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From:   Guillaume Ranquet <granquet@baylibre.com>
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References: <20220919-v1-0-4844816c9808@baylibre.com> <20220919-v1-9-4844816c9808@baylibre.com>
 <5920ba96-886c-1195-656a-a98d7b1f6623@collabora.com>
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Date:   Mon, 3 Oct 2022 17:39:25 +0200
Message-ID: <CABnWg9vdYYgxPxMY=qm=JSd4ZV4hHB7g8M4he3GzUj6-rzmfQw@mail.gmail.com>
Subject: Re: [PATCH v1 09/17] drm/mediatek: hdmi: add connector flag
To:     AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@collabora.com>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        Vinod Koul <vkoul@kernel.org>, Stephen Boyd <sboyd@kernel.org>,
        David Airlie <airlied@linux.ie>,
        Rob Herring <robh+dt@kernel.org>,
        Philipp Zabel <p.zabel@pengutronix.de>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Daniel Vetter <daniel@ffwll.ch>,
        Chunfeng Yun <chunfeng.yun@mediatek.com>,
        CK Hu <ck.hu@mediatek.com>, Jitao shi <jitao.shi@mediatek.com>,
        Chun-Kuang Hu <chunkuang.hu@kernel.org>,
        Michael Turquette <mturquette@baylibre.com>,
        Kishon Vijay Abraham I <kishon@ti.com>
Cc:     linux-mediatek@lists.infradead.org,
        dri-devel@lists.freedesktop.org,
        Pablo Sun <pablo.sun@mediatek.com>, linux-clk@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        Mattijs Korpershoek <mkorpershoek@baylibre.com>,
        linux-arm-kernel@lists.infradead.org,
        linux-phy@lists.infradead.org, devicetree@vger.kernel.org
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On Tue, 20 Sep 2022 12:38, AngeloGioacchino Del Regno
<angelogioacchino.delregno@collabora.com> wrote:
>Il 19/09/22 18:56, Guillaume Ranquet ha scritto:
>> Add a flag to indicate support for an external connector
>>
>> Signed-off-by: Guillaume Ranquet <granquet@baylibre.com>
>>
>> diff --git a/drivers/gpu/drm/mediatek/mtk_hdmi_common.c b/drivers/gpu/drm/mediatek/mtk_hdmi_common.c
>> index 86653ebaacfd..30407603d693 100644
>> --- a/drivers/gpu/drm/mediatek/mtk_hdmi_common.c
>> +++ b/drivers/gpu/drm/mediatek/mtk_hdmi_common.c
>> @@ -199,20 +199,22 @@ int mtk_hdmi_dt_parse_pdata(struct mtk_hdmi *hdmi, struct platform_device *pdev,
>>   		goto put_device;
>>   	}
>>
>> -	remote = of_graph_get_remote_node(np, 1, 0);
>> -	if (!remote) {
>> -		ret = -EINVAL;
>> -		goto put_device;
>> -	}
>> -
>> -	if (!of_device_is_compatible(remote, "hdmi-connector")) {
>> -		hdmi->next_bridge = of_drm_find_bridge(remote);
>> -		if (!hdmi->next_bridge) {
>> -			dev_err(dev, "Waiting for external bridge\n");
>> -			of_node_put(remote);
>> -			ret = -EPROBE_DEFER;
>> +	if (hdmi->conf->has_connector) {
>
>If MT8195's DPI uses the internal HDMI->DP converter, I say that the external
>DP has HDMI input and DP output.
>Logically, you can't have a HDMI port that's connected to nothing.
>
>Please, rethink this change.
>
>Regards,
>Angelo

Hi Angelo,
Sorry for the late answer.

I have reworked this for V2, to use an hdmi connector device node to "bind"
both the hdmi and hdmi-ddc driver together as with "legacy" code.
So this patch is dropped in V2 (hopefully ready soon).

Just to make things clear, the hardware path on mt8195 is:
DPI1 -> HDMI Tx -> HDMI Phy
DP Intf1 -> DP Tx -> USB Type C Mux -> DP over USB-C

So there's no HDMI->DP converter involved.

Thx,
Guillaume.