linux-kernel - Re: [PATCH v4 4/7] drm/rockchip: cdn-dp: Support handle lane info without extcon

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Message-ID: <gcgiszrrpqkoi3mhajn4i72awbffqv6mayahmnyswoitxxmrgd@nr2z4cpurbwq>
Date: Mon, 22 Sep 2025 13:01:44 +0300
From: Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>
To: Chaoyi Chen <kernel@...kyi.com>
Cc: Rob Herring <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>,
        Conor Dooley <conor+dt@...nel.org>, Vinod Koul <vkoul@...nel.org>,
        Kishon Vijay Abraham I <kishon@...nel.org>,
        Heiko Stuebner <heiko@...ech.de>, Sandy Huang <hjc@...k-chips.com>,
        Andy Yan <andy.yan@...k-chips.com>,
        Yubing Zhang <yubing.zhang@...k-chips.com>,
        Frank Wang <frank.wang@...k-chips.com>,
        Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Maxime Ripard <mripard@...nel.org>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>,
        Amit Sunil Dhamne <amitsd@...gle.com>,
        Heikki Krogerus <heikki.krogerus@...ux.intel.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Chaoyi Chen <chaoyi.chen@...k-chips.com>,
        Dragan Simic <dsimic@...jaro.org>, Johan Jonker <jbx6244@...il.com>,
        Diederik de Haas <didi.debian@...ow.org>,
        Peter Robinson <pbrobinson@...il.com>, linux-usb@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-phy@...ts.infradead.org, linux-arm-kernel@...ts.infradead.org,
        linux-rockchip@...ts.infradead.org, dri-devel@...ts.freedesktop.org
Subject: Re: [PATCH v4 4/7] drm/rockchip: cdn-dp: Support handle lane info
 without extcon

On Mon, Sep 22, 2025 at 09:20:36AM +0800, Chaoyi Chen wrote:
> From: Chaoyi Chen <chaoyi.chen@...k-chips.com>
> 
> This patch add support for get PHY lane info without help of extcon.
> 
> There is no extcon needed if the Type-C controller is present. In this
> case, the lane info can be get from PHY instead of extcon.
> 
> The extcon device should still be supported if Type-C controller is
> not present.
> 
> Signed-off-by: Chaoyi Chen <chaoyi.chen@...k-chips.com>
> ---
> 
> Changes in v4:
> - Remove cdn_dp_hpd_notify().
> 
> (no changes since v3)
> 
> Changes in v2:
> - Ignore duplicate HPD events.
> 
>  drivers/gpu/drm/rockchip/cdn-dp-core.c | 25 +++++++++++++++++--------
>  1 file changed, 17 insertions(+), 8 deletions(-)
> 
> @@ -1120,14 +1129,14 @@ static int cdn_dp_probe(struct platform_device *pdev)
>  		    PTR_ERR(phy) == -EPROBE_DEFER)
>  			return -EPROBE_DEFER;
>  
> -		if (IS_ERR(extcon) || IS_ERR(phy))
> +		if (IS_ERR(phy) || PTR_ERR(extcon) != -ENODEV)
>  			continue;

This will break the case when the extcon is present. It should be
(IS_ERR(extcon) && PTR_ERR(extcon) != -ENODEV)

>  
>  		port = devm_kzalloc(dev, sizeof(*port), GFP_KERNEL);
>  		if (!port)
>  			return -ENOMEM;
>  
> -		port->extcon = extcon;
> +		port->extcon = IS_ERR(extcon) ? NULL : extcon;
>  		port->phy = phy;
>  		port->dp = dp;
>  		port->id = i;
> -- 
> 2.49.0
> 

-- 
With best wishes
Dmitry