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

[Shawn Lin]

On 2017/1/5 19:15, Heiko Stübner wrote:
> Hi Shawn,
>
> 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@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.
>
> 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
> Documentation/devicetree/bindings/property-units.txt
>
> Also properties should use dashes ("-") not underscores.
>
> Judging by the second patch, these are Ohm, so combining the above you
> probably want
>
> 	drive-impedance-ohms
>
> as property name.
>
> Also the patch subject is slightly misleading and should probably specify the
> rockchip-emmc as well :-)

Thanks, will fix them.

> Heiko


--
Best Regards
Shawn Lin