From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Warren Subject: Re: [PATCH 3/4] pinctrl: remove slew-rate parameter from tz1090 Date: Tue, 25 Jun 2013 15:40:50 -0600 Message-ID: <51CA0E62.2080403@wwwdotorg.org> References: <201306251455.01540.heiko@sntech.de> <201306251456.36499.heiko@sntech.de> <51C99581.2010403@imgtec.com> <201306251521.55634.heiko@sntech.de> <51C99AB5.1080002@imgtec.com> <51C9A039.4090804@imgtec.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Linus Walleij Cc: James Hogan , =?ISO-8859-1?Q?Heiko_St=FCbne?= =?ISO-8859-1?Q?r?= , "linux-kernel@vger.kernel.org" , "devicetree-discuss@lists.ozlabs.org" , Grant Likely , Rob Herring List-Id: devicetree@vger.kernel.org On 06/25/2013 09:39 AM, Linus Walleij wrote: > On Tue, Jun 25, 2013 at 3:50 PM, James Hogan wrote: >> On 25/06/13 14:32, Linus Walleij wrote: > >>> Patches adding it back in with SI measures will be welcomed! >> >> Okay. >> >> So the most descriptive documentation I can find for the slew rate in >> the TZ1090 pin config hardware is basically: >> >> 0: slow (half frequency) >> 1: fast >> >> Sounds like this pretty much precludes it from having a generic DT >> binding unless it can be mapped to some physical value, so I'll add a >> tz1090,slew-rate and use PIN_CONFIG_END+1 instead of PIN_CONFIG_SLEW_RATE. > > Okay... ut the Nomadik pin controller incidentally have a > similar definition: NMK_GPIO_LOWEMI. By slashing the > slew rate in half the EMI is of course reduced so that was > another name for the same thing. > > Maybe this is something that should just be boolean? > > slewrate-reduced-slope; Tegra has, IIRC, 4 different slew rates. I'm not sure that a Boolean/dual-state value would be appropriate here; it'd be limited to supporting some arbitrary cases rather than being something generic.