From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from sender4-op-o11.zoho.com (sender4-op-o11.zoho.com [136.143.188.11]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 135DF391833 for ; Thu, 6 Aug 2026 18:01:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=pass smtp.client-ip=136.143.188.11 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786039273; cv=pass; b=V4iOGVfA/LvBtH5QWH0Rpjb6cS9FL5j0ms4QtVyar9hk8Xe3Ffu60m9CePpqwVreTWrdwtZt8SiLF7nLP4e8vbc6VJUmJ9beDMDA5l0msHVoksoEykljpt+fcdpBE0wxK9PSqyVqWWKyB/8uZqW33AxZuDQpEGdQifWsQzm5QZ4= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786039273; c=relaxed/simple; bh=//NFac+bt7HPmmzpA2dVFxW9toapOCYNon74yu3QWDs=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=OeG4j3VC2MsOFHGn19I3QpyG9hFtKXCpYEc12E9iUxEfy72a6rkY+kOfA71aVKD6AfPrkldiS+dI93wTJ0Ko6mJTqmN7nD08CCGcPgcDeUc5HBn6FVKF5Kb92IhW8xuwNmi+2QdWE8AiymqutaEiNrljm74i5+60jfj23okLnuM= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=collabora.com; spf=pass smtp.mailfrom=collabora.com; dkim=pass (1024-bit key) header.d=collabora.com header.i=sebastian.reichel@collabora.com header.b=bkoij3dw; arc=pass smtp.client-ip=136.143.188.11 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=collabora.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=collabora.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=collabora.com header.i=sebastian.reichel@collabora.com header.b="bkoij3dw" ARC-Seal: i=1; a=rsa-sha256; t=1786039210; cv=none; d=zohomail.com; s=zohoarc; b=AdF3bXdw4ifqRQn+Z14k05G3vBN2Zbw5ryBRX7nMIR34yKc3lqGiWCaUWIIW15KEjMwvZs2F6rVqE2sF3B3sYifDvM0o0dARZ3AFwIIyVEzAkVxP0plAROr31J7AnjQ8h6HZxKSGnUnxaq4AtvzWaM+GAmEAnmf7M/JvHEjppNE= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1786039210; h=Content-Type:Cc:Cc:Date:Date:From:From:In-Reply-To:MIME-Version:Message-ID:Subject:Subject:To:To:Message-Id:Reply-To; bh=gtpJ1OnihTTKEzJSRRxLvCmwCvQZFllDLgsiyAu84JA=; b=gN+QSq/EjgbOrzI3g/KtImaxS//xi0X0mGZykSqQBMUizTaab+6rZ1eDK3DxudoXFpl2pUcsI9cL5ym0IJuvnKkdCAlHTX+koWiMO7Vzx1fXNDUsUh1p+K4axrxQuYk7e4Rhtz8RTdZgRWDhBAV605/B3jYUlKnK8QgOBNOTGck= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass header.i=collabora.com; spf=pass smtp.mailfrom=sebastian.reichel@collabora.com; dmarc=pass header.from= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; t=1786039210; s=zohomail; d=collabora.com; i=sebastian.reichel@collabora.com; h=Date:Date:From:From:To:To:Cc:Cc:Subject:Subject:Message-ID:MIME-Version:Content-Type:In-Reply-To:Message-Id:Reply-To; bh=gtpJ1OnihTTKEzJSRRxLvCmwCvQZFllDLgsiyAu84JA=; b=bkoij3dwB37+3nzXWtd8k7W3YzUKADxohIby+J7vcduon7XaNipa84gteRdEMpf6 zVJrdo/JL+tTDaZrrTsQeioZst9VNocpTmgzmM4q4Px7dQgsDLXKrv0GDSmvTtucNvo WC/fMPuv+L2yPf0ElTXtt+/5TF8rm5yDGM96VBt8= Received: by mx.zohomail.com with SMTPS id 1786039208126323.7662493941132; Thu, 6 Aug 2026 11:00:08 -0700 (PDT) Received: by venus (Postfix, from userid 1000) id CF44C1808BD; Thu, 06 Aug 2026 20:00:01 +0200 (CEST) Date: Thu, 6 Aug 2026 20:00:01 +0200 From: Sebastian Reichel To: Chaoyi Chen Cc: Andrzej Hajda , Neil Armstrong , Robert Foss , Laurent Pinchart , Jonas Karlman , Jernej Skrabec , Luca Ceresoli , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Sandy Huang , Heiko =?utf-8?Q?St=C3=BCbner?= , Andy Yan , Vinod Koul , Chaoyi Chen , Nicolas Frattaroli , Heikki Krogerus , linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-arm-kernel@lists.infradead.org, linux-rockchip@lists.infradead.org, linux-phy@lists.infradead.org Subject: Re: [PATCH v6 2/7] drm/bridge: Implement generic USB Type-C DP HPD bridge Message-ID: References: <20260804070730.68-1-kernel@airkyi.com> <20260804070730.68-3-kernel@airkyi.