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Fri, 28 Nov 2025 10:04:27 +0800 (CST) X-QQ-SSF: 0000000000000000000000000000000 X-QQ-GoodBg: 0 X-BIZMAIL-ID: 12748416008944445316 From: Chaoyi Chen To: Heikki Krogerus , Greg Kroah-Hartman , Dmitry Baryshkov , Peter Chen , Luca Ceresoli , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Vinod Koul , Kishon Vijay Abraham I , Heiko Stuebner , Sandy Huang , Andy Yan , Yubing Zhang , Frank Wang , Andrzej Hajda , Neil Armstrong , Robert Foss , Laurent Pinchart , Jonas Karlman , Jernej Skrabec , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Amit Sunil Dhamne , Chaoyi Chen , Dragan Simic , Johan Jonker , Diederik de Haas , Peter Robinson Cc: linux-usb@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-phy@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-rockchip@lists.infradead.org, dri-devel@lists.freedesktop.org Subject: [PATCH v11 03/11] drm/bridge: Implement generic USB Type-C DP HPD bridge Date: Fri, 28 Nov 2025 10:03:57 +0800 Message-Id: <20251128020405.90-4-kernel@airkyi.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20251128020405.90-1-kernel@airkyi.com> References: <20251128020405.90-1-kernel@airkyi.com> X-QQ-SENDSIZE: 520 Feedback-ID: esmtpsz:airkyi.com:qybglogicsvrgz:qybglogicsvrgz6b-0 X-QQ-XMAILINFO: NPgAY+7cethfznNSp3gZfZkJ6tKUsTHVqrJyzVF7zIxU2WfZ2YmRnPD8 06Nk5zwYJUam625TrWrAeARdvZ/O6c/RWVzPinD8uR+cJ7MTtqveKOYXcJM6qBxKvFTMaTg CUHJjCMOEZhRnZa7+sSA6xVr8CQuJYg/JFG5eSjAQaVqE9MvuBvVpzn9Euf/iogRfP+BgIO KwcWQGLZbew+fx7KCfVrz2f2iPz/nL+c7IWD6uZ/iKc2TEfZXIufNuqyYUf/+v5JQJag1+t V2B5sVl5dyFLj2g9G/5JEIxT+QQSBmQfyELaBNRFMSXQi2fz4Mv6XwLFHX6YC31xdImHcGl oAOJ3Q9EsoUL6bYuPiP8ewEezVIT5VrTfvGQusx89QuXcEgPv0d7GCtrbm9hwG5zK/x2Vzu oYWWglNyPLLV7QPH5A9fpfDBiMsKQcSnuF+OcSbPV4HkL/sc//r4c9airMXt4DIAmsR7VLS PpxOzMhyIKe+pXnm7aEawZ3GNGWEdkSb7aWC7oti7HahDSh1LX66l3ys3li5eRkSyYtin7V 2SGWPJMxnO+FxW0iiFXO3ZWg6va2d1zDrNA9QPQcRWTHuDI/2QUi0HtGlvAAfZXDDLx4rkE f4Q539M3Hg+sTmdMqvo/yHAF7bI38VarBZKrCw/cNwpkZbpbqiN18YZJY18BnO9RoSzHBXz r860+Ie5B0EgrZEAWIIKlKQ/4S+WZ6gH+w9xIdK/uEZ7ggbQW05Eu2+FsXwueysb/tiNQxn RdvDkHwP+pxdHDoBo40fmQRRtBpsaPKcYiXh5Oiml6Uup/UmRH3zGWoA416Z/cG+Ux3RLt2 fSw1DOrSIxdgXPVJc5fDhiSdKKz9KlBDb1Le1RmMF/hxOntZUg1iikkolEkNbl7LZjHsy4K OC6kRapp9zY7onn1MgWAY3BSNK96CdB5TuulnGybBPJVZ3Mea2VUiGr4XAYvdLPSRPAtH89 THKUC6K0/ZjOQTODUPvMHcu24QXYM759XTa38zcO2UDnwa/ItbGcH0dH6rIl2DSgcn3jDlV 4cv/AmxA4L0hdxUQZpfDeWTc+z0wdvxdxXJplasg== X-QQ-XMRINFO: Mp0Kj//9VHAxr69bL5MkOOs= X-QQ-RECHKSPAM: 0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" From: Chaoyi Chen The HPD function of Type-C DP is implemented through drm_connector_oob_hotplug_event(). For embedded DP, it is required that the DRM connector fwnode corresponds to the Type-C port fwnode. To describe the relationship between the DP controller and the Type-C port device, we usually using drm_bridge to build a bridge chain. Now several USB-C controller drivers have already implemented the DP HPD bridge function provided by aux-hpd-bridge.c, it will build a DP HPD bridge on USB-C connector port device. But this requires the USB-C controller driver to manually register the HPD bridge. If the driver does not implement this feature, the bridge will not be create. So this patch implements a generic DP HPD bridge based on aux-hpd-bridge.c. It will monitor Type-C bus events, and when a Type-C port device containing the DP svid is registered, it will