brock@uncacsci-pi3-d:~$ cd /sys/bus brock@uncacsci-pi3-d:/sys/bus$ ls amba container gpio iscsi_flashnode platform spi clockevents cpu hid mipi-dsi scsi usb clocksource event_source i2c mmc sdio workqueue brock@uncacsci-pi3-d:/sys/bus$ cd /sys/bug/gpio bash: cd: /sys/bug/gpio: No such file or directory brock@uncacsci-pi3-d:/sys/bus$ ls -l total 0 drwxr-xr-x 4 root root 0 Dec 31 1969 amba drwxr-xr-x 4 root root 0 Dec 31 1969 clockevents drwxr-xr-x 4 root root 0 Dec 31 1969 clocksource drwxr-xr-x 4 root root 0 Dec 31 1969 container drwxr-xr-x 4 root root 0 Dec 31 1969 cpu drwxr-xr-x 4 root root 0 Dec 31 1969 event_source drwxr-xr-x 4 root root 0 Dec 31 1969 gpio drwxr-xr-x 4 root root 0 Dec 31 1969 hid drwxr-xr-x 4 root root 0 Dec 31 1969 i2c drwxr-xr-x 4 root root 0 Dec 31 1969 iscsi_flashnode drwxr-xr-x 4 root root 0 Dec 31 1969 mipi-dsi drwxr-xr-x 4 root root 0 Dec 31 1969 mmc drwxr-xr-x 4 root root 0 Dec 31 1969 platform drwxr-xr-x 4 root root 0 Dec 31 1969 scsi drwxr-xr-x 4 root root 0 Dec 31 1969 sdio drwxr-xr-x 4 root root 0 Dec 31 1969 spi drwxr-xr-x 4 root root 0 Dec 31 1969 usb drwxr-xr-x 4 root root 0 Dec 31 1969 workqueue brock@uncacsci-pi3-d:/sys/bus$ ls -l /dev total 0 crw------- 1 root root 10, 235 Feb 2 19:32 autofs drwxr-xr-x 2 root root 600 Feb 2 19:32 block crw------- 1 root root 10, 234 Feb 2 19:32 btrfs-control drwxr-xr-x 3 root root 60 Dec 31 1969 bus crw------- 1 root root 10, 63 Feb 2 19:32 cachefiles drwxr-xr-x 2 root root 2480 Feb 2 19:32 char crw------- 1 root root 5, 1 Feb 2 19:32 console crw------- 1 root root 10, 62 Feb 2 19:32 cpu_dma_latency crw------- 1 root root 10, 203 Feb 2 19:32 cuse drwxr-xr-x 7 root root 140 Feb 2 19:32 disk crw-rw---- 1 root video 29, 0 Feb 2 19:32 fb0 lrwxrwxrwx 1 root root 13 Dec 31 1969 fd -> /proc/self/fd crw-rw-rw- 1 root root 1, 7 Feb 2 19:32 full crw-rw-rw- 1 root root 10, 229 Feb 2 19:32 fuse crw------- 1 root root 254, 0 Feb 2 19:32 gpiochip0 crw------- 1 root root 254, 1 Feb 2 19:32 gpiochip1 crw------- 1 root root 254, 2 Feb 2 19:32 gpiochip2 crw-rw---- 1 root gpio 243, 0 Feb 2 19:32 gpiomem crw------- 1 root root 10, 183 Feb 2 19:32 hwrng crw-rw---- 1 root i2c 89, 1 Feb 2 19:32 i2c-1 lrwxrwxrwx 1 root root 25 Dec 31 1969 initctl -> /run/systemd/initctl/fifo drwxr-xr-x 2 root root 60 Dec 31 1969 input crw-r--r-- 1 root root 1, 11 Feb 2 19:32 