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
Date: Fri, 4 Feb 2022 16:37:16 -0600 [thread overview]
Message-ID: <Yf2qnHguXCyWLj4f@robh.at.kernel.org> (raw)
In-Reply-To: <1643573719-32095-2-git-send-email-quic_rajeevny@quicinc.com>
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>
WARNING: multiple messages have this Message-ID (diff)
From: Rob Herring <robh@kernel.org>
To: Rajeev Nandan <quic_rajeevny@quicinc.com>
Cc: quic_kalyant@quicinc.com, devicetree@vger.kernel.org,
jonathan@marek.ca, airlied@linux.ie,
linux-arm-msm@vger.kernel.org, freedreno@lists.freedesktop.org,
linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org,
quic_abhinavk@quicinc.com, robh+dt@kernel.org,
quic_mkrishn@quicinc.com, dmitry.baryshkov@linaro.org,
swboyd@chromium.org, sean@poorly.run
Subject: Re: [v5 1/3] dt-bindings: msm/dsi: Add 10nm dsi phy tuning properties
Date: Fri, 4 Feb 2022 16:37:16 -0600 [thread overview]
Message-ID: <Yf2qnHguXCyWLj4f@robh.at.kernel.org> (raw)
In-Reply-To: <1643573719-32095-2-git-send-email-quic_rajeevny@quicinc.com>
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>
next prev parent reply other threads:[~2022-02-04 22:37 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-30 20:15 [v5 0/3] drm/msm/dsi: Add 10nm dsi phy tuning configuration support Rajeev Nandan
2022-01-30 20:15 ` Rajeev Nandan
2022-01-30 20:15 ` [v5 1/3] dt-bindings: msm/dsi: Add 10nm dsi phy tuning properties Rajeev Nandan
2022-01-30 20:15 ` Rajeev Nandan
2022-02-04 22:37 ` Rob Herring [this message]
2022-02-04 22:37 ` Rob Herring
2022-01-30 20:15 ` [v5 2/3] drm/msm/dsi: Add dsi phy tuning configuration support Rajeev Nandan
2022-01-30 20:15 ` Rajeev Nandan
2022-01-30 20:15 ` [v5 3/3] drm/msm/dsi: Add 10nm " Rajeev Nandan
2022-01-30 20:15 ` Rajeev Nandan
2022-01-31 17:08 ` Dmitry Baryshkov
2022-01-31 17:08 ` Dmitry Baryshkov
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