Freek de Kruijf wrote:
> I have been struggling with this on a Raspberry Pi 1B and made the Python
> module for that device called RPi.GPIO. However there is a difference between
> a RPi1 and other RPi's. RPi1 shows "export gpio321 gpiochip298 unexport"
> in
> /sys/class/gpio/, where the start of N is clearly 298. However on a RPi4 /sys/
> class/gpio/ shows "export gpiochip446 gpiochip454 unexport". To me the
> question is: which one of 446 and 454 is the start value?
454 is the correct start value. You get more info running (from libgpiod-utils)
Pi4:~ # gpiodetect
gpiochip0 [pinctrl-bcm2711] (58 lines)
gpiochip1 [raspberrypi-exp-gpio] (8 lines)
Pi4:~ # cat /sys/class/gpio/gpiochip454/label
pinctrl-bcm2711
> On a RPi3 with Raspbian one gets in /sys/class/gpio/ "export gpiochip0
> gpiochip100 gpiochip504 unexport", as mentioned earlier the start value is 0.
I got several other replies - not sure why they don't show up here on the
list. Upshot is, Raspbian has a downstream patch that changes that number for
the 'right' gpiochip to 0 :(
I'm now using python3-gpiod. Seems straight forward, given that even I with my
absolutely basic python knowledge was able to make the needed changes.
import gpiod
chip=gpiod.Chip("gpiochip0")
fan=chip.get_lines([17])
fan.request(consumer='fancontrol', type=gpiod.LINE_REQ_DIR_OUT)
fan.set_values([1])
fan.get_values()
fan.release()
chip.close()
:D
