diff mbox series

[v3,1/3] dt-bindings: msm/dsi: Add 10nm dsi phy tuning properties

Message ID 1642538320-1127-2-git-send-email-quic_rajeevny@quicinc.com (mailing list archive)
State New, archived
Headers show
Series drm/msm/dsi: Add 10nm dsi phy tuning configuration support | expand

Commit Message

Rajeev Nandan Jan. 18, 2022, 8:38 p.m. UTC 
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)


 .../bindings/display/msm/dsi-phy-10nm.yaml         | 34 ++++++++++++++++++++++
 1 file changed, 34 insertions(+)

Comments

Rob Herring Jan. 19, 2022, 2:55 a.m. UTC | #1 
On Wed, 19 Jan 2022 02:08:38 +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)
> 
> 
>  .../bindings/display/msm/dsi-phy-10nm.yaml         | 34 ++++++++++++++++++++++
>  1 file changed, 34 insertions(+)
> 

My bot found errors running 'make DT_CHECKER_FLAGS=-m dt_binding_check'
on your patch (DT_CHECKER_FLAGS is new in v5.13):

yamllint warnings/errors:

dtschema/dtc warnings/errors:
/builds/robherring/linux-dt-review/Documentation/devicetree/bindings/display/msm/dsi-phy-10nm.yaml: properties:qcom,phy-rescode-offset-bot: 'minimum' should not be valid under {'enum': ['const', 'enum', 'exclusiveMaximum', 'exclusiveMinimum', 'minimum', 'maximum', 'multipleOf', 'pattern']}
	hint: Scalar and array keywords cannot be mixed
	from schema $id: http://devicetree.org/meta-schemas/keywords.yaml#
/builds/robherring/linux-dt-review/Documentation/devicetree/bindings/display/msm/dsi-phy-10nm.yaml: properties:qcom,phy-rescode-offset-bot: 'maximum' should not be valid under {'enum': ['const', 'enum', 'exclusiveMaximum', 'exclusiveMinimum', 'minimum', 'maximum', 'multipleOf', 'pattern']}
	hint: Scalar and array keywords cannot be mixed
	from schema $id: http://devicetree.org/meta-schemas/keywords.yaml#
/builds/robherring/linux-dt-review/Documentation/devicetree/bindings/display/msm/dsi-phy-10nm.yaml: properties:qcom,phy-rescode-offset-bot: 'minimum' should not be valid under {'enum': ['const', 'enum', 'exclusiveMaximum', 'exclusiveMinimum', 'minimum', 'maximum', 'multipleOf', 'pattern']}
	hint: Scalar and array keywords cannot be mixed
	from schema $id: http://devicetree.org/meta-schemas/keywords.yaml#
/builds/robherring/linux-dt-review/Documentation/devicetree/bindings/display/msm/dsi-phy-10nm.yaml: properties:qcom,phy-rescode-offset-bot: 'maximum' should not be valid under {'enum': ['const', 'enum', 'exclusiveMaximum', 'exclusiveMinimum', 'minimum', 'maximum', 'multipleOf', 'pattern']}
	hint: Scalar and array keywords cannot be mixed
	from schema $id: http://devicetree.org/meta-schemas/keywords.yaml#
/builds/robherring/linux-dt-review/Documentation/devicetree/bindings/display/msm/dsi-phy-10nm.yaml: properties:qcom,phy-rescode-offset-top: 'minimum' should not be valid under {'enum': ['const', 'enum', 'exclusiveMaximum', 'exclusiveMinimum', 'minimum', 'maximum', 'multipleOf', 'pattern']}
	hint: Scalar and array keywords cannot be mixed
	from schema $id: http://devicetree.org/meta-schemas/keywords.yaml#
/builds/robherring/linux-dt-review/Documentation/devicetree/bindings/display/msm/dsi-phy-10nm.yaml: properties:qcom,phy-rescode-offset-top: 'maximum' should not be valid under {'enum': ['const', 'enum', 'exclusiveMaximum', 'exclusiveMinimum', 'minimum', 'maximum', 'multipleOf', 'pattern']}
	hint: Scalar and array keywords cannot be mixed
	from schema $id: http://devicetree.org/meta-schemas/keywords.yaml#
/builds/robherring/linux-dt-review/Documentation/devicetree/bindings/display/msm/dsi-phy-10nm.yaml: properties:qcom,phy-rescode-offset-top: 'minimum' should not be valid under {'enum': ['const', 'enum', 'exclusiveMaximum', 'exclusiveMinimum', 'minimum', 'maximum', 'multipleOf', 'pattern']}
	hint: Scalar and array keywords cannot be mixed
	from schema $id: http://devicetree.org/meta-schemas/keywords.yaml#
/builds/robherring/linux-dt-review/Documentation/devicetree/bindings/display/msm/dsi-phy-10nm.yaml: properties:qcom,phy-rescode-offset-top: 'maximum' should not be valid under {'enum': ['const', 'enum', 'exclusiveMaximum', 'exclusiveMinimum', 'minimum', 'maximum', 'multipleOf', 'pattern']}
	hint: Scalar and array keywords cannot be mixed
	from schema $id: http://devicetree.org/meta-schemas/keywords.yaml#
/builds/robherring/linux-dt-review/Documentation/devicetree/bindings/display/msm/dsi-phy-10nm.yaml: ignoring, error in schema: properties: qcom,phy-rescode-offset-bot
Documentation/devicetree/bindings/display/msm/dsi-phy-10nm.example.dt.yaml:0:0: /example-0/dsi-phy@ae94400: failed to match any schema with compatible: ['qcom,dsi-phy-10nm']

