[PATCH 09/14] serial: Add Milbeaut M10V serial control

[Sugaya Taichi]

Add Milbeaut M10V serial control.

Signed-off-by: Sugaya Taichi <sugaya.taichi@xxxxxxxxxxxxx>
---
 drivers/tty/serial/Kconfig       |  24 ++
 drivers/tty/serial/Makefile      |   1 +
 drivers/tty/serial/m10v_usio.c   | 605 +++++++++++++++++++++++++++++++++++++++
 include/uapi/linux/serial_core.h |   3 +
 4 files changed, 633 insertions(+)
 create mode 100644 drivers/tty/serial/m10v_usio.c

diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
index 32886c3..cd28a7e 100644
--- a/drivers/tty/serial/Kconfig
+++ b/drivers/tty/serial/Kconfig
@@ -1529,6 +1529,30 @@ config SERIAL_OWL_CONSOLE
 	  Say 'Y' here if you wish to use Actions Semiconductor S500/S900 UART
 	  as the system console.
 
+config SERIAL_M10V_USIO
+	tristate "M10V USIO/UART serial port support"
+	depends on ARCH_MILBEAUT
+	default y
+	select SERIAL_CORE
+	help
+	  This selects the USIO/UART IP found in Socionext Milbeaut M10V.
+
+config SERIAL_M10V_USIO_PORTS
+	int "Maximum number of CSIO/UART ports (1-8)"
+	range 1 8
+	depends on SERIAL_M10V_USIO
+	default "4"
+
+config SERIAL_M10V_USIO_CONSOLE
+	bool "Support for console on M10V USIO/UART serial port"
+	depends on SERIAL_M10V_USIO=y
+	select SERIAL_CORE_CONSOLE
+	help
+	  Say 'Y' here if you wish to use a USIO/UART of Socionext Milbeaut
+	  M10V as the system console (the system console is the device which
+	  receives all kernel messages and warnings and which allows logins in
+	  single user mode).
+
 endmenu
 
 config SERIAL_MCTRL_GPIO
diff --git a/drivers/tty/serial/Makefile b/drivers/tty/serial/Makefile
index daac675..5ea46bc 100644
--- a/drivers/tty/serial/Makefile
+++ b/drivers/tty/serial/Makefile
@@ -89,6 +89,7 @@ obj-$(CONFIG_SERIAL_MVEBU_UART)	+= mvebu-uart.o
 obj-$(CONFIG_SERIAL_PIC32)	+= pic32_uart.o
 obj-$(CONFIG_SERIAL_MPS2_UART)	+= mps2-uart.o
 obj-$(CONFIG_SERIAL_OWL)	+= owl-uart.o
+obj-$(CONFIG_SERIAL_M10V_USIO)   += m10v_usio.o
 
 # GPIOLIB helpers for modem control lines
 obj-$(CONFIG_SERIAL_MCTRL_GPIO)	+= serial_mctrl_gpio.o
diff --git a/drivers/tty/serial/m10v_usio.c b/drivers/tty/serial/m10v_usio.c
new file mode 100644
index 0000000..3abb465
--- /dev/null
+++ b/drivers/tty/serial/m10v_usio.c
@@ -0,0 +1,605 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2018 Socionext Inc.
