Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753044Ab3ISPXR (ORCPT ); Thu, 19 Sep 2013 11:23:17 -0400 Received: from eu1sys200aog104.obsmtp.com ([207.126.144.117]:49643 "EHLO eu1sys200aog104.obsmtp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751797Ab3ISPXO convert rfc822-to-8bit (ORCPT ); Thu, 19 Sep 2013 11:23:14 -0400 From: Maxime COQUELIN To: Srinivas KANDAGATLA Cc: Lee Jones , Wolfram Sang , Rob Herring , Pawel Moll , Mark Rutland , Stephen Warren , Ian Campbell , Rob Landley , Russell King , Grant Likely , "devicetree@vger.kernel.org" , "linux-doc@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "linux-i2c@vger.kernel.org" , Stephen GALLIMORE , Stuart MENEFY , Gabriel FERNANDEZ , Olivier CLERGEAUD Date: Thu, 19 Sep 2013 17:22:30 +0200 Subject: Re: [PATCH 2/4] ARM: STi: Supply I2C configuration to STiH416 SoC Thread-Topic: [PATCH 2/4] ARM: STi: Supply I2C configuration to STiH416 SoC Thread-Index: AQHOtUwO9YE1fhMorUmIqSpGJM/Akg== Message-ID: <84625B87D65BCF478CC1E9C886A4C314DEF1BD957D@SAFEX1MAIL4.st.com> References: <1379498483-4236-1-git-send-email-maxime.coquelin@st.com> <1379498483-4236-3-git-send-email-maxime.coquelin@st.com> <20130918120340.GF16984@lee--X1> <84625B87D65BCF478CC1E9C886A4C314DEF1BD9578@SAFEX1MAIL4.st.com> <5239A322.5010004@st.com> <84625B87D65BCF478CC1E9C886A4C314DEF1BD9579@SAFEX1MAIL4.st.com> <523AF548.30400@st.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: acceptlanguage: en-US Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3835 Lines: 100 On 09/19/2013 03:01 PM, Srinivas KANDAGATLA wrote: > On 19/09/13 08:16, Maxime COQUELIN wrote: >> Hi Srini, >> >> On 09/18/2013 03:17 PM, Srinivas KANDAGATLA wrote: >>> On 18/09/13 13:46, Maxime COQUELIN wrote: >>>> On 09/18/2013 02:03 PM, Lee Jones wrote: >>>>>>>> This patch supplies I2C configuration to STiH416 SoC. >>>>>>>> >>>>>>>> Cc: Srinivas Kandagatla >>>>>>>> Signed-off-by: Maxime Coquelin >>>>>>>> --- >>>>>>>> arch/arm/boot/dts/stih416-pinctrl.dtsi | 35 ++++++++++++++++++++ >>>>>>>> arch/arm/boot/dts/stih416.dtsi | 57 ++++++++++++++++++++++++++++++++ >>>>>>>> 2 files changed, 92 insertions(+) >>>>>>>> >>>>>>>> diff --git a/arch/arm/boot/dts/stih416-pinctrl.dtsi b/arch/arm/boot/dts/stih416-pinctrl.dtsi >>>>>> I genuinely don't know the answer to this question, but are these >>>>>> nodes identical to the ones you've just put in the stih415 DTSI file? >>>>>> If so, I think it will be worth creating a stih41x DTSI rather than >>>>>> duplicating lots of stuff unnecessarily. >>>> There are close to be identical indeed. >>>> For the clocks and pinctrl, the references names are the same, but they are >>>> pointing on different nodes, as STiH415 and STiH416 have their own >>>> clocks and pinctrl dtsi files. >>>> >>>> Srini, what is opinion about this? >>> There is already a stih41x.dtsi file, but I don't think it is the right >>> place for the pinctrl nodes there. >>> >>> Am not OK with the idea of common pinctrl nodes for STiH415 and STiH416 >>> for two reasons. >>> >>> 1> If we common up the pinctrl nodes, it will be very difficult to >>> accommodate new pinctrls layout which is not guaranteed to be in same >>> layout in future SOCs. >>> >>> 2> The retiming values in the pinctrl nodes tend to change as per SOC, >>> so it will be difficult to manage it if we common it up. >>> >>> Am sure we can come up with a dt layout which can reduce duplication, >>> but we have to be careful here not to lose the flexiblity to accommodate >>> new picntrl layouts, new retimings values based on SOC. >> Ok. What do you think of declaring the i2c nodes inside the stih41x.dtsi >> file, >> and overload them with the pinctrl and clock properties in the stih416 >> and stih415 dtsi files? > Am not very comfortable with this idea. > > As there is no guarantee that the interrupt number/memory map and the > i2c numbering will be same in future SOCs or other IPs. > > You might be already aware that the number of i2cs on each SOC are > different as example on STiH415 we have 10 SSCs and on STiH416 we have > 11 SSCs. So, At what point you decide that which devices/IPs should be > in stih41x and which should in stih415/Stih416? Yes, I know there is one more SSC on STiH416. On one hand, this could add some confusion. But on the other hand, someone who will need to activate a SSP will know which one he has to activate. > > Each i2c node will save around 5 lines if we common it up, but if the > interrupt number or map changes this difference will be negligible. > > Common up at this level and mixing un-common ones in stih415.dtsi or > stih416.dtsi will add confusion to readers as the information is split > at multiple places. I agree it will be messy if one part of the node declared at one place, and the rest at another place. > > IMO the common up idea sounds good but reduces the readability and has > no effect on final dtb size. Fair enough. Lee, are you ok with keeping it as is? Thanks, Maxime > > Thanks, > srini > > >> Regards, >> Maxime >>> >>> thanks, >>> srini >>> >>> >> >> > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/