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

[air windows]

在 2025/7/19 18:53, Dmitry Baryshkov 写道:

On Fri, Jul 18, 2025 at 02:26:17PM +0800, Chaoyi Chen wrote:

From: Chaoyi Chen <chaoyi.c...@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.

Yes, that's exactly the case for the DP Altmode driver! I've thought of a few 
approaches, but none of them are elegant. Now it relying on the PHY driver to 
call the drm_connector_oob_hotplug_event(). You'll find the relevant code in 
the PHY driver.

The extcon device should still be supported if Type-C controller is
not present.

Signed-off-by: Chaoyi Chen <chaoyi.c...@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