config-pin beaglebone start up

config-pin beaglebone start up.md

Create file /usr/bin/enable-i2c-pins.sh

• sudo vi /usr/bin/enable-i2c-pins.sh

#!/bin/bash

config-pin p9.17 i2c
config-pin p9.18 i2c

• sudo chmod 755 /usr/bin/enable-i2c-pins.sh

Create file /lib/systemd/system/enable-i2c-pins.service

• sudo vi /lib/systemd/system/enable-i2c-pins.service

[Unit]
Description=Enable I2C pins
After=generic-board-startup.service

[Service]
Type=simple
ExecStart=/usr/bin/enable-i2c-pins.sh

[Install]
WantedBy=multi-user.target

Enable the new systemd service

• sudo systemctl daemon-reload
• sudo systemctl enable enable-i2c-pins.service

Created symlink /etc/systemd/system/multi-user.target.wants/enable-i2c-pins.service → /lib/systemd/system/enable-i2c-pins.service.

Reboot and test

• sudo systemctl status enable-i2c-pins.service

debian@beaglebone:~$ sudo systemctl status enable-i2c-pins.service
● enable-i2c-pins.service - Enable I2C pins
   Loaded: loaded (/lib/systemd/system/enable-i2c-pins.service; enabled)
   Active: inactive (dead) since Wed 2017-04-19 06:35:06 UTC; 48s ago
  Process: 649 ExecStart=/usr/bin/enable-i2c-pins.sh (code=exited, status=0/SUCCESS)
 Main PID: 649 (code=exited, status=0/SUCCESS)

Apr 19 06:35:05 beaglebone sudo[664]: root : TTY=unknown ; PWD=/ ; USER=root ; COMMAND=/bin/bash -c echo i2c > /sys/devices/platform/ocp/ocp:P9_17_pinmux/state
Apr 19 06:35:05 beaglebone sudo[664]: pam_unix(sudo:session): session opened for user root by (uid=0)
Apr 19 06:35:05 beaglebone sudo[664]: pam_unix(sudo:session): session closed for user root
Apr 19 06:35:06 beaglebone sudo[677]: root : TTY=unknown ; PWD=/ ; USER=root ; COMMAND=/bin/bash -c echo i2c > /sys/devices/platform/ocp/ocp:P9_18_pinmux/state
Apr 19 06:35:06 beaglebone sudo[677]: pam_unix(sudo:session): session opened for user root by (uid=0)
Apr 19 06:35:06 beaglebone sudo[677]: pam_unix(sudo:session): session closed for user root

• config-pin -q p9.17 && config-pin -q p9.18

debian@beaglebone:~$ config-pin -q p9.17 && config-pin -q p9.18
P9_17 Mode: i2c
P9_18 Mode: i2c

@mvduin
cdsteinkuehler/beaglebone-universal-io#41 (comment)
To reduce boot time, systemd (the init system used on beaglebone debian images) starts services in parallel as much as allowed by the ordering constraints specified by those services.

To ensure you can use config-pin you need to add a constraint ordering your service after the one which loads cape-universal, which is generic-board-startup.service.

A minimal service file for doing one-time setup would be something like

[Unit]
Description=insert description here

After=generic-board-startup.service

[Install]
WantedBy=multi-user.target

[Service]
Type=oneshot
RemainAfterExit=yes
ExecStart=/path/to/executable and arguments

/usr/bin/enable-i2c-pins.sh

#!/bin/bash

config-pin p9.17 i2c
config-pin p9.18 i2c

debian@beaglebone:/lib/systemd$ sudo chmod 755 /usr/bin/enable-i2c-pins.sh

/lib/systemd/system/enable-i2c-pins.service

[Unit]
Description=Enable I2C pins
After=generic-board-startup.service

[Service]
Type=simple
ExecStart=/usr/bin/enable-i2c-pins.sh

[Install]
WantedBy=multi-user.target

sudo systemctl daemon-reload
sudo systemctl enable enable-i2c-pins.service

Created symlink /etc/systemd/system/multi-user.target.wants/enable-i2c-pins.service → /lib/systemd/system/enable-i2c-pins.service.

debian@beaglebone:/lib/systemd$ config-pin -q p9.17 && config-pin -q p9.18
P9_17 Mode: i2c
P9_18 Mode: i2c

debian@beaglebone:~$ sudo systemctl status enable-i2c-pins.service
● enable-i2c-pins.service - Enable I2C pins
   Loaded: loaded (/lib/systemd/system/enable-i2c-pins.service; enabled)
   Active: inactive (dead) since Wed 2017-04-19 06:35:06 UTC; 48s ago
  Process: 649 ExecStart=/usr/bin/enable-i2c-pins.sh (code=exited, status=0/SUCCESS)
 Main PID: 649 (code=exited, status=0/SUCCESS)

Apr 19 06:35:05 beaglebone sudo[664]: root : TTY=unknown ; PWD=/ ; USER=root ; COMMAND=/bin/bash -c echo i2c > /sys/devices/platform/ocp/ocp:P9_17_pinmux/state
Apr 19 06:35:05 beaglebone sudo[664]: pam_unix(sudo:session): session opened for user root by (uid=0)
Apr 19 06:35:05 beaglebone sudo[664]: pam_unix(sudo:session): session closed for user root
Apr 19 06:35:06 beaglebone sudo[677]: root : TTY=unknown ; PWD=/ ; USER=root ; COMMAND=/bin/bash -c echo i2c > /sys/devices/platform/ocp/ocp:P9_18_pinmux/state
Apr 19 06:35:06 beaglebone sudo[677]: pam_unix(sudo:session): session opened for user root by (uid=0)
Apr 19 06:35:06 beaglebone sudo[677]: pam_unix(sudo:session): session closed for user root
debian@beaglebone:~$ config-pin -q p9.17 && config-pin -q p9.18
P9_17 Mode: i2c
P9_18 Mode: i2c

debian@beaglebone:~/adafruit-beaglebone-io-python$ vi /usr/bin/enable-i2c-pins.sh
debian@beaglebone:~/adafruit-beaglebone-io-python$ vi /usr/bin/enable-i2c-pins.sh
debian@beaglebone:~/adafruit-beaglebone-io-python$ sudo vi /usr/bin/enable-i2c-pins.sh
debian@beaglebone:~/adafruit-beaglebone-io-python$ sudo chmod 755 /usr/bin/enable-i2c-pins.sh
debian@beaglebone:~/adafruit-beaglebone-io-python$ /usr/bin/enable-i2c-pins.sh
debian@beaglebone:~/adafruit-beaglebone-io-python$ sudo vi /lib/systemd/system/enable-i2c-pins.service
debian@beaglebone:~/adafruit-beaglebone-io-python$ sudo systemctl daemon-reload
debian@beaglebone:~/adafruit-beaglebone-io-python$ sudo systemctl daemon-reload^C
debian@beaglebone:~/adafruit-beaglebone-io-python$ sudo systemctl enable enable-i2c-pins.service
Created symlink from /etc/systemd/system/multi-user.target.wants/enable-i2c-pins.service to /lib/systemd/system/enable-i2c-pins.service.

sudo vi /usr/bin/enable-i2c-pins.sh
sudo chmod 755 /usr/bin/enable-i2c-pins.sh
sudo vi /lib/systemd/system/enable-i2c-pins.service
sudo systemctl daemon-reload
sudo systemctl enable enable-i2c-pins.service
sudo systemctl start enable-i2c-pins.service
config-pin -q p9.17 && config-pin -q p9.18