Table of Contents
GPIO
The old sysfs GPIO interface is deprecated and will be phased out of the kernel. As part of this the base offset of GPIO ports has been omitted in the kernel. Setting the base GPIO number to zero will result in a boot up error on kernels from 6.6. At the same time, the sysfs interface to the GPIOs has been deprecated - some distributions have already disabled it and are expecting users to go through libgpiod. In 6.6, high-numbered GPIOs - probably still available by sysfs, but eventually that will be switched off.
Query GPIO ports
From 6.5 onwards, the Pi kernel is not forcing a base GPIO for the main GPIO driver. Whilst the sysfs API is still enabled, the base GPIOs will change. The dynamic assignment generally starts at 512 and counts down. If you really need to track down a GPIO using sysfs, look through /sys/class/gpiochipN/ for a device with an appropriate label or ngpio, and then use base to determine the GPIO number.
cat /sys/kernel/debug/gpio -------------------------- gpiochip0: GPIOs 512-565, parent: platform/3f200000.gpio, pinctrl-bcm2835: gpio-512 (ID_SDA ) gpio-513 (ID_SCL ) gpio-514 (GPIO2 ) gpio-515 (GPIO3 ) gpio-516 (GPIO4 ) gpio-517 (GPIO5 |sysfs ) in hi gpio-518 (GPIO6 ) gpio-519 (GPIO7 ) gpio-520 (GPIO8 ) gpio-521 (GPIO9 ) gpio-522 (GPIO10 ) gpio-523 (GPIO11 ) gpio-524 (GPIO12 ) gpio-525 (GPIO13 ) gpio-526 (GPIO14 ) gpio-527 (GPIO15 ) gpio-528 (GPIO16 ) gpio-529 (GPIO17 ) gpio-530 (GPIO18 ) gpio-531 (GPIO19 ) gpio-532 (GPIO20 ) gpio-533 (GPIO21 ) gpio-534 (GPIO22 ) gpio-535 (GPIO23 ) gpio-536 (GPIO24 ) gpio-537 (GPIO25 ) gpio-538 (GPIO26 ) gpio-539 (GPIO27 ) gpio-540 (SDA0 ) gpio-541 (SCL0 ) gpio-542 (NC ) gpio-543 (LAN_RUN ) gpio-544 (CAM_GPIO1 ) gpio-545 (NC ) gpio-546 (NC ) gpio-547 (PWR_LOW_N |PWR ) in lo gpio-548 (NC ) gpio-549 (NC ) gpio-550 (USB_LIMIT ) gpio-551 (NC ) gpio-552 (PWM0_OUT ) gpio-553 (CAM_GPIO0 |cam1_regulator ) out lo gpio-554 (SMPS_SCL ) gpio-555 (SMPS_SDA ) gpio-556 (ETH_CLK ) gpio-557 (PWM1_OUT ) gpio-558 (HDMI_HPD_N |hpd ) in hi ACTIVE LOW gpio-559 (STATUS_LED |ACT ) out lo gpio-560 (SD_CLK_R ) gpio-561 (SD_CMD_R ) gpio-562 (SD_DATA0_R ) gpio-563 (SD_DATA1_R ) gpio-564 (SD_DATA2_R ) gpio-565 (SD_DATA3_R ) gpiochip1: GPIOs 566-569, parent: usb/1-1.4:1.0, ftdi-cbus, can sleep:
GPIOD
You can install the libraries and tools to interact with this device, using sudo apt install gpiod. This will install the gpiod tools, and the libgpiod2 library to let you interact with the device from your own code.
# apt install gpiod --> runtime # apt install libgpiod2 --> build libraries
- gpiodetect – list all gpiochips present on the system, their names, labels and number of GPIO lines
- gpioinfo – list all lines of specified gpiochips, their names, consumers, direction, active state and additional flags
- gpioget – read values of specified GPIO lines
- gpioset – set values of specified GPIO lines, potentially keep the lines exported and wait until timeout, user input or signal
- gpiofind – find the gpiochip name and line offset given the line name
- gpiomon – wait for events on GPIO lines, specify which events to watch, how many events to process before exiting or if the events should be reported to the console
gpiodetect
The first column represents name of the chip (also the device node name). The second column (in square brackets) is the device label which is normally set by the GPIO driver (this will match the value of /sys/class/gpio/gpiochipX/label). The last column shows how many GPIO lines the chip has.
# gpiodetect ------------ gpiochip0 [pinctrl-bcm2835] (54 lines) gpiochip1 [ftdi-cbus] (4 lines)
# gpioinfo ---------- gpiochip0 - 54 lines: line 0: "ID_SDA" unused input active-high line 1: "ID_SCL" unused input active-high line 2: "GPIO2" unused input active-high line 3: "GPIO3" unused input active-high line 4: "GPIO4" unused input active-high line 5: "GPIO5" "sysfs" input active-high [used] line 6: "GPIO6" unused input active-high line 7: "GPIO7" unused input active-high line 8: "GPIO8" unused input active-high line 9: "GPIO9" unused input active-high line 10: "GPIO10" unused input active-high line 11: "GPIO11" unused input active-high line 12: "GPIO12" unused input active-high line 13: "GPIO13" unused input active-high line 14: "GPIO14" unused input active-high line 15: "GPIO15" unused input active-high line 16: "GPIO16" unused input active-high line 17: "GPIO17" unused input active-high line 18: "GPIO18" unused input active-high line 19: "GPIO19" unused input active-high line 20: "GPIO20" unused input active-high line 21: "GPIO21" unused input active-high line 22: "GPIO22" unused input active-high line 23: "GPIO23" unused input active-high line 24: "GPIO24" unused input active-high line 25: "GPIO25" unused input active-high line 26: "GPIO26" unused input active-high line 27: "GPIO27" unused input active-high line 28: "SDA0" unused input active-high line 29: "SCL0" unused input active-high line 30: "NC" unused input active-high line 31: "LAN_RUN" unused output active-high line 32: "CAM_GPIO1" unused output active-high line 33: "NC" unused input active-high line 34: "NC" unused input active-high line 35: "PWR_LOW_N" "PWR" input active-high [used] line 36: "NC" unused input active-high line 37: "NC" unused input active-high line 38: "USB_LIMIT" unused output active-high line 39: "NC" unused input active-high line 40: "PWM0_OUT" unused input active-high line 41: "CAM_GPIO0" "cam1_regulator" output active-high [used] line 42: "SMPS_SCL" unused output active-high line 43: "SMPS_SDA" unused input active-high line 44: "ETH_CLK" unused input active-high line 45: "PWM1_OUT" unused input active-high line 46: "HDMI_HPD_N" "hpd" input active-low [used] line 47: "STATUS_LED" "ACT" output active-high [used] line 48: "SD_CLK_R" unused input active-high line 49: "SD_CMD_R" unused input active-high line 50: "SD_DATA0_R" unused input active-high line 51: "SD_DATA1_R" unused input active-high line 52: "SD_DATA2_R" unused input active-high line 53: "SD_DATA3_R" unused input active-high gpiochip1 - 4 lines: line 0: unnamed kernel input active-high [used] line 1: unnamed kernel input active-high [used] line 2: unnamed kernel input active-high [used] line 3: unnamed kernel input active-high [used]