+ */
+
+#if defined(CONFIG_SERIAL_M10V_USIO_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
+#define SUPPORT_SYSRQ
+#endif
+
+#include <linux/clk.h>
+#include <linux/console.h>
+#include <linux/module.h>
+#include <linux/of_irq.h>
+#include <linux/platform_device.h>
+#include <linux/serial_core.h>
+#include <linux/tty.h>
+#include <linux/tty_flip.h>
+
+
+#define USIO_NAME		"sn-usio-uart"
+#define USIO_UART_DEV_NAME	"ttyUSI"
+
+static struct uart_port usio_ports[CONFIG_SERIAL_M10V_USIO_PORTS];
+
+#define RX	0
+#define TX	1
+static int usio_irq[CONFIG_SERIAL_M10V_USIO_PORTS][2];
+
+#define SN_USIO_REG_SMR		0
+#define SN_USIO_REG_SCR		1
+#define SN_USIO_REG_ESCR	2
+#define SN_USIO_REG_SSR		3
+#define SN_USIO_REG_DR		4
+#define SN_USIO_REG_BGR		6
+#define SN_USIO_REG_FCR		12
+#define SN_USIO_REG_FBYTE	14
+
+#define SN_USIO_SMR_SOE		BIT(0)
+#define SN_USIO_SMR_SBL		BIT(3)
+#define SN_USIO_SCR_TXE		BIT(0)
+#define SN_USIO_SCR_RXE		BIT(1)
+#define SN_USIO_SCR_TBIE	BIT(2)
+#define SN_USIO_SCR_TIE		BIT(3)
+#define SN_USIO_SCR_RIE		BIT(4)
+#define SN_USIO_SCR_UPCL	BIT(7)
+#define SN_USIO_ESCR_L_8BIT	0
+#define SN_USIO_ESCR_L_5BIT	1
+#define SN_USIO_ESCR_L_6BIT	2
+#define SN_USIO_ESCR_L_7BIT	3
+#define SN_USIO_ESCR_P		BIT(3)
+#define SN_USIO_ESCR_PEN	BIT(4)
+#define SN_USIO_ESCR_FLWEN	BIT(7)
+#define SN_USIO_SSR_TBI		BIT(0)
+#define SN_USIO_SSR_TDRE	BIT(1)
+#define SN_USIO_SSR_RDRF	BIT(2)
+#define SN_USIO_SSR_ORE		BIT(3)
+#define SN_USIO_SSR_FRE		BIT(4)
+#define SN_USIO_SSR_PE		BIT(5)
+#define SN_USIO_SSR_REC		BIT(7)
+#define SN_USIO_SSR_BRK		BIT(8)
+#define SN_USIO_FCR_FE1		BIT(0)
+#define SN_USIO_FCR_FE2		BIT(1)
+#define SN_USIO_FCR_FCL1	BIT(2)
+#define SN_USIO_FCR_FCL2	BIT(3)
+#define SN_USIO_FCR_FSET	BIT(4)
+#define SN_USIO_FCR_FTIE	BIT(9)
+#define SN_USIO_FCR_FDRQ	BIT(10)
+#define SN_USIO_FCR_FRIIE	BIT(11)
+
+static void usio_stop_tx(struct uart_port *port)
+{
+	writew(readw(port->membase + SN_USIO_REG_FCR) & ~SN_USIO_FCR_FTIE,
+	       port->membase + SN_USIO_REG_FCR);
+	writeb(readb(port->membase + SN_USIO_REG_SCR) & ~SN_USIO_SCR_TBIE,
+	       port->membase + SN_USIO_REG_SCR);
+}
+
+static void usio_tx_chars(struct uart_port *port)
+{
+	struct circ_buf *xmit = &port->state->xmit;
+	int count;
+
+	writew(readw(port->membase + SN_USIO_REG_FCR) & ~SN_USIO_FCR_FTIE,
+	       port->membase + SN_USIO_REG_FCR);
+	writeb(readb(port->membase + SN_USIO_REG_SCR) &
+	       ~(SN_USIO_SCR_TIE | SN_USIO_SCR_TBIE),
+	       port->membase + SN_USIO_REG_SCR);
+
+	if (port->x_char) {
+		writew(port->x_char, port->membase + SN_USIO_REG_DR);
+		port->icount.tx++;
+		port->x_char = 0;
+		return;
+	}
+	if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
+		usio_stop_tx(port);
+		return;
+	}
+
+	count = port->fifosize -
+		(readw(port->membase + SN_USIO_REG_FBYTE) & 0xff);
+
+	do {
+		writew(xmit->buf[xmit->tail], port->membase + SN_USIO_REG_DR);
+
+		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
+		port->icount.tx++;
+		if (uart_circ_empty(xmit))
+			break;
+
+	} while (--count > 0);
+
+	writew(readw(port->membase + SN_USIO_REG_FCR) & ~SN_USIO_FCR_FDRQ,
+	       port->membase + SN_USIO_REG_FCR);
