On Fri, Apr 02, 2021 at 01:05:48PM +0200, Robert Hodaszi wrote:
> From: Robert Hodaszi <robert.hodaszi@xxxxxxxx>
>
> If the mode had been changed to RS-485 after at least one character had
> been sent in RS-232 mode, the RS-485 transmission was not working.
>
> Commit cb1a609236096c278ecbfb7be678a693a70283f1 ("serial: imx: implement
> rts delaying for rs485") added a TX state variable to keep track, when
> it needs to enable / disable the RS-485 transmitter.
>
> In RS-232 mode, the start TX function just sets the state to SEND, and
> the stop function supposed to set it to OFF.
>
> In RS-485 mode, the start TX function expects the state to be either
> OFF, WAIT_AFTER_SEND, or WAIT_AFTER RTS. It cannot do anything if the
> state is set to SEND, expects a stop first.
>
> But stop TX function in RS-232 mode usually didn't set the state to OFF,
> as it first checked if the shifter is empty, and if not, it just
> returned, waiting for a TransmitComplete interrupt, which is only
> enabled in RS-485 mode. So the stop function was never called again.
>
> That check, and the subsequent code part is not needed for RS-232, it
> just have to set the TX state to OFF.
>
> Signed-off-by: Robert Hodaszi <robert.hodaszi@xxxxxxxx>
> ---
> drivers/tty/serial/imx.c | 46 +++++++++++++++++++++-------------------
> 1 file changed, 24 insertions(+), 22 deletions(-)
>
> diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
> index 8257597d034d..511badce3edd 100644
> --- a/drivers/tty/serial/imx.c
> +++ b/drivers/tty/serial/imx.c
> @@ -443,6 +443,12 @@ static void imx_uart_stop_tx(struct uart_port *port)
> ucr1 = imx_uart_readl(sport, UCR1);
> imx_uart_writel(sport, ucr1 & ~UCR1_TRDYEN, UCR1);
>
> + if (!(port->rs485.flags & SER_RS485_ENABLED)) {
> + /* Set the TX state in non-RS485 mode, nothing else to do */
> + sport->tx_state = OFF;
> + return;
> + }
> +
> usr2 = imx_uart_readl(sport, USR2);
> if (!(usr2 & USR2_TXDC)) {
> /* The shifter is still busy, so retry once TC triggers */
> @@ -453,33 +459,29 @@ static void imx_uart_stop_tx(struct uart_port *port)
> ucr4 &= ~UCR4_TCEN;
> imx_uart_writel(sport, ucr4, UCR4);
>
> - /* in rs485 mode disable transmitter */
> - if (port->rs485.flags & SER_RS485_ENABLED) {
> - if (sport->tx_state == SEND) {
> - sport->tx_state = WAIT_AFTER_SEND;
> - start_hrtimer_ms(&sport->trigger_stop_tx,
> - port->rs485.delay_rts_after_send);
> - return;
> - }
> + if (sport->tx_state == SEND) {
> + sport->tx_state = WAIT_AFTER_SEND;
> + start_hrtimer_ms(&sport->trigger_stop_tx,
> + port->rs485.delay_rts_after_send);
> + return;
> + }
>
> - if (sport->tx_state == WAIT_AFTER_RTS ||
> - sport->tx_state == WAIT_AFTER_SEND) {
> - u32 ucr2;
> + if (sport->tx_state == WAIT_AFTER_RTS ||
> + sport->tx_state == WAIT_AFTER_SEND) {
> + /* in rs485 mode disable transmitter */
> + u32 ucr2;
>
> - hrtimer_try_to_cancel(&sport->trigger_start_tx);
> + hrtimer_try_to_cancel(&sport->trigger_start_tx);
>
> - ucr2 = imx_uart_readl(sport, UCR2);
> - if (port->rs485.flags & SER_RS485_RTS_AFTER_SEND)
> - imx_uart_rts_active(sport, &ucr2);
> - else
> - imx_uart_rts_inactive(sport, &ucr2);
> - imx_uart_writel(sport, ucr2, UCR2);
> + ucr2 = imx_uart_readl(sport, UCR2);
> + if (port->rs485.flags & SER_RS485_RTS_AFTER_SEND)
> + imx_uart_rts_active(sport, &ucr2);
> + else
> + imx_uart_rts_inactive(sport, &ucr2);
> + imx_uart_writel(sport, ucr2, UCR2);
>
> - imx_uart_start_rx(port);
> + imx_uart_start_rx(port);
>
> - sport->tx_state = OFF;
> - }
> - } else {
> sport->tx_state = OFF;
> }
> }
> --
> 2.27.0
Your patch is corrupted, all the tabs are turned to spaces and it can
not be applied :(
Please fix up and resend.
thanks,
greg k-h
