linux-kernel - Re: [PATCH 4/4] drm/mediatek: support the DSI0 output on the MT8195 VDOSYS0

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Date:   Fri, 1 Dec 2023 10:22:54 +0100
From:   AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...labora.com>
To:     Michael Walle <mwalle@...nel.org>,
        Chun-Kuang Hu <chunkuang.hu@...nel.org>,
        Philipp Zabel <p.zabel@...gutronix.de>,
        Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Maxime Ripard <mripard@...nel.org>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        David Airlie <airlied@...il.com>,
        Daniel Vetter <daniel@...ll.ch>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Conor Dooley <conor+dt@...nel.org>,
        Chunfeng Yun <chunfeng.yun@...iatek.com>,
        Vinod Koul <vkoul@...nel.org>,
        Kishon Vijay Abraham I <kishon@...nel.org>,
        Matthias Brugger <matthias.bgg@...il.com>,
        Jitao Shi <jitao.shi@...iatek.com>,
        Xinlei Lee <xinlei.lee@...iatek.com>
Cc:     dri-devel@...ts.freedesktop.org,
        linux-mediatek@...ts.infradead.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-phy@...ts.infradead.org
Subject: Re: [PATCH 4/4] drm/mediatek: support the DSI0 output on the MT8195
 VDOSYS0

Il 30/11/23 13:47, Michael Walle ha scritto:
>> With the latest dynamic selection of the output component, we can now
>> support different outputs. Move current output component into the
>> dynamic routes array and add the new DSI0 output.
>>
>> Signed-off-by: Michael Walle <mwalle@...nel.org>
>> ---
>>  drivers/gpu/drm/mediatek/mtk_drm_drv.c | 8 +++++++-
>>  1 file changed, 7 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/mediatek/mtk_drm_drv.c 
>> b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
>> index 2b0c35cacbc6..6fa88976376e 100644
>> --- a/drivers/gpu/drm/mediatek/mtk_drm_drv.c
>> +++ b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
>> @@ -222,7 +222,11 @@ static const unsigned int mt8195_mtk_ddp_main[] = {
>>      DDP_COMPONENT_DITHER0,
>>      DDP_COMPONENT_DSC0,
>>      DDP_COMPONENT_MERGE0,
>> -    DDP_COMPONENT_DP_INTF0,
> 
> Please disregard this patch (the others are ok). There must gone something
> wrong during my testing. DDP_COMPONENT_MERGE0 won't work with
> DDP_COMPONENT_DSI0. If anyone has more insights, I'm all ears.
> 

I was *convinced* that the MERGE0 SOUT was connected to DSI0!!!

...but you're right, here, and thanks for catching that: there's no way to
get MERGE0 connected to DSI0; if you check in the datasheet for VDO_SEL_IN,
you can get data from MERGE0 only for DSI*1*, not 0.

The only way is to connect DSC_WRAP0 (DDP_COMPONENT_DSC0 in mtk_drm_drv btw)
directly to DSI0 (or dither to dsi0)... unless there is a way to change the
pinmux to invert the pins for DSI0/1?

You could assign the DSI1 controller to the one that is currently DSI0 for you.

That would solve the issue here.

Cheers!
Angelo

> -michael
> 
>> +};
>> +
>> +static const struct mtk_drm_route mt8195_mtk_ddp_main_routes[] = {
>> +    { 0, DDP_COMPONENT_DP_INTF0 },
>> +    { 0, DDP_COMPONENT_DSI0 },
>>  };
>>
>>  static const unsigned int mt8195_mtk_ddp_ext[] = {
>> @@ -308,6 +312,8 @@ static const struct mtk_mmsys_driver_data 
>> mt8192_mmsys_driver_data = {
>>  static const struct mtk_mmsys_driver_data mt8195_vdosys0_driver_data = {
>>      .main_path = mt8195_mtk_ddp_main,
>>      .main_len = ARRAY_SIZE(mt8195_mtk_ddp_main),
>> +    .conn_routes = mt8195_mtk_ddp_main_routes,
>> +    .num_conn_routes = ARRAY_SIZE(mt8195_mtk_ddp_main_routes),
>>      .mmsys_dev_num = 2,
>>  };