• in the chains. This is done by acquiring the appropriate bridge with

• • of_drm_find_bridge() or drm_of_find_panel_or_bridge(), or creating it for a
• • panel with drm_panel_bridge_add_typed() (or the managed version
• • devm_drm_panel_bridge_add_typed()). Once acquired, the bridge shall be
• • attached to the encoder with a call to drm_bridge_attach().

• • devm_drm_of_get_bridge(). Once acquired, the bridge shall be attached to the
• • encoder with a call to drm_bridge_attach().
  • Bridges are responsible for linking themselves with the next bridge in the
  • chain, if any. This is done the same way as for encoders, with the call to

@@ -1233,6 +1232,41 @@ struct drm_bridge *of_drm_find_bridge(struct device_node *np) return NULL; } EXPORT_SYMBOL(of_drm_find_bridge);

+/**

• • devm_drm_of_get_bridge - Return next bridge in the chain
• • @dev: device to tie the bridge lifetime to
• • @np: device tree node containing encoder output ports
• • @port: port in the device tree node
• • @endpoint: endpoint in the device tree node
• • Given a DT node's port and endpoint number, finds the connected node
• • and returns the associated bridge if any, or creates and returns a
• • drm panel bridge instance if a panel is connected.
• • Returns a pointer to the bridge if successful, or an error pointer
• • otherwise.
• */

+struct drm_bridge *devm_drm_of_get_bridge(struct device *dev,

• 			  struct device_node *np,
  

• 			  unsigned int port,
  

• 			  unsigned int endpoint)
  

+{

• struct drm_bridge *bridge;
• struct drm_panel *panel;
• int ret;
• ret = drm_of_find_panel_or_bridge(np, port, endpoint,

• 			  &panel, &bridge);
  

• if (ret)

• return ERR_PTR(ret);
  

• if (panel)

• bridge = devm_drm_panel_bridge_add(dev, panel);
  

• return bridge;

I really like the idea, I've wanted to do something like this for a long time. I however wonder if this is the best approach, or if we could get the panel core to register the bridge itself. The part that bothers me here is the assymetry in the lifetime of the bridges, the returned pointer is either looked up or allocated.

When drm_panel_bridge was proposed 1st time I suggested that instead of it we should just merge panels with bridges (maybe with new name, my favorite is drm_sink), but I was outvoted :)

Apparently with this patch we go to the same direction: since panels will be accessed only via drm_panel_bridge they will become actually bridges :) Somebody could then clean-up the whole intermediate code.

Regards

Andrzej

Bridge lifetime is such a mess that it may not make a big difference, but eventually we'll have to address that problem globally.

...

+} +EXPORT_SYMBOL(devm_drm_of_get_bridge); #endif

MODULE_AUTHOR("Ajay Kumar ajaykumar.rs@samsung.com"); diff --git a/drivers/gpu/drm/drm_of.c b/drivers/gpu/drm/drm_of.c index 997b8827fed2..37c34146eea8 100644 --- a/drivers/gpu/drm/drm_of.c +++ b/drivers/gpu/drm/drm_of.c @@ -231,6 +231,9 @@ EXPORT_SYMBOL_GPL(drm_of_encoder_active_endpoint);

• return either the associated struct drm_panel or drm_bridge device. Either
• @panel or @bridge must not be NULL.

• • This function is deprecated and should not be used in new drivers. Use
• • devm_drm_of_get_bridge() instead.
• • Returns zero if successful, or one of the standard error codes if it fails.
  */ int drm_of_find_panel_or_bridge(const struct device_node *np,

diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h index 46bdfa48c413..f70c88ca96ef 100644 --- a/include/drm/drm_bridge.h +++ b/include/drm/drm_bridge.h @@ -911,6 +911,8 @@ struct drm_bridge *devm_drm_panel_bridge_add(struct device *dev, struct drm_bridge *devm_drm_panel_bridge_add_typed(struct device *dev, struct drm_panel *panel, u32 connector_type); +struct drm_bridge *devm_drm_of_get_bridge(struct device *dev, struct device_node *node,

• 			unsigned int port, unsigned int endpoint);
  

  struct drm_connector *drm_panel_bridge_connector(struct drm_bridge *bridge); #endif

On Fri, Sep 10, 2021 at 03:09:40PM +0200, Maxime Ripard wrote:

The new devm_drm_of_get_bridge removes most of the boilerplate we have to deal with. Let's switch to it.

