Hi, I have an Olimex SAM9-L9260 board with an AT91SAM9260 controller on it. The board is running a sound-2.6 git kernel (2.6.35). My problem is that for USART1 (which uses the RXD1 and TXD1 pins), the transmit pin (i.e. TXD1) is not working. I looked at it with my scope and discovered that it is high all the time (which is most likely due to the configured pull-up resistor). Here is what I did to get the UART up and running (just like what I already did for the DBG UART and UART0): In my board file (arch/arm/mach-at91/board-sam9-l9260.c) I added the following line to ek_map_io(), to register USART1 as ttyS2: ----------------------------------------------------------------------- at91_register_uart(AT91SAM9260_ID_US1, 2, 0); ----------------------------------------------------------------------- A look at at91sam9260_devices.c reveals that this will lead to a call of ----------------------------------------------------------------------- configure_usart1_pins(pins); ----------------------------------------------------------------------- which in turn does the following: ----------------------------------------------------------------------- at91_set_A_periph(AT91_PIN_PB6, 1); /* TXD1 */ at91_set_A_periph(AT91_PIN_PB7, 0); /* RXD1 */ ----------------------------------------------------------------------- Hence the pins PB6 and PB7 are configured to be UART pins. I also made sure that there is no other code, that sets the functionality of those pins to something else (e.g. pin PB6 could also be used as TCLK1). Then, when I boot the kernel, I get the following lines, which show that the UARTs are recognized: ----------------------------------------------------------------------- atmel_usart.0: ttyS0 at MMIO 0xfefff200 (irq = 1) is a ATMEL_SERIAL atmel_usart.1: ttyS1 at MMIO 0xfffb0000 (irq = 6) is a ATMEL_SERIAL atmel_usart.2: ttyS2 at MMIO 0xfffb4000 (irq = 7) is a ATMEL_SERIAL ----------------------------------------------------------------------- While this looks good so far, the odd behavior is that I can correctly receive data on /dev/ttyS2 (i.e. data is received on the RXD1/PB7 pin), but I can not send (i.e. *no* data is being transmitted on the TXD1/PB6 pin). * Is this a bug in the kernel or am I doing something wrong here ? * Did you experience similar behavior on the at91sam9260 ? As I already said, I have done this with other UART devices as well (i.e. USART0) and it worked flawlessly. cheers, stefan -- To unsubscribe from this list: send the line "unsubscribe linux-embedded" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
