[PATCH 0/2] Add enable gpio to display connector

[PATCH 0/2] Add enable gpio to display connector

[Prahlad Valluru]

In some cases, dp-connectors may need to enable gpios to
select or enable the port. For cases like those, we don't have
any gpio devicetree option.
In this patch, add optional enable gpio to handle them in
display-connector, so that it can be used for any connector.

---
Prahlad Valluru (2):
      dt-bindings: dp-connector: describe enable gpio
      drm: bridge: add enable gpio for display-connector

 .../devicetree/bindings/display/connector/dp-connector.yaml        | 4 ++++
 drivers/gpu/drm/bridge/display-connector.c                         | 7 +++++++
 2 files changed, 11 insertions(+)
---
base-commit: 4f9ffd2c80a2fa09dcc8dfa0482cb7e0fb6fcf6c
change-id: 20251028-enable-gpio-dp-connector-1e4e8611ec08

Best regards,
-- 
Prahlad Valluru <venkata.valluru@oss.qualcomm.com>

[PATCH 1/2] dt-bindings: dp-connector: describe enable gpio

[Prahlad Valluru]

In some cases, dp-connector need a gpio for
connector to be enabled. Currently, there is no such
entry so, add enable-gpios for such cases.

Signed-off-by: Prahlad Valluru <venkata.valluru@oss.qualcomm.com>
---
 Documentation/devicetree/bindings/display/connector/dp-connector.yaml | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/Documentation/devicetree/bindings/display/connector/dp-connector.yaml b/Documentation/devicetree/bindings/display/connector/dp-connector.yaml
index 1f2b449dc910..e703b19b7168 100644
--- a/Documentation/devicetree/bindings/display/connector/dp-connector.yaml
+++ b/Documentation/devicetree/bindings/display/connector/dp-connector.yaml
@@ -20,6 +20,10 @@ properties:
       - full-size
       - mini
 
+  enable-gpios:
+    description: A GPIO line connected to enable connector
+    maxItems: 1
+
   hpd-gpios:
     description: A GPIO line connected to HPD
     maxItems: 1

-- 
2.34.1

Re: [PATCH 1/2] dt-bindings: dp-connector: describe enable gpio

[Krzysztof Kozlowski]

On 28/10/2025 16:26, Prahlad Valluru wrote:
> In some cases, dp-connector need a gpio for
> connector to be enabled. Currently, there is no such

In what cases? Please describe the hardware because I am surprised to
see that connector need to be enabled. Seems like you are solving
completely different problem.

Best regards,
Krzysztof

[PATCH 2/2] drm: bridge: add enable gpio for display-connector

[Prahlad Valluru]

In some cases, need gpio to be set for the connector
enable. Add optional enable gpio to display-connector.

Signed-off-by: Prahlad Valluru <venkata.valluru@oss.qualcomm.com>
---
 drivers/gpu/drm/bridge/display-connector.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/gpu/drm/bridge/display-connector.c b/drivers/gpu/drm/bridge/display-connector.c
index e9f16dbc9535..52f5e4175e64 100644
--- a/drivers/gpu/drm/bridge/display-connector.c
+++ b/drivers/gpu/drm/bridge/display-connector.c
@@ -21,6 +21,7 @@ struct display_connector {
 	struct drm_bridge	bridge;
 
 	struct gpio_desc	*hpd_gpio;
+	struct gpio_desc	*enable_gpio;
 	int			hpd_irq;
 
 	struct regulator	*supply;
@@ -298,6 +299,12 @@ static int display_connector_probe(struct platform_device *pdev)
 					     "Unable to retrieve HPD GPIO\n");
 
 		conn->hpd_irq = gpiod_to_irq(conn->hpd_gpio);
+
+		conn->enable_gpio = devm_gpiod_get_optional(&pdev->dev, "enable",
+							 GPIOD_OUT_HIGH);
+		if (IS_ERR(conn->enable_gpio))
+			return dev_err_probe(&pdev->dev, PTR_ERR(conn->enable_gpio),
+					     "Unable to retrieve enable GPIO\n");
 	} else {
 		conn->hpd_irq = -EINVAL;
 	}

-- 
2.34.1

Re: [PATCH 2/2] drm: bridge: add enable gpio for display-connector

[Laurent Pinchart]

