LINUX-I2C
From Variscite Wiki
VAR-SOM-AM33 I2C
Available I2C buses
List of available I2C buses on VAR-SOM-AM33:
# ls -l /dev/i2c-* crw------- 1 root root 89, 0 Mar 10 16:55 /dev/i2c-0 crw------- 1 root root 89, 1 Mar 10 16:55 /dev/i2c-1
System class:
# ls /sys/class/i2c-dev/ i2c-0 i2c-1
I2C devices per bus
Scan bus 0:
# i2cdetect -y -r 0
0 1 2 3 4 5 6 7 8 9 a b c d e f
00: -- -- -- -- -- -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
Scan bus 1:
# i2cdetect -y -r 1
0 1 2 3 4 5 6 7 8 9 a b c d e f
00: -- -- -- -- -- -- -- -- -- -- -- -- --
10: -- -- 12 -- -- -- -- -- -- -- -- UU -- -- -- --
20: -- -- -- -- -- -- -- -- -- -- -- -- -- UU -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- --
When the device is marked with "UU" it means that a driver is using it.
When the device is marked with numbers it means that no driver is using it.
Reading / Writing from an I2C device
Variscite includes I2CTools as a part of the default file system build, examples of optional commands:
i2cdump - dump the content of an I2C device
i2cset - write a single character to an I2C device
i2cget - read a single character to an I2C device
In addition follow 'C' code example as describe in the linux kernel documentation : https://www.kernel.org/doc/Documentation/i2c/dev-interface
Variscite's system integrated I2C devices
Note: Do not write to Variscite's on-SOM EEPROM or you will damage the SOM!
Variscite devices:
I2C-1 0x1b - Audio codec on SOM I2C-1 0x2d - PMIC on SoM