+
+	writeb(readb(port->membase + SN_USIO_REG_SCR) | SN_USIO_SCR_TBIE,
+	       port->membase + SN_USIO_REG_SCR);
+
+	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
+		uart_write_wakeup(port);
+
+	if (uart_circ_empty(xmit))
+		usio_stop_tx(port);
+}
+
+static void usio_start_tx(struct uart_port *port)
+{
+	u16 fcr = readw(port->membase + SN_USIO_REG_FCR);
+
+	writew(fcr | SN_USIO_FCR_FTIE, port->membase + SN_USIO_REG_FCR);
+	if (!(fcr & SN_USIO_FCR_FDRQ))
+		return;
+
+	writeb(readb(port->membase + SN_USIO_REG_SCR) | SN_USIO_SCR_TBIE,
+	       port->membase + SN_USIO_REG_SCR);
+
+	if (readb(port->membase + SN_USIO_REG_SSR) & SN_USIO_SSR_TBI)
+		usio_tx_chars(port);
+}
+
+static void usio_stop_rx(struct uart_port *port)
+{
+	writeb(readb(port->membase + SN_USIO_REG_SCR) & ~SN_USIO_SCR_RIE,
+	       port->membase + SN_USIO_REG_SCR);
+}
+
+static void usio_enable_ms(struct uart_port *port)
+{
+	writeb(readb(port->membase + SN_USIO_REG_SCR) |
+	       SN_USIO_SCR_RIE | SN_USIO_SCR_RXE,
+	       port->membase + SN_USIO_REG_SCR);
+}
+
+static void usio_rx_chars(struct uart_port *port)
+{
+	struct tty_port *ttyport = &port->state->port;
+	unsigned long flag = 0;
+	char ch = 0;
+	u8 status;
+	int max_count = 2;
+
+	while (max_count--) {
+		status = readb(port->membase + SN_USIO_REG_SSR);
+
+		if (!(status & SN_USIO_SSR_RDRF))
+			break;
+
+		if (!(status & (SN_USIO_SSR_ORE | SN_USIO_SSR_FRE |
+				SN_USIO_SSR_PE))) {
+			ch = readw(port->membase + SN_USIO_REG_DR);
+			flag = TTY_NORMAL;
+			port->icount.rx++;
+			if (uart_handle_sysrq_char(port, ch))
+				continue;
+			uart_insert_char(port, status, SN_USIO_SSR_ORE,
+					 ch, flag);
+			continue;
+		}
+		if (status & SN_USIO_SSR_PE)
+			port->icount.parity++;
+		if (status & SN_USIO_SSR_ORE)
+			port->icount.overrun++;
+		status &= port->read_status_mask;
+		if (status & SN_USIO_SSR_BRK) {
+			flag = TTY_BREAK;
+			ch = 0;
+		} else
+			if (status & SN_USIO_SSR_PE) {
+				flag = TTY_PARITY;
+				ch = 0;
+			} else
+				if (status & SN_USIO_SSR_FRE) {
+					flag = TTY_FRAME;
+					ch = 0;
+				}
+		if (flag)
+			uart_insert_char(port, status, SN_USIO_SSR_ORE,
+					 ch, flag);
+
+		writeb(readb(port->membase + SN_USIO_REG_SSR) | SN_USIO_SSR_REC,
+			port->membase + SN_USIO_REG_SSR);
+
+		max_count = readw(port->membase + SN_USIO_REG_FBYTE) >> 8;
+		writew(readw(port->membase + SN_USIO_REG_FCR) |
+		       SN_USIO_FCR_FE2 | SN_USIO_FCR_FRIIE,
+		port->membase + SN_USIO_REG_FCR);
+	}
+
+	tty_flip_buffer_push(ttyport);
+}
+
+static irqreturn_t usio_rx_irq(int irq, void *dev_id)
+{
+	struct uart_port *port = dev_id;
+
+	spin_lock(&port->lock);
+	usio_rx_chars(port);
+	spin_unlock(&port->lock);
+
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t usio_tx_irq(int irq, void *dev_id)
+{
+	struct uart_port *port = dev_id;
+
+	spin_lock(&port->lock);
+	if (readb(port->membase + SN_USIO_REG_SSR) & SN_USIO_SSR_TBI)
+		usio_tx_chars(port);
+	spin_unlock(&port->lock);
+
+	return IRQ_HANDLED;
+}
+
+static unsigned int usio_tx_empty(struct uart_port *port)
+{
+	return (readb(port->membase + SN_USIO_REG_SSR) & SN_USIO_SSR_TBI) ?
