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Date:   Fri, 4 Feb 2022 16:37:16 -0600
From:   Rob Herring <robh@kernel.org>
To:     Rajeev Nandan <quic_rajeevny@quicinc.com>
Cc:     dri-devel@lists.freedesktop.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org, sean@poorly.run, daniel@ffwll.ch,
        quic_abhinavk@quicinc.com, quic_kalyant@quicinc.com,
        quic_mkrishn@quicinc.com, linux-arm-msm@vger.kernel.org,
        airlied@linux.ie, jonathan@marek.ca, dmitry.baryshkov@linaro.org,
        swboyd@chromium.org, freedreno@lists.freedesktop.org,
        robh+dt@kernel.org, robdclark@gmail.com
Subject: Re: [v5 1/3] dt-bindings: msm/dsi: Add 10nm dsi phy tuning properties
Message-ID: <Yf2qnHguXCyWLj4f@robh.at.kernel.org>
References: <1643573719-32095-1-git-send-email-quic_rajeevny@quicinc.com>
 <1643573719-32095-2-git-send-email-quic_rajeevny@quicinc.com>
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On Mon, 31 Jan 2022 01:45:17 +0530, Rajeev Nandan wrote:
> In most cases, the default values of DSI PHY tuning registers should be
> sufficient as they are fully optimized. However, in some cases where
> extreme board parasitics cause the eye shape to degrade, the override
> bits can be used to improve the signal quality.
> 
> The general guidelines for DSI PHY tuning include:
> - High and moderate data rates may benefit from the drive strength and
>   drive level tuning.
> - Drive strength tuning will affect the output impedance and may be used
>   for matching optimization.
> - Drive level tuning will affect the output levels without affecting the
>   impedance.
> 
> The clock and data lanes have a calibration circuitry feature. The drive
> strength tuning can be done by adjusting rescode offset for hstop/hsbot,
> and the drive level tuning can be done by adjusting the LDO output level
> for the HSTX drive.
> 
> Signed-off-by: Rajeev Nandan <quic_rajeevny@quicinc.com>
> ---
> 
> Changes in v2:
>  - More details in the commit text (Stephen Boyd)
>  - Use human understandable values (Stephen Boyd, Dmitry Baryshkov)
>  - Do not take values that are going to be unused (Dmitry Baryshkov)
> 
> Changes in v3:
>  - Use "qcom," prefix (Dmitry Baryshkov)
>  - Remove encoding from phy-drive-ldo-level (Dmitry Baryshkov)
>  - Use negative values instead of two's complement (Dmitry, Rob Herring)
> 
> Changes in v4:
>  - Fix dt_binding_check error (Rob Herring's bot)
> 
> Changes in v5:
>  - None
> 
>  .../bindings/display/msm/dsi-phy-10nm.yaml         | 36 ++++++++++++++++++++++
>  1 file changed, 36 insertions(+)
> 

Reviewed-by: Rob Herring <robh@kernel.org>