linux-kernel - Re: [PATCH V4 3/6] drm: bridge: samsung-dsim: Fetch pll-clock-frequency automatically

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <CAHCN7xLQaqP19zeMy27uUjFxgigKgh8vDRRM1P_uEXzuw5bN=g@mail.gmail.com>
Date:   Sat, 6 May 2023 13:27:45 -0500
From:   Adam Ford <aford173@...il.com>
To:     dri-devel@...ts.freedesktop.org
Cc:     aford@...conembedded.com, Chen-Yu Tsai <wenst@...omium.org>,
        Frieder Schrempf <frieder.schrempf@...tron.de>,
        Andrzej Hajda <andrzej.hajda@...el.com>,
        Neil Armstrong <neil.armstrong@...aro.org>,
        Robert Foss <rfoss@...nel.org>,
        Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
        Jonas Karlman <jonas@...boo.se>,
        Jernej Skrabec <jernej.skrabec@...il.com>,
        David Airlie <airlied@...il.com>,
        Daniel Vetter <daniel@...ll.ch>,
        Inki Dae <inki.dae@...sung.com>,
        Jagan Teki <jagan@...rulasolutions.com>,
        Marek Szyprowski <m.szyprowski@...sung.com>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH V4 3/6] drm: bridge: samsung-dsim: Fetch
 pll-clock-frequency automatically

On Fri, May 5, 2023 at 8:09 PM Adam Ford <aford173@...il.com> wrote:
>
> Make the pll-clock-frequency optional.  If it's present, use it
> to maintain backwards compatibility with existing hardware.  If it
> is absent, read clock rate of "sclk_mipi" to determine the rate.
>
> Signed-off-by: Adam Ford <aford173@...il.com>
> Tested-by: Chen-Yu Tsai <wenst@...omium.org>
> Tested-by: Frieder Schrempf <frieder.schrempf@...tron.de>
> Reviewed-by: Frieder Schrempf <frieder.schrempf@...tron.de>


Sorry for the noise.  I forgot to merge in the suggested updates for
the messages so they don't look like errors.  A V5 is coming once I
merge and test the changes.

adam
> ---
>  drivers/gpu/drm/bridge/samsung-dsim.c | 12 ++++++++++--
>  1 file changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c b/drivers/gpu/drm/bridge/samsung-dsim.c
> index bf4b33d2de76..2dc02a9e37c0 100644
> --- a/drivers/gpu/drm/bridge/samsung-dsim.c
> +++ b/drivers/gpu/drm/bridge/samsung-dsim.c
> @@ -1726,12 +1726,20 @@ static int samsung_dsim_parse_dt(struct samsung_dsim *dsi)
>  {
>         struct device *dev = dsi->dev;
>         struct device_node *node = dev->of_node;
> +       struct clk *pll_clk;
>         int ret;
>
>         ret = samsung_dsim_of_read_u32(node, "samsung,pll-clock-frequency",
>                                        &dsi->pll_clk_rate);
> -       if (ret < 0)
> -               return ret;
> +
> +       /* If it doesn't exist, read it from the clock instead of failing */
> +       if (ret < 0) {
> +               pll_clk = devm_clk_get(dev, "sclk_mipi");
> +               if (!IS_ERR(pll_clk))
> +                       dsi->pll_clk_rate = clk_get_rate(pll_clk);
> +               else
> +                       return PTR_ERR(pll_clk);
> +       }
>
>         ret = samsung_dsim_of_read_u32(node, "samsung,burst-clock-frequency",
>                                        &dsi->burst_clk_rate);
> --
> 2.39.2
>