driver: serial: Add UART driver initial version of RTS5912.

Add UART driver for Realtek RTS5912.

Signed-off-by: Lin Yu-Cheng <lin_yu_cheng@realtek.com>

drivers/serial/CMakeLists.txt

@@ -61,6 +61,7 @@ zephyr_library_sources_ifdef(CONFIG_UART_RCAR uart_rcar.c)
 zephyr_library_sources_ifdef(CONFIG_UART_RENESAS_RA uart_renesas_ra.c)
 zephyr_library_sources_ifdef(CONFIG_UART_RENESAS_RZ_SCIF uart_renesas_rz_scif.c)
 zephyr_library_sources_ifdef(CONFIG_UART_RPI_PICO_PIO uart_rpi_pico_pio.c)
+zephyr_library_sources_ifdef(CONFIG_UART_RTS5912 uart_realtek_rts5912.c)
 zephyr_library_sources_ifdef(CONFIG_UART_RTT_DRIVER uart_rtt.c)
 zephyr_library_sources_ifdef(CONFIG_UART_RV32M1_LPUART uart_rv32m1_lpuart.c)
 zephyr_library_sources_ifdef(CONFIG_UART_RZT2M uart_rzt2m.c)

drivers/serial/Kconfig

@@ -230,4 +230,6 @@ source "drivers/serial/Kconfig.si32"
 
 source "drivers/serial/Kconfig.wch_usart"
 
+source "drivers/serial/Kconfig.realtek_rts5912"
+
 endif # SERIAL

drivers/serial/Kconfig.realtek_rts5912

@@ -0,0 +1,19 @@
+# SPDX-License-Identifier: Apache-2.0
+#
+# Copyright (c) 2024 Realtek Semiconductor Corporation, SIBG-SD7
+#
+
+config UART_RTS5912
+	bool "UART driver for Realtek RTS5912 EC"
+	default y if DT_HAS_REALTEK_RTS5912_UART_ENABLED
+	select PINCTRL
+	select CLOCK_CONTROL
+	help
+	  This option enables the RTS5912 UART wrapper driver.
+
+config UART_RTS5912_INIT_PRIORITY
+	int "RTS5912 UART wrapper init priority"
+	default 49
+	depends on UART_RTS5912
+	help
+	  Initialization priority for Realtek RTS5912 UART wrapper driver.

drivers/serial/uart_realtek_rts5912.c

@@ -0,0 +1,75 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Copyright (c) 2024 Realtek Semiconductor Corporation, SIBG-SD7
+ * Author: Lin Yu-Cheng <lin_yu_cheng@realtek.com>
+ */
+
+#define DT_DRV_COMPAT realtek_rts5912_uart
+
+#include <zephyr/kernel.h>
+#include <zephyr/drivers/pinctrl.h>
+#include <zephyr/drivers/uart.h>
+#include <zephyr/drivers/gpio.h>
+#include <zephyr/drivers/clock_control.h>
+#include <zephyr/drivers/clock_control/clock_control_rts5912.h>
+#include <zephyr/logging/log.h>
+
+LOG_MODULE_REGISTER(uart_rts5912, CONFIG_UART_LOG_LEVEL);
+
+BUILD_ASSERT(CONFIG_UART_RTS5912_INIT_PRIORITY < CONFIG_SERIAL_INIT_PRIORITY,
+	     "The uart_realtek_rts5912 driver must be initialized before the uart_ns16550 driver");
+
+/* device config */
+struct uart_rts5912_device_config {
+	const struct pinctrl_dev_config *pcfg;
+	const struct device *clk_dev;
+	struct rts5912_sccon_subsys sccon_cfg;
+};
+
+/** Device data structure */
+struct uart_rts5912_dev_data {
+};
+
+static int rts5912_uart_init(const struct device *dev)
+{
+	const struct uart_rts5912_device_config *const dev_cfg = dev->config;
+	int rc;
+
+	if (!device_is_ready(dev_cfg->clk_dev)) {
+		return -ENODEV;
+	}
+
+	rc = clock_control_on(dev_cfg->clk_dev, (clock_control_subsys_t)&dev_cfg->sccon_cfg);
+	if (rc != 0) {
+		return rc;
+	}
+
+	rc = pinctrl_apply_state(dev_cfg->pcfg, PINCTRL_STATE_DEFAULT);
+	if (rc != 0) {
+		return rc;
+	}
+
+	return 0;
+}
+
+#define UART_RTS5912_DEVICE_INIT(n)                                                                \
+	PINCTRL_DT_INST_DEFINE(n);                                                                 \
+                                                                                                   \
+	static const struct uart_rts5912_device_config uart_rts5912_dev_cfg_##n = {                \
+		.pcfg = PINCTRL_DT_INST_DEV_CONFIG_GET(n),                                         \
+		.clk_dev = DEVICE_DT_GET(DT_INST_CLOCKS_CTLR(n)),                                  \
+		.sccon_cfg =                                                                       \
+			{                                                                          \
+				.clk_grp = DT_INST_CLOCKS_CELL_BY_NAME(n, uart##n, clk_grp),       \
+				.clk_idx = DT_INST_CLOCKS_CELL_BY_NAME(n, uart##n, clk_idx),       \
+			},                                                                         \
+	};                                                                                         \
+                                                                                                   \
+	static struct uart_rts5912_dev_data uart_rts5912_dev_data_##n;                             \
+                                                                                                   \
+	DEVICE_DT_INST_DEFINE(n, &rts5912_uart_init, NULL, &uart_rts5912_dev_data_##n,             \
+			      &uart_rts5912_dev_cfg_##n, PRE_KERNEL_1,                             \
+			      CONFIG_UART_RTS5912_INIT_PRIORITY, NULL);
+
+DT_INST_FOREACH_STATUS_OKAY(UART_RTS5912_DEVICE_INIT)

dts/arm/realtek/ec/rts5912.dtsi

@@ -92,6 +92,24 @@
 			status = "okay";
 		};
 
+		uart0: uart@40010100 {
+			compatible = "ns16550";
+			reg = <0x40010100 0x100>;
+			reg-shift = <2>;
+			clock-frequency = <25000000>;
+			interrupts = <191 0>;
+			status = "disabled";
+		};
+
+		uart0_wrapper: uart_wrapper@40010200 {
+			compatible = "realtek,rts5912-uart";
+			reg = <0x40010200 0x0020>;
+			port = <0>;
+			clocks = <&sccon RTS5912_SCCON_UART UART0_CLKPWR>;
+			clock-names = "uart0";
+			status = "disabled";
+		};
+
 		pinctrl: pin-controller@40090000 {
 			compatible = "realtek,rts5912-pinctrl";
 			#address-cells = <1>;

dts/bindings/serial/realtek,rts5912-uart.yaml

@@ -0,0 +1,24 @@
+# SPDX-License-Identifier: Apache-2.0
+#
+# Copyright (c) 2024 Realtek Semiconductor Corporation, SIBG-SD7
+#
+
+description: Realtek RTS5912 UART
+
+compatible: "realtek,rts5912-uart"
+
+include: [uart-controller.yaml, pinctrl-device.yaml]
+
+properties:
+  reg:
+    required: true
+
+  port:
+    type: int
+    required: true
+
+  pinctrl-0:
+    required: true
+
+  pinctrl-names:
+    required: true