Message-Id: <1327478704-4233-1-git-send-email-u.kleine-koenig@pengutronix.de>
Date:	Wed, 25 Jan 2012 09:05:04 +0100
From:	Uwe Kleine-König 
	<u.kleine-koenig@...gutronix.de>
To:	Greg KH <greg@...ah.com>
Cc:	linux-kernel@...r.kernel.org, Alan Cox <alan@...ux.intel.com>,
	kernel@...gutronix.de, devicetree-discuss@...ts.ozlabs.org,
	Greg Kroah-Hartman <gregkh@...e.de>,
	linux-serial@...r.kernel.org
Subject: [PATCH v4] serial/efm32: add new driver

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@...gutronix.de>
---
changes since v3 (id:1326127447-20284-1-git-send-email-u.kleine-koenig@...gutronix.de)
 - increase number of ports to support UART additionally to USART ports
 - implement choosing route location
 - implement setting stopbit config
   (before one stop bit was configured and CSTOPB was set unconditionally which
   is wrong. Spotted by Russell King.)
 - implement break, sysrq and overflow detection
 - drop unrelated changing to make patch apply on v3.3-rc1

Hello Greg,

On Tue, Jan 24, 2012 at 02:05:22PM -0800, Greg KH wrote:
> On Mon, Jan 09, 2012 at 05:44:07PM +0100, Uwe Kleine-König wrote:
> > Signed-off-by: Uwe Kleine-König <u.kleine-koenig@...gutronix.de>
> > ---
> > Hello,
> > 
> > changes since v2:
> > - use {read,write}l_relaxed
> > - rename driver to efm32-uart as USARTs and UARTs can be handled both
> >   with it
> > - disable TX in .stop_tx (which needs some changes related to
> >   USARTn_IF_TXC)
> > 
> > Best regards
> > Uwe
> > 
> >  .../devicetree/bindings/tty/serial/efm32-uart.txt  |   14 +
> >  arch/arm/boot/dts/efm32gg-dk3750.dts               |    2 +-
> >  arch/arm/mach-efm32/devices/pdev-efm32-usart.c     |    6 +-
> 
> This file isn't in 3.3-rc1, so I can't apply this patch :(
> 
> What tree is it supposed to be against?
Sorry, I messed this up, it bases on my private development tree. These
two changes should go independant of the driver patch via an ARM tree
(if at all).

I added a few more features in the meantime, so the options are:
 - take v3 simply droping the hunks changing
   arch/arm/boot/dts/efm32gg-dk3750.dts and
   arch/arm/mach-efm32/devices/pdev-efm32-usart.c
 - take this for 3.3
 - take this for 3.4

My preference would be of course the second option, but for me the other two
would be OK if you don't like taking the update that late, too.

Thanks
Uwe

---
 .../devicetree/bindings/tty/serial/efm32-uart.txt  |   14 +
 drivers/tty/serial/Kconfig                         |   13 +
 drivers/tty/serial/Makefile                        |    1 +
 drivers/tty/serial/efm32-uart.c                    |  830 ++++++++++++++++++++
 include/linux/platform_data/efm32-uart.h           |   18 +
 include/linux/serial_core.h                        |    2 +
 6 files changed, 878 insertions(+), 0 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/tty/serial/efm32-uart.txt
 create mode 100644 drivers/tty/serial/efm32-uart.c
 create mode 100644 include/linux/platform_data/efm32-uart.h

diff --git a/Documentation/devicetree/bindings/tty/serial/efm32-uart.txt b/Documentation/devicetree/bindings/tty/serial/efm32-uart.txt
new file mode 100644
index 0000000..6588b69
--- /dev/null
+++ b/Documentation/devicetree/bindings/tty/serial/efm32-uart.txt
@@ -0,0 +1,14 @@
+* Energymicro efm32 UART
+
+Required properties:
+- compatible : Should be "efm32,uart"
+- reg : Address and length of the register set
+- interrupts : Should contain uart interrupt
+
+Example:
+
+uart@...000c400 {
+	compatible = "efm32,uart";
+	reg = <0x4000c400 0x400>;
+	interrupts = <15>;
+};
diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
index aca2386..6e24a8f 100644
--- a/drivers/tty/serial/Kconfig
+++ b/drivers/tty/serial/Kconfig
@@ -1628,4 +1628,17 @@ config SERIAL_AR933X_NR_UARTS
 	  Set this to the number of serial ports you want the driver
 	  to support.
