[PATCH 6.19 372/844] serial: rsci: Add set_rtrg() callback

[Sasha Levin]

From: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>

[ Upstream commit b346e5d7dbf6696176417923c49838a1beb1d785 ]

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@xxxxxxxxxxxxxx>
Tested-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx>
Link: https://patch.msgid.link/20251129164325.209213-4-biju.das.jz@xxxxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 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 b3c48dc1e07db..0533a4bb1d03c 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,
 };
 
-- 
2.51.0