Hi,
----- Alexander Graf <[email protected]> a écrit : > > > On 05.09.18 11:00, Volker Kuhlmann wrote: > > On Wed 05 Sep 2018 19:42:18 NZST +1200, Alexander Graf wrote: > > > >> You need to first make sure the pin is muxed properly as GPIO and not > >> associated with a special function: > >> > >> /sys/kernel/debug/pinctrl/3f200000.gpio/pinmux-pins > >> > >> Once that's clear, you can use the GPIO export to actually access the > >> GPIO function. > > > > Ahh, how obvious... ;-) Thanks! OK, makes sense. > > grep gpio4 pinmux-pins says > > pin 4 (gpio4): (MUX UNCLAIMED) (GPIO UNCLAIMED) > > and I guess it ought to not say "MUX UNCLAIMED". > > > > But I can't find how to do that. All online instructions go straight to > > exporting the pin (assuming a base of 0...). > > > > Appending > > [all] > > gpio=4=op,dh > > gpio=462=op,dh > > to /boot/efi/extraconfig.txt and rebooting makes no difference. > > > > I'm stuck again :-( > > Looks like the pin muxing actually happens automatically :) > > rpi:~ # grep 'pin 4 ' /sys/kernel/debug/pinctrl/3f200000.gpio/pins > pin 4 (gpio4) function gpio_in in hi; irq 83 (none) > rpi:~ # echo $(( 458 + 4 )) > /sys/class/gpio/export > rpi:~ # echo out > /sys/class/gpio/gpio462/direction > rpi:~ # grep 'pin 4 ' /sys/kernel/debug/pinctrl/3f200000.gpio/pins > pin 4 (gpio4) function gpio_out in lo; irq 83 (none) > rpi:~ # echo 1 > /sys/class/gpio/gpio462/value > rpi:~ # grep 'pin 4 ' /sys/kernel/debug/pinctrl/3f200000.gpio/pins > pin 4 (gpio4) function gpio_out in hi; irq 83 (none) For information, I created a wiki page for GPIO as it seems to be a problem for some people: https://en.opensuse.org/openSUSE:GPIO It is general usage information, not specific to a board (even if there are output examples) Guillaume > > > Alex > -- > To unsubscribe, e-mail: [email protected] > To contact the owner, e-mail: [email protected] > -- To unsubscribe, e-mail: [email protected] To contact the owner, e-mail: [email protected]
