Luban Cat sets permissions for GPIO

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Luban Cat sets permissions for GPIO [Copy link]

When Python of Luban Cat controls GPIO, if the permissions for gpiochip are not set, an error will always be reported during operation, indicating that there is no permission to access "/dev/gpipchip4".

Although you can use sudo chmod 777 "/dev/gpiochip4" to temporarily grant permissions, it is inconvenient when it is delivered to users. After checking, you can modify /etc/udev/rules.d/99-rockchip-permissions.rules

# SPI, I2C, gpio devices
SUBSYSTEM=="spidev", GROUP="devuser", MODE="0660"
SUBSYSTEM=="i2c-dev", GROUP="devuser", MODE="0660"
# The gpio part did not take effect. The specific reason is still under investigation.
KERNEL="gpiochip[0-4]*" GROUP="devuser",MODE="0666"

This configuration rule tells udev that as long as the subsystem hardware matches spidev and i2c-dev, the device user group should be changed to devuser and the permissions should be changed to 0660.
Next, we need to create a devuser group and add the cat user to this group. Enter the following command

1. sudo groupadd devuser
2. sudo adduser "$USER" devuser
3. south reboo

Then you can access i2c spi and gpiochip normally.

freebsder

Thanks for sharing! The operation of Linux is indeed different from that of MCU.