Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx> writes: > On Thu, May 30, 2019 at 06:29:45PM +0300, Sergey Organov wrote: >> imx_set_mctrl() cleared RTS on every call > > >> >> Signed-off-by: Sergey Organov <sorganov@xxxxxxxxx> >> --- >> drivers/tty/serial/imx.c | 4 ++-- >> 1 file changed, 2 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c >> index 6577552..13face9 100644 >> --- a/drivers/tty/serial/imx.c >> +++ b/drivers/tty/serial/imx.c >> @@ -1648,7 +1648,6 @@ imx_uart_set_termios(struct uart_port *port, struct ktermios *termios, >> >> /* then, disable everything */ >> imx_uart_writel(sport, old_ucr2 & ~(UCR2_TXEN | UCR2_RXEN | UCR2_ATEN), UCR2); >> - old_ucr2 &= (UCR2_TXEN | UCR2_RXEN | UCR2_ATEN); >> >> /* custom-baudrate handling */ >> div = sport->port.uartclk / (baud * 16); >> @@ -1686,7 +1685,8 @@ imx_uart_set_termios(struct uart_port *port, struct ktermios *termios, >> >> imx_uart_writel(sport, old_ucr1, UCR1); >> >> - /* set the parity, stop bits and data size */ >> + /* Set parity, stop bits, data size, etc. Keep bits we don't compute. */ >> + old_ucr2 &= (UCR2_CTS | UCR2_TXEN | UCR2_RXEN | UCR2_ATEN); > > I wonder if that fixes a certain usecase and breaks another. > > If I change the baud rate of the UART the sequence I actually want to > have is: > > clear RTS (to not encourage the other side to send data) > disable receiver > reconfigure requested settings > reenable receiver > (maybe) reactivate RTS to signal being ready again Sorry, I fail to see how this patch breaks anything here. It just now correctly does: > (maybe) reactivate RTS to signal being ready again step, touching nothing else. Please notice that the line >> - old_ucr2 &= (UCR2_TXEN | UCR2_RXEN | UCR2_ATEN); just changes internal variable, and changed to: >> + old_ucr2 &= (UCR2_CTS | UCR2_TXEN | UCR2_RXEN | UCR2_ATEN); exactly to restore RTS state at exit. It's then moved down to where it's used, to make code and comments clearer. I decided it's too much granularity to break this into 2 separate patches. -- Sergey
