Add enable gpio to display connector

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

Posted by Prahlad Valluru 3 months, 1 week ago

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

Posted by Laurent Pinchart 3 months, 1 week ago

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

Posted by Prahlad Valluru 3 months ago

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