 
+config SERIAL_EFM32_UART
+	tristate "EFM32 UART/USART port."
+	depends on ARCH_EFM32
+	select SERIAL_CORE
+	help
+	  This driver support the USART and UART ports on
+	  Energy Micro's efm32 SoCs.
+
+config SERIAL_EFM32_UART_CONSOLE
+	bool "EFM32 UART/USART console support"
+	depends on SERIAL_EFM32_UART=y
+	select SERIAL_CORE_CONSOLE
+
 endmenu
diff --git a/drivers/tty/serial/Makefile b/drivers/tty/serial/Makefile
index f5b01f2..1997ad4 100644
--- a/drivers/tty/serial/Makefile
+++ b/drivers/tty/serial/Makefile
@@ -92,3 +92,4 @@ obj-$(CONFIG_SERIAL_LANTIQ)	+= lantiq.o
 obj-$(CONFIG_SERIAL_XILINX_PS_UART) += xilinx_uartps.o
 obj-$(CONFIG_SERIAL_SIRFSOC) += sirfsoc_uart.o
 obj-$(CONFIG_SERIAL_AR933X)   += ar933x_uart.o
+obj-$(CONFIG_SERIAL_EFM32_UART) += efm32-uart.o
diff --git a/drivers/tty/serial/efm32-uart.c b/drivers/tty/serial/efm32-uart.c
new file mode 100644
index 0000000..615e464
--- /dev/null
+++ b/drivers/tty/serial/efm32-uart.c
@@ -0,0 +1,830 @@
+#if defined(CONFIG_SERIAL_EFM32_UART_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
+#define SUPPORT_SYSRQ
+#endif
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/io.h>
+#include <linux/platform_device.h>
+#include <linux/console.h>
+#include <linux/sysrq.h>
+#include <linux/serial_core.h>
+#include <linux/tty_flip.h>
+#include <linux/slab.h>
+#include <linux/clk.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+
+#include <linux/platform_data/efm32-uart.h>
+
+#define DRIVER_NAME "efm32-uart"
+#define DEV_NAME "ttyefm"
+
+#define UARTn_CTRL		0x00
+#define UARTn_CTRL_SYNC		0x0001
+#define UARTn_CTRL_TXBIL		0x1000
+
+#define UARTn_FRAME		0x04
+#define UARTn_FRAME_DATABITS__MASK	0x000f
+#define UARTn_FRAME_DATABITS(n)		((n) - 3)
+#define UARTn_FRAME_PARITY_NONE		0x0000
+#define UARTn_FRAME_PARITY_EVEN		0x0200
+#define UARTn_FRAME_PARITY_ODD		0x0300
+#define UARTn_FRAME_STOPBITS_HALF	0x0000
+#define UARTn_FRAME_STOPBITS_ONE	0x1000
+#define UARTn_FRAME_STOPBITS_TWO	0x3000
+
+#define UARTn_CMD		0x0c
+#define UARTn_CMD_RXEN			0x0001
+#define UARTn_CMD_RXDIS		0x0002
+#define UARTn_CMD_TXEN			0x0004
+#define UARTn_CMD_TXDIS		0x0008
+
+#define UARTn_STATUS		0x10
+#define UARTn_STATUS_TXENS		0x0002
+#define UARTn_STATUS_TXC		0x0020
+#define UARTn_STATUS_TXBL		0x0040
+#define UARTn_STATUS_RXDATAV		0x0080
+
+#define UARTn_CLKDIV		0x14
+
+#define UARTn_RXDATAX		0x18
+#define UARTn_RXDATAX_RXDATA__MASK	0x01ff
+#define UARTn_RXDATAX_PERR		0x4000
+#define UARTn_RXDATAX_FERR		0x8000
+/*
+ * This is a software only flag used for ignore_status_mask and
+ * read_status_mask! It's used for breaks that the hardware doesn't report
+ * explicitly.
