serial: sh-sci: Add support for RZ/G3L RSCI

Add support for RZ/G3L RSCI. The RSCI IP found on the RZ/G3L SoC is
similar to RZ/G3E, but it has 3 clocks (2 module clocks + 1 external
clock) instead of 6 clocks (5 module clocks + 1 external clock) on the
RZ/G3E. Both RZ/G3L and RZ/G3E have a 32-bit FIFO, but RZ/G3L has a
single TCLK with internal dividers, whereas the RZ/G3E has explicit
clocks for TCLK and its dividers. Add a new port type
RSCI_PORT_SCIF32_SINGLE_TCLK to handle this clock difference.

Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://patch.msgid.link/20260312082708.98835-3-biju.das.jz@bp.renesas.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: bijudas

drivers/tty/serial/rsci.c

@@ -695,6 +695,13 @@ struct sci_of_data of_rsci_rzg3e_data = {
 	.params = &rsci_rzg3e_port_params,
 };
 
+struct sci_of_data of_rsci_rzg3l_data = {
+	.type = RSCI_PORT_SCIF32_SINGLE_TCLK,
+	.ops = &rsci_port_ops,
+	.uart_ops = &rsci_uart_ops,
+	.params = &rsci_rzg3e_port_params,
+};
+
 struct sci_of_data of_rsci_rzt2h_data = {
 	.type = RSCI_PORT_SCIF16,
 	.ops = &rsci_port_ops,
@@ -703,6 +710,11 @@ struct sci_of_data of_rsci_rzt2h_data = {
 };
 
 #ifdef CONFIG_SERIAL_SH_SCI_EARLYCON
+static int __init rsci_rzg3l_early_console_setup(struct earlycon_device *device,
+						 const char *opt)
+{
+	return scix_early_console_setup(device, &of_rsci_rzg3l_data);
+}
 
 static int __init rsci_rzg3e_early_console_setup(struct earlycon_device *device,
 						 const char *opt)
@@ -716,6 +728,7 @@ static int __init rsci_rzt2h_early_console_setup(struct earlycon_device *device,
 	return scix_early_console_setup(device, &of_rsci_rzt2h_data);
 }
 
+OF_EARLYCON_DECLARE(rsci, "renesas,r9a08g046-rsci", rsci_rzg3l_early_console_setup);
 OF_EARLYCON_DECLARE(rsci, "renesas,r9a09g047-rsci", rsci_rzg3e_early_console_setup);
 OF_EARLYCON_DECLARE(rsci, "renesas,r9a09g077-rsci", rsci_rzt2h_early_console_setup);
 

drivers/tty/serial/rsci.h

@@ -6,6 +6,7 @@
 #include "sh-sci-common.h"
 
 extern struct sci_of_data of_rsci_rzg3e_data;
+extern struct sci_of_data of_rsci_rzg3l_data;
 extern struct sci_of_data of_rsci_rzt2h_data;
 
 #endif /* __RSCI_H__ */

drivers/tty/serial/sh-sci-common.h

@@ -9,6 +9,7 @@
 enum SCI_PORT_TYPE {
 	RSCI_PORT_SCIF16 = BIT(7) | 0,
 	RSCI_PORT_SCIF32 = BIT(7) | 1,
+	RSCI_PORT_SCIF32_SINGLE_TCLK = BIT(7) | 2,
 };
 
 enum SCI_CLKS {

drivers/tty/serial/sh-sci.c

@@ -1184,7 +1184,8 @@ static int sci_handle_errors(struct uart_port *port)
 
 static bool sci_is_rsci_type(u8 type)
 {
-	return (type == RSCI_PORT_SCIF16 || type == RSCI_PORT_SCIF32);
+	return (type == RSCI_PORT_SCIF16 || type == RSCI_PORT_SCIF32 ||
+		type == RSCI_PORT_SCIF32_SINGLE_TCLK);
 }
 
 static int sci_handle_fifo_overrun(struct uart_port *port)
@@ -3181,7 +3182,8 @@ static int sci_init_clocks(struct sci_port *sci_port, struct device *dev)
 
 	if (sci_port->type == PORT_HSCIF) {
 		clk_names[SCI_SCK] = "hsck";
-	} else if (sci_port->type == RSCI_PORT_SCIF16) {
+	} else if (sci_port->type == RSCI_PORT_SCIF16 ||
+		   sci_port->type == RSCI_PORT_SCIF32_SINGLE_TCLK) {
 		clk_names[SCI_FCK] = "operation";
 		clk_names[SCI_BRG_INT] = "bus";
 	} else if (sci_port->type == RSCI_PORT_SCIF32) {
@@ -3196,7 +3198,8 @@ static int sci_init_clocks(struct sci_port *sci_port, struct device *dev)
 		if (IS_ERR(clk))
 			return PTR_ERR(clk);
 
-		if (!clk && sci_port->type == RSCI_PORT_SCIF16 &&
+		if (!clk && (sci_port->type == RSCI_PORT_SCIF16 ||
+			     sci_port->type == RSCI_PORT_SCIF32_SINGLE_TCLK) &&
 		    (i == SCI_FCK || i == SCI_BRG_INT))
 			return dev_err_probe(dev, -ENODEV, "failed to get %s\n", name);
 
@@ -3330,6 +3333,7 @@ static int sci_init_single(struct platform_device *dev,
 		break;
 	case PORT_SCIFA:
 	case RSCI_PORT_SCIF32:
+	case RSCI_PORT_SCIF32_SINGLE_TCLK:
 		sci_port->rx_trigger = 32;
 		break;
 	case PORT_SCIF:
@@ -3663,6 +3667,10 @@ static const struct of_device_id of_sci_match[] __maybe_unused = {
 		.data = &of_sci_scif_rzv2h,
 	},
 #ifdef CONFIG_SERIAL_RSCI
+	{
+		.compatible = "renesas,r9a08g046-rsci",
+		.data = &of_rsci_rzg3l_data,
+	},
 	{
 		.compatible = "renesas,r9a09g047-rsci",
 		.data = &of_rsci_rzg3e_data,