doc reference errors (make refcheckdocs):

See https://patchwork.ozlabs.org/patch/1581518

This check can fail if there are any dependencies. The base for a patch
series is generally the most recent rc1.

If you already ran 'make dt_binding_check' and didn't see the above
error(s), then make sure 'yamllint' is installed and dt-schema is up to
date:

pip3 install dtschema --upgrade

Please check and re-submit.
diff mbox series

Patch

diff --git a/Documentation/devicetree/bindings/display/msm/dsi-phy-10nm.yaml b/Documentation/devicetree/bindings/display/msm/dsi-phy-10nm.yaml
index 4399715..e9ba57e 100644
--- a/Documentation/devicetree/bindings/display/msm/dsi-phy-10nm.yaml
+++ b/Documentation/devicetree/bindings/display/msm/dsi-phy-10nm.yaml
@@ -35,6 +35,36 @@  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
 
+  qcom,phy-rescode-offset-top:
+    $ref: /schemas/types.yaml#/definitions/int8-array
+    minItems: 5
+    maxItems: 5
+    minimum: -32
+    maximum: 31
+    description:
+      Integer array of offset for pull-up legs rescode for all five lanes.
+      To offset the drive strength from the calibrated value in an increasing
+      manner, -32 is the weakest and +31 is the strongest.
+
+  qcom,phy-rescode-offset-bot:
+    $ref: /schemas/types.yaml#/definitions/int8-array
+    minItems: 5
+    maxItems: 5
+    minimum: -32
+    maximum: 31
+    description:
+      Integer array of offset for pull-down legs rescode for all five lanes.
+      To offset the drive strength from the calibrated value in a decreasing
+      manner, -32 is the weakest and +31 is the strongest.
+
+  qcom,phy-drive-ldo-level:
+    $ref: "/schemas/types.yaml#/definitions/uint32"
+    description:
+      The PHY LDO has an amplitude tuning feature to adjust the LDO output
+      for the HSTX drive. Use supported levels (mV) to offset the drive level
+      from the default value.
+    enum: [ 375, 400, 425, 450, 475, 500 ]
+
 required:
   - compatible
   - reg
@@ -64,5 +94,9 @@  examples:
          clocks = <&dispcc DISP_CC_MDSS_AHB_CLK>,
                   <&rpmhcc RPMH_CXO_CLK>;
          clock-names = "iface", "ref";
+
+         qcom,phy-rescode-offset-top = /bits/ 8 <0 0 0 0 0>;
+         qcom,phy-rescode-offset-bot = /bits/ 8 <0 0 0 0 0>;
+         qcom,phy-drive-ldo-level = <400>;
      };
 ...