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="ugiil5heltqaqved" Content-Disposition: inline In-Reply-To: <20260804070730.68-3-kernel@airkyi.com> X-Zoho-Virus-Status: 1 X-Zoho-AV-Stamp: zmail-av-0.2.10.1.5.2/286.26.37 X-ZohoMailClient: External --ugiil5heltqaqved Content-Type: text/plain; protected-headers=v1; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Subject: Re: [PATCH v6 2/7] drm/bridge: Implement generic USB Type-C DP HPD bridge MIME-Version: 1.0 Hi, On Tue, Aug 04, 2026 at 03:07:25PM +0800, Chaoyi Chen wrote: > From: Chaoyi Chen >=20 > 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. >=20 > To describe the relationship between the DP controller and the Type-C > port device, we usually using drm_bridge to build a bridge chain. >=20 > 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. >=20 > 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. >=20 > 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. >=20 > Signed-off-by: Chaoyi Chen > Reviewed-by: Heikki Krogerus > Reviewed-by: Nicolas Frattaroli > --- Reviewed-by: Sebastian Reichel Tested-by: Sebastian Reichel As mentioned in previous patch, 1x duplication still happens for drivers that currently do a manual HPD bridge registration. IMHO this is fine as the manual registration can be removed as a follow-up anyways. Greetings, -- Sebastian > Changes in v6: > - Avoid duplicate registration of the same DisplayPort HPD bridge.=20 >=20 > (no changes since v5) >=20 > Changes in v4: > - Scan the entire typec_bus and attempt to register the hpd bridge, > so as not to miss devices that were already added during initialization. >=20 > (no changes since v3) >=20 > Changes in v2: > - Add copyright text. > - Remove useless goto. > --- > drivers/gpu/drm/bridge/Kconfig | 10 +++ > drivers/gpu/drm/bridge/Makefile | 1 + > .../gpu/drm/bridge/aux-hpd-typec-dp-bridge.c | 67 +++++++++++++++++++ > 3 files changed, 78 insertions(+) > create mode 100644 drivers/gpu/drm/bridge/aux-hpd-typec-dp-bridge.c >=20 > diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kcon= fig > index 4a57d49b4c6d..9739b2a19758 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/Mak= efile > index 15cc821d85b7..d88a9e1ccc9a 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/g= pu/drm/bridge/aux-hpd-typec-dp-bridge.c > new file mode 100644 > index 000000000000..682bc192e093 > --- /dev/null > +++ b/drivers/gpu/drm/bridge/aux-hpd-typec-dp-bridge.c > @@ -0,0 +1,67 @@ > +// SPDX-License-Identifier: GPL-2.0+ > +/* > + * Copyright (C) 2026 Rockchip Electronics Co., Ltd. > + * > + * Author: Chaoyi Chen > + */ > +#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); > + struct device_node *np; > + > + if (action !=3D BUS_NOTIFY_ADD_DEVICE) > + return NOTIFY_OK; > + > + /* > + * alt->dev.parent->parent : USB-C controller device > + * alt->dev.parent : USB-C connector device > + */ > + if (is_typec_port_altmode(&alt->dev) && alt->svid =3D=3D USB_TYPEC_DP_S= ID) { > + np =3D to_of_node(alt->dev.parent->fwnode); > + if (!drm_dev_has_dp_hpd_bridge(alt->dev.parent->parent, np)) > + drm_dp_hpd_bridge_register(alt->dev.parent->parent, np); > + } > + > + return NOTIFY_OK; > +} > + > +static struct notifier_block drm_typec_event_nb =3D { > + .notifier_call =3D drm_typec_bus_event, > +}; > + > +static int check_device_already_added(struct device *dev, void *data) > +{ > + drm_typec_bus_event(NULL, BUS_NOTIFY_ADD_DEVICE, dev); > + return 0; > +} > + > +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); > + /* > + * Before module initialization, some devices may have already been add= ed. > + * Register the HPD bridge for these devices. > + */ > + bus_for_each_dev(&typec_bus, NULL, NULL, check_device_already_added); > + return 0; > +} > + > +module_init(drm_aux_hpd_typec_dp_bridge_module_init); > +module_exit(drm_aux_hpd_typec_dp_bridge_module_exit); > + > +MODULE_AUTHOR("Chaoyi Chen "); > +MODULE_DESCRIPTION("DRM TYPEC DP HPD BRIDGE"); > +MODULE_LICENSE("GPL"); > --=20 > 2.53.0 >=20 --ugiil5heltqaqved Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEE72YNB0Y/i3JqeVQT2O7X88g7+poFAmp0y6EACgkQ2O7X88g7 +pqeMhAAop4PMlriumn53C/b8+hkuAPzNz/c9n07pHZ2RNEh/j+6cvJEwZob4kkH isJNqDmSlD8GnlIbAwLKzxqmj55Uvza59VhpLORJOFGxVtXYPLZt4Y9JRwVSm59C bQIJ7zBuRDrpaPXrobdKnn0DLUJA7eSGwIQFNDbtS8z4DDzFLbR+nVlO+kvBMTBw BLQY9h4cjoD62tz4f8uMdsVGq2KaSRo/xacF2Ey5JFTtZkdXD0+8VIUZ5BFaJOjz jCb1jHkEniLDIRJO4a4Fz6WQJTMvGRjqPFe/rR1KLX7UHUTbqyfMUGq+8FoTOcep loV5Mqb02BRdl6b2X0y5Cr7fYpAVKe7edctXyjXVAKwmGmm5dasp8MtRuNg4hZij N5Jcz9q9sySzU+VVd6v6B2KAzUnjJAi3h2i4QhklU2CYsmy+h67LqFvvvbopVT7I Cb4XDGy3QRrkVoV5SELhBKY161Y9mo0mEeZSaRMt6ZeGJHbIVx5tSU1nthFcRFJi 45arT2hkhE8DUGf3YHwHeJKNx6pyl0PoDZM4bUrwW051Dx5dYW4iq/clCvWwSthS SFK+6h3yqcKZGHM+YMM2GQTIbf6dS8uMwvHy5t135ifFLu7FuLbnnhPYASbhQbKH LAiToqKpTM7BlMAuaVK0dMQcArbpdx4cnYysWDuAB408gQppyhY= =VzYA -----END PGP SIGNATURE----- --ugiil5heltqaqved--