+		TIOCSER_TEMT : 0;
+}
+
+static void usio_set_mctrl(struct uart_port *port, unsigned int mctrl)
+{
+}
+
+static unsigned int usio_get_mctrl(struct uart_port *port)
+{
+	return TIOCM_CAR | TIOCM_DSR | TIOCM_CTS;
+
+}
+
+static void usio_break_ctl(struct uart_port *port, int break_state)
+{
+}
+
+static int usio_startup(struct uart_port *port)
+{
+	const char *portname = to_platform_device(port->dev)->name;
+	unsigned long flags;
+	int ret, index = port->line;
+	unsigned char  escr;
+
+	ret = request_irq(usio_irq[index][RX], usio_rx_irq, 0, portname, port);
+	if (ret)
+		return ret;
+	ret = request_irq(usio_irq[index][TX], usio_tx_irq, 0, portname, port);
+	if (ret) {
+		free_irq(usio_irq[index][RX], port);
+		return ret;
+	}
+
+	escr = readb(port->membase + SN_USIO_REG_ESCR);
+	if (of_property_read_bool(port->dev->of_node, "uart-flow-enable"))
+		escr |= SN_USIO_ESCR_FLWEN;
+	spin_lock_irqsave(&port->lock, flags);
+	writeb(0, port->membase + SN_USIO_REG_SCR);
+	writeb(escr, port->membase + SN_USIO_REG_ESCR);
+	writeb(SN_USIO_SCR_UPCL, port->membase + SN_USIO_REG_SCR);
+	writeb(SN_USIO_SSR_REC, port->membase + SN_USIO_REG_SSR);
+	writew(0, port->membase + SN_USIO_REG_FCR);
+	writew(SN_USIO_FCR_FCL1 | SN_USIO_FCR_FCL2,
+	       port->membase + SN_USIO_REG_FCR);
+	writew(SN_USIO_FCR_FE1 | SN_USIO_FCR_FE2 | SN_USIO_FCR_FRIIE,
+	       port->membase + SN_USIO_REG_FCR);
+	writew(0, port->membase + SN_USIO_REG_FBYTE);
+	writew(BIT(12), port->membase + SN_USIO_REG_FBYTE);
+
+	writeb(SN_USIO_SCR_TXE  | SN_USIO_SCR_RIE | SN_USIO_SCR_TBIE |
+	       SN_USIO_SCR_RXE, port->membase + SN_USIO_REG_SCR);
+	spin_unlock_irqrestore(&port->lock, flags);
+
+	return 0;
+}
+
+static void usio_shutdown(struct uart_port *port)
+{
+	int index = port->line;
+
+	free_irq(usio_irq[index][RX], port);
+	free_irq(usio_irq[index][TX], port);
+}
+
+static void usio_set_termios(struct uart_port *port, struct ktermios *termios,
+			     struct ktermios *old)
+{
+	unsigned int escr, smr = SN_USIO_SMR_SOE;
+	unsigned long flags, baud, quot;
+
+	switch (termios->c_cflag & CSIZE) {
+	case CS5:
+		escr = SN_USIO_ESCR_L_5BIT;
+		break;
+	case CS6:
+		escr = SN_USIO_ESCR_L_6BIT;
+		break;
+	case CS7:
+		escr = SN_USIO_ESCR_L_7BIT;
+		break;
+	case CS8:
+	default:
+		escr = SN_USIO_ESCR_L_8BIT;
+		break;
+	}
+
+	if (termios->c_cflag & CSTOPB)
+		smr |= SN_USIO_SMR_SBL;
+
+	if (termios->c_cflag & PARENB) {
+		escr |= SN_USIO_ESCR_PEN;
+		if (termios->c_cflag & PARODD)
+			escr |= SN_USIO_ESCR_P;
+	}
+	/* Set hard flow control */
+	if (of_property_read_bool(port->dev->of_node, "uart-flow-enable") ||
+			(termios->c_cflag & CRTSCTS))
+		escr |= SN_USIO_ESCR_FLWEN;
+
+	baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk);
+	if (baud > 1)
+		quot = port->uartclk / baud - 1;
+	else
+		quot = 0;
+
+	spin_lock_irqsave(&port->lock, flags);
+	uart_update_timeout(port, termios->c_cflag, baud);
+	port->read_status_mask = SN_USIO_SSR_ORE | SN_USIO_SSR_RDRF |
+				 SN_USIO_SSR_TDRE;
+	if (termios->c_iflag & INPCK)
+		port->read_status_mask |= SN_USIO_SSR_FRE | SN_USIO_SSR_PE;
+
+	port->ignore_status_mask = 0;
+	if (termios->c_iflag & IGNPAR)
+		port->ignore_status_mask |= SN_USIO_SSR_FRE | SN_USIO_SSR_PE;
+	if ((termios->c_iflag & IGNBRK) && (termios->c_iflag & IGNPAR))
+		port->ignore_status_mask |= SN_USIO_SSR_ORE;
+	if ((termios->c_cflag & CREAD) == 0)
