Re: [PATCH 1/8] dt-bindings: mmc: Add DQS trim value to Tegra SDHCI

[Thierry Reding]

On Tue, Aug 07, 2018 at 04:59:57PM +0300, Aapo Vienamo wrote:
> Document HS400 DQS trim value device tree property.
> 
> Signed-off-by: Aapo Vienamo <avienamo@xxxxxxxxxx>
> ---
>  Documentation/devicetree/bindings/mmc/nvidia,tegra20-sdhci.txt | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/mmc/nvidia,tegra20-sdhci.txt b/Documentation/devicetree/bindings/mmc/nvidia,tegra20-sdhci.txt
> index 3c7960a..7d294f3 100644
> --- a/Documentation/devicetree/bindings/mmc/nvidia,tegra20-sdhci.txt
> +++ b/Documentation/devicetree/bindings/mmc/nvidia,tegra20-sdhci.txt
> @@ -72,6 +72,7 @@ Optional properties for Tegra210 and Tegra186:
>    trimmer value for non-tunable modes.
>  - nvidia,default-trim : Specify the default outbound clock trimmer
>    value.
> +- nvidia,dqs-trim : Specify DQS trim value for HS400 timing
>  
>    Notes on the pad calibration pull up and pulldown offset values:
>      - The property values are drive codes which are programmed into the
> @@ -88,6 +89,8 @@ Optional properties for Tegra210 and Tegra186:
>      - The values are programmed to the Vendor Clock Control Register.
>        Please refer to the reference manual of the SoC for correct
>        values.
> +    - The DQS trim values are only used on controllers which support
> +      HS400 timing.

One of these additions says "DQS trim values", the other says "DQS trim
value". It is unclear from the above how many values there are. I think
this should be more explicit. Also, I don't see why the note about which
controllers the DQS trim value(s) applies to is in a separate paragraph.
Couldn't it be moved to the property description?

Also, I think the bindings should specify which generations of Tegra do
support HS400. Where else are people supposed to find that information?

Thierry

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