linux-kernel - Re: [PATCH] drm/mediatek: fine tune the data lane trail by project dts

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Date:   Thu, 18 Mar 2021 08:31:02 +0800
From:   Chun-Kuang Hu <chunkuang.hu@...nel.org>
To:     Jitao Shi <jitao.shi@...iatek.com>
Cc:     Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Matthias Brugger <matthias.bgg@...il.com>,
        Daniel Vetter <daniel@...ll.ch>,
        David Airlie <airlied@...ux.ie>,
        DRI Development <dri-devel@...ts.freedesktop.org>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        DTML <devicetree@...r.kernel.org>,
        srv_heupstream <srv_heupstream@...iatek.com>,
        huijuan.xie@...iatek.com, stonea168@....com,
        Cawa Cheng <cawa.cheng@...iatek.com>, shuijing.li@...iatek.com,
        "moderated list:ARM/Mediatek SoC support" 
        <linux-mediatek@...ts.infradead.org>, yingjoe.chen@...iatek.com,
        eddie.huang@...iatek.com,
        Linux ARM <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH] drm/mediatek: fine tune the data lane trail by project dts

Hi, Jitao:

Jitao Shi <jitao.shi@...iatek.com> 於 2021年2月1日 週一 上午11:48寫道：
>
> Some panels or bridges require customized hs_da_trail time.
> So add a property in devicetree for this panels and bridges.
>
> Signed-off-by: Jitao Shi <jitao.shi@...iatek.com>
> ---
>  drivers/gpu/drm/mediatek/mtk_dsi.c | 10 +++++++++-
>  1 file changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
> index 8c70ec39bfe1..6e7092fa2fee 100644
> --- a/drivers/gpu/drm/mediatek/mtk_dsi.c
> +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
> @@ -194,6 +194,7 @@ struct mtk_dsi {
>         struct clk *hs_clk;
>
>         u32 data_rate;
> +       u32 da_trail_delta;
>
>         unsigned long mode_flags;
>         enum mipi_dsi_pixel_format format;
> @@ -234,7 +235,7 @@ static void mtk_dsi_phy_timconfig(struct mtk_dsi *dsi)
>         timing->da_hs_prepare = (80 * data_rate_mhz + 4 * 1000) / 8000;
>         timing->da_hs_zero = (170 * data_rate_mhz + 10 * 1000) / 8000 + 1 -
>                              timing->da_hs_prepare;
> -       timing->da_hs_trail = timing->da_hs_prepare + 1;
> +       timing->da_hs_trail = timing->da_hs_prepare + 1 + dsi->da_trail_delta;
>
>         timing->ta_go = 4 * timing->lpx - 2;
>         timing->ta_sure = timing->lpx + 2;
> @@ -1094,6 +1095,13 @@ static int mtk_dsi_probe(struct platform_device *pdev)
>                 goto err_unregister_host;
>         }
>
> +       ret = of_property_read_u32_index(dev->of_node, "da_trail_delta", 0,
> +                                        &dsi->da_trail_delta);

This value depends on panel, so I think we should get some value from
panel's device node to calculate this value.

Regards,
Chun-Kuang.

> +       if (ret) {
> +               dev_info(dev, "Can't get da_trail_delta, keep it as 0: %d\n", ret);
> +               dsi->da_trail_delta = 0;
> +       }
> +
>         comp_id = mtk_ddp_comp_get_id(dev->of_node, MTK_DSI);
>         if (comp_id < 0) {
>                 dev_err(dev, "Failed to identify by alias: %d\n", comp_id);
> --
> 2.12.5
> _______________________________________________
> dri-devel mailing list
> dri-devel@...ts.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel

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