[PATCH v2 01/19] tty: serial: samsung: fix tx_empty() to return TIOCSER_TEMT

[Sam Protsenko]

On Fri, Jan 19, 2024 at 4:45 AM Tudor Ambarus <tudor.ambarus at linaro.org> wrote:
>
> The core expects for tx_empty() either TIOCSER_TEMT when the tx is
> empty or 0 otherwise. s3c24xx_serial_txempty_nofifo() might return
> 0x4, and at least uart_get_lsr_info() tries to clear exactly
> TIOCSER_TEMT (BIT(1)). Fix tx_empty() to return TIOCSER_TEMT.
>
> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
> Signed-off-by: Tudor Ambarus <tudor.ambarus at linaro.org>
> ---

Reviewed-by: Sam Protsenko <semen.protsenko at linaro.org>

>  drivers/tty/serial/samsung_tty.c | 5 ++---
>  1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/tty/serial/samsung_tty.c b/drivers/tty/serial/samsung_tty.c
> index 71d17d804fda..6fdb32b83346 100644
> --- a/drivers/tty/serial/samsung_tty.c
> +++ b/drivers/tty/serial/samsung_tty.c
> @@ -987,11 +987,10 @@ static unsigned int s3c24xx_serial_tx_empty(struct uart_port *port)
>                 if ((ufstat & info->tx_fifomask) != 0 ||
>                     (ufstat & info->tx_fifofull))
>                         return 0;
> -
> -               return 1;
> +               return TIOCSER_TEMT;
>         }
>
> -       return s3c24xx_serial_txempty_nofifo(port);
> +       return s3c24xx_serial_txempty_nofifo(port) ? TIOCSER_TEMT : 0;
>  }
>
>  /* no modem control lines */
> --
> 2.43.0.429.g432eaa2c6b-goog
>