Hi Chris, On Tue, Nov 13, 2018 at 8:26 PM Chris Brandt <Chris.Brandt@xxxxxxxxxxx> wrote: > On Tuesday, November 13, 2018, Geert Uytterhoeven wrote: > > > It makes the files show up under /sys look nice. > > > > > > For example, P5_6 is button SW4: > > > > > > $ echo 912 > /sys/class/gpio/export > > > > > > Then you end up with "/sys/class/gpio/P5_6/" > > > > > > $ echo in > /sys/class/gpio/P5_6/direction > > > $ cat /sys/class/gpio/P5_6/direction > > > $ cat /sys/class/gpio/P5_6/value > > > > (Ah, the legacy and deprecated sysfs GPIO interface, being replaced > > by /dev/gpiochip[0-9]+ and https://github.com/brgl/libgpiod) > > > > Cool, I didn't know that. > > But you still need to know which number to write to the export file > > in the first place? > > True, meaning the table does not help you as much as you want. > Jacopo also mentioned the new libgpiod. > So, I think I might just drop this table in the next revision. > > What I really want to do is just say "make P5_6 an input" and > not have to convert to a global ID number. But, I'm not sure how > libgpiod is going to know what "P5_6" is. There are two parts: 1. New kernel /dev/gpiochip[0-9]+ interface Sample code comes with the kernel under tools/gpio/. E.g. root@koelsch:~# lsgpio -n gpiochip7 GPIO chip: gpiochip7, "e6055800.gpio", 26 GPIO lines line 0: unnamed "SW30" [kernel active-low] line 1: unnamed "SW31" [kernel active-low] line 2: unnamed "SW32" [kernel active-low] line 3: unnamed "SW33" [kernel active-low] line 4: unnamed "SW34" [kernel active-low] line 5: unnamed "SW35" [kernel active-low] line 6: unnamed "SW36" [kernel active-low] line 7: unnamed unused line 8: unnamed unused line 9: unnamed unused line 10: unnamed unused line 11: unnamed unused line 12: unnamed unused line 13: unnamed unused line 14: unnamed unused line 15: unnamed unused line 16: unnamed unused line 17: unnamed "regulator-vcc-sdhi0" [kernel output] line 18: unnamed "regulator-vcc-sdhi1" [kernel output] line 19: unnamed "regulator-vcc-sdhi2" [kernel output] line 20: unnamed unused line 21: unnamed unused line 22: unnamed unused line 23: unnamed unused line 24: unnamed unused line 25: unnamed unused 2. Userspace library libgpiod, incl. a few tools like gpioinfo/gpioset/gpioget. These accept whatever reference to identify a GPIO. As your driver fills in pins[i].name, I expect you can pass names like P5_6. Have fun! ;-) Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
