From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933218AbbCRNXc (ORCPT ); Wed, 18 Mar 2015 09:23:32 -0400 Received: from mail-wi0-f174.google.com ([209.85.212.174]:38100 "EHLO mail-wi0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932855AbbCRNX0 (ORCPT ); Wed, 18 Mar 2015 09:23:26 -0400 Message-ID: <55097C46.9010605@gmail.com> Date: Wed, 18 Mar 2015 14:23:18 +0100 From: Sebastian Hesselbarth User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.5.0 To: Wolfram Sang CC: Jason Cooper , Andrew Lunn , Gregory Clement , Gabriel Dobato , Stephen Warren , linux-i2c@vger.kernel.org, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3 1/4] i2c: mux-pinctrl: Rework to honor disabled child nodes References: <1425039885-5137-2-git-send-email-sebastian.hesselbarth@gmail.com> <1425903665-19343-1-git-send-email-sebastian.hesselbarth@gmail.com> <20150318123012.GA3580@katana> In-Reply-To: <20150318123012.GA3580@katana> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 18.03.2015 13:30, Wolfram Sang wrote: > On Mon, Mar 09, 2015 at 01:21:05PM +0100, Sebastian Hesselbarth wrote: >> I2C mux pinctrl driver currently determines the number of sub-busses by >> counting available pinctrl-names. Unfortunately, this requires each >> incarnation of the devicetree node with different available sub-busses >> to be rewritten. >> >> This patch reworks i2c-mux-pinctrl driver to count the number of >> available sub-nodes instead. The rework should be compatible to the old >> way of probing for sub-busses and additionally allows to disable unused >> sub-busses with standard DT property status = "disabled". > > Not sure about this change. With DYNAMIC_OF these days, you can't rely > that 'disabled' stays disabled all the time. My gut feeling tells me > that people will want to use this someday. Possible. But this change just makes i2c-mux-pinctrl honor status property at all. There is no functional change except it now allows you to disable any of the sub-busses. I agree that this driver still does not cope well with DYNAMIC_OF but neither did the former implementation. How about we settle this driver to this implementation now and wait for any maniac that wants to use it the way you are suggesting above? The other option would be to leave the driver as is - but at least on Dove where the muxing-options are not used often, it will always create 4 i2c-busses (controller plus the three muxing options) on any board even though the pins are not accessible at all. I think that will just create massive confusion from the user point-of-view? BTW, I have received a patchwork update notification - it may be unrelated but I prefer the Dove dts/dtsi changes to go through mvebu tree. Sebastian From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sebastian Hesselbarth Subject: Re: [PATCH v3 1/4] i2c: mux-pinctrl: Rework to honor disabled child nodes Date: Wed, 18 Mar 2015 14:23:18 +0100 Message-ID: <55097C46.9010605@gmail.com> References: <1425039885-5137-2-git-send-email-sebastian.hesselbarth@gmail.com> <1425903665-19343-1-git-send-email-sebastian.hesselbarth@gmail.com> <20150318123012.GA3580@katana> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20150318123012.GA3580@katana> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Wolfram Sang Cc: Jason Cooper , Andrew Lunn , Gregory Clement , Gabriel Dobato , Stephen Warren , linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: devicetree@vger.kernel.org On 18.03.2015 13:30, Wolfram Sang wrote: > On Mon, Mar 09, 2015 at 01:21:05PM +0100, Sebastian Hesselbarth wrote: >> I2C mux pinctrl driver currently determines the number of sub-busses by >> counting available pinctrl-names. Unfortunately, this requires each >> incarnation of the devicetree node with different available sub-busses >> to be rewritten. >> >> This patch reworks i2c-mux-pinctrl driver to count the number of >> available sub-nodes instead. The rework should be compatible to the old >> way of probing for sub-busses and additionally allows to disable unused >> sub-busses with standard DT property status = "disabled". > > Not sure about this change. With DYNAMIC_OF these days, you can't rely > that 'disabled' stays disabled all the time. My gut feeling tells me > that people will want to use this someday. Possible. But this change just makes i2c-mux-pinctrl honor status property at all. There is no functional change except it now allows you to disable any of the sub-busses. I agree that this driver still does not cope well with DYNAMIC_OF but neither did the former implementation. How about we settle this driver to this implementation now and wait for any maniac that wants to use it the way you are suggesting above? The other option would be to leave the driver as is - but at least on Dove where the muxing-options are not used often, it will always create 4 i2c-busses (controller plus the three muxing options) on any board even though the pins are not accessible at all. I think that will just create massive confusion from the user point-of-view? BTW, I have received a patchwork update notification - it may be unrelated but I prefer the Dove dts/dtsi changes to go through mvebu tree. Sebastian -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html From mboxrd@z Thu Jan 1 00:00:00 1970 From: sebastian.hesselbarth@gmail.com (Sebastian Hesselbarth) Date: Wed, 18 Mar 2015 14:23:18 +0100 Subject: [PATCH v3 1/4] i2c: mux-pinctrl: Rework to honor disabled child nodes In-Reply-To: <20150318123012.GA3580@katana> References: <1425039885-5137-2-git-send-email-sebastian.hesselbarth@gmail.com> <1425903665-19343-1-git-send-email-sebastian.hesselbarth@gmail.com> <20150318123012.GA3580@katana> Message-ID: <55097C46.9010605@gmail.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 18.03.2015 13:30, Wolfram Sang wrote: > On Mon, Mar 09, 2015 at 01:21:05PM +0100, Sebastian Hesselbarth wrote: >> I2C mux pinctrl driver currently determines the number of sub-busses by >> counting available pinctrl-names. Unfortunately, this requires each >> incarnation of the devicetree node with different available sub-busses >> to be rewritten. >> >> This patch reworks i2c-mux-pinctrl driver to count the number of >> available sub-nodes instead. The rework should be compatible to the old >> way of probing for sub-busses and additionally allows to disable unused >> sub-busses with standard DT property status = "disabled". > > Not sure about this change. With DYNAMIC_OF these days, you can't rely > that 'disabled' stays disabled all the time. My gut feeling tells me > that people will want to use this someday. Possible. But this change just makes i2c-mux-pinctrl honor status property at all. There is no functional change except it now allows you to disable any of the sub-busses. I agree that this driver still does not cope well with DYNAMIC_OF but neither did the former implementation. How about we settle this driver to this implementation now and wait for any maniac that wants to use it the way you are suggesting above? The other option would be to leave the driver as is - but at least on Dove where the muxing-options are not used often, it will always create 4 i2c-busses (controller plus the three muxing options) on any board even though the pins are not accessible at all. I think that will just create massive confusion from the user point-of-view? BTW, I have received a patchwork update notification - it may be unrelated but I prefer the Dove dts/dtsi changes to go through mvebu tree. Sebastian