Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
MIME-Version: 1.0
References: <20230506010933.170939-1-aford173@gmail.com> <20230506010933.170939-4-aford173@gmail.com>
In-Reply-To: <20230506010933.170939-4-aford173@gmail.com>
From:   Adam Ford <aford173@gmail.com>
Date:   Sat, 6 May 2023 13:27:45 -0500
Message-ID: <CAHCN7xLQaqP19zeMy27uUjFxgigKgh8vDRRM1P_uEXzuw5bN=g@mail.gmail.com>
Subject: Re: [PATCH V4 3/6] drm: bridge: samsung-dsim: Fetch
 pll-clock-frequency automatically
To:     dri-devel@lists.freedesktop.org
Cc:     aford@beaconembedded.com, Chen-Yu Tsai <wenst@chromium.org>,
        Frieder Schrempf <frieder.schrempf@kontron.de>,
        Andrzej Hajda <andrzej.hajda@intel.com>,
        Neil Armstrong <neil.armstrong@linaro.org>,
        Robert Foss <rfoss@kernel.org>,
        Laurent Pinchart <Laurent.pinchart@ideasonboard.com>,
        Jonas Karlman <jonas@kwiboo.se>,
        Jernej Skrabec <jernej.skrabec@gmail.com>,
        David Airlie <airlied@gmail.com>,
        Daniel Vetter <daniel@ffwll.ch>,
        Inki Dae <inki.dae@samsung.com>,
        Jagan Teki <jagan@amarulasolutions.com>,
        Marek Szyprowski <m.szyprowski@samsung.com>,
        linux-kernel@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
Precedence: bulk

On Fri, May 5, 2023 at 8:09=E2=80=AFPM Adam Ford <aford173@gmail.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@gmail.com>
> Tested-by: Chen-Yu Tsai <wenst@chromium.org>
> Tested-by: Frieder Schrempf <frieder.schrempf@kontron.de>
> Reviewed-by: Frieder Schrempf <frieder.schrempf@kontron.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/brid=
ge/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_d=
sim *dsi)
>  {
>         struct device *dev =3D dsi->dev;
>         struct device_node *node =3D dev->of_node;
> +       struct clk *pll_clk;
>         int ret;
>
>         ret =3D samsung_dsim_of_read_u32(node, "samsung,pll-clock-frequen=
cy",
>                                        &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 =3D devm_clk_get(dev, "sclk_mipi");
> +               if (!IS_ERR(pll_clk))
> +                       dsi->pll_clk_rate =3D clk_get_rate(pll_clk);
> +               else
> +                       return PTR_ERR(pll_clk);
> +       }
>
>         ret =3D samsung_dsim_of_read_u32(node, "samsung,burst-clock-frequ=
ency",
>                                        &dsi->burst_clk_rate);
> --
> 2.39.2
>