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In-Reply-To: <1640856276-14697-2-git-send-email-quic_rajeevny@quicinc.com>
From:   Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Date:   Thu, 30 Dec 2021 17:14:34 +0300
Message-ID: <CAA8EJppoe8ebU-yNKF6fbuDK4nf=09eNzVvaq_wQ+qKdjWEf4w@mail.gmail.com>
Subject: Re: [v1 1/2] dt-bindings: msm/dsi: Add 10nm dsi phy tuning properties
To:     Rajeev Nandan <quic_rajeevny@quicinc.com>
Cc:     dri-devel@lists.freedesktop.org, linux-arm-msm@vger.kernel.org,
        freedreno@lists.freedesktop.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org, sean@poorly.run, robdclark@gmail.com,
        robh+dt@kernel.org, robh@kernel.org, quic_abhinavk@quicinc.com,
        quic_kalyant@quicinc.com, quic_mkrishn@quicinc.com,
        jonathan@marek.ca, airlied@linux.ie, daniel@ffwll.ch,
        swboyd@chromium.org
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On Thu, 30 Dec 2021 at 12:25, Rajeev Nandan <quic_rajeevny@quicinc.com> wrote:
>
> Add 10nm dsi phy tuning properties for phy drive strength and
> phy drive level adjustemnt.
>
> Signed-off-by: Rajeev Nandan <quic_rajeevny@quicinc.com>
> ---
>  .../devicetree/bindings/display/msm/dsi-phy-10nm.yaml | 19 +++++++++++++++++++
>  1 file changed, 19 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/display/msm/dsi-phy-10nm.yaml b/Documentation/devicetree/bindings/display/msm/dsi-phy-10nm.yaml
> index 4399715..9406982 100644
> --- a/Documentation/devicetree/bindings/display/msm/dsi-phy-10nm.yaml
> +++ b/Documentation/devicetree/bindings/display/msm/dsi-phy-10nm.yaml
> @@ -35,6 +35,18 @@ properties:
>        Connected to DSI0_MIPI_DSI_PLL_VDDA0P9 pin for sc7180 target and
>        connected to VDDA_MIPI_DSI_0_PLL_0P9 pin for sdm845 target
>
> +  phy-drive-strength-cfg:
> +    type: array
> +    description:
> +      Register values of DSIPHY_RESCODE_OFFSET_TOP and DSIPHY_RESCODE_OFFSET_BOT
> +      for all five lanes to adjust the phy drive strength.
> +
> +  phy-drive-level-cfg:
> +    type: array
> +    description:
> +      Register values of DSIPHY_RESCODE_OFFSET_TOP for all five lanes to adjust
> +      phy drive level/amplitude.
> +
>  required:
>    - compatible
>    - reg
> @@ -64,5 +76,12 @@ examples:
>           clocks = <&dispcc DISP_CC_MDSS_AHB_CLK>,
>                    <&rpmhcc RPMH_CXO_CLK>;
>           clock-names = "iface", "ref";
> +
> +         phy-drive-strength-cfg = [00 00
> +                                   00 00
> +                                   00 00
> +                                   00 00
> +                                   00 00];
> +         phy-drive-level-cfg = [59 59 59 59 59];

And second notice. This interface seems to be too register-centric.
You provide register values without any actual way to interpret them.
I'd prefer to have something closer to pinctrl. Specify strength and
level in some logical way and then in the driver interpret that into
register values.

-- 
With best wishes
Dmitry