I'm using the 11.09 Linux BSP (188.8.131.52 kernel) on a custom i.mx53 board.
I have UART5_RXD_MUX and UART5_TXD_MUX connected on CSIO_DAT15 (alt 2) and CSIO_DAT14 (alt 2) respectively. I have added in the list of pads for the board MX53_PAD_CSI0_DAT15__UART5_RXD_MUX and MX53_PAD_CSI0_DAT14__UART5_TXD_MUX for iomuxing.
I have looped back the RX and TX pins with a jumper wire on the board so that anything sent on TX should be received on RX. If I connect my scope to the RXD pin and transmit some data, I can see it transmitting just fine. However, the imx53 does not seem to receive anything.
I have modified arch/arm/mach-mx5/serial.c and arch/arm/mach-mx5/serial.h so that all of the UARTS have the same settings. The other UARTS seem to be working fine and I have configured them the same way.
I have also verified that I have the right pin, U2 of the imx53 that I am using on my board. I also dont believe that the pin is damaged because I have two boards and they both show the identical problem.
Please let me know if anybody has any ideas or suggestions as to why the RXD might not be working on UART5.