> This chip is a DUART but the clksel bit, although present for > both channels, (in MCR bit 7) is actually shared (as is the external > CLKSEL pin). Hence if the kernel determines whether to enable > /4 or /1 based on the requested baud rate for one channel it > may break the baud rate for the other channel. Gak. > As a general question how should this type of dependency between > ports due to them being part of the same chip be handled? It sounds to me an even bigger reason for having the kernel 8250 termios code have a ->clock_select() method but you'd need some way to find the pair of the device. Ok thats uglier. Can you at least define the DT as setting the *initial* divisor. That way we can later fix the kernel to be smart about clocks without breaking any assumption about what the DT entry means. > So I've just refactored the existing code to share setting this bit - > this shouldn't change the existing behaviour. > > Maybe I should have done this as a seperate patch to make it clearer. Got it - and yes please make that a separate patch. > If UART_CAP_EFR is not set but UART_CAP_SLEEP or UART_CAP_CLKSEL is > set is assumed that it is not necessary to enable access via the EFR > (whether > that is a valid combination for any existing UART is another question). Probably not. Alan -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
