From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steffen Trumtrar Subject: Re: [PATCH v9] gpio: add a driver for Synopsys DesignWare APB GPIO Date: Thu, 30 Jan 2014 22:32:32 +0100 Message-ID: <20140130213232.GC26861@pengutronix.de> References: <1386364179-28650-1-git-send-email-delicious.quinoa@gmail.com> <20131212090838.GD25478@pengutronix.de> <20140130205000.GB26861@pengutronix.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-doc-owner@vger.kernel.org To: delicious quinoa Cc: Linus Walleij , linux-kernel , "linux-gpio@vger.kernel.org" , "linux-doc@vger.kernel.org" , Jamie Iles , "devicetree@vger.kernel.org" , Grant Likely , Sebastian Hesselbarth , Heiko Stuebner , Alan Tull , Dinh Nguyen , Yves Vandervennet List-Id: linux-gpio@vger.kernel.org On Thu, Jan 30, 2014 at 03:15:11PM -0600, delicious quinoa wrote: > On Thu, Jan 30, 2014 at 2:50 PM, Steffen Trumtrar > wrote: > > Hi! > > > > On Thu, Jan 30, 2014 at 01:40:04PM -0600, delicious quinoa wrote: > >> On Thu, Dec 12, 2013 at 3:08 AM, Steffen Trumtrar > >> wrote: > >> > >> > Second: The interrupt is registered as "GIC 37", which is a real interrupt on > >> > the Socfpga. I would expect it to be marked as "GPIO 2xx" (or something in that > >> > range). The interrupt from the gpiochip itself isn't registered at all ?! > >> > >> Hi Stephen, > >> > >> Did you export the gpio lines and set the edge in sysfs? Because the > >> interrupts aren't allocated otherwise. > >> > >> For instance: > >> > >> root@socfpga_cyclone5:~# echo 195 > /sys/class/gpio/export > >> root@socfpga_cyclone5:~# echo rising > /sys/class/gpio/gpio195/edge > >> > >> Now I can see a pretty nicely named interrupt in /proc/interrupts: > >> > >> 256: 0 0 gpio-dwapb 24 gpiolib > >> > > > > I didn't try that and I think this behaviour is pretty uncommon. > > This should be fixed in the driver. I never wrote a gpiochip-driver, > > so I don't know what is missing, but maybe just some functioncall ?! > > All other drivers I came across have that entry from probing without > > any fiddling. > > Hi Steffen, > > Do you mean 'all other gpio drivers' or 'all other non-gpio drivers'? I meant gpio drivers (at least the ones I have used). > > This is the behavior that is implemented in the community gpio > framework drivers/gpio/gpiolib.c, not anything special implemented in > this dw gpio driver. > > It's documented in Documentation/gpio/sysfs.txt and > Documentation/ABI/testing/sysfs-gpio. > > You get userspace control of a gpio by 'export'ing it in sysfs. And > then by default, the interrupt edge is set to 'none' (no irq) until > you set the edge in sysfs. > Hm, okay...for GPIOs I'm with you. But when I specify a gpio as interrupt for a device, I have to first export it manually before I can use the device? Sounds weird. Steffen -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |