On 9/23/2025 9:50 AM, Dmitry Baryshkov wrote:
On Mon, Sep 22, 2025 at 09:20:37AM +0800, Chaoyi Chen wrote:From: Chaoyi Chen <[email protected]>The RK3399 has two USB/DP combo PHY and one CDN-DP controller. And the CDN-DP can be switched to output to one of the PHYs. If both ports are plugged into DP, DP will select the first port for output. This patch adds support for multiple bridges, enabling users to flexibly select the output port. For each PHY port, a separate encoder and bridge are registered. The change is based on the DRM AUX HPD bridge, rather than the extcon approach. This requires the DT to correctly describe the connections between the PHY, USB connector, and DP controller. And cdn_dp_parse_hpd_bridge_dt() will parses it and determines whether to register one or two bridges. Since there is only one DP controller, only one of the PHY ports can output at a time. The key is how to switch between different PHYs, which is handled by cdn_dp_switch_port() and cdn_dp_enable(). There are two cases: 1. Neither bridge is enabled. In this case, both bridges can independently read the EDID, and the PHY port may switch before reading the EDID. 2. One bridge is already enabled. In this case, other bridges are not allowed to read the EDID. Since the scenario of two ports plug in at the same time is rare, I don't have a board which support two TypeC connector to test this. Therefore, I tested forced switching on a single PHY port, as well as output using a fake PHY port alongside a real PHY port. Signed-off-by: Chaoyi Chen <[email protected]> --- drivers/gpu/drm/rockchip/Kconfig | 1 + drivers/gpu/drm/rockchip/cdn-dp-core.c | 398 +++++++++++++++++++++---- drivers/gpu/drm/rockchip/cdn-dp-core.h | 23 +- 3 files changed, 366 insertions(+), 56 deletions(-) diff --git a/drivers/gpu/drm/rockchip/Kconfig b/drivers/gpu/drm/rockchip/Kconfig index faf50d872be3..3a6266279323 100644 --- a/drivers/gpu/drm/rockchip/Kconfig +++ b/drivers/gpu/drm/rockchip/Kconfig @@ -55,6 +55,7 @@ config ROCKCHIP_CDN_DP select DRM_DISPLAY_HELPER select DRM_BRIDGE_CONNECTOR select DRM_DISPLAY_DP_HELPER + select DRM_AUX_HPD_BRIDGE help This selects support for Rockchip SoC specific extensions for the cdn DP driver. If you want to enable Dp on diff --git a/drivers/gpu/drm/rockchip/cdn-dp-core.c b/drivers/gpu/drm/rockchip/cdn-dp-core.c index 1e27301584a4..784f5656fcc4 100644 --- a/drivers/gpu/drm/rockchip/cdn-dp-core.c +++ b/drivers/gpu/drm/rockchip/cdn-dp-core.c @@ -27,16 +27,17 @@ #include "cdn-dp-core.h" #include "cdn-dp-reg.h"-static inline struct cdn_dp_device *bridge_to_dp(struct drm_bridge *bridge)+static int cdn_dp_switch_port(struct cdn_dp_device *dp, struct cdn_dp_port *prev_port, + struct cdn_dp_port *port); + +static inline struct cdn_dp_bridge *bridge_to_dp_bridge(struct drm_bridge *bridge) { - return container_of(bridge, struct cdn_dp_device, bridge); + return container_of(bridge, struct cdn_dp_bridge, bridge); }-static inline struct cdn_dp_device *encoder_to_dp(struct drm_encoder *encoder)+static inline struct cdn_dp_device *bridge_to_dp(struct drm_bridge *bridge) { - struct rockchip_encoder *rkencoder = to_rockchip_encoder(encoder); - - return container_of(rkencoder, struct cdn_dp_device, encoder); + return bridge_to_dp_bridge(bridge)->parent; }#define GRF_SOC_CON9 0x6224@@ -191,14 +192,27 @@ static int cdn_dp_get_sink_count(struct cdn_dp_device *dp, u8 *sink_count) static struct cdn_dp_port *cdn_dp_connected_port(struct cdn_dp_device *dp) { struct cdn_dp_port *port; - int i, lanes; + int i, lanes[MAX_PHY];for (i = 0; i < dp->ports; i++) {port = dp->port[i]; - lanes = cdn_dp_get_port_lanes(port); - if (lanes) + lanes[i] = cdn_dp_get_port_lanes(port); + if (!dp->hpd_bridge_valid) return port; } + + if (dp->hpd_bridge_valid) { + /* If