I'm trying to use the GPIO expander of the i.MX8MM EVK board (OS android) from the user space.
From U-Boot, on the I2C-2 bus, I can find a device at address 20 but once Android has started, I cannot find any i2c device with i2cdetect.
From U-Boot:
u-boot=> i2c dev 0
Setting bus to 0
u-boot=> i2c probe
Valid chip addresses: 25
u-boot=> i2c dev 1
Setting bus to 1
u-boot=> i2c probe
Valid chip addresses: 00 14 50 52 72 73
u-boot=> i2c dev 2
Setting bus to 2
u-boot=> i2c probe
Valid chip addresses: 20
From userspace:
evk_8mm:/ # i2cdetect -y 0
i2cdetect: /dev/i2c-0: No such file or directory
evk_8mm:/ # i2cdetect -y 1
i2cdetect: /dev/i2c-1: No such file or directory
evk_8mm:/ # i2cdetect -y 2
i2cdetect: /dev/i2c-2: No such file or directory
Please refer this case: https://community.nxp.com/t5/i-MX-Processors/i2c-question-of-i-MX8MPlus-EVK/m-p/1261121