Hi all,
I'm porting Android OS to board based on Sitara AM3984, I'm using Android-Linux port for TI816 EVM board as a reference and starting point for my system. I've added spidev driver to my kernel, because I need to drive SPI from user applications. Driver is added to system without any problem, it appears in kernel devices (/dev/spidev1.0 for my system). When I tried to test SPI with spidev_test program, that is a part of kernel documentation folder, I get clock and chip select to appear on scope, MOSI data is present on SPI_D[1] pin!
Then I looked at schematic of EVM and my board:
On EVM board SPI_D[0] is connected to MISO line and SPI_D[1] is connected to MOSI line. In my hardware system configuration, pin SPI_D[0] is set to MOSI and pin SPI_D[1] is connected to MISO. So there is a difference on two systems. After looking in technical reference manual, Sitara register MCSPI_SYST has configuration bits that determine which pin is going to be input and ouput (SPIDATDIR1 and SPIDATDIR0).
I have set those bit values to SPIDATDIR1=input and SPIDATDIR0=output! But after I rebuilt the kernel and tried spidev_test program once again the result is same. Output data (MOSI) is appearing on SPI_D[1] pin and not on the SPI_D[0] pin like I wanted it to be! Because in my system, regarding data lines, I have reverse situation in comparison with TI816 EVM board.
I looked in to rest of the code (mux settings, device.c, board-ti8186evm.c etc.) but I haven't found anything that seems to overwrite those pin setting for SPI peripheral! Can anybody give me clue regarding this problem?? How can I set SPI_D[0] = MOSI and SPI_D[1] = MISO??
Kind regards,
Srdjan
