I²C (Inter-Integrated Circuit), pronounced I-squared-C, is a multi-master, multi-slave, single-ended, serial computer bus invented by Philips Semiconductor (now NXP Semiconductors). It is typically used for attaching lower-speed peripheral ICs to processors and microcontrollers.
Required Hardware
One I2C sensor
Kernel Integration
Kernel Display Message
root@edison:~# dmesg | grep -i i2c
[ 0.190675] I2C bus = 1, name = pcal9555a-1, irq = 0x 0, addr = 0x20
[ 0.190711] I2C bus = 1, name = pcal9555a-2, irq = 0x 0, addr = 0x21
[ 0.190743] I2C bus = 1, name = pcal9555a-3, irq = 0x 0, addr = 0x22
[ 0.190774] I2C bus = 1, name = pcal9555a-4, irq = 0x 0, addr = 0x23
[ 0.746686] i2c /dev entries driver
Userspace Interfaces
SysFs
root@edison:~# ls /sys/class/i2c-dev/
i2c-1 i2c-2 i2c-3 i2c-4 i2c-5 i2c-6 i2c-7
DevFs
root@edison:~# ls /dev/i2c-*
/dev/i2c-1 /dev/i2c-2 /dev/i2c-3 /dev/i2c-4 /dev/i2c-5 /dev/i2c-6 /dev/i2c-7