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

Dmitry Baryshkov
2025-07-19T10:53:56Z

On Fri, Jul 18, 2025 at 02:26:17PM +0800, Chaoyi Chen wrote:
> From: Chaoyi Chen <chaoyi.chen@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@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