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From:   Guillaume Ranquet <granquet@baylibre.com>
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Date:   Mon, 3 Oct 2022 17:29:36 +0200
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Subject: Re: [PATCH v1 17/17] drm/mediatek: Add mt8195-dpi support to drm_drv
To:     Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>,
        Kishon Vijay Abraham I <kishon@ti.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>
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, 27 Sep 2022 16:28, Krzysztof Kozlowski
<krzysztof.kozlowski@linaro.org> wrote:
>On 27/09/2022 15:04, Guillaume Ranquet wrote:
>> On Thu, 22 Sep 2022 09:20, Krzysztof Kozlowski
>> <krzysztof.kozlowski@linaro.org> wrote:
>>> On 19/09/2022 18:56, Guillaume Ranquet wrote:
>>>> Add dpi support to enable the HDMI path.
>>>>
>>>> Signed-off-by: Guillaume Ranquet <granquet@baylibre.com>
>>>>
>>>> diff --git a/drivers/gpu/drm/mediatek/mtk_drm_drv.c b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
>>>> index 72049a530ae1..27f029ca760b 100644
>>>> --- a/drivers/gpu/drm/mediatek/mtk_drm_drv.c
>>>> +++ b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
>>>> @@ -820,6 +820,8 @@ static const struct of_device_id mtk_ddp_comp_dt_ids[] = {
>>>>  	  .data = (void *)MTK_DPI },
>>>>  	{ .compatible = "mediatek,mt8192-dpi",
>>>>  	  .data = (void *)MTK_DPI },
>>>> +	{ .compatible = "mediatek,mt8195-dpi",
>>>> +	  .data = (void *)MTK_DPI },
>>>
>>> It's compatible with the others. You don't need more compatibles.
>>
>> Hi Krzysztof,
>>
>> It's a bit confusing, because this compatible is used in both
>> mtk_drm_drv.c and in mtk_dpi.c
>>
>> Albeit it's entirely the same thing regarding the mtk_drm_drv module,
>> it's pretty different
>> regarding the mtk_dpi module.
>
>Sure, but this does not explain why do you need these entries here in
>mtk_drm_drv.
>
>Best regards,
>Krzysztof
>

Hi Krzysztof,

Sorry for the late answer.
The mtk_drm_drv is the component master of the full mediatek drm stack.

it "binds" all of the crtc/dpi/ovl/mutex/merge... components of the stack.

That mtk_ddp_comp_dt_ids array is iterated over to find all of the components
from the device tree.

Hope this clarifies things?

Thx,
Guillaume.