Hi Geert,
> -----Original Message-----
> From: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
> Sent: Friday, April 21, 2023 10:50 AM
> To: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>
> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>; Jiri Slaby
> <jirislaby@xxxxxxxxxx>; Yoshinori Sato <ysato@xxxxxxxxxxxxxxxxxxxx>; linux-
> serial@xxxxxxxxxxxxxxx; Prabhakar Mahadev Lad <prabhakar.mahadev-
> lad.rj@xxxxxxxxxxxxxx>; linux-renesas-soc@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH v4 5/5] tty: serial: sh-sci: Fix end of transmission on
> SCI
>
> Hi Biju,
>
> On Wed, Apr 12, 2023 at 4:51 PM Biju Das <biju.das.jz@xxxxxxxxxxxxxx> wrote:
> > We need to set TE to "0" (i.e., disable serial transmission) to get
> > the expected behavior of the end of serial transmission.
> >
> > Signed-off-by: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>
>
> Thanks for your patch!
>
> > --- a/drivers/tty/serial/sh-sci.c
> > +++ b/drivers/tty/serial/sh-sci.c
> > @@ -847,6 +847,11 @@ static void sci_transmit_chars(struct uart_port
> *port)
> > } else if (!uart_circ_empty(xmit) && !stopped) {
> > c = xmit->buf[xmit->tail];
> > xmit->tail = (xmit->tail + 1) &
> > (UART_XMIT_SIZE - 1);
> > + } else if (port->type == PORT_SCI &&
> uart_circ_empty(xmit)) {
> > + ctrl = serial_port_in(port, SCSCR);
> > + ctrl &= ~SCSCR_TE;
> > + serial_port_out(port, SCSCR, ctrl);
> > + return;
>
> So nothing after the while loop should be done anymore?
> What about clearing SCSCR_TE in sci_stop_tx() (which is called after the
> while loop) instead?
>
> > } else {
> > break;
> > }
>
> So combined with my comments on patch 4/5, that would become
>
> - if (port->type == PORT_SCI)
> + if (port->type == PORT_SCI) {
> ctrl |= SCSCR_TEIE;
> + ctrl &= ~SCSCR_TE;
> + }
>
> in sci_stop_tx().
I get stray chars at the end and Carriage return not happening.
Basically tx is not working as expected.
Cheers,
Biju
