linux-kernel - Re: [PATCH v4] drm: mediatek: Modify dpi power on/off sequence.

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Date:   Mon, 14 Nov 2022 07:33:57 +0800
From:   Chun-Kuang Hu <chunkuang.hu@...nel.org>
To:     xinlei.lee@...iatek.com
Cc:     chunkuang.hu@...nel.org, p.zabel@...gutronix.de, airlied@...ux.ie,
        daniel@...ll.ch, matthias.bgg@...il.com, jitao.shi@...iatek.com,
        dri-devel@...ts.freedesktop.org,
        linux-mediatek@...ts.infradead.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Project_Global_Chrome_Upstream_Group@...iatek.com
Subject: Re: [PATCH v4] drm: mediatek: Modify dpi power on/off sequence.

Hi, Xinlei:

<xinlei.lee@...iatek.com> 於 2022年11月9日 週三 下午6:01寫道：
>
> From: Xinlei Lee <xinlei.lee@...iatek.com>
>
> Modify dpi power on/off sequence so that the first gpio operation will take effect.

Applied to mediatek-drm-next [1], thanks.

[1] https://git.kernel.org/pub/scm/linux/kernel/git/chunkuang.hu/linux.git/log/?h=mediatek-drm-next

Regards,
Chun-Kuang.

>
> Fixes: 6bd4763fd532 ("drm/mediatek: set dpi pin mode to gpio low to avoid leakage current")
> Signed-off-by: Xinlei Lee <xinlei.lee@...iatek.com>
> ---
> change note:
> v3: Moved pull-down pin control after mtk_dpi_power_off.
>
> v2: Remove the empty line between Fixes: and S-o-b.
>
> v1: Rebase on linus/master v6.1-rc1. Change nothing.
>
> Because dpi power_on/off is protected by dpi->refcount, the first time
> it cannot be powered on and off successfully, it will cause leakage.
> ---
> ---
>  drivers/gpu/drm/mediatek/mtk_dpi.c | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/gpu/drm/mediatek/mtk_dpi.c b/drivers/gpu/drm/mediatek/mtk_dpi.c
> index 508a6d994e83..1f5d39a4077c 100644
> --- a/drivers/gpu/drm/mediatek/mtk_dpi.c
> +++ b/drivers/gpu/drm/mediatek/mtk_dpi.c
> @@ -461,9 +461,6 @@ static void mtk_dpi_power_off(struct mtk_dpi *dpi)
>         if (--dpi->refcount != 0)
>                 return;
>
> -       if (dpi->pinctrl && dpi->pins_gpio)
> -               pinctrl_select_state(dpi->pinctrl, dpi->pins_gpio);
> -
>         mtk_dpi_disable(dpi);
>         clk_disable_unprepare(dpi->pixel_clk);
>         clk_disable_unprepare(dpi->engine_clk);
> @@ -488,9 +485,6 @@ static int mtk_dpi_power_on(struct mtk_dpi *dpi)
>                 goto err_pixel;
>         }
>
> -       if (dpi->pinctrl && dpi->pins_dpi)
> -               pinctrl_select_state(dpi->pinctrl, dpi->pins_dpi);
> -
>         return 0;
>
>  err_pixel:
> @@ -721,12 +715,18 @@ static void mtk_dpi_bridge_disable(struct drm_bridge *bridge)
>         struct mtk_dpi *dpi = bridge_to_dpi(bridge);
>
>         mtk_dpi_power_off(dpi);
> +
> +       if (dpi->pinctrl && dpi->pins_gpio)
> +               pinctrl_select_state(dpi->pinctrl, dpi->pins_gpio);
>  }
>
>  static void mtk_dpi_bridge_enable(struct drm_bridge *bridge)
>  {
>         struct mtk_dpi *dpi = bridge_to_dpi(bridge);
>
> +       if (dpi->pinctrl && dpi->pins_dpi)
> +               pinctrl_select_state(dpi->pinctrl, dpi->pins_dpi);
> +
>         mtk_dpi_power_on(dpi);
>         mtk_dpi_set_display_mode(dpi, &dpi->mode);
>         mtk_dpi_enable(dpi);
> --
> 2.18.0
>