From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexander Sverdlin Subject: Re: [PATCH] of: i2c: Add DT bindings for idle states to PCA954x mux driver Date: Tue, 16 Dec 2014 21:13:47 +0100 Message-ID: <5490927B.1010705@nsn.com> References: <548E387E.2020502@nsn.com> <5722849.lDq3gpSIfD@avalon> <54902A49.7030804@nsn.com> <3857435.mVCtkYnmde@avalon> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <3857435.mVCtkYnmde@avalon> Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: ext Laurent Pinchart Cc: Jean Delvare , devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Rob Herring , grant.likely-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org, Lawnick Michael 61283229 , Maxime Ripard , Stephen Warren List-Id: devicetree@vger.kernel.org Hello Laurent! On 16/12/14 14:38, ext Laurent Pinchart wrote: >>> I understand the use cases of the idle-disconnect property. What do you >>> > > use idle-state for, when the idle state is different from disconnecting >>> > > the bus ? >> > >> > We do not have a use case for that. It was done only for the sake of >> > completeness. Because other MUXes actually offer user this possibility. I >> > was initially thinking about providing this on i2c-mux level for all of >> > them, but unfortunately they all use deselect callback in different way and >> > pinctrl is the worst case, as idle state cannot be represented with an int, >> > but should be a pointer. >> > >> > Anyway, if you think there is no use-case for this, I can drop this part. > Adding a DT property without a clear use case usually makes me a bit wary. I > would thus prefer going for either idle-disconnect alone, or for an idle-state > property that would allow selecting disconnection as one of the possible > values. I thought about this, but this would require some magic value for idle-state property, which would not be obvious for the readers of .dts file without consulting the documentation. So, I would prefer to drop the idle channel selection completely... -- Best regards, Alexander Sverdlin.