more than one port is available, pick the last active port */ + if (dp->active_port > 0 && lanes[dp->active_port]) + return dp->port[dp->active_port]; + + /* If the last active port is not available, pick an available port in order */ + for (i = 0; i < dp->bridge_count; i++) { + if (lanes[i]) + return dp->port[i]; + } + } + return NULL; }@@ -239,10 +253,11 @@ static enum drm_connector_statuscdn_dp_bridge_detect(struct drm_bridge *bridge, struct drm_connector *connector) { struct cdn_dp_device *dp = bridge_to_dp(bridge); + struct cdn_dp_bridge *dp_bridge = bridge_to_dp_bridge(bridge); enum drm_connector_status status = connector_status_disconnected;mutex_lock(&dp->lock);- if (dp->connected) + if (dp_bridge->connected && dp->connected) status = connector_status_connected; mutex_unlock(&dp->lock);@@ -253,10 +268,36 @@ static const struct drm_edid *cdn_dp_bridge_edid_read(struct drm_bridge *bridge, struct drm_connector *connector) { struct cdn_dp_device *dp = bridge_to_dp(bridge); - const struct drm_edid *drm_edid; + struct cdn_dp_bridge *dp_bridge = bridge_to_dp_bridge(bridge); + struct cdn_dp_port *port = dp->port[dp_bridge->id]; + struct cdn_dp_port *prev_port; + const struct drm_edid *drm_edid = NULL; + int i, ret;mutex_lock(&dp->lock);+ + /* More than one port is available */ + if (dp->bridge_count > 1 && !port->phy_enabled) { + for (i = 0; i < dp->bridge_count; i++) { + /* Another port already enable */ + if (dp->bridge_list[i] != dp_bridge && dp->bridge_list[i]->enabled) + goto unlock; + /* Find already enabled port */ + if (dp->port[i]->phy_enabled) + prev_port = dp->port[i]; + } + + /* Switch to current port */ + if (prev_port) { + ret = cdn_dp_switch_port(dp, prev_port, port); + if (ret) + goto unlock; + } + } + drm_edid = drm_edid_read_custom(connector, cdn_dp_get_edid_block, dp);So... If I try reading EDID for the PHY 2 while PHY 1 is enabled, will it return NULL, even if there is a monitor there? It totally feels like this is one of the rare cases when caching EDIDs might make sense.
Of course. I did consider using cache, but if the monitor changes, then caching the EDID doesn't seem to be of much use…
+ +unlock: mutex_unlock(&dp->lock);return drm_edid;@@ -267,12 +308,13 @@ cdn_dp_bridge_mode_valid(struct drm_bridge *bridge, const struct drm_display_info *display_info, const struct drm_display_mode *mode) { + struct cdn_dp_bridge *dp_bridge = bridge_to_dp_bridge(bridge); struct cdn_dp_device *dp = bridge_to_dp(bridge); u32 requested, actual, rate, sink_max, source_max = 0; u8 lanes, bpc;/* If DP is disconnected, every mode is invalid */- if (!dp->connected) + if (!dp_bridge->connected || !dp->connected) return MODE_BAD;switch (display_info->bpc) {@@ -571,6 +613,7 @@ static void cdn_dp_display_info_update(struct cdn_dp_device *dp, static void cdn_dp_bridge_atomic_enable(struct drm_bridge *bridge, struct drm_atomic_state *state) { struct cdn_dp_device *dp = bridge_to_dp(bridge); + struct cdn_dp_bridge *dp_bridge = bridge_to_dp_bridge(bridge); struct drm_connector *connector; int ret, val;@@ -580,7 +623,7 @@ static void cdn_dp_bridge_atomic_enable(struct drm_bridge *bridge, struct drm_at cdn_dp_display_info_update(dp, &connector->display_info); - ret = drm_of_encoder_active_endpoint_id(dp->dev->of_node, &dp->encoder.encoder);+ ret = drm_of_encoder_active_endpoint_id(dp->dev->of_node, &dp_bridge->encoder.encoder); if (ret < 0) { DRM_DEV_ERROR(dp->dev, "Could not get vop id, %d", ret); return; @@ -599,6 +642,9 @@ static void cdn_dp_bridge_atomic_enable(struct drm_bridge *bridge, struct drm_atmutex_lock(&dp->lock); + if (dp->hpd_bridge_valid)+ dp->active_port = dp_bridge->id; +Don't you need to switch port here? Consider reading EDID from port 1, port 2 then enabling output on port 1.
