Hi,
I am working with a board based off the am335x CPU and I am going to use SPI through u-boot. I've therefore been fiddling with u-boot and enabling spi0 through devicetree and all, which works fine (at least probing and so on). I am using CONFIG_DM_SPI for this, and u-boot-2016.05-rc3. However when I try to access the SPI peripheral, u-boot hanged.
Debugging through this showed that the culprit lies within the spi_reset call inside omap3_spi.c when the SPI bus is being claimed. The function tries to write to the sysconfig register, based 0x110 off the BASE. Problem is that the base defined in device tree include I am basing myself off (am335x.dtsi) is 0x48030000, and the offset is defined to 0x10, which means the register being written to is 0x48030010 and not 0x48030110 as it is supposed to, again resulting in the hang due to the endless do-while loop in spi_reset. This I guess is due to this part priv->regs = (struct mcspi *)dev_get_addr(dev); of omap3_spi_probe as it reads the reg property off the device tree.
OK, so for my question, what is really the correct way to fix this? 0x48030000 is the "real" base of McSPI0, although the first 0x100 part is revision stuff according to the technical datasheet of the am335x. If I change the reg value of the device tree to 0x48030100 then it does not hang, reset seems to work fine, however I have no idea of the influences this will have (the device tree is also used in the kernel and so on), I would guess its not the "right" way.
Any input/output is appreciated.
Best regards, Martin Hejnfelt