From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnd Bergmann Subject: Re: [PATCH RFC 4/6] net: rfkill: gpio: add device tree support Date: Tue, 21 Jan 2014 19:50:06 +0100 Message-ID: <201401211950.07011.arnd@arndb.de> References: <1389941251-32692-1-git-send-email-wens@csie.org> <201401211335.16885.arnd@arndb.de> Reply-To: linux-sunxi-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org Mime-Version: 1.0 Content-Type: Text/Plain; charset=UTF-8 Cc: "linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org" , Linus Walleij , "devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , Heikki Krogerus , netdev , "linux-wireless" , "linux-sunxi" , "linux-kernel" , Maxime Ripard , "Chen-Yu Tsai" , Johannes Berg , Mika Westerberg , "David S. Miller" , "linux-gpio-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" To: Alexandre Courbot Return-path: In-Reply-To: List-Post: , List-Help: , List-Archive: Sender: linux-sunxi-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org List-Subscribe: , List-Unsubscribe: , List-Id: netdev.vger.kernel.org On Tuesday 21 January 2014, Alexandre Courbot wrote: > >> As discussed earlier in this thread I'm not sure the con_id is > >> suitable for labelling GPIOs. It'd be better to have a proper name > >> specified in DT/ACPI instead. > > > > +1 > > I wonder why you guys prefer to have the name defined in the GPIO > mapping. Having the driver decide the label makes it easier to look up > which GPIO does what in debugfs, whereas nothing prevents people to > name GPIOs whatever inadequate name they want in the device DT node. > What am I overlooking here? I should have another look at the debugfs representation, but isn't there a global namespace that gets used for all gpios? Neither the con_id nor the name that the driver picks would be globally unique and stable across kernel versions, so they don't make a good user interface. I think what we want here is a system-wide unique identifier for each gpio line that may get represented in debugfs, and use a new DT mechanism to communicate that. Arnd