kmsg lrwxrwxrwx 1 root root 28 Dec 31 1969 log -> /run/systemd/journal/dev-log brw-rw---- 1 root disk 7, 0 Feb 2 19:32 loop0 brw-rw---- 1 root disk 7, 1 Feb 2 19:32 loop1 brw-rw---- 1 root disk 7, 2 Feb 2 19:32 loop2 brw-rw---- 1 root disk 7, 3 Feb 2 19:32 loop3 brw-rw---- 1 root disk 7, 4 Feb 2 19:32 loop4 brw-rw---- 1 root disk 7, 5 Feb 2 19:32 loop5 brw-rw---- 1 root disk 7, 6 Feb 2 19:32 loop6 brw-rw---- 1 root disk 7, 7 Feb 2 19:32 loop7 crw-rw---- 1 root disk 10, 237 Feb 2 19:32 loop-control drwxr-xr-x 2 root root 60 Feb 2 19:32 mapper crw-r----- 1 root kmem 1, 1 Feb 2 19:32 mem crw------- 1 root root 10, 59 Feb 2 19:32 memory_bandwidth brw-rw---- 1 root disk 179, 0 Feb 2 19:32 mmcblk0 brw-rw---- 1 root disk 179, 1 Feb 2 19:32 mmcblk0p1 brw-rw---- 1 root disk 179, 2 Feb 2 19:32 mmcblk0p2 brw-rw---- 1 root disk 179, 3 Feb 2 19:32 mmcblk0p3 drwxrwxrwt 2 root root 40 Dec 31 1969 mqueue drwxr-xr-x 2 root root 60 Feb 2 19:32 net crw------- 1 root root 10, 61 Feb 2 19:32 network_latency crw------- 1 root root 10, 60 Feb 2 19:32 network_throughput crw-rw-rw- 1 root root 1, 3 Feb 2 19:32 null crw------- 1 root root 108, 0 Feb 2 19:32 ppp crw-rw-rw- 1 root tty 5, 2 Feb 2 20:58 ptmx drwxr-xr-x 2 root root 0 Dec 31 1969 pts brw-rw---- 1 root disk 1, 0 Feb 2 19:32 ram0 brw-rw---- 1 root disk 1, 1 Feb 2 19:32 ram1 brw-rw---- 1 root disk 1, 10 Feb 2 19:32 ram10 brw-rw---- 1 root disk 1, 11 Feb 2 19:32 ram11 brw-rw---- 1 root disk 1, 12 Feb 2 19:32 ram12 brw-rw---- 1 root disk 1, 13 Feb 2 19:32 ram13 brw-rw---- 1 root disk 1, 14 Feb 2 19:32 ram14 brw-rw---- 1 root disk 1, 15 Feb 2 19:32 ram15 brw-rw---- 1 root disk 1, 2 Feb 2 19:32 ram2 brw-rw---- 1 root disk 1, 3 Feb 2 19:32 ram3 brw-rw---- 1 root disk 1, 4 Feb 2 19:32 ram4 brw-rw---- 1 root disk 1, 5 Feb 2 19:32 ram5 brw-rw---- 1 root disk 1, 6 Feb 2 19:32 ram6 brw-rw---- 1 root disk 1, 7 Feb 2 19:32 ram7 brw-rw---- 1 root disk 1, 8 Feb 2 19:32 ram8 brw-rw---- 1 root disk 1, 9 Feb 2 19:32 ram9 crw-rw-rw- 1 root root 1, 8 Feb 2 19:32 random drwxr-xr-x 2 root root 60 Dec 31 1969 raw crw-rw-r-- 1 root root 10, 58 Feb 2 19:32 rfkill lrwxrwxrwx 1 root root 7 Feb 2 19:32 serial1 -> ttyAMA0 drwxrwxrwt 2 root root 40 Feb 2 19:32 shm drwxr-xr-x 3 root root 160 Feb 2 19:32 snd lrwxrwxrwx 1 root root 15 Dec 31 1969 stderr -> /proc/self/fd/2 lrwxrwxrwx 1 root root 15 Dec 31 