From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexandre Courbot Subject: Re: Userspace and Device-Tree Date: Sat, 29 Aug 2015 21:09:48 +0900 Message-ID: References: <01e601d0e0f9$614450d0$23ccf270$@gmail.com> <20150828101227.GD31748@leverpostej> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Return-path: In-Reply-To: <20150828101227.GD31748@leverpostej> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Mark Rutland Cc: Chris R , "devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , Linus Walleij , Mark Brown , Liam Girdwood , Markus Pargmann List-Id: devicetree@vger.kernel.org >> Similarly, I'd like to be able to signal the export of a GPIO to userspace >> (/sys/class/gpio/gpioWXY) without a customized board file. Since we're >> using DT to specify the hardware in a system, it would be a convenient place >> to specify exporting GPIOs to userspace. > > I believe that the GPIO subsystem maintainers (Linus Walleij and > Alexandre Courbot) were trying to make GPIO control from userspace more > consistent (independent of DT) for a while. However I am not all that > familiar with the GPIO subsystem and may have misunderstood some of the > work that's going on there. If I properly understood what Chris wants, he may want to have a look at the following works: - GPIO hogging mechanism to configure a GPIO using the device tree - not sure if you can also export at that time? - Markus' ongoing work on GPIO naming: http://www.spinics.net/lists/linux-gpio/msg07844.html - Device tree overlays, to separate the configuration of GPIOs for user-space use (which is arguably specific to one's use case) from the rest of the board's definition With these 3 works I think Chris' needs would be fulfilled, at least as far as GPIOs are concerned. -- 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