From mboxrd@z Thu Jan 1 00:00:00 1970 From: Heiko =?ISO-8859-1?Q?St=FCbner?= Subject: Re: [PATCH 1/2] Documentation: phy: introduce new optional property to specify drive impedance Date: Thu, 05 Jan 2017 12:15:18 +0100 Message-ID: <11505388.Y1Yzh8HsIT@diego> References: <1483608682-226716-1-git-send-email-shawn.lin@rock-chips.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1483608682-226716-1-git-send-email-shawn.lin-TNX95d0MmH7DzftRWevZcw@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-rockchip" Errors-To: linux-rockchip-bounces+glpar-linux-rockchip=m.gmane.org-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org To: Shawn Lin Cc: devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Douglas Anderson , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-rockchip-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, Rob Herring , Kishon Vijay Abraham I List-Id: devicetree@vger.kernel.org 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 > --- > > 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 :-) Heiko