drivers: serial: Added support for raspberry pi

Signed-off-by: Yonatan Schachter <[email protected]>

Author: yonsch

CODEOWNERS

@@ -288,6 +288,7 @@
 /drivers/serial/uart_mcux_iuart.c         @Mani-Sadhasivam
 /drivers/serial/Kconfig.rtt               @carlescufi @pkral78
 /drivers/serial/uart_rtt.c                @carlescufi @pkral78
+/drivers/serial/uart_raspberrypi.c        @yonsch
 /drivers/serial/Kconfig.xlnx              @wjliang
 /drivers/serial/uart_xlnx_ps.c            @wjliang
 /drivers/serial/uart_xlnx_uartlite.c      @henrikbrixandersen

drivers/serial/CMakeLists.txt

@@ -30,6 +30,7 @@ zephyr_library_sources_ifdef(CONFIG_UART_SAM0 uart_sam0.c)
 zephyr_library_sources_ifdef(CONFIG_UART_PSOC6 uart_psoc6.c)
 zephyr_library_sources_ifdef(CONFIG_UART_PL011 uart_pl011.c)
 zephyr_library_sources_ifdef(CONFIG_UART_RV32M1_LPUART uart_rv32m1_lpuart.c)
+zephyr_library_sources_ifdef(CONFIG_UART_RASPBERRYPI uart_raspberrypi.c)
 zephyr_library_sources_ifdef(CONFIG_UART_LITEUART uart_liteuart.c)
 zephyr_library_sources_ifdef(CONFIG_UART_RTT_DRIVER uart_rtt.c)
 zephyr_library_sources_ifdef(CONFIG_UART_XLNX_PS uart_xlnx_ps.c)

drivers/serial/Kconfig

@@ -120,6 +120,8 @@ source "drivers/serial/Kconfig.pl011"
 
 source "drivers/serial/Kconfig.rv32m1_lpuart"
 
+source "drivers/serial/Kconfig.raspberrypi"
+
 source "drivers/serial/Kconfig.litex"
 
 source "drivers/serial/Kconfig.rtt"

drivers/serial/Kconfig.raspberrypi

@@ -0,0 +1,6 @@
+# Copyright (c) 2021 Yonatan Schachter
+# SPDX-License-Identifier: Apache-2.0
+
+config UART_RASPBERRYPI
+	bool "Raspberry Pi UART driver"
+	select SERIAL_HAS_DRIVER

drivers/serial/uart_raspberrypi.c

@@ -0,0 +1,77 @@
+/*
+ * Copyright (c) 2021, Yonatan Schachter
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <drivers/uart.h>
+#include <hardware/uart.h>
+#include <hardware/gpio.h>
+
+struct uart_rpi_config {
+	uart_inst_t *const uart_dev;
+	uint32_t baudrate;
+	uint32_t tx_pin;
+	uint32_t rx_pin;
+};
+
+struct uart_rpi_data {
+
+};
+
+static int uart_rpi_poll_in(const struct device *dev, unsigned char *c)
+{
+	const struct uart_rpi_config *config = dev->config;
+
+	if (!uart_is_readable(config->uart_dev))
+		return -1;
+
+	*c = (unsigned char)uart_get_hw(config->uart_dev)->dr;
+	return 0;
+}
+
+static void uart_rpi_poll_out(const struct device *dev, unsigned char c)
+{
+	const struct uart_rpi_config *config = dev->config;
+
+	uart_putc_raw(config->uart_dev, c);
+}
+
+static int uart_rpi_init(const struct device *dev)
+{
+	const struct uart_rpi_config *config = dev->config;
+
+	gpio_init(config->tx_pin);
+	gpio_init(config->rx_pin);
+	gpio_set_function(config->tx_pin, GPIO_FUNC_UART);
+	gpio_set_function(config->rx_pin, GPIO_FUNC_UART);
+
+	return !uart_init(config->uart_dev, config->baudrate);
+}
+
+static const struct uart_driver_api uart_rpi_driver_api = {
+	.poll_in = uart_rpi_poll_in,
+	.poll_out = uart_rpi_poll_out,
+};
+
+#undef DT_DRV_COMPAT
+#define DT_DRV_COMPAT raspberrypi_rp2_uart
+
+#define RPI_UART_INIT(idx)						\
+	static const struct uart_rpi_config uart_rpi_cfg_##idx = {	\
+		.uart_dev = (uart_inst_t *)DT_INST_REG_ADDR(idx),	\
+		.baudrate = DT_INST_PROP(idx, current_speed),		\
+		.tx_pin = DT_INST_PROP(idx, tx_pin),			\
+		.rx_pin = DT_INST_PROP(idx, rx_pin),			\
+	};								\
+									\
+	static struct uart_rpi_data uart_rpi_data_##idx;		\
+									\
+	DEVICE_DT_INST_DEFINE(idx, &uart_rpi_init,			\
+				device_pm_control_nop,			\
+				&uart_rpi_data_##idx, 			\
+				&uart_rpi_cfg_##idx, PRE_KERNEL_1,	\
+				CONFIG_KERNEL_INIT_PRIORITY_DEVICE,	\
+				&uart_rpi_driver_api);
+
+DT_INST_FOREACH_STATUS_OKAY(RPI_UART_INIT)

dts/bindings/serial/raspberrypi,rp2-uart.yaml

@@ -0,0 +1,22 @@
+description: Raspberry Pi UART
+
+compatible: "raspberrypi,rp2-uart"
+
+include: uart-controller.yaml
+
+properties:
+    reg:
+      required: true
+
+    interrupts:
+      required: true
+
+    tx-pin:
+      type: int
+      required: true
+      description: TX pin as a GPIO number
+
+    rx-pin:
+      type: int
+      required: true
+      description: RX pin as a GPIO number