+		port->ignore_status_mask |= SN_USIO_SSR_RDRF;
+
+	writeb(0, port->membase + SN_USIO_REG_SCR);
+	writeb(SN_USIO_SCR_UPCL, port->membase + SN_USIO_REG_SCR);
+	writeb(SN_USIO_SSR_REC, port->membase + SN_USIO_REG_SSR);
+	writew(0, port->membase + SN_USIO_REG_FCR);
+	writeb(smr, port->membase + SN_USIO_REG_SMR);
+	writeb(escr, port->membase + SN_USIO_REG_ESCR);
+	writew(quot, port->membase + SN_USIO_REG_BGR);
+	writew(0, port->membase + SN_USIO_REG_FCR);
+	writew(SN_USIO_FCR_FCL1 | SN_USIO_FCR_FCL2 | SN_USIO_FCR_FE1 |
+	       SN_USIO_FCR_FE2 | SN_USIO_FCR_FRIIE,
+	       port->membase + SN_USIO_REG_FCR);
+	writew(0, port->membase + SN_USIO_REG_FBYTE);
+	writew(BIT(12), port->membase + SN_USIO_REG_FBYTE);
+	writeb(SN_USIO_SCR_RIE | SN_USIO_SCR_RXE | SN_USIO_SCR_TBIE |
+	       SN_USIO_SCR_TXE, port->membase + SN_USIO_REG_SCR);
+	spin_unlock_irqrestore(&port->lock, flags);
+}
+
+static const char *usio_type(struct uart_port *port)
+{
+	return ((port->type == PORT_SN_USIO) ? USIO_NAME : NULL);
+}
+
+static void usio_config_port(struct uart_port *port, int flags)
+{
+	if (flags & UART_CONFIG_TYPE)
+		port->type = PORT_SN_USIO;
+}
+
+static const struct uart_ops usio_ops = {
+	.tx_empty	= usio_tx_empty,
+	.set_mctrl	= usio_set_mctrl,
+	.get_mctrl	= usio_get_mctrl,
+	.stop_tx	= usio_stop_tx,
+	.start_tx	= usio_start_tx,
+	.stop_rx	= usio_stop_rx,
+	.enable_ms	= usio_enable_ms,
+	.break_ctl	= usio_break_ctl,
+	.startup	= usio_startup,
+	.shutdown	= usio_shutdown,
+	.set_termios	= usio_set_termios,
+	.type		= usio_type,
+	.config_port	= usio_config_port,
+};
+
+#ifdef CONFIG_SERIAL_M10V_USIO_CONSOLE
+
+static void usio_console_putchar(struct uart_port *port, int c)
+{
+	while (!(readb(port->membase + SN_USIO_REG_SSR) & SN_USIO_SSR_TDRE))
+		cpu_relax();
+
+	writew(c, port->membase + SN_USIO_REG_DR);
+}
+
+static void usio_console_write(struct console *co, const char *s,
+			       unsigned int count)
+{
+	struct uart_port *port = &usio_ports[co->index];
+
+	uart_console_write(port, s, count, usio_console_putchar);
+}
+
+static int __init usio_console_setup(struct console *co, char *options)
+{
+	struct uart_port *port;
+	int baud = 115200;
+	int parity = 'n';
+	int flow = 'n';
+	int bits = 8;
+
+	if (co->index >= CONFIG_SERIAL_M10V_USIO_PORTS)
+		return -ENODEV;
+
+	port = &usio_ports[co->index];
+	if (!port->membase)
+		return -ENODEV;
+
+
+	if (options)
+		uart_parse_options(options, &baud, &parity, &bits, &flow);
+
+	if (of_property_read_bool(port->dev->of_node, "uart-flow-enable"))
+		flow = 'r';
+
+	return uart_set_options(port, co, baud, parity, bits, flow);
+}
+
+
+static struct uart_driver usio_uart_driver;
+static struct console usio_console = {
+	.name   = USIO_UART_DEV_NAME,
+	.write  = usio_console_write,
+	.device = uart_console_device,
+	.setup  = usio_console_setup,
+	.flags  = CON_PRINTBUFFER,
+	.index  = -1,
+	.data   = &usio_uart_driver,
+};
+
+static int __init usio_console_init(void)
+{
+	register_console(&usio_console);
+	return 0;
+}
+console_initcall(usio_console_init);
+
+#define USIO_CONSOLE	(&usio_console)
+#else
+#define USIO_CONSOLE	NULL
+#endif
+
+
+static struct  uart_driver usio_uart_driver = {
+	.owner		= THIS_MODULE,
+	.driver_name	= USIO_NAME,
+	.dev_name	= USIO_UART_DEV_NAME,
+	.cons           = USIO_CONSOLE,
+	.nr		= CONFIG_SERIAL_M10V_USIO_PORTS,
+};
+
