From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnd Bergmann Subject: Re: [RFC PATCH v2 00/13] arm/tegra: Initialize GPIO & pinmux from DT Date: Tue, 16 Aug 2011 16:37:16 +0200 Message-ID: <201108161637.16620.arnd@arndb.de> References: <1313440100-17131-1-git-send-email-swarren@nvidia.com> <201108161509.17157.arnd@arndb.de> Mime-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-tegra-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Linus Walleij Cc: Stephen Warren , Grant Likely , Colin Cross , Erik Gilling , Olof Johansson , Russell King , devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org, linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Belisko Marek , Jamie Iles , Shawn Guo , Sergei Shtylyov List-Id: linux-tegra@vger.kernel.org On Tuesday 16 August 2011, Linus Walleij wrote: > One specific thing worries me: Grant asked me to make sure > to NOT create a global pin number space for the pinmuxes (and thus > pinctrl). This means that in order to proceed, mappings of pinmux > groups or pincontrol (such as bias) groups, each device using such > an entity need to reference the intended pincontroller/mux instance. > > Say mmc instance 0 need pingroup foo on pincontroller bar > means that there must be a specific reference from mmc.0:s > struct device * to pinctrl bar:s struct device *. Maybe this is > peanuts in DT, sorry not enough insight. I think what you are looking for is the equivalent of the interrupt-parent property for pinmux. The idea is that each node in the device tree can point to a device managing the pinmux, so reference would point to a local number in that space. We have discussed this for the GPIO case already, and I suspect that the two should be identical (gpio-controller and pinmux-controller using the same device node and same property to refer to them). Since the pinmux-parent (gpio-parent, ...) property gets inherited by all child devices, you only need to set it once at the root of the device tree for the simple case where there is only one controller. Arnd