!DRAFT! This document describes how to test the I2C demux feature on the newly added I2C busses on various R-Car Gen2 based boards.
Kernel Version and Configuration
Support for this feature is expected to land upstream in v4.16. It is currently available in a topic branch:
The shmobile_defconfig is suitable for these tests.
Busses on the following boards can be tested:
Lager/r8a7790 (R-Car H2 SoC): I2C2, I2C3 Koelsch/r8a7791 (R-Car M2-W SoC): I2C2, I2C4 Porter/r8a7791 (R-Car M2-W SoC): I2C2 Gose/r8a7793 (R-Car M2-N SoC): I2C2, I2C4 Alt/r8a7794 (R-Car E2 SoC): I2C1 Silk/r8a7794 (R-Car E2 SoC): I2C1
No hardware modifications are needed.
A busybox with standard commands like cd, cat, echo is needed. Also, i2cdump and i2cdetect from the i2c-tools package should be available.