linux-kernel - Re: [PATCH 19/21] drm/mediatek: dpi: add support for dpi clock

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Date:   Mon, 13 Mar 2023 23:21:08 +0800
From:   Chun-Kuang Hu <chunkuang.hu@...nel.org>
To:     Alexandre Mergnat <amergnat@...libre.com>
Cc:     Daniel Vetter <daniel@...ll.ch>, CK Hu <ck.hu@...iatek.com>,
        Jitao Shi <jitao.shi@...iatek.com>,
        Thierry Reding <thierry.reding@...il.com>,
        Philipp Zabel <p.zabel@...gutronix.de>,
        Sam Ravnborg <sam@...nborg.org>,
        Rob Herring <robh+dt@...nel.org>,
        Uwe Kleine-König 
        <u.kleine-koenig@...gutronix.de>,
        Chun-Kuang Hu <chunkuang.hu@...nel.org>,
        Matthias Brugger <matthias.bgg@...il.com>,
        David Airlie <airlied@...il.com>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Xinlei Lee <xinlei.lee@...iatek.com>,
        Guillaume La Roque <glaroque@...libre.com>,
        linux-arm-kernel@...ts.infradead.org,
        linux-mediatek@...ts.infradead.org,
        dri-devel@...ts.freedesktop.org,
        Fabien Parent <fparent@...libre.com>,
        Neil Armstrong <neil.armstrong@...aro.org>,
        linux-pwm@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 19/21] drm/mediatek: dpi: add support for dpi clock

Hi, Alexandre:

Alexandre Mergnat <amergnat@...libre.com> 於 2023年3月9日 週四 下午10:23寫道：
>
> From: Fabien Parent <fparent@...libre.com>
>
> MT8365 requires an additional clock for DPI. Add support for that
> additional clock.
>
> Signed-off-by: Fabien Parent <fparent@...libre.com>
> Signed-off-by: Alexandre Mergnat <amergnat@...libre.com>
> ---
>  drivers/gpu/drm/mediatek/mtk_dpi.c | 18 +++++++++++++++++-
>  1 file changed, 17 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/mediatek/mtk_dpi.c b/drivers/gpu/drm/mediatek/mtk_dpi.c
> index 4317595a15d1..474c6e5bbf04 100644
> --- a/drivers/gpu/drm/mediatek/mtk_dpi.c
> +++ b/drivers/gpu/drm/mediatek/mtk_dpi.c
> @@ -68,6 +68,7 @@ struct mtk_dpi {
>         struct device *dev;
>         struct clk *engine_clk;
>         struct clk *pixel_clk;
> +       struct clk *dpi_clk;
>         struct clk *tvd_clk;
>         int irq;
>         struct drm_display_mode mode;
> @@ -464,6 +465,7 @@ static void mtk_dpi_power_off(struct mtk_dpi *dpi)
>         mtk_dpi_disable(dpi);
>         clk_disable_unprepare(dpi->pixel_clk);
>         clk_disable_unprepare(dpi->engine_clk);
> +       clk_disable_unprepare(dpi->dpi_clk);
>  }
>
>  static int mtk_dpi_power_on(struct mtk_dpi *dpi)
> @@ -473,10 +475,16 @@ static int mtk_dpi_power_on(struct mtk_dpi *dpi)
>         if (++dpi->refcount != 1)
>                 return 0;
>
> +       ret = clk_prepare_enable(dpi->dpi_clk);
> +       if (ret) {
> +               dev_err(dpi->dev, "failed to enable dpi clock: %d\n", ret);
> +               goto err_refcount;
> +       }
> +
>         ret = clk_prepare_enable(dpi->engine_clk);
>         if (ret) {
>                 dev_err(dpi->dev, "Failed to enable engine clock: %d\n", ret);
> -               goto err_refcount;
> +               goto err_engine;
>         }
>
>         ret = clk_prepare_enable(dpi->pixel_clk);
> @@ -489,6 +497,8 @@ static int mtk_dpi_power_on(struct mtk_dpi *dpi)
>
>  err_pixel:
>         clk_disable_unprepare(dpi->engine_clk);
> +err_engine:
> +       clk_disable_unprepare(dpi->dpi_clk);
>  err_refcount:
>         dpi->refcount--;
>         return ret;
> @@ -1044,6 +1054,12 @@ static int mtk_dpi_probe(struct platform_device *pdev)
>                 return ret;
>         }
>
> +       dpi->dpi_clk = devm_clk_get_optional(dev, "dpi");

For MT8365, DPI clock is not optional, so make sure that MT8365 DPI
should have this clock.

Regards,
Chun-Kuang.

> +       if (IS_ERR(dpi->dpi_clk)) {
> +               return dev_err_probe(dev, ret, "Failed to get dpi clock: %p\n",
> +                                    dpi->dpi_clk);
> +       }
> +
>         dpi->irq = platform_get_irq(pdev, 0);
>         if (dpi->irq <= 0)
>                 return -EINVAL;
>
> --
> b4 0.10.1