On 2017/1/5 19:15, Heiko St?bner 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 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 >> 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