From: Heiko Stuebner <heiko@sntech•de>
To: Heikki Krogerus <heikki.krogerus@linux•intel.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation•org>,
Dmitry Baryshkov <dmitry.baryshkov@oss•qualcomm.com>,
Peter Chen <hzpeterchen@gmail•com>,
Luca Ceresoli <luca.ceresoli@bootlin•com>,
Rob Herring <robh@kernel•org>,
Krzysztof Kozlowski <krzk+dt@kernel•org>,
Conor Dooley <conor+dt@kernel•org>, Vinod Koul <vkoul@kernel•org>,
Kishon Vijay Abraham I <kishon@kernel•org>,
Sandy Huang <hjc@rock-chips•com>,
Andy Yan <andy.yan@rock-chips•com>,
Yubing Zhang <yubing.zhang@rock-chips•com>,
Frank Wang <frank.wang@rock-chips•com>,
Andrzej Hajda <andrzej.hajda@intel•com>,
Neil Armstrong <neil.armstrong@linaro•org>,
Robert Foss <rfoss@kernel•org>,
Laurent Pinchart <Laurent.pinchart@ideasonboard•com>,
Jonas Karlman <jonas@kwiboo•se>,
Jernej Skrabec <jernej.skrabec@gmail•com>,
Maarten Lankhorst <maarten.lankhorst@linux•intel.com>,
Maxime Ripard <mripard@kernel•org>,
Thomas Zimmermann <tzimmermann@suse•de>,
David Airlie <airlied@gmail•com>, Simona Vetter <simona@ffwll•ch>,
Amit Sunil Dhamne <amitsd@google•com>,
Dragan Simic <dsimic@manjaro•org>,
Johan Jonker <jbx6244@gmail•com>,
Diederik de Haas <didi.debian@cknow•org>,
Peter Robinson <pbrobinson@gmail•com>,
Hugh Cole-Baker <sigmaris@gmail•com>,
Chaoyi Chen <kernel@airkyi•com>
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,
Chaoyi Chen <chaoyi.chen@rock-chips•com>
Subject: Re: [PATCH v15 7/9] drm/rockchip: cdn-dp: Add multiple bridges to support PHY port selection
Date: Wed, 20 May 2026 13:12:49 +0200 [thread overview]
Message-ID: <12511061.0AQdONaE2F@phil> (raw)
In-Reply-To: <20260304094152.92-8-kernel@airkyi.com>
Am Mittwoch, 4. März 2026, 10:41:50 Mitteleuropäische Sommerzeit schrieb Chaoyi Chen:
> From: Chaoyi Chen <chaoyi.chen@rock-chips•com>
>
> 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 first bridge in bridge chain and DP
> controller. For example, the bridge chain may be like this:
>
> PHY aux birdge -> fsa4480 analog audio switch bridge ->
> onnn,nb7vpq904m USB reminder bridge -> USB-C controller AUX HPD bridge
>
> In this case, the connection relationships among the PHY aux bridge
> and the DP contorller need to be described in DT.
>
> In addition, the cdn_dp_parse_next_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. So we will try to return the cached 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 <chaoyi.chen@rock-chips•com>
> Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin•com>
Reviewed-by: Heiko Stuebner <heiko@sntech•de>
next prev parent reply other threads:[~2026-05-20 11:13 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-04 9:41 [PATCH v15 0/9] Add Type-C DP support for RK3399 EVB IND board Chaoyi Chen
2026-03-04 9:41 ` [PATCH v15 1/9] drm/bridge: Implement generic USB Type-C DP HPD bridge Chaoyi Chen
2026-05-28 15:37 ` Nicolas Frattaroli
2026-05-29 1:18 ` Chaoyi Chen
2026-03-04 9:41 ` [PATCH v15 2/9] drm/bridge: aux: Add drm_aux_bridge_register_from_node() Chaoyi Chen
2026-05-28 15:46 ` Nicolas Frattaroli
2026-03-04 9:41 ` [PATCH v15 3/9] dt-bindings: phy: rockchip: rk3399-typec-phy: Support mode-switch Chaoyi Chen
2026-03-04 9:41 ` [PATCH v15 4/9] phy: rockchip: phy-rockchip-typec: Add typec_mux/typec_switch support Chaoyi Chen
2026-05-28 20:16 ` Nicolas Frattaroli
2026-05-29 8:13 ` Chaoyi Chen
2026-03-04 9:41 ` [PATCH v15 5/9] phy: rockchip: phy-rockchip-typec: Add DRM AUX bridge Chaoyi Chen
2026-03-04 9:41 ` [PATCH v15 6/9] drm/rockchip: cdn-dp: Support handle lane info without extcon Chaoyi Chen
2026-05-20 11:10 ` Heiko Stuebner
2026-03-04 9:41 ` [PATCH v15 7/9] drm/rockchip: cdn-dp: Add multiple bridges to support PHY port selection Chaoyi Chen
2026-05-20 11:12 ` Heiko Stuebner [this message]
2026-03-04 9:41 ` [PATCH v15 8/9] arm64: dts: rockchip: Add missing dp_out port for RK3399 CDN-DP Chaoyi Chen
2026-03-04 9:41 ` [PATCH v15 9/9] arm64: dts: rockchip: rk3399-evb-ind: Add support for DisplayPort Chaoyi Chen
2026-05-20 11:06 ` Heiko Stuebner
2026-05-19 13:43 ` [PATCH v15 0/9] Add Type-C DP support for RK3399 EVB IND board Heikki Krogerus
2026-05-20 1:13 ` Chaoyi Chen
2026-05-20 11:03 ` Heiko Stuebner
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