Re: [PATCH v2 05/10] dt-bindings: Add Tegra SDHCI pad pdpu offset bindings

[Rob Herring <robh@kernel.org>]

On Thu, Jul 26, 2018 at 03:26:51PM +0300, Aapo Vienamo wrote:
> Add bindings documentation for pad pull up and pull down offset values to be
> programmed before executing automatic pad drive strength calibration.
> 
> Signed-off-by: Aapo Vienamo <avienamo@nvidia.com>
> ---
>  .../bindings/mmc/nvidia,tegra20-sdhci.txt          | 34 ++++++++++++++++++++++
>  1 file changed, 34 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/mmc/nvidia,tegra20-sdhci.txt b/Documentation/devicetree/bindings/mmc/nvidia,tegra20-sdhci.txt
> index 95010cf..c3d8a15 100644
> --- a/Documentation/devicetree/bindings/mmc/nvidia,tegra20-sdhci.txt
> +++ b/Documentation/devicetree/bindings/mmc/nvidia,tegra20-sdhci.txt
> @@ -24,6 +24,7 @@ Required properties:
>  Optional properties:
>  - power-gpios : Specify GPIOs for power control
>  
> +Optional properties for Tegra210 and Tegra186:
>  Example:
>  
>  sdhci@c8000200 {
> @@ -47,6 +48,35 @@ Optional properties for Tegra210 and Tegra186:
>    pinctrl-1.
>  - nvidia,only-1-8-v : The presence of this property indicates that the
>    controller operates at a 1.8 V fixed I/O voltage.

> +- nvidia,pad-autocal-pull-up-offset-3v3,
> +  nvidia,pad-autocal-pull-down-offset-3v3 : Specify drive strength
> +  calibration offsets for 3.3 V signaling modes.

Perhaps a single property with 2 values?

> +- nvidia,pad-autocal-pull-up-offset-1v8,
> +  nvidia,pad-autocal-pull-down-offset-1v8 : Specify drive strength
> +  calibration offsets for 1.8 V signaling modes.
> +- nvidia,pad-autocal-pull-up-offset-3v3-timeout,
> +  nvidia,pad-autocal-pull-down-offset-3v3-timeout : Specify drive
> +  strength used as a fallback in case the automatic calibration times
> +  out on a 3.3 V signaling mode.
> +- nvidia,pad-autocal-pull-up-offset-1v8-timeout,
> +  nvidia,pad-autocal-pull-down-offset-1v8-timeout : Specify drive
> +  strength used as a fallback in case the automatic calibration times
> +  out on a 1.8 V signaling mode.
> +- nvidia,pad-autocal-pull-up-offset-sdr104,
> +  nvidia,pad-autocal-pull-down-offset-sdr104 : Specify drive strength
> +  calibration offsets for SDR104 mode.
> +- nvidia,pad-autocal-pull-up-offset-hs400,
> +  nvidia,pad-autocal-pull-down-offset-hs400 : Specify drive strength
> +  calibration offsets for HS400 mode.
> +
> +  Notes on the pad calibration pull up and pulldown offset values:
> +    - The property values are drive codes which are programmed into the
> +      PD_OFFSET and PU_OFFSET sections of the
> +      SDHCI_TEGRA_AUTO_CAL_CONFIG register.
> +    - A higher value corresponds to higher drive strength. Please refer
> +      to the reference manual of the SoC for correct values.
> +    - The SDR104 and HS400 timing specific values are used in
> +      corresponding modes if specified.
>  
>  Example:
>  sdhci@700b0000 {
> @@ -60,5 +90,9 @@ sdhci@700b0000 {
>  	pinctrl-names = "sdmmc-3v3", "sdmmc-1v8";
>  	pinctrl-0 = <&sdmmc1_3v3>;
>  	pinctrl-1 = <&sdmmc1_1v8>;
> +	pad-autocal-pull-up-offset-3v3 = <0x00>;
> +	pad-autocal-pull-down-offset-3v3 = <0x7d>;
> +	pad-autocal-pull-up-offset-1v8 = <0x7b>;
> +	pad-autocal-pull-down-offset-1v8 = <0x7b>;

Doesn't match the doc.

>  	status = "disabled";
>  };
> -- 
> 2.7.4
>