Oh, I missed that. Thank you, I'll add it in v5.
ret = cdn_dp_enable(dp); if (ret) { DRM_DEV_ERROR(dp->dev, "Failed to enable bridge %d\n", @@ -631,6 +677,7 @@ static void cdn_dp_bridge_atomic_enable(struct drm_bridge *bridge, struct drm_at goto out; }+ dp_bridge->enabled = true;out: mutex_unlock(&dp->lock); } @@ -638,9 +685,11 @@ static void cdn_dp_bridge_atomic_enable(struct drm_bridge *bridge, struct drm_at static void cdn_dp_bridge_atomic_disable(struct drm_bridge *bridge, struct drm_atomic_state *state) { struct cdn_dp_device *dp = bridge_to_dp(bridge); + struct cdn_dp_bridge *dp_bridge = bridge_to_dp_bridge(bridge); int ret;mutex_lock(&dp->lock);+ dp_bridge->enabled = false;if (dp->active) {ret = cdn_dp_disable(dp); @@ -885,7 +934,8 @@ static void cdn_dp_pd_event_work(struct work_struct *work) { struct cdn_dp_device *dp = container_of(work, struct cdn_dp_device, event_work); - int ret; + bool connected; + int i, ret;mutex_lock(&dp->lock); @@ -944,9 +994,12 @@ static void cdn_dp_pd_event_work(struct work_struct *work) out:mutex_unlock(&dp->lock); - drm_bridge_hpd_notify(&dp->bridge, - dp->connected ? connector_status_connected - : connector_status_disconnected); + for (i = 0; i < dp->bridge_count; i++) { + connected = dp->connected && dp->bridge_list[i]->connected; + drm_bridge_hpd_notify(&dp->bridge_list[i]->bridge, + connected ? connector_status_connected + : connector_status_disconnected); + } }static int cdn_dp_pd_event(struct notifier_block *nb,@@ -966,28 +1019,99 @@ static int cdn_dp_pd_event(struct notifier_block *nb, return NOTIFY_DONE; }-static int cdn_dp_bind(struct device *dev, struct device *master, void *data)+static void cdn_dp_typec_hpd_cb(void *data, enum drm_connector_status status) { - struct cdn_dp_device *dp = dev_get_drvdata(dev); - struct drm_encoder *encoder; - struct drm_connector *connector; - struct cdn_dp_port *port; - struct drm_device *drm_dev = data; - int ret, i; + struct cdn_dp_hpd_bridge *hpd_bridge = data; + struct cdn_dp_device *dp = hpd_bridge->parent;- ret = cdn_dp_parse_dt(dp);- if (ret < 0) - return ret; + dp->bridge_list[hpd_bridge->id]->connected = status == connector_status_connected; + schedule_work(&dp->event_work); +}- dp->drm_dev = drm_dev;- dp->connected = false; - dp->active = false; - dp->active_port = -1; - dp->fw_loaded = false; +static void cdn_dp_bridge_hpd_enable(struct cdn_dp_device *dp) +{ + int i;- INIT_WORK(&dp->event_work, cdn_dp_pd_event_work);+ if (!dp->hpd_bridge_valid) + return; + + for (i = 0; i < dp->bridge_count; i++) { + drm_bridge_hpd_enable(dp->hpd_bridge_list[i].bridge, cdn_dp_typec_hpd_cb, + &dp->hpd_bridge_list[i]); + } +} + +static void cdn_dp_bridge_hpd_disable(struct cdn_dp_device *dp) +{ + int i; + + if (!dp->hpd_bridge_valid) + return; + + for (i = 0; i < dp->bridge_count; i++) { + drm_bridge_hpd_disable(dp->hpd_bridge_list[i].bridge); + } +} + +static int cdn_dp_switch_port(struct cdn_dp_device *dp, struct