1969 stdin -> /proc/self/fd/0 lrwxrwxrwx 1 root root 15 Dec 31 1969 stdout -> /proc/self/fd/1 crw-rw-rw- 1 root tty 5, 0 Feb 2 20:58 tty crw--w---- 1 root tty 4, 0 Feb 2 19:32 tty0 crw--w---- 1 root tty 4, 1 Feb 2 19:32 tty1 crw--w---- 1 root tty 4, 10 Feb 2 19:32 tty10 crw--w---- 1 root tty 4, 11 Feb 2 19:32 tty11 crw--w---- 1 root tty 4, 12 Feb 2 19:32 tty12 crw--w---- 1 root tty 4, 13 Feb 2 19:32 tty13 crw--w---- 1 root tty 4, 14 Feb 2 19:32 tty14 crw--w---- 1 root tty 4, 15 Feb 2 19:32 tty15 crw--w---- 1 root tty 4, 16 Feb 2 19:32 tty16 crw--w---- 1 root tty 4, 17 Feb 2 19:32 tty17 crw--w---- 1 root tty 4, 18 Feb 2 19:32 tty18 crw--w---- 1 root tty 4, 19 Feb 2 19:32 tty19 crw--w---- 1 root tty 4, 2 Feb 2 19:32 tty2 crw--w---- 1 root tty 4, 20 Feb 2 19:32 tty20 crw--w---- 1 root tty 4, 21 Feb 2 19:32 tty21 crw--w---- 1 root tty 4, 22 Feb 2 19:32 tty22 crw--w---- 1 root tty 4, 23 Feb 2 19:32 tty23 crw--w---- 1 root tty 4, 24 Feb 2 19:32 tty24 crw--w---- 1 root tty 4, 25 Feb 2 19:32 tty25 crw--w---- 1 root tty 4, 26 Feb 2 19:32 tty26 crw--w---- 1 root tty 4, 27 Feb 2 19:32 tty27 crw--w---- 1 root tty 4, 28 Feb 2 19:32 tty28 crw--w---- 1 root tty 4, 29 Feb 2 19:32 tty29 crw--w---- 1 root tty 4, 3 Feb 2 19:32 tty3 crw--w---- 1 root tty 4, 30 Feb 2 19:32 tty30 crw--w---- 1 root tty 4, 31 Feb 2 19:32 tty31 crw--w---- 1 root tty 4, 32 Feb 2 19:32 tty32 crw--w---- 1 root tty 4, 33 Feb 2 19:32 tty33 crw--w---- 1 root tty 4, 34 Feb 2 19:32 tty34 crw--w---- 1 root tty 4, 35 Feb 2 19:32 tty35 crw--w---- 1 root tty 4, 36 Feb 2 19:32 tty36 crw--w---- 1 root tty 4, 37 Feb 2 19:32 tty37 crw--w---- 1 root tty 4, 38 Feb 2 19:32 tty38 crw--w---- 1 root tty 4, 39 Feb 2 19:32 tty39 crw--w---- 1 root tty 4, 4 Feb 2 19:32 tty4 crw--w---- 1 root tty 4, 40 Feb 2 19:32 tty40 crw--w---- 1 root tty 4, 41 Feb 2 19:32 tty41 crw--w---- 1 root tty 4, 42 Feb 2 19:32 tty42 crw--w---- 1 root tty 4, 43 Feb 2 19:32 tty43 crw--w---- 1 root tty 4, 44 Feb 2 19:32 tty44 crw--w---- 1 root tty 4, 45 Feb 2 19:32 tty45 crw--w---- 1 root tty 4, 46 Feb 2 19:32 tty46 crw--w---- 1 root tty 4, 47 Feb 2 19:32 tty47 crw--w---- 1 root tty 4, 48 Feb 2 19:32 tty48 crw--w---- 1 root tty 4, 49 Feb 2 19:32 tty49 crw--w---- 1 root tty 4, 5 Feb 2 19:32 tty5 crw--w---- 1 root tty 4, 50 Feb 2 19:32 tty50 crw--w---- 1 root tty 4, 51 Feb 2 19:32 tty51 crw--w---- 1 root