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: Wed, 13 Jun 2012 13:28:17 +0100 Message-ID: <4FD88761.9050703@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> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Linus Walleij Cc: linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linus.walleij-0IS4wlFg1OjSUeElwK9/Pw@public.gmane.org, arnd-r2nGTMty4D4@public.gmane.org, grant.likely-s3s/WqlpOiPyB63q8FvJNQ@public.gmane.org, linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-i2c@vger.kernel.org On 13/06/12 09:12, Linus Walleij wrote: > On Wed, Jun 13, 2012 at 9:01 AM, Lee Jones wro= te: > >> Board specific is fine, as the data is protected by a board specific >> property. Do you mean that the properties are *bus specific*? In whi= ch case >> I see your point and will apply the correct bindings. > > I cannot parse this, the board for me is a SoC, busses and a > number of components connected via e.g. I2C. > > Can you define what you mean with a "board specific property"? > It seems you are talking about what I would call an > "SoC-specific property", i.e. something out of a .dtsi file for > a certain SoC, whereas the .dts for an entire board is, > well, for a board, a set of components on a PCB. > > The arrangement of accelerometers and battery monitors on a > certain board is board-specific, and it is also by definition > bus-specific. Okay, let's put it another way. We can individualise any board, bus,=20 platform, machine or system by placing all of the information in a DT=20 node so long as we plonk it in the correct place within the Device Tree= =2E=20 However, we have just as much control by keeping them in separate=20 structs in the C file and selecting the right one using the compatible=20 sting. The real item for discussion is; if we have varying configurations for=20 each of the i2c buses residing on the same SoC, do we really want to us= e=20 different compatible strings to identify each one. If the answer is no,= =20 which I think it is, then I need to write the bindings and have=20 everything individually configurable from Device Tree. While you're mulling this over, I'm just going to write the bindings an= yway. --=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