From: Biju Das <biju.das.jz@bp.renesas.com>

The rtrg variable is populated in sci_init_single() for RZ/T2H. Add
set_rtrg() callback for setting the rtrg value.

Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
---
v5:
 * New patch.
---
 drivers/tty/serial/rsci.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/drivers/tty/serial/rsci.c b/drivers/tty/serial/rsci.c
index b3c48dc1e07d..0533a4bb1d03 100644
--- a/drivers/tty/serial/rsci.c
+++ b/drivers/tty/serial/rsci.c
@@ -151,6 +151,22 @@ static void rsci_start_rx(struct uart_port *port)
 	rsci_serial_out(port, CCR0, ctrl);
 }
 
+static int rsci_scif_set_rtrg(struct uart_port *port, int rx_trig)
+{
+	u32 fcr = rsci_serial_in(port, FCR);
+
+	if (rx_trig >= port->fifosize)
+		rx_trig = port->fifosize - 1;
+	else if (rx_trig < 1)
+		rx_trig = 0;
+
+	fcr &= ~FCR_RTRG4_0;
+	fcr |= field_prep(FCR_RTRG4_0, rx_trig);
+	rsci_serial_out(port, FCR, fcr);
+
+	return rx_trig;
+}
+
 static void rsci_set_termios(struct uart_port *port, struct ktermios *termios,
 			     const struct ktermios *old)
 {
@@ -454,6 +470,7 @@ static const struct sci_port_ops rsci_port_ops = {
 	.poll_put_char		= rsci_poll_put_char,
 	.prepare_console_write	= rsci_prepare_console_write,
 	.suspend_regs_size	= rsci_suspend_regs_size,
+	.set_rtrg		= rsci_scif_set_rtrg,
 	.shutdown_complete	= rsci_shutdown_complete,
 };
 
-- 
2.43.0

Hi Biju,

On Sat, 29 Nov 2025 at 17:43, Biju <biju.das.au@gmail.com> wrote:
> From: Biju Das <biju.das.jz@bp.renesas.com>
>
> The rtrg variable is populated in sci_init_single() for RZ/T2H. Add
> set_rtrg() callback for setting the rtrg value.
>
> Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
> ---
> v5:
>  * New patch.

Thanks for your patch, which is now commit b346e5d7dbf66961 ("serial:
rsci: Add set_rtrg() callback") in tty/tty-next.

> --- a/drivers/tty/serial/rsci.c
> +++ b/drivers/tty/serial/rsci.c
> @@ -151,6 +151,22 @@ static void rsci_start_rx(struct uart_port *port)
>         rsci_serial_out(port, CCR0, ctrl);
>  }
>
> +static int rsci_scif_set_rtrg(struct uart_port *port, int rx_trig)
> +{
> +       u32 fcr = rsci_serial_in(port, FCR);
> +
> +       if (rx_trig >= port->fifosize)
> +               rx_trig = port->fifosize - 1;
> +       else if (rx_trig < 1)
> +               rx_trig = 0;
> +
> +       fcr &= ~FCR_RTRG4_0;
> +       fcr |= field_prep(FCR_RTRG4_0, rx_trig);

FIELD_PREP(), as FCR_RTRG4_0 is a constant.
However, this can be combined with the previous line, using
FIELD_MODIFY().

I have sent a follow-up patch: "[PATCH] serial: rsci: Convert to
FIELD_MODIFY()".
https://lore.kernel.org/ada3faf4698155a618ae6371b35eab121eb8b19c.1766411924.git.geert+renesas@glider.be


> +       rsci_serial_out(port, FCR, fcr);
> +
> +       return rx_trig;
> +}
> +
>  static void rsci_set_termios(struct uart_port *port, struct ktermios *termios,
>                              const struct ktermios *old)
>  {

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds