I2C Expansion Board

[xalius]

Yeah I was also wondering if I was looking at the right I2C interface... I had a look at the devicetree-file we use for the Linux kernel. Seems the I2C Interface for pin PL8/9 is not mapped. I then checked the usermanual and found out that this particular interface is actually different from TWI0/TWI1/TWI2.... it is named R_TWI and while it is the same hardware block, it does not sit on the APB2 bus like the others, it sits in the secure domain of the SoC on the APBS bus... so you can't just copy the dts entry from the others, fix the addresses/clocks/pins and call it a day... I am not sure what implications this has for adding it to the devicetree-file but I looked at R_UART - which is already configured (the name in the dts is s_uart though....) and found out that the secure devices have their own pin-control section, so that seems to be doable. What I do not know, what clock needs to be assigned to drive devices on the APBS bus? Also what are the correct IRQ definitions, I looked at the GIC IRQ table from the usermanual but couldnt figure out how the IRQ line numbers and vectors translate to the interrupt entries in the dts...