tty 4, 52 Feb 2 19:32 tty52 crw--w---- 1 root tty 4, 53 Feb 2 19:32 tty53 crw--w---- 1 root tty 4, 54 Feb 2 19:32 tty54 crw--w---- 1 root tty 4, 55 Feb 2 19:32 tty55 crw--w---- 1 root tty 4, 56 Feb 2 19:32 tty56 crw--w---- 1 root tty 4, 57 Feb 2 19:32 tty57 crw--w---- 1 root tty 4, 58 Feb 2 19:32 tty58 crw--w---- 1 root tty 4, 59 Feb 2 19:32 tty59 crw--w---- 1 root tty 4, 6 Feb 2 19:32 tty6 crw--w---- 1 root tty 4, 60 Feb 2 19:32 tty60 crw--w---- 1 root tty 4, 61 Feb 2 19:32 tty61 crw--w---- 1 root tty 4, 62 Feb 2 19:32 tty62 crw--w---- 1 root tty 4, 63 Feb 2 19:32 tty63 crw--w---- 1 root tty 4, 7 Feb 2 19:32 tty7 crw--w---- 1 root tty 4, 8 Feb 2 19:32 tty8 crw--w---- 1 root tty 4, 9 Feb 2 19:32 tty9 crw-rw---- 1 root dialout 204, 64 Feb 2 19:32 ttyAMA0 crw------- 1 root root 5, 3 Feb 2 19:32 ttyprintk crw------- 1 root root 10, 239 Feb 2 19:32 uhid crw------- 1 root root 10, 223 Feb 2 19:32 uinput crw-rw-rw- 1 root root 1, 9 Feb 2 19:32 urandom crw------- 1 root root 250, 0 Feb 2 19:32 vc-cma crw-rw---- 1 root video 246, 0 Feb 2 19:32 vchiq crw-rw---- 1 root video 248, 0 Feb 2 19:32 vcio crw------- 1 root root 249, 0 Feb 2 19:32 vc-mem crw-rw---- 1 root tty 7, 0 Feb 2 19:32 vcs crw-rw---- 1 root tty 7, 1 Feb 2 19:32 vcs1 crw-rw---- 1 root tty 7, 2 Feb 2 19:32 vcs2 crw-rw---- 1 root tty 7, 3 Feb 2 19:32 vcs3 crw-rw---- 1 root tty 7, 4 Feb 2 19:32 vcs4 crw-rw---- 1 root tty 7, 5 Feb 2 19:32 vcs5 crw-rw---- 1 root tty 7, 6 Feb 2 19:32 vcs6 crw-rw---- 1 root tty 7, 128 Feb 2 19:32 vcsa crw-rw---- 1 root tty 7, 129 Feb 2 19:32 vcsa1 crw-rw---- 1 root tty 7, 130 Feb 2 19:32 vcsa2 crw-rw---- 1 root tty 7, 131 Feb 2 19:32 vcsa3 crw-rw---- 1 root tty 7, 132 Feb 2 19:32 vcsa4 crw-rw---- 1 root tty 7, 133 Feb 2 19:32 vcsa5 crw-rw---- 1 root tty 7, 134 Feb 2 19:32 vcsa6 crw-rw---- 1 root video 245, 0 Feb 2 19:32 vcsm crw------- 1 root root 10, 137 Feb 2 19:32 vhci crw------- 1 root root 10, 130 Feb 2 19:32 watchdog crw------- 1 root root 252, 0 Feb 2 19:32 watchdog0 prw-r----- 1 root adm 0 Feb 2 19:39 xconsole crw-rw-rw- 1 root root 1, 5 Feb 2 19:32 zero brock@uncacsci-pi3-d:/sys/bus$ ls -l /sys/class/gpio/ total 0 -rwxrwx--- 1 root gpio 4096 Feb 2 20:19 export lrwxrwxrwx 1 root gpio 0 Feb 2 20:19 gpio27 -> ../../devices/platform/soc/3f200000.gpio/gpiochip0/gpio/gpio27 lrwxrwxrwx 1 root gpio 0 Feb 2 19:32 gpiochip0 -> ../../devices/platform/soc/3f200000.gpio/gpio/gpiochip0 lrwxrwxrwx 1 root gpio 0 Feb 2 19:32 gpiochip100 -> ../../devices/gpiochip2/gpio/gpiochip100 lrwxrwxrwx 1 root gpio 0 Feb 2 19:32 gpiochip128 -> ../../devices/gpiochip1/gpio/gpiochip128 -rwxrwx--- 1 root gpio 4096 Feb 2 20:19 unexport brock@uncacsci-pi3-d:/sys/bus$ ls -l /sys/bus/gpio/ total 0 drwxr-xr-x 2 root root 0 Dec 31 1969 devices drwxr-xr-x 2 root root 0 Dec 31 1969 drivers -rw-r--r-- 1 root root 4096 Feb 2 20:59 drivers_autoprobe --w------- 1 root root 4096 Feb 2 20:59 drivers_probe --w------- 1 root root 4096 Dec 31 1969 uevent brock@uncacsci-pi3-d:/sys/bus$ ls -l /sys/bus/gpio/devices/ total 0 lrwxrwxrwx 1 root root 0 Dec 31 1969 gpiochip0 -> ../../../devices/platform/soc/3f200000.gpio/gpiochip0 lrwxrwxrwx 1 root root 0 Dec 31 1969 gpiochip1 -> ../../../devices/gpiochip1 lrwxrwxrwx 1 root root 0 Dec 31 1969 gpiochip2 -> ../../../devices/gpiochip2 brock@uncacsci-pi3-d:/sys/bus$ ls -l /sys/bus/gpio/drivers total 0 brock@uncacsci-pi3-d:/sys/bus$ ls /dev/gpio* /dev/gpiochip0 /dev/gpiochip1 /dev/gpiochip2 /dev/gpiomem brock@uncacsci-pi3-d:/sys/bus$ ls -l /dev/gpio* crw------- 1 root root 254, 0 Feb 2 19:32 /dev/gpiochip0 crw------- 1 root root 254, 1 Feb 2 19:32 /dev/gpiochip1 crw------- 1 root root 254, 2 Feb 2 19:32 /dev/gpiochip2 crw-rw---- 1 root gpio 243, 0 Feb 2 19:32 /dev/gpiomem brock@uncacsci-pi3-d:/sys/bus$ echo https://www.kernel.org/doc/Documentation/gpio/drivers-on-gpio.txt https://www.kernel.org/doc/Documentation/gpio/drivers-on-gpio.txt brock@uncacsci-pi3-d:/sys/bus$ echo https://www.kernel.org/doc/Documentation/gpio/ https://www.kernel.org/doc/Documentation/gpio/ brock@uncacsci-pi3-d:/sys/bus$ echo https://www.raspberrypi.org/forums/viewtopic.php?f=29&t=130811 [1] 1378 brock@uncacsci-pi3-d:/sys/bus$ https://www.raspberrypi.org/forums/viewtopic.php?f=29 https://github.com/torvalds/linux/tree/master/Documentation/gpio https://github.com/torvalds/linux/tree/master/tools/gpio https://raspberrypi.stackexchange.com/questions/40105/access-gpio-pins-without-root-no-access-to-dev-mem-try-running-as-root /dev/mem vs /dev/gpiomem http://bob.cs.sonoma.edu/IntroCompOrg-RPi/intro-co-rpi.html http://bob.cs.sonoma.edu/IntroCompOrg-x64/book.html https://www.cnx-software.com/2017/11/03/learn-more-about-linuxs-new-gpio-user-space-subsystem-libgpiod/