Re: [PATCH 1/2] Documentation: phy: introduce new optional property to specify drive impedance

From: Rob Herring
Date: Mon Jan 09 2017 - 13:06:36 EST


On Thu, Jan 05, 2017 at 05:31:21PM +0800, Shawn Lin wrote:
> We need to modify the drive impedance according to the
> different hardware condition. So let's expose this to
> the DT.
>
> Signed-off-by: Shawn Lin <shawn.lin@xxxxxxxxxxxxxx>
> ---
>
> Documentation/devicetree/bindings/phy/rockchip-emmc-phy.txt | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/phy/rockchip-emmc-phy.txt b/Documentation/devicetree/bindings/phy/rockchip-emmc-phy.txt
> index e3ea557..731aeb9 100644
> --- a/Documentation/devicetree/bindings/phy/rockchip-emmc-phy.txt
> +++ b/Documentation/devicetree/bindings/phy/rockchip-emmc-phy.txt
> @@ -14,6 +14,11 @@ specified by name:
> access to it), it is strongly suggested.
> - clocks: Should have a phandle to the card clock exported by the SDHCI driver.
>
> +Optional Properties:
> +- drive_impedance: Must be one of 33, 40, 50, 66, 100. This property allows
> + different boards to specify their own drive impedance depending on the
> + hardware condition.

Needs a vendor prefix. Don't use '_'. And needs unit suffix (-ohms).

> +
> Example:
>
>
> --
> 1.9.1
>
>