From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id B8786CE8D6B for ; Mon, 17 Nov 2025 08:40:46 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 09BAF10E2F2; Mon, 17 Nov 2025 08:40:46 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.b="VS1dBBIy"; dkim-atps=neutral Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.16]) by gabe.freedesktop.org (Postfix) with ESMTPS id A78DE10E2F2 for ; Mon, 17 Nov 2025 08:40:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1763368844; x=1794904844; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=gkncn3MOxKMpS7fFx8b0bIjvCegdIq2/X6RbhxiwYLI=; b=VS1dBBIy5LB54X0xWPsXJ+ltM4fQY0mulOYCeHAsjRgI9stA/GMUfwCf e0PiwGWnUtnd5rrvLolPeBbez4lD1ofjyRFJJXxyxqOcIv5nDtrMb3Ivq Sl1GND5H1BZp5dk17qnSmS2npdgwwXPrXgVEON9tJSnd3G/LKztWuLr5L olb5zlvWJZOE+BYONgsS7inotrrp7MRajxtP9QQ92GI2vtFNAbnzjvPUU 8axFy2nFWPftpwUNIhy5SJeRiaP3Ems0KWA7aAEzX1UfJUdFLJh8lLGlD KwRuIb+859NH3fgIGu5IKwM+K8y+JP4O9VcbMAGX+M4zbcMobjmqN9xJD A==; X-CSE-ConnectionGUID: CriQ5UdYRBm7Y/W3ABocWw== X-CSE-MsgGUID: Et9+HNWXTqqnhdNlxSHKqA== X-IronPort-AV: E=McAfee;i="6800,10657,11615"; a="52930423" X-IronPort-AV: E=Sophos;i="6.19,311,1754982000"; d="scan'208";a="52930423" Received: from fmviesa002.fm.intel.com ([10.60.135.142]) by fmvoesa110.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 17 Nov 2025 00:40:44 -0800 X-CSE-ConnectionGUID: +E6Bi6sGSmS+xsZI5u+9Xw== X-CSE-MsgGUID: u/K5zt9SSo2D8r6X/N8XtQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.19,311,1754982000"; d="scan'208";a="213794754" Received: from mgoodin-mobl3.amr.corp.intel.com (HELO kuha.fi.intel.com) ([10.124.220.176]) by fmviesa002.fm.intel.com with SMTP; 17 Nov 2025 00:40:33 -0800 Received: by kuha.fi.intel.com (sSMTP sendmail emulation); Mon, 17 Nov 2025 10:40:30 +0200 Date: Mon, 17 Nov 2025 10:40:30 +0200 From: Heikki Krogerus To: Chaoyi Chen Cc: Greg Kroah-Hartman , Dmitry Baryshkov , Peter Chen , 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 , 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: Re: [PATCH v9 03/10] drm/bridge: Implement generic USB Type-C DP HPD bridge Message-ID: References: <20251111105040.94-1-kernel@airkyi.com> <20251111105040.94-4-kernel@airkyi.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20251111105040.94-4-kernel@airkyi.com> X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Tue, Nov 11, 2025 at 06:50:33PM +0800, Chaoyi Chen kirjoitti: > 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 Normally there is no "help" section for hidden config options. I guess it can not cause any harm? It is a bit confusing, though. But FWIW: Reviewed-by: Heikki Krogerus > --- > > 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 | 50 +++++++++++++++++++ > 3 files changed, 61 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. > > +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 > > diff --git a/drivers/gpu/drm/bridge/Makefile b/drivers/gpu/drm/bridge/Makefile > 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-$(CONFIG_DRM_AUX_BRIDGE) += aux-bridge.o > obj-$(CONFIG_DRM_AUX_HPD_BRIDGE) += aux-hpd-bridge.o > +obj-$(CONFIG_DRM_AUX_HPD_TYPEC_BRIDGE) += aux-hpd-typec-dp-bridge.o > obj-$(CONFIG_DRM_CHIPONE_ICN6211) += chipone-icn6211.o > obj-$(CONFIG_DRM_CHRONTEL_CH7033) += chrontel-ch7033.o > obj-$(CONFIG_DRM_CROS_EC_ANX7688) += 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..9cb6a0cb0f0a > --- /dev/null > +++ b/drivers/gpu/drm/bridge/aux-hpd-typec-dp-bridge.c > @@ -0,0 +1,50 @@ > +// 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 typec_altmode *alt = (struct typec_altmode *)data; > + > + if (action != TYPEC_ALTMODE_REGISTERED) > + goto done; > + > + if (is_typec_partner(&alt->dev) || alt->svid != USB_TYPEC_DP_SID) > + 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 = { > + .notifier_call = drm_typec_bus_event, > +}; > + > +static void drm_aux_hpd_typec_dp_bridge_module_exit(void) > +{ > + typec_altmode_unregister_notify(&drm_typec_event_nb); > +} > + > +static int __init drm_aux_hpd_typec_dp_bridge_module_init(void) > +{ > + typec_altmode_register_notify(&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"); > -- > 2.51.1 -- heikki