From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-m1973176.qiye.163.com (mail-m1973176.qiye.163.com [220.197.31.76]) (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 0BF2E241691; Mon, 17 Nov 2025 08:52:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=220.197.31.76 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763369569; cv=none; b=HS+HvfX3mv8pGcEn2NbaizOMpTV5QC1mTmSwtkm6HO8eDOrgxilH7OJN2SbK5OOzT6OiG8E7+YWVSWlr/kRhl7UDe22vXV6XGjgm/66jrWBJsjxfryLNFGgmcYe5MGSj3LP6mc4capkZImZSx11XTiXOGXB3SZKBw/qw9ggyKIQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763369569; c=relaxed/simple; bh=9M/PZ3geKQeaYE500yl7cwRVd4tkyeyO+eowp0ec8rI=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=IqcsedyqAwqziIRnv3Z8NbCZfg20lrhM/6aiMb6X6mMBeON8eJrkgw/gtiXYY3xTmBgLjDWjbzTI960WooBSvuEL2byMoUd7f/Kov7lrqqvtWNojq3ptkDv2xox2IyAlwr4TIPkGnA5FQWFmrbRpVgMmdqLlK7Y9i9aiSXonTj8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=rock-chips.com; spf=pass smtp.mailfrom=rock-chips.com; dkim=pass (1024-bit key) header.d=rock-chips.com header.i=@rock-chips.com header.b=TxAbeCZF; arc=none smtp.client-ip=220.197.31.76 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=rock-chips.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=rock-chips.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=rock-chips.com header.i=@rock-chips.com header.b="TxAbeCZF" Received: from [172.16.12.51] (unknown [58.22.7.114]) by smtp.qiye.163.com (Hmail) with ESMTP id 29d4759ae; Mon, 17 Nov 2025 16:47:26 +0800 (GMT+08:00) Message-ID: <140cd555-d512-4712-9d71-2d7f188a74fb@rock-chips.com> Date: Mon, 17 Nov 2025 16:47:25 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v9 03/10] drm/bridge: Implement generic USB Type-C DP HPD bridge To: Heikki Krogerus , 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 , 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 References: <20251111105040.94-1-kernel@airkyi.com> <20251111105040.94-4-kernel@airkyi.com> Content-Language: en-US From: Chaoyi Chen In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-HM-Tid: 0a9a90ff5e3f03abkunm2a6b77ad8f27ca X-HM-MType: 1 X-HM-Spam-Status: e1kfGhgUHx5ZQUpXWQgPGg8OCBgUHx5ZQUlOS1dZFg8aDwILHllBWSg2Ly tZV1koWUFDSUNOT01LS0k3V1ktWUFJV1kPCRoVCBIfWUFZQkpPQ1ZCHR0ZSE4ZGEkaS0tWFRQJFh oXVRMBExYaEhckFA4PWVdZGBILWUFZTkNVSUlVTFVKSk9ZV1kWGg8SFR0UWUFZT0tIVUpLSEpPSE xVSktLVUpCS0tZBg++ DKIM-Signature: a=rsa-sha256; b=TxAbeCZFY7eqkjxpcivUMqwOH8QFtRL/B2e4tf+GteqsvSZy467ZXu17S6C/ZqVYLBEPPxecTuUo+uZ16WS5iY68xy9ealSCVZp0U6FKLSNqzRNh1vr58YTSeVBSum2ZFTjltiUSSyEJsWu6PKSkNbO0JitC3s7a642vFVxtj4U=; c=relaxed/relaxed; s=default; d=rock-chips.com; v=1; bh=/VyBu/i0fSLSIZpB/cn2Lo04jmSlwZbXvvGuWwLCrig=; h=date:mime-version:subject:message-id:from; On 11/17/2025 4:40 PM, Heikki Krogerus wrote: > 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: The hidden options "DRM_AUX_BRIDGE" and "DRM_AUX_HPD_BRIDGE" also have a help section. I think this is just for comment purposes :) > > 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 -- Best, Chaoyi