+ */
+#define SW_UARTn_RXDATAX_BERR		0x2000
+
+#define UARTn_TXDATA		0x34
+
+#define UARTn_IF		0x40
+#define UARTn_IF_TXC			0x0001
+#define UARTn_IF_TXBL			0x0002
+#define UARTn_IF_RXDATAV		0x0004
+#define UARTn_IF_RXOF			0x0010
+
+#define UARTn_IFS		0x44
+#define UARTn_IFC		0x48
+#define UARTn_IEN		0x4c
+
+#define UARTn_ROUTE		0x54
+#define UARTn_ROUTE_LOCATION__MASK	0x0700
+#define UARTn_ROUTE_LOCATION(n)		(((n) << 8) & UARTn_ROUTE_LOCATION__MASK)
+#define UARTn_ROUTE_RXPEN		0x0001
+#define UARTn_ROUTE_TXPEN		0x0002
+
+struct efm32_uart_port {
+	struct uart_port port;
+	unsigned int txirq;
+	struct clk *clk;
+};
+#define to_efm_port(_port) container_of(_port, struct efm32_uart_port, port)
+#define efm_debug(efm_port, format, arg...)			\
+	dev_dbg(efm_port->port.dev, format, ##arg)
+
+static void efm32_uart_write32(struct efm32_uart_port *efm_port,
+		u32 value, unsigned offset)
+{
+	writel_relaxed(value, efm_port->port.membase + offset);
+}
+
+static u32 efm32_uart_read32(struct efm32_uart_port *efm_port,
+		unsigned offset)
+{
+	return readl_relaxed(efm_port->port.membase + offset);
+}
+
+static unsigned int efm32_uart_tx_empty(struct uart_port *port)
+{
+	struct efm32_uart_port *efm_port = to_efm_port(port);
+	u32 status = efm32_uart_read32(efm_port, UARTn_STATUS);
+
+	if (status & UARTn_STATUS_TXC)
+		return TIOCSER_TEMT;
+	else
+		return 0;
+}
+
+static void efm32_uart_set_mctrl(struct uart_port *port, unsigned int mctrl)
+{
+	/* sorry, neither handshaking lines nor loop functionallity */
+}
+
+static unsigned int efm32_uart_get_mctrl(struct uart_port *port)
+{
+	/* sorry, no handshaking lines available */
+	return TIOCM_CAR | TIOCM_CTS | TIOCM_DSR;
+}
+
+static void efm32_uart_stop_tx(struct uart_port *port)
+{
+	struct efm32_uart_port *efm_port = to_efm_port(port);
+	u32 ien = efm32_uart_read32(efm_port,  UARTn_IEN);
+
+	efm32_uart_write32(efm_port, UARTn_CMD_TXDIS, UARTn_CMD);
+	ien &= ~(UARTn_IF_TXC | UARTn_IF_TXBL);
+	efm32_uart_write32(efm_port, ien, UARTn_IEN);
+}
+
+static void efm32_uart_tx_chars(struct efm32_uart_port *efm_port)
+{
+	struct uart_port *port = &efm_port->port;
+	struct circ_buf *xmit = &port->state->xmit;
+
+	while (efm32_uart_read32(efm_port, UARTn_STATUS) &
+			UARTn_STATUS_TXBL) {
+		if (port->x_char) {
+			port->icount.tx++;
+			efm32_uart_write32(efm_port, port->x_char,
+					UARTn_TXDATA);
+			port->x_char = 0;
+			continue;
+		}
+		if (!uart_circ_empty(xmit) && !uart_tx_stopped(port)) {
+			port->icount.tx++;
+			efm32_uart_write32(efm_port, xmit->buf[xmit->tail],
+					UARTn_TXDATA);
+			xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
+		} else
+			break;
+	}
+
+	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
+		uart_write_wakeup(port);
+
+	if (!port->x_char && uart_circ_empty(xmit) &&
+			efm32_uart_read32(efm_port, UARTn_STATUS) &
+				UARTn_STATUS_TXC)
+		efm32_uart_stop_tx(port);
+}
+
+static void efm32_uart_start_tx(struct uart_port *port)
+{
+	struct efm32_uart_port *efm_port = to_efm_port(port);
+	u32 ien;
+
+	efm32_uart_write32(efm_port,
+			UARTn_IF_TXBL | UARTn_IF_TXC, UARTn_IFC);
+	ien = efm32_uart_read32(efm_port, UARTn_IEN);
+	efm32_uart_write32(efm_port,
+			ien | UARTn_IF_TXBL | UARTn_IF_TXC, UARTn_IEN);
+	efm32_uart_write32(efm_port, UARTn_CMD_TXEN, UARTn_CMD);
+
+	efm32_uart_tx_chars(efm_port);
+}
+
+static void efm32_uart_stop_rx(struct uart_port *port)
+{
+	struct efm32_uart_port *efm_port = to_efm_port(port);
+
+	efm32_uart_write32(efm_port, UARTn_CMD_RXDIS, UARTn_CMD);
+}
+
+static void efm32_uart_enable_ms(struct uart_port *port)
+{
+	/* no handshake lines, no modem status interrupts */
+}
+
+static void efm32_uart_break_ctl(struct uart_port *port, int ctl)
+{
+	/* not possible without fiddling with gpios */
+}
+
+static void efm32_uart_rx_chars(struct efm32_uart_port *efm_port,
+		struct tty_struct *tty)
+{
+	struct uart_port *port = &efm_port->port;
+
+	while (efm32_uart_read32(efm_port, UARTn_STATUS) &
+			UARTn_STATUS_RXDATAV) {
+		u32 rxdata = efm32_uart_read32(efm_port, UARTn_RXDATAX);
+		int flag = 0;
+
+		/*
+		 * This is a reserved bit and I only saw it read as 0. But to be
+		 * sure not to be confused too much by new devices adhere to the
+		 * warning in the reference manual that reserverd bits might
+		 * read as 1 in the future.