create an HPD bridge for it without the need for the USB-C controller driver to implement it. Signed-off-by: Chaoyi Chen --- Changes in v11: - Switch to using typec bus notifiers. (no changes since v10) Changes in v9: - Remove the exposed DRM_AUX_HPD_BRIDGE option, and select DRM_AUX_HPD_TYPEC_BRIDGE when it is available. - Add more commit comment about problem background. Changes in v8: - Merge generic DP HPD bridge into one module. drivers/gpu/drm/bridge/Kconfig | 10 ++++ drivers/gpu/drm/bridge/Makefile | 1 + .../gpu/drm/bridge/aux-hpd-typec-dp-bridge.c | 51 +++++++++++++++++++ 3 files changed, 62 insertions(+) create mode 100644 drivers/gpu/drm/bridge/aux-hpd-typec-dp-bridge.c diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig index a250afd8d662..559487aa09a9 100644 --- a/drivers/gpu/drm/bridge/Kconfig +++ b/drivers/gpu/drm/bridge/Kconfig @@ -30,6 +30,16 @@ config DRM_AUX_HPD_BRIDGE Simple bridge that terminates the bridge chain and provides HPD support. =20 +if DRM_AUX_HPD_BRIDGE +config DRM_AUX_HPD_TYPEC_BRIDGE + tristate + depends on TYPEC || !TYPEC + default TYPEC + help + Simple bridge that terminates the bridge chain and provides HPD + support. It build bridge on each USB-C connector device node. +endif + menu "Display Interface Bridges" depends on DRM && DRM_BRIDGE =20 diff --git a/drivers/gpu/drm/bridge/Makefile b/drivers/gpu/drm/bridge/Makef= ile index c7dc03182e59..a3a0393d2e72 100644 --- a/drivers/gpu/drm/bridge/Makefile +++ b/drivers/gpu/drm/bridge/Makefile @@ -1,6 +1,7 @@ # SPDX-License-Identifier: GPL-2.0 obj-$(CONFIG_DRM_AUX_BRIDGE) +=3D aux-bridge.o obj-$(CONFIG_DRM_AUX_HPD_BRIDGE) +=3D aux-hpd-bridge.o +obj-$(CONFIG_DRM_AUX_HPD_TYPEC_BRIDGE) +=3D aux-hpd-typec-dp-bridge.o obj-$(CONFIG_DRM_CHIPONE_ICN6211) +=3D chipone-icn6211.o obj-$(CONFIG_DRM_CHRONTEL_CH7033) +=3D chrontel-ch7033.o obj-$(CONFIG_DRM_CROS_EC_ANX7688) +=3D cros-ec-anx7688.o diff --git a/drivers/gpu/drm/bridge/aux-hpd-typec-dp-bridge.c b/drivers/gpu= /drm/bridge/aux-hpd-typec-dp-bridge.c new file mode 100644 index 000000000000..94be3d5f69e9 --- /dev/null +++ b/drivers/gpu/drm/bridge/aux-hpd-typec-dp-bridge.c @@ -0,0 +1,51 @@ +// SPDX-License-Identifier: GPL-2.0+ +#include +#include +#include + +#include + +static int drm_typec_bus_event(struct notifier_block *nb, + unsigned long action, void *data) +{ + struct device *dev =3D (struct device *)data; + struct typec_altmode *alt =3D to_typec_altmode(dev); + + if (action !=3D BUS_NOTIFY_ADD_DEVICE) + goto done; + + if (is_typec_partner_altmode(&alt->dev) || alt->svid !=3D USB_TYPEC_DP_SI= D) + goto done; + + /* + * alt->dev.parent->parent : USB-C controller device + * alt->dev.parent : USB-C connector device + */ + drm_dp_hpd_bridge_register(alt->dev.parent->parent, + to_of_node(alt->dev.parent->fwnode)); + +done: + return NOTIFY_OK; +} + +static struct notifier_block drm_typec_event_nb =3D { + .notifier_call =3D drm_typec_bus_event, +}; + +static void drm_aux_hpd_typec_dp_bridge_module_exit(void) +{ + bus_unregister_notifier(&typec_bus, &drm_typec_event_nb); +} + +static int __init drm_aux_hpd_typec_dp_bridge_module_init(void) +{ + bus_register_notifier(&typec_bus, &drm_typec_event_nb); + + return 0; +} + +module_init(drm_aux_hpd_typec_dp_bridge_module_init); +module_exit(drm_aux_hpd_typec_dp_bridge_module_exit); + +MODULE_DESCRIPTION("DRM TYPEC DP HPD BRIDGE"); +MODULE_LICENSE("GPL"); --=20 2.51.1