On Tue, Oct 28, 2025 at 08:56:50PM +0530, Prahlad Valluru wrote:
> In some cases, need gpio to be set for the connector
> enable. Add optional enable gpio to display-connector.
> 
> Signed-off-by: Prahlad Valluru <venkata.valluru@oss.qualcomm.com>
> ---
>  drivers/gpu/drm/bridge/display-connector.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/drivers/gpu/drm/bridge/display-connector.c b/drivers/gpu/drm/bridge/display-connector.c
> index e9f16dbc9535..52f5e4175e64 100644
> --- a/drivers/gpu/drm/bridge/display-connector.c
> +++ b/drivers/gpu/drm/bridge/display-connector.c
> @@ -21,6 +21,7 @@ struct display_connector {
>  	struct drm_bridge	bridge;
>  
>  	struct gpio_desc	*hpd_gpio;
> +	struct gpio_desc	*enable_gpio;
>  	int			hpd_irq;
>  
>  	struct regulator	*supply;
> @@ -298,6 +299,12 @@ static int display_connector_probe(struct platform_device *pdev)
>  					     "Unable to retrieve HPD GPIO\n");
>  
>  		conn->hpd_irq = gpiod_to_irq(conn->hpd_gpio);
> +
> +		conn->enable_gpio = devm_gpiod_get_optional(&pdev->dev, "enable",
> +							 GPIOD_OUT_HIGH);

What does it mean to "enable the connector" ? Given that you don't set
the GPIO value at runtime, this seems to be a hack that is probably
better handled with GPIO hogs in the device tree.

> +		if (IS_ERR(conn->enable_gpio))
> +			return dev_err_probe(&pdev->dev, PTR_ERR(conn->enable_gpio),
> +					     "Unable to retrieve enable GPIO\n");
>  	} else {
>  		conn->hpd_irq = -EINVAL;
>  	}

-- 
Regards,

Laurent Pinchart

Re: [PATCH 2/2] drm: bridge: add enable gpio for display-connector

[Prahlad Valluru]

On Tue, Oct 28, 2025 at 05:49:29PM +0200, Laurent Pinchart wrote:
> On Tue, Oct 28, 2025 at 08:56:50PM +0530, Prahlad Valluru wrote:
> > In some cases, need gpio to be set for the connector
> > enable. Add optional enable gpio to display-connector.
> > 
> > Signed-off-by: Prahlad Valluru <venkata.valluru@oss.qualcomm.com>
> > ---
> >  drivers/gpu/drm/bridge/display-connector.c | 7 +++++++
> >  1 file changed, 7 insertions(+)
> > 
> > diff --git a/drivers/gpu/drm/bridge/display-connector.c b/drivers/gpu/drm/bridge/display-connector.c
> > index e9f16dbc9535..52f5e4175e64 100644
> > --- a/drivers/gpu/drm/bridge/display-connector.c
> > +++ b/drivers/gpu/drm/bridge/display-connector.c
> > @@ -21,6 +21,7 @@ struct display_connector {
> >  	struct drm_bridge	bridge;
> >  
> >  	struct gpio_desc	*hpd_gpio;
> > +	struct gpio_desc	*enable_gpio;
> >  	int			hpd_irq;
> >  
> >  	struct regulator	*supply;
> > @@ -298,6 +299,12 @@ static int display_connector_probe(struct platform_device *pdev)
> >  					     "Unable to retrieve HPD GPIO\n");
> >  
> >  		conn->hpd_irq = gpiod_to_irq(conn->hpd_gpio);
> > +
> > +		conn->enable_gpio = devm_gpiod_get_optional(&pdev->dev, "enable",
> > +							 GPIOD_OUT_HIGH);
> 
> What does it mean to "enable the connector" ? Given that you don't set
> the GPIO value at runtime, this seems to be a hack that is probably
> better handled with GPIO hogs in the device tree.
DP_PWR 3.3v for the connector is enabled by a gpio. gpio hog will perfectly
work for this scenario, thanks for the suggestion.
> 
> > +		if (IS_ERR(conn->enable_gpio))
> > +			return dev_err_probe(&pdev->dev, PTR_ERR(conn->enable_gpio),
> > +					     "Unable to retrieve enable GPIO\n");
> >  	} else {
> >  		conn->hpd_irq = -EINVAL;
> >  	}
> 
> -- 
> Regards,
> 
> Laurent Pinchart