[PATCH v2 3/5] drm/rockchip: cdn-dp: Support handle lane info and HPD without extcon

[Dmitry Baryshkov]

On Fri, Jul 18, 2025 at 02:26:17PM +0800, Chaoyi Chen wrote:
> From: Chaoyi Chen <chaoyi.chen at rock-chips.com>
> 
> This patch add support for get PHY lane info and handle HPD state
> without help of extcon.
> 
> There is no extcon needed if the Type-C controller is present. In this
> case, cdn_dp_hpd_notify() will handle HPD event from USB/DP combo PHY,
> and the lane info can be get from PHY instead of extcon.

The DP AltMode driver will send drm_connector_oob_hotplug_event() to the
DRM connector associated with the USB-C connector fwnode. However your
DP connector will have fwnode set to the DP controller, if I'm not
mistaken. So I doubt that HPD events are going to be delivered
correctly.

> 
> The extcon device should still be supported if Type-C controller is
> not present.
> 
> Signed-off-by: Chaoyi Chen <chaoyi.chen at rock-chips.com>
> ---
> 
> Changes in v2:
> - Ignore duplicate HPD events.
> 
>  drivers/gpu/drm/rockchip/cdn-dp-core.c | 37 ++++++++++++++++++++------
>  1 file changed, 29 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/gpu/drm/rockchip/cdn-dp-core.c b/drivers/gpu/drm/rockchip/cdn-dp-core.c
> index 24f6b3879f4b..b574b059b58d 100644
> --- a/drivers/gpu/drm/rockchip/cdn-dp-core.c
> +++ b/drivers/gpu/drm/rockchip/cdn-dp-core.c
> @@ -156,6 +156,9 @@ static int cdn_dp_get_port_lanes(struct cdn_dp_port *port)
>  	int dptx;
>  	u8 lanes;
>  
> +	if (!edev)
> +		return phy_get_bus_width(port->phy);
> +
>  	dptx = extcon_get_state(edev, EXTCON_DISP_DP);
>  	if (dptx > 0) {
>  		extcon_get_property(edev, EXTCON_DISP_DP,
> @@ -219,7 +222,7 @@ static bool cdn_dp_check_sink_connection(struct cdn_dp_device *dp)
>  	 * some docks need more time to power up.
>  	 */
>  	while (time_before(jiffies, timeout)) {
> -		if (!extcon_get_state(port->extcon, EXTCON_DISP_DP))
> +		if (port->extcon && !extcon_get_state(port->extcon, EXTCON_DISP_DP))
>  			return false;
>  
>  		if (!cdn_dp_get_sink_count(dp, &sink_count))
> @@ -385,11 +388,14 @@ static int cdn_dp_enable_phy(struct cdn_dp_device *dp, struct cdn_dp_port *port)
>  		goto err_power_on;
>  	}
>  
> -	ret = extcon_get_property(port->extcon, EXTCON_DISP_DP,
> -				  EXTCON_PROP_USB_TYPEC_POLARITY, &property);
> -	if (ret) {
> -		DRM_DEV_ERROR(dp->dev, "get property failed\n");
> -		goto err_power_on;
> +	property.intval = 0;
> +	if (port->extcon) {
> +		ret = extcon_get_property(port->extcon, EXTCON_DISP_DP,
> +					  EXTCON_PROP_USB_TYPEC_POLARITY, &property);
> +		if (ret) {
> +			DRM_DEV_ERROR(dp->dev, "get property failed\n");
> +			goto err_power_on;
> +		}
>  	}
>  
>  	port->lanes = cdn_dp_get_port_lanes(port);
> @@ -821,6 +827,17 @@ static int cdn_dp_audio_mute_stream(struct drm_connector *connector,
>  	return ret;
>  }
>  
> +static void cdn_dp_hpd_notify(struct drm_bridge *bridge,
> +			      enum drm_connector_status status)
> +{
> +	struct cdn_dp_device *dp = bridge_to_dp(bridge);
> +	enum drm_connector_status last_status =
> +		dp->connected ? connector_status_connected : connector_status_disconnected;
> +
> +	if (last_status != status)
> +		schedule_work(&dp->event_work);
> +}
> +
>  static const struct drm_bridge_funcs cdn_dp_bridge_funcs = {
>  	.atomic_duplicate_state = drm_atomic_helper_bridge_duplicate_state,
>  	.atomic_destroy_state = drm_atomic_helper_bridge_destroy_state,
> @@ -831,6 +848,7 @@ static const struct drm_bridge_funcs cdn_dp_bridge_funcs = {
>  	.atomic_disable = cdn_dp_bridge_atomic_disable,
>  	.mode_valid = cdn_dp_bridge_mode_valid,
>  	.mode_set = cdn_dp_bridge_mode_set,
> +	.hpd_notify = cdn_dp_hpd_notify,
>  
>  	.dp_audio_prepare = cdn_dp_audio_prepare,
>  	.dp_audio_mute_stream = cdn_dp_audio_mute_stream,
> @@ -1028,6 +1046,9 @@ static int cdn_dp_bind(struct device *dev, struct device *master, void *data)
>  	for (i = 0; i < dp->ports; i++) {
>  		port = dp->port[i];
>  
> +		if (!port->extcon)
> +			continue;
> +
>  		port->event_nb.notifier_call = cdn_dp_pd_event;
>  		ret = devm_extcon_register_notifier(dp->dev, port->extcon,
>  						    EXTCON_DISP_DP,
> @@ -1120,14 +1141,14 @@ static int cdn_dp_probe(struct platform_device *pdev)
>  		    PTR_ERR(phy) == -EPROBE_DEFER)
>  			return -EPROBE_DEFER;
>  
> -		if (IS_ERR(extcon) || IS_ERR(phy))
> +		if (IS_ERR(phy) || PTR_ERR(extcon) != -ENODEV)
>  			continue;
>  
>  		port = devm_kzalloc(dev, sizeof(*port), GFP_KERNEL);
>  		if (!port)
>  			return -ENOMEM;
>  
> -		port->extcon = extcon;
> +		port->extcon = IS_ERR(extcon) ? NULL : extcon;
>  		port->phy = phy;
>  		port->dp = dp;
>  		port->id = i;
> -- 
> 2.49.0
> 

-- 
With best wishes
Dmitry