Signed-off-by: Maxime Ripard maxime@cerno.tech

Acked-by: Sam Ravnborg sam@ravnborg.org

---

drivers/gpu/drm/vc4/vc4_dpi.c | 15 ++++----------- 1 file changed, 4 insertions(+), 11 deletions(-)

diff --git a/drivers/gpu/drm/vc4/vc4_dpi.c b/drivers/gpu/drm/vc4/vc4_dpi.c index a90f2545baee..c180eb60bee8 100644 --- a/drivers/gpu/drm/vc4/vc4_dpi.c +++ b/drivers/gpu/drm/vc4/vc4_dpi.c @@ -229,26 +229,19 @@ static const struct of_device_id vc4_dpi_dt_match[] = { static int vc4_dpi_init_bridge(struct vc4_dpi *dpi) { struct device *dev = &dpi->pdev->dev;

• struct drm_panel *panel; struct drm_bridge *bridge;

• int ret;

• ret = drm_of_find_panel_or_bridge(dev->of_node, 0, 0,

• 			  &panel, &bridge);
  

• if (ret) {

• bridge = devm_drm_of_get_bridge(dev, dev->of_node, 0, 0);
• if (IS_ERR(bridge)) { /* If nothing was connected in the DT, that's not an
  • error.
  */

• if (ret == -ENODEV)
  

• if (PTR_ERR(bridge) == -ENODEV)
  return 0;
  

  else

• 	return ret;
  

• 	return PTR_ERR(bridge);
  

  }

• if (panel)

• bridge = drm_panel_bridge_add_typed(panel,
  

• 				    DRM_MODE_CONNECTOR_DPI);
  

• return drm_bridge_attach(dpi->encoder, bridge, NULL, 0);

}

-- 2.31.1

On Fri, Sep 10, 2021 at 03:09:41PM +0200, Maxime Ripard wrote:

The new devm_drm_of_get_bridge removes most of the boilerplate we have to deal with. Let's switch to it.

Signed-off-by: Maxime Ripard maxime@cerno.tech

With the includes updated:

Acked-by: Sam Ravnborg sam@ravnborg.org

Sam

---

drivers/gpu/drm/vc4/vc4_drv.c | 2 ++ drivers/gpu/drm/vc4/vc4_dsi.c | 28 ++++------------------------ 2 files changed, 6 insertions(+), 24 deletions(-)

diff --git a/drivers/gpu/drm/vc4/vc4_drv.c b/drivers/gpu/drm/vc4/vc4_drv.c index 16abc3a3d601..96c526f1022e 100644 --- a/drivers/gpu/drm/vc4/vc4_drv.c +++ b/drivers/gpu/drm/vc4/vc4_drv.c @@ -25,7 +25,9 @@ #include <linux/device.h> #include <linux/dma-mapping.h> #include <linux/io.h> +#include <linux/i2c.h>

I fail to see why this include is needed?

#include <linux/module.h> +#include <linux/of_graph.h>

I think this should be drm_bridge.h. And drm_bridge.h hopefully pulls in what is needed.

#include <linux/of_platform.h> #include <linux/platform_device.h> #include <linux/pm_runtime.h> diff --git a/drivers/gpu/drm/vc4/vc4_dsi.c b/drivers/gpu/drm/vc4/vc4_dsi.c index a185027911ce..a229da58962a 100644 --- a/drivers/gpu/drm/vc4/vc4_dsi.c +++ b/drivers/gpu/drm/vc4/vc4_dsi.c @@ -1497,7 +1497,6 @@ static int vc4_dsi_bind(struct device *dev, struct device *master, void *data) struct drm_device *drm = dev_get_drvdata(master); struct vc4_dsi *dsi = dev_get_drvdata(dev); struct vc4_dsi_encoder *vc4_dsi_encoder;

• struct drm_panel *panel; const struct of_device_id *match; dma_cap_mask_t dma_mask; int ret;

@@ -1609,27 +1608,9 @@ static int vc4_dsi_bind(struct device *dev, struct device *master, void *data) return ret; }

• ret = drm_of_find_panel_or_bridge(dev->of_node, 0, 0,

• 			  &panel, &dsi->bridge);
  

• if (ret) {

• /* If the bridge or panel pointed by dev->of_node is not
  

•  * enabled, just return 0 here so that we don't prevent the DRM
  

•  * dev from being registered. Of course that means the DSI
  

•  * encoder won't be exposed, but that's not a problem since
  

•  * nothing is connected to it.
  

•  */
  

• if (ret == -ENODEV)
  

• 	return 0;
  

• return ret;
  

• }
• if (panel) {

• dsi->bridge = devm_drm_panel_bridge_add_typed(dev, panel,
  

• 					      DRM_MODE_CONNECTOR_DSI);
  

• if (IS_ERR(dsi->bridge))
  

• 	return PTR_ERR(dsi->bridge);
  

• }

• dsi->bridge = devm_drm_of_get_bridge(dev, dev->of_node, 0, 0);

• if (IS_ERR(dsi->bridge))

• return PTR_ERR(dsi->bridge);
  
  

  /* The esc clock rate is supposed to always be 100Mhz. */ ret = clk_set_rate(dsi->escape_clock, 100 * 1000000);

@@ -1667,8 +1648,7 @@ static void vc4_dsi_unbind(struct device *dev, struct device *master, { struct vc4_dsi *dsi = dev_get_drvdata(dev);

• if (dsi->bridge)

• pm_runtime_disable(dev);
  

• pm_runtime_disable(dev);

  /*

  • Restore the bridge_chain so the bridge detach procedure can happen

-- 2.31.1