IC (Inter-Integrated Circuit) was proposed by Philips in the 1980s. This interface uses two signal lines to achieve one master and multiple slaves communication, one is the bidirectional data line SDA, and the other is the clock line SCL. All serial data SDA connected to the I2C bus device is connected to the bus SDA, and the clock line SCL of each device is connected to the bus SCL.
Rockchip I2C controller supports the following features:
# cat /sys/kernel/debug/pinctrl/pinctrl-rockchip-pinctrl/pinmux-pins | grep i2c
pin 23 (gpio0-23): fec80000.i2c (GPIO UNCLAIMED) function i2c6 group i2c6m0-xfer
pin 24 (gpio0-24): fec80000.i2c (GPIO UNCLAIMED) function i2c6 group i2c6m0-xfer
pin 25 (gpio0-25): fd880000.i2c (GPIO UNCLAIMED) function i2c0 group i2c0m2-xfer
pin 26 (gpio0-26): fd880000.i2c (GPIO UNCLAIMED) function i2c0 group i2c0m2-xfer
pin 28 (gpio0-28): fea90000.i2c (GPIO UNCLAIMED) function i2c1 group i2c1m2-xfer
pin 29 (gpio0-29): fea90000.i2c (GPIO UNCLAIMED) function i2c1 group i2c1m2-xfer
pin 32 (gpio1-0): feaa0000.i2c (GPIO UNCLAIMED) function i2c2 group i2c2m4-xfer
pin 33 (gpio1-1): feaa0000.i2c (GPIO UNCLAIMED) function i2c2 group i2c2m4-xfer
pin 34 (gpio1-2): feac0000.i2c (GPIO UNCLAIMED) function i2c4 group i2c4m3-xfer
pin 35 (gpio1-3): feac0000.i2c (GPIO UNCLAIMED) function i2c4 group i2c4m3-xfer
pin 48 (gpio1-16): feab0000.i2c (GPIO UNCLAIMED) function i2c3 group i2c3m0-xfer
pin 49 (gpio1-17): feab0000.i2c (GPIO UNCLAIMED) function i2c3 group i2c3m0-xfer
pin 56 (gpio1-24): fec90000.i2c (GPIO UNCLAIMED) function i2c7 group i2c7m0-xfer
pin 57 (gpio1-25): fec90000.i2c (GPIO UNCLAIMED) function i2c7 group i2c7m0-xfer
# ls /dev/i2c-*
/dev/i2c-0 /dev/i2c-10 /dev/i2c-2 /dev/i2c-4 /dev/i2c-7
/dev/i2c-1 /dev/i2c-11 /dev/i2c-3 /dev/i2c-6 /dev/i2c-9
# List all available I2C buses
# i2cdetect -l
i2c-0 i2c rk3x-i2c I2C adapter
i2c-1 i2c rk3x-i2c I2C adapter
i2c-2 i2c rk3x-i2c I2C adapter
i2c-3 i2c rk3x-i2c I2C adapter
i2c-4 i2c rk3x-i2c I2C adapter
i2c-6 i2c rk3x-i2c I2C adapter
i2c-7 i2c rk3x-i2c I2C adapter
i2c-9 i2c DP-AUX I2C adapter
i2c-10 i2c ddc I2C adapter
i2c-11 i2c fde50000.dp I2C adapter
# Scan a specific bus (e.g. bus 6)
# sudo i2cdetect -y 6
0 1 2 3 4 5 6 7 8 9 a b c d e f
00: -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
20: -- -- UU -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
50: -- UU -- -- -- -- -- -- -- -- -- -- -- UU -- --
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- --
# i2cdump -f -y 6 0x5d
No size specified (using byte-data access)
0 1 2 3 4 5 6 7 8 9 a b c d e f 0123456789abcdef
00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ............
10: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ............
20: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ............
30: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00............
40: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ............
50: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ............
60: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ............
70: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ............
80: 22 04 ef 00 00 00 00 00 00 00 00 03 00 00 00 00 "??..........?....
90: 00 00 00 00 00 ff 89 00 00 00 00 00 00 00 00 00......?.........
a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 04 00 00 .............?..
b0: 00 00 00 00 00 00 00 00 00 00 00 00 04 00 00 00......?...
c0: 00 00 00 00 00 00 00 00 ff 00 00 00 00 00 00 b0 ...............?
d0: 40 e0 53 44 40 e0 52 04 40 e0 53 04 40 e0 53 04 @?SD@?R?@?S?@?S?
e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
# i2cget -f -y 6 0x5d 0xD0
0x40
# sudo i2cset -f -y 6 0x5d 0x00 0x55