From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lee Jones Subject: Re: [PATCH 09/14] i2c: Add Device Tree support to the Nomadik I2C driver Date: Thu, 14 Jun 2012 19:57:32 +0100 Message-ID: <4FDA341C.8010501@linaro.org> References: <1339428307-3850-1-git-send-email-lee.jones@linaro.org> <1339428307-3850-10-git-send-email-lee.jones@linaro.org> <4FD6F0E8.5040606@linaro.org> <4FD83AAD.2010701@linaro.org> <4FD88761.9050703@linaro.org> <20120614183636.GB30185@sirena.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <20120614183636.GB30185-GFdadSzt00ze9xe1eoZjHA@public.gmane.org> Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Mark Brown Cc: Linus Walleij , linus.walleij-0IS4wlFg1OjSUeElwK9/Pw@public.gmane.org, arnd-r2nGTMty4D4@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, grant.likely-s3s/WqlpOiPyB63q8FvJNQ@public.gmane.org, linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org List-Id: linux-i2c@vger.kernel.org On 14/06/12 19:36, Mark Brown wrote: > On Wed, Jun 13, 2012 at 01:28:17PM +0100, Lee Jones wrote: > >> Device Tree. However, we have just as much control by keeping them >> in separate structs in the C file and selecting the right one using >> the compatible sting. > > You're not understanding Linus' point. The compatible string isn't > useful here because properties like the maximum clock rate of the bus > depend on the board design, not the silicon. The controller may be > perfectly happy to run at a given rate but other devices on the bus o= r > the electrical engineering of the PCB itself may restrict this furthe= r. And you're not understanding mine. ;) You can have multiple compatible strings for a single driver. Which one= =20 you reference from the Device Tree will dictate which group of settings= =20 are used, including variation of clock rates. --=20 Lee Jones Linaro ST-Ericsson Landing Team Lead M: +44 77 88 633 515 Linaro.org =E2=94=82 Open source software for ARM SoCs =46ollow Linaro: Facebook | Twitter | Blog