[PATCH 1/2] Documentation: phy: introduce new optional property to specify drive impedance
heiko at sntech.de
Thu Jan 5 03:15:18 PST 2017
Am Donnerstag, 5. Januar 2017, 17:31:21 schrieb Shawn Lin:
> 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 at rock-chips.com>
> 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
> +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.
In what unit are your 33, 40 etc values?
It is recommended that properties should specify their unit, see all the
properties ending in "-ma", "-ns" and so on and also
Also properties should use dashes ("-") not underscores.
Judging by the second patch, these are Ohm, so combining the above you
as property name.
Also the patch subject is slightly misleading and should probably specify the
rockchip-emmc as well :-)
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