+		 */
+		rxdata &= ~SW_UARTn_RXDATAX_BERR;
+
+		port->icount.rx++;
+
+		if ((rxdata & UARTn_RXDATAX_FERR) &&
+				!(rxdata & UARTn_RXDATAX_RXDATA__MASK)) {
+			rxdata |= SW_UARTn_RXDATAX_BERR;
+			port->icount.brk++;
+			if (uart_handle_break(port))
+				continue;
+		} else if (rxdata & UARTn_RXDATAX_PERR)
+			port->icount.parity++;
+		else if (rxdata & UARTn_RXDATAX_FERR)
+			port->icount.frame++;
+
+		rxdata &= port->read_status_mask;
+
+		if (rxdata & SW_UARTn_RXDATAX_BERR)
+			flag = TTY_BREAK;
+		else if (rxdata & UARTn_RXDATAX_PERR)
+			flag = TTY_PARITY;
+		else if (rxdata & UARTn_RXDATAX_FERR)
+			flag = TTY_FRAME;
+		else if (uart_handle_sysrq_char(port,
+					rxdata & UARTn_RXDATAX_RXDATA__MASK))
+			continue;
+
+		if (tty && (rxdata & port->ignore_status_mask) == 0)
+			tty_insert_flip_char(tty,
+					rxdata & UARTn_RXDATAX_RXDATA__MASK, flag);
+	}
+}
+
+static irqreturn_t efm32_uart_rxirq(int irq, void *data)
+{
+	struct efm32_uart_port *efm_port = data;
+	u32 irqflag = efm32_uart_read32(efm_port, UARTn_IF);
+	int handled = IRQ_NONE;
+	struct uart_port *port = &efm_port->port;
+	struct tty_struct *tty;
+
+	spin_lock(&port->lock);
+
+	tty = tty_kref_get(port->state->port.tty);
+
+	if (irqflag & UARTn_IF_RXDATAV) {
+		efm32_uart_write32(efm_port, UARTn_IF_RXDATAV, UARTn_IFC);
+		efm32_uart_rx_chars(efm_port, tty);
+
+		handled = IRQ_HANDLED;
+	}
+
+	if (irqflag & UARTn_IF_RXOF) {
+		efm32_uart_write32(efm_port, UARTn_IF_RXOF, UARTn_IFC);
+		port->icount.overrun++;
+		if (tty)
+			tty_insert_flip_char(tty, 0, TTY_OVERRUN);
+
+		handled = IRQ_HANDLED;
+	}
+
+	if (tty) {
+		tty_flip_buffer_push(tty);
+		tty_kref_put(tty);
+	}
+
+	spin_unlock(&port->lock);
+
+	return handled;
+}
+
+static irqreturn_t efm32_uart_txirq(int irq, void *data)
+{
+	struct efm32_uart_port *efm_port = data;
+	u32 irqflag = efm32_uart_read32(efm_port, UARTn_IF);
+
+	/* TXBL doesn't need to be cleared */
+	if (irqflag & UARTn_IF_TXC)
+		efm32_uart_write32(efm_port, UARTn_IF_TXC, UARTn_IFC);
+
+	if (irqflag & (UARTn_IF_TXC | UARTn_IF_TXBL)) {
+		efm32_uart_tx_chars(efm_port);
+		return IRQ_HANDLED;
+	} else
+		return IRQ_NONE;
+}
+
+static int efm32_uart_startup(struct uart_port *port)
+{
+	struct efm32_uart_port *efm_port = to_efm_port(port);
+	u32 location = 0;
+	struct efm32_uart_pdata *pdata = dev_get_platdata(port->dev);
+	int ret;
+
+	if (pdata)
+		location = UARTn_ROUTE_LOCATION(pdata->location);
+
+	ret = clk_enable(efm_port->clk);