cdn_dp_port *prev_port, + struct cdn_dp_port *port) +{ + int ret; + + if (dp->active) + return 0; + + cdn_dp_bridge_hpd_disable(dp); + + ret = cdn_dp_disable_phy(dp, prev_port); + if (ret) + goto out; + ret = cdn_dp_enable_phy(dp, port); + if (ret) + goto out; + + ret = cdn_dp_get_sink_capability(dp); + if (ret) { + cdn_dp_disable_phy(dp, port); + goto out; + } + + dp->active = true; + dp->lanes = port->lanes; + + if (!cdn_dp_check_link_status(dp)) { + dev_info(dp->dev, "Connected with sink; re-train link\n"); + + ret = cdn_dp_train_link(dp); + if (ret) { + dev_err(dp->dev, "Training link failed: %d\n", ret); + goto out; + } + + ret = cdn_dp_set_video_status(dp, CONTROL_VIDEO_IDLE); + if (ret) { + dev_err(dp->dev, "Failed to idle video %d\n", ret); + goto out; + } + + ret = cdn_dp_config_video(dp); + if (ret) + dev_err(dp->dev, "Failed to configure video: %d\n", ret); + }- encoder = &dp->encoder.encoder;+out: + cdn_dp_bridge_hpd_enable(dp); + return ret; +} + +static int cdn_bridge_add(struct device *dev, + struct drm_bridge *bridge, + struct drm_encoder *encoder) +{ + struct cdn_dp_device *dp = dev_get_drvdata(dev); + struct drm_device *drm_dev = dp->drm_dev; + struct drm_connector *connector; + int ret;encoder->possible_crtcs = drm_of_find_possible_crtcs(drm_dev,dev->of_node); @@ -1002,23 +1126,23 @@ static int cdn_dp_bind(struct device *dev, struct device *master, void *data)drm_encoder_helper_add(encoder, &cdn_dp_encoder_helper_funcs); - dp->bridge.ops =- DRM_BRIDGE_OP_DETECT | - DRM_BRIDGE_OP_EDID | - DRM_BRIDGE_OP_HPD | - DRM_BRIDGE_OP_DP_AUDIO; - dp->bridge.of_node = dp->dev->of_node; - dp->bridge.type = DRM_MODE_CONNECTOR_DisplayPort; - dp->bridge.hdmi_audio_dev = dp->dev; - dp->bridge.hdmi_audio_max_i2s_playback_channels = 8; - dp->bridge.hdmi_audio_spdif_playback = 1; - dp->bridge.hdmi_audio_dai_port = -1; - - ret = devm_drm_bridge_add(dev, &dp->bridge); + bridge->ops = + DRM_BRIDGE_OP_DETECT | + DRM_BRIDGE_OP_EDID | + DRM_BRIDGE_OP_HPD | + DRM_BRIDGE_OP_DP_AUDIO; + bridge->of_node = dp->dev->of_node; + bridge->type = DRM_MODE_CONNECTOR_DisplayPort; + bridge->hdmi_audio_dev = dp->dev; + bridge->hdmi_audio_max_i2s_playback_channels = 8; + bridge->hdmi_audio_spdif_playback = 1; + bridge->hdmi_audio_dai_port = -1; + + ret = devm_drm_bridge_add(dev, bridge); if (ret) return ret;- ret = drm_bridge_attach(encoder, &dp->bridge, NULL, DRM_BRIDGE_ATTACH_NO_CONNECTOR);+ ret = drm_bridge_attach(encoder, bridge, NULL, DRM_BRIDGE_ATTACH_NO_CONNECTOR); if (ret) return ret;@@ -1031,6 +1155,167 @@ static int cdn_dp_bind(struct device *dev, struct device *master, void *data) drm_connector_attach_encoder(connector, encoder); + return 0;+} + +static int cdn_dp_parse_hpd_bridge_dt(struct cdn_dp_device *dp) +{ + struct device_node *np = dp->dev->of_node; + struct device_node *port __free(device_node) = of_graph_get_port_by_id(np, 1); + struct drm_bridge *bridge; + int count = 0; + int ret = 0; + int i; + + /* If device use extcon, do not use hpd bridge */ + for (i = 0; i < dp->ports; i++) { + if (dp->port[i]->extcon) { + dp->bridge_count = 1; + return 0; + } + } + + /* + * + * &dp_out { + * dp_controller_output0: endpoint@0 { + * remote-endpoint = <&dp_phy0_in> + * }; + * + * dp_controller_output1: endpoint@1 { + * remote-endpoint = <&dp_phy1_in> + * }; + * }; + * + * &tcphy0_dp { + * port { + * tcphy0_typec_dp: endpoint@0 { + * reg = <0>; + * remote-endpoint = <&usbc0_dp>; + * }; + * + * dp_phy0_in: endpoint@1 { + * reg = <1>; + * remote-endpoint = <&dp_controller_output0>; + * }; + * }; + * }; + * + * &tcphy1_dp { + * ... + * }; + * + * usbcon0: connector { + * ... + * ports { + * ... + * port@2 { + * reg = <2>; + * + * usbc0_dp: endpoint { + * remote-endpoint = <&tcphy0_typec_dp>; + * }; + * }; + * }; + * }; + * + * usbcon1: connector { + * ... + * }; + * + */ + + /* One endpoint may correspond to one HPD bridge. */ + for_each_of_graph_port_endpoint(port, dp_ep) { + /* Try to get "port" node of correspond PHY device */ + struct device_node *phy_ep __free(device_node) = + of_graph_get_remote_endpoint(dp_ep); + struct device_node *phy_port __free(device_node) = + of_get_parent(phy_ep); + + if (!phy_port) { + continue; + } + + /* + * A PHY port may contain two endpoints: USB connector port or CDN-DP port. + * Try to find the node of USB connector.And then there can be a retimer between PHY and the USB-C connector. Or some signal MUX. Or DP-to-HDMI bridge. Please, don't parse DT for other devices. Instead you can add drm_aux_bridge to your PHY and let DRM core build the bridge chain following OF graph.
Okay, I will try to do it in v5.
+ */ + for_each_of_graph_port_endpoint(phy_port, typec_ep) { + struct device_node *connector_port __free(device_node) = + of_graph_get_remote_port_parent(typec_ep); + struct device_node *hpd_bridge_np __free(device_node) = + of_get_parent(connector_port); + + if (typec_ep == phy_ep) + continue; + + bridge = of_drm_find_bridge(hpd_bridge_np); + if (!bridge) { + ret = -EPROBE_DEFER; + goto out; + } + + dp->hpd_bridge_valid = true; + dp->hpd_bridge_list[count].bridge = bridge; + dp->hpd_bridge_list[count].parent = dp; + dp->hpd_bridge_list[count].id = count; + count++; + break; + } + } + +out: + dp->bridge_count = count ? count : 1; + return ret; +} + +static int cdn_dp_bind(struct device *dev, struct device *master, void *data) +{ + struct cdn_dp_device *dp = dev_get_drvdata(dev); + struct drm_bridge *bridge; + struct drm_encoder *encoder; + struct cdn_dp_port *port; + struct drm_device *drm_dev = data; + struct cdn_dp_bridge *bridge_list; + int ret, i; + + ret = cdn_dp_parse_dt(dp); + if (ret < 0) + return ret; + + ret = cdn_dp_parse_hpd_bridge_dt(dp); + if (ret) + return ret; + + dp->drm_dev = drm_dev; + dp->connected = false; + dp->active = false; + dp->active_port = -1; + dp->fw_loaded = false; + + for (i = 0; i < dp->bridge_count; i++) { + bridge_list = devm_drm_bridge_alloc(dev, struct cdn_dp_bridge, bridge, + &cdn_dp_bridge_funcs); + if (IS_ERR(bridge_list)) + return PTR_ERR(bridge_list); + bridge_list->id = i; + bridge_list->parent = dp; + if (!dp->hpd_bridge_valid) + bridge_list->connected = true; + dp->bridge_list[i] = bridge_list; + } + + for (i = 0; i < dp->bridge_count; i++) { + encoder = &dp->bridge_list[i]->encoder.encoder; + bridge = &dp->bridge_list[i]->bridge; + ret = cdn_bridge_add(dev, bridge, encoder); + if (ret) + return ret; + } + + INIT_WORK(&dp->event_work, cdn_dp_pd_event_work); + for (i = 0; i < dp->ports; i++) { port = dp->port[i];@@ -1050,6 +1335,7 @@ static int cdn_dp_bind(struct device *dev, struct device *master, void *data) pm_runtime_enable(dev); + cdn_dp_bridge_hpd_enable(dp);schedule_work(&dp->event_work);return 0;@@ -1058,10 +1344,14 @@ static int cdn_dp_bind(struct device *dev, struct device *master, void *data) static void cdn_dp_unbind(struct device *dev, struct device *master, void *data) { struct cdn_dp_device *dp = dev_get_drvdata(dev); - struct drm_encoder *encoder = &dp->encoder.encoder; + struct drm_encoder *encoder; + int i;cancel_work_sync(&dp->event_work);- encoder->funcs->destroy(encoder); + for (i = 0; i < dp->bridge_count; i++) { + encoder = &dp->bridge_list[i]->encoder.encoder; + encoder->funcs->destroy(encoder); + }pm_runtime_disable(dev);if (dp->fw_loaded) @@ -1112,10 +1402,10 @@ static int cdn_dp_probe(struct platform_device *pdev) int ret; int i;- dp = devm_drm_bridge_alloc(dev, struct cdn_dp_device, bridge,- &cdn_dp_bridge_funcs); - if (IS_ERR(dp)) - return PTR_ERR(dp); + dp = devm_kzalloc(dev, sizeof(*dp), GFP_KERNEL); + if (!dp) + return -ENOMEM; + dp->dev = dev;match = of_match_node(cdn_dp_dt_ids, pdev->dev.of_node);diff --git a/drivers/gpu/drm/rockchip/cdn-dp-core.h b/drivers/gpu/drm/rockchip/cdn-dp-core.h index e9c30b9fd543..215f3da61af2 100644 --- a/drivers/gpu/drm/rockchip/cdn-dp-core.h +++ b/drivers/gpu/drm/rockchip/cdn-dp-core.h @@ -38,6 +38,8 @@ enum vic_pxl_encoding_format { Y_ONLY = 0x10, };+struct cdn_dp_device;+ struct video_info { bool h_sync_polarity; bool v_sync_polarity; @@ -63,16 +65,33 @@ struct cdn_dp_port { u8 id; };+struct cdn_dp_bridge {+ struct cdn_dp_device *parent; + struct drm_bridge bridge; + struct rockchip_encoder encoder; + bool connected; + bool enabled; + int id; +}; + +struct cdn_dp_hpd_bridge { + struct cdn_dp_device *parent; + struct drm_bridge *bridge; + int id; +}; + struct cdn_dp_device { struct device *dev; struct drm_device *drm_dev; - struct drm_bridge bridge; - struct rockchip_encoder encoder; + int bridge_count; + struct cdn_dp_bridge *bridge_list[MAX_PHY]; + struct cdn_dp_hpd_bridge hpd_bridge_list[MAX_PHY]; struct drm_display_mode mode; struct platform_device *audio_pdev; struct work_struct event_work;struct mutex lock;+ bool hpd_bridge_valid; bool connected; bool active; bool suspended; -- 2.49.0
-- Best, Chaoyi
