On Thu, Jan 30, 2014 at 3:32 PM, Steffen Trumtrar <s.trumtrar@xxxxxxxxxxxxxx> wrote: > On Thu, Jan 30, 2014 at 03:15:11PM -0600, delicious quinoa wrote: >> On Thu, Jan 30, 2014 at 2:50 PM, Steffen Trumtrar >> <s.trumtrar@xxxxxxxxxxxxxx> 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 >> >> <s.trumtrar@xxxxxxxxxxxxxx> 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 Seems normal usage both in userspace and in kernel drivers that need a gpio. Looking at other kernel drivers that use a gpio, I can see examples that do gpio_request() to get the gpio that they care about. Then gpio_to_irq() and request_irq(). If you grep for 'gpio_to_irq' then look to see how they got the gpio, you'll see it pretty quickly. Alan -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