+	if (ret) {
+		efm_debug(efm_port, "failed to enable clk\n");
+		goto err_clk_enable;
+	}
+	port->uartclk = clk_get_rate(efm_port->clk);
+
+	/* Enable pins at configured location */
+	efm32_uart_write32(efm_port, location | UARTn_ROUTE_RXPEN | UARTn_ROUTE_TXPEN,
+			UARTn_ROUTE);
+
+	ret = request_irq(port->irq, efm32_uart_rxirq, 0,
+			DRIVER_NAME, efm_port);
+	if (ret) {
+		efm_debug(efm_port, "failed to register rxirq\n");
+		goto err_request_irq_rx;
+	}
+
+	/* disable all irqs */
+	efm32_uart_write32(efm_port, 0, UARTn_IEN);
+
+	ret = request_irq(efm_port->txirq, efm32_uart_txirq, 0,
+			DRIVER_NAME, efm_port);
+	if (ret) {
+		efm_debug(efm_port, "failed to register txirq\n");
+		free_irq(port->irq, efm_port);
+err_request_irq_rx:
+
+		clk_disable(efm_port->clk);
+	} else {
+		efm32_uart_write32(efm_port,
+				UARTn_IF_RXDATAV | UARTn_IF_RXOF, UARTn_IEN);
+		efm32_uart_write32(efm_port, UARTn_CMD_RXEN, UARTn_CMD);
+	}
+
+err_clk_enable:
+	return ret;
+}
+
+static void efm32_uart_shutdown(struct uart_port *port)
+{
+	struct efm32_uart_port *efm_port = to_efm_port(port);
+
+	efm32_uart_write32(efm_port, 0, UARTn_IEN);
+	free_irq(port->irq, efm_port);
+
+	clk_disable(efm_port->clk);
+}
+
+static void efm32_uart_set_termios(struct uart_port *port,
+		struct ktermios *new, struct ktermios *old)
+{
+	struct efm32_uart_port *efm_port = to_efm_port(port);
+	unsigned long flags;
+	unsigned baud;
+	u32 clkdiv;
+	u32 frame = 0;
+
+	/* no modem control lines */
+	new->c_cflag &= ~(CRTSCTS | CMSPAR);
+
+	baud = uart_get_baud_rate(port, new, old,
+			DIV_ROUND_CLOSEST(port->uartclk, 16 * 8192),
+			DIV_ROUND_CLOSEST(port->uartclk, 16));
+
+	switch (new->c_cflag & CSIZE) {
+	case CS5:
+		frame |= UARTn_FRAME_DATABITS(5);
+		break;
+	case CS6:
+		frame |= UARTn_FRAME_DATABITS(6);
+		break;
+	case CS7:
+		frame |= UARTn_FRAME_DATABITS(7);
+		break;
+	case CS8:
+		frame |= UARTn_FRAME_DATABITS(8);
+		break;
+	}
+
+	if (new->c_cflag & CSTOPB)
+		/* the receiver only verifies the first stop bit */
+		frame |= UARTn_FRAME_STOPBITS_TWO;
+	else
+		frame |= UARTn_FRAME_STOPBITS_ONE;
+
+	if (new->c_cflag & PARENB) {
+		if (new->c_cflag & PARODD)
+			frame |= UARTn_FRAME_PARITY_ODD;
+		else
+			frame |= UARTn_FRAME_PARITY_EVEN;
+	} else
+		frame |= UARTn_FRAME_PARITY_NONE;
+
+	/*
+	 * the 6 lowest bits of CLKDIV are dc, bit 6 has value 0.25.
+	 * port->uartclk <= 14e6, so 4 * port->uartclk doesn't overflow.