+static int usio_probe(struct platform_device *pdev)
+{
+	struct clk *clk = devm_clk_get(&pdev->dev, 0);
+	struct uart_port *port;
+	struct resource *res;
+	int index = 0;
+	int ret;
+
+	if (IS_ERR(clk)) {
+		dev_err(&pdev->dev, "Missing clock\n");
+		return PTR_ERR(clk);
+	}
+	ret = clk_prepare_enable(clk);
+	if (ret) {
+		dev_err(&pdev->dev, "Clock enable failed: %d\n", ret);
+		return ret;
+	}
+	of_property_read_u32(pdev->dev.of_node, "index", &index);
+	port = &usio_ports[index];
+
+	port->private_data = (void *)clk;
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (res == NULL) {
+		dev_err(&pdev->dev, "Missing regs\n");
+		ret = -ENODEV;
+		goto failed;
+	}
+	port->mapbase = res->start;
+	port->membase = ioremap(res->start, (res->end - res->start + 1));
+	port->membase = devm_ioremap(&pdev->dev, res->start,
+				resource_size(res));
+
+	ret = platform_get_irq_byname(pdev, "rx");
+	usio_irq[index][RX] = ret;
+
+	ret = platform_get_irq_byname(pdev, "tx");
+	usio_irq[index][TX] = ret;
+
+	port->irq = usio_irq[index][RX];
+	port->uartclk = clk_get_rate(clk);
+	port->fifosize = 128;
+	port->iotype = UPIO_MEM32;
+	port->flags = UPF_BOOT_AUTOCONF | UPF_SPD_VHI;
+	port->line = index;
+	port->ops = &usio_ops;
+	port->dev = &pdev->dev;
+
+	ret = uart_add_one_port(&usio_uart_driver, port);
+	if (ret) {
+		dev_err(&pdev->dev, "Adding port failed: %d\n", ret);
+		goto failed1;
+	}
+	return 0;
+
+failed1:
+	iounmap(port->membase);
+
+failed:
+	clk_disable_unprepare(clk);
+	clk_put(clk);
+
+	return ret;
+}
+
+static int usio_remove(struct platform_device *pdev)
+{
+	struct uart_port *port = &usio_ports[pdev->id];
+	struct clk *clk = port->private_data;
+
+	uart_remove_one_port(&usio_uart_driver, port);
+	clk_disable_unprepare(clk);
+	clk_put(clk);
+
+	return 0;
+}
+
+#define usio_suspend NULL
+#define usio_resume NULL
+
+static const struct of_device_id m10v_usio_dt_ids[] = {
+	{ .compatible = "socionext,milbeaut-m10v-usio-uart" },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, m10v_usio_dt_ids);
+
+static struct platform_driver usio_driver = {
+	.probe          = usio_probe,
+	.remove         = usio_remove,
+	.suspend        = usio_suspend,
+	.resume         = usio_resume,
+	.driver         = {
+		.name   = USIO_NAME,
+		.of_match_table = m10v_usio_dt_ids,
+	},
+};
+
+static int __init usio_init(void)
+{
+	int ret = uart_register_driver(&usio_uart_driver);
+
+	if (ret) {
+		pr_err("%s: uart registration failed: %d\n", __func__, ret);
+		return ret;
+	}
+	ret = platform_driver_register(&usio_driver);
+	if (ret) {
+		uart_unregister_driver(&usio_uart_driver);
+		pr_err("%s: drv registration failed: %d\n", __func__, ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static void __exit usio_exit(void)
+{
+	platform_driver_unregister(&usio_driver);
+	uart_unregister_driver(&usio_uart_driver);
+}
+
+module_init(usio_init);
+module_exit(usio_exit);
+
+MODULE_AUTHOR("SOCIONEXT");
+MODULE_DESCRIPTION("SN_USIO/UART Driver");
+MODULE_LICENSE("GPL");
+
diff --git a/include/uapi/linux/serial_core.h b/include/uapi/linux/serial_core.h
index dce5f9d..984df0d 100644
--- a/include/uapi/linux/serial_core.h
+++ b/include/uapi/linux/serial_core.h
@@ -281,4 +281,7 @@
 /* MediaTek BTIF */
 #define PORT_MTK_BTIF	117
 
+/* Socionext UART */
+#define PORT_SN_USIO    118
+
 #endif /* _UAPILINUX_SERIAL_CORE_H */
-- 
1.9.1