linux-kernel - Re: [PATCH 04/12] drm/sun4i: sun6i_mipi

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Message-ID: <CAGb2v66No3-AODYCCGifBrm9uvPjaNdR2W5MDQdazRAPomT9CQ@mail.gmail.com>
Date:   Thu, 27 Sep 2018 20:42:53 +0800
From:   Chen-Yu Tsai <wens@...e.org>
To:     Jagan Teki <jagan@...rulasolutions.com>
Cc:     Maxime Ripard <maxime.ripard@...e-electrons.com>,
        Icenowy Zheng <icenowy@...c.io>,
        Jernej Skrabec <jernej.skrabec@...l.net>,
        Vasily Khoruzhick <anarsoul@...il.com>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will.deacon@....com>,
        David Airlie <airlied@...ux.ie>,
        dri-devel <dri-devel@...ts.freedesktop.org>,
        Mike Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>,
        linux-clk <linux-clk@...r.kernel.org>,
        Michael Trimarchi <michael@...rulasolutions.com>,
        linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
        devicetree <devicetree@...r.kernel.org>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        linux-sunxi <linux-sunxi@...glegroups.com>
Subject: Re: [PATCH 04/12] drm/sun4i: sun6i_mipi_dsi: Enable missing DSI bus clock

Hi,

On Thu, Sep 27, 2018 at 7:49 PM Jagan Teki <jagan@...rulasolutions.com> wrote:
>
> DSI bus_clk is already available in sun6i_dsi but missed to
> get the clk and process for enable/disable.
>
> This patch add support for it.
>
> Signed-off-by: Jagan Teki <jagan@...rulasolutions.com>
> ---
>  drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
>
> diff --git a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
> index 8e9c76febca2..156b371243c6 100644
> --- a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
> +++ b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
> @@ -1004,6 +1004,12 @@ static int sun6i_dsi_probe(struct platform_device *pdev)
>                 return PTR_ERR(dsi->reset);
>         }
>
> +       dsi->bus_clk = devm_clk_get(dev, "bus");
> +       if (IS_ERR(dsi->bus_clk)) {
> +               dev_err(dev, "Couldn't get the DSI bus clock\n");
> +               return PTR_ERR(dsi->bus_clk);
> +       }
> +

The DSI driver uses devm_regmap_init_mmio_clk, which enables the
clock behind the scenes when regmap access needs it enabled.

Did you have any issues without this patch?

ChenYu

>         if (dsi->variant->has_mod_clk) {
>                 dsi->mod_clk = devm_clk_get(dev, "mod");
>                 if (IS_ERR(dsi->mod_clk)) {
> @@ -1012,6 +1018,7 @@ static int sun6i_dsi_probe(struct platform_device *pdev)
>                 }
>         }
>
> +       clk_prepare_enable(dsi->bus_clk);
>         /*
>          * In order to operate properly, that clock seems to be always
>          * set to 297MHz.
> @@ -1065,6 +1072,7 @@ static int sun6i_dsi_remove(struct platform_device *pdev)
>         sun6i_dphy_remove(dsi);
>         if (dsi->variant->has_mod_clk)
>                 clk_rate_exclusive_put(dsi->mod_clk);
> +       clk_disable_unprepare(dsi->bus_clk);
>
>         return 0;
>  }
> --
> 2.18.0.321.gffc6fa0e3
>