[PATCH v2] serial:xilinx_uartps:fix rs485 delay_rts_after_send

[Shubhrajyoti Datta]

On Sun, Dec 21, 2025 at 4:03 PM j.turek <jakub.turek at elsta.tech> wrote:
>
> RTS line control with delay should be triggered when there is no more bytes
> in kfifo and hardware buffer is empty. Without this patch RTS control is
> scheduled right after feeding hardware buffer and this is too early.
> RTS line may change state before hardware buffer is empty.
> With this patch delayed RTS state change is triggered when function
> cdns_uart_handle_tx is called from cdns_uart_isr on CDNS_UART_IXR_TXEMPTY
> exactly when hardware completed transmission
>
> Signed-off-by: Jakub Turek  <jakub.turek at elsta.tech>
>
> Fixes: fccc9d9233f9 ("tty: serial: uartps: Add rs485 support to uartps driver")


Reviewed-by: Shubhrajyoti Datta <shubhrajyoti.datta at amd.com>