+	 */
+	clkdiv = (DIV_ROUND_CLOSEST(4 * port->uartclk, 16 * baud) - 4) << 6;
+
+	spin_lock_irqsave(&port->lock, flags);
+
+	efm32_uart_write32(efm_port,
+			UARTn_CMD_TXDIS | UARTn_CMD_RXDIS, UARTn_CMD);
+
+	port->read_status_mask = UARTn_RXDATAX_RXDATA__MASK;
+	if (new->c_iflag & INPCK)
+		port->read_status_mask |=
+			UARTn_RXDATAX_FERR | UARTn_RXDATAX_PERR;
+	if (new->c_iflag & (BRKINT | PARMRK))
+		port->read_status_mask |= SW_UARTn_RXDATAX_BERR;
+
+	port->ignore_status_mask = 0;
+	if (new->c_iflag & IGNPAR)
+		port->ignore_status_mask |=
+			UARTn_RXDATAX_FERR | UARTn_RXDATAX_PERR;
+	if (new->c_iflag & IGNBRK)
+		port->ignore_status_mask |= SW_UARTn_RXDATAX_BERR;
+
+	uart_update_timeout(port, new->c_cflag, baud);
+
+	efm32_uart_write32(efm_port, UARTn_CTRL_TXBIL, UARTn_CTRL);
+	efm32_uart_write32(efm_port, frame, UARTn_FRAME);
+	efm32_uart_write32(efm_port, clkdiv, UARTn_CLKDIV);
+
+	efm32_uart_write32(efm_port, UARTn_CMD_TXEN | UARTn_CMD_RXEN,
+			UARTn_CMD);
+
+	spin_unlock_irqrestore(&port->lock, flags);
+}
+
+static const char *efm32_uart_type(struct uart_port *port)
+{
+	return port->type == PORT_EFMUART ? "efm32-uart" : NULL;
+}
+
+static void efm32_uart_release_port(struct uart_port *port)
+{
+	struct efm32_uart_port *efm_port = to_efm_port(port);
+
+	clk_unprepare(efm_port->clk);
+	clk_put(efm_port->clk);
+	iounmap(port->membase);
+}
+
+static int efm32_uart_request_port(struct uart_port *port)
+{
+	struct efm32_uart_port *efm_port = to_efm_port(port);
+	int ret;
+
+	port->membase = ioremap(port->mapbase, 60);
+	if (!efm_port->port.membase) {
+		ret = -ENOMEM;
+		efm_debug(efm_port, "failed to remap\n");
+		goto err_ioremap;
+	}
+
+	efm_port->clk = clk_get(port->dev, NULL);
+	if (IS_ERR(efm_port->clk)) {
+		ret = PTR_ERR(efm_port->clk);
+		efm_debug(efm_port, "failed to get clock\n");
+		goto err_clk_get;
+	}
+
+	ret = clk_prepare(efm_port->clk);
+	if (ret) {
+		clk_put(efm_port->clk);
+err_clk_get:
+
+		iounmap(port->membase);
+err_ioremap:
+		return ret;
+	}
+	return 0;
+}
+
+static void efm32_uart_config_port(struct uart_port *port, int type)
+{
+	if (type & UART_CONFIG_TYPE &&
+			!efm32_uart_request_port(port))
+		port->type = PORT_EFMUART;
+}
+
+static int efm32_uart_verify_port(struct uart_port *port,
+		struct serial_struct *serinfo)
+{
+	int ret = 0;
+
+	if (serinfo->type != PORT_UNKNOWN && serinfo->type != PORT_EFMUART)
+		ret = -EINVAL;
+
+	return ret;
+}
+
+static struct uart_ops efm32_uart_pops = {
+	.tx_empty = efm32_uart_tx_empty,
+	.set_mctrl = efm32_uart_set_mctrl,
+	.get_mctrl = efm32_uart_get_mctrl,
+	.stop_tx = efm32_uart_stop_tx,
+	.start_tx = efm32_uart_start_tx,
+	.stop_rx = efm32_uart_stop_rx,
+	.enable_ms = efm32_uart_enable_ms,
+	.break_ctl = efm32_uart_break_ctl,
+	.startup = efm32_uart_startup,
+	.shutdown = efm32_uart_shutdown,
+	.set_termios = efm32_uart_set_termios,
+	.type = efm32_uart_type,
+	.release_port = efm32_uart_release_port,
+	.request_port = efm32_uart_request_port,
+	.config_port = efm32_uart_config_port,
+	.verify_port = efm32_uart_verify_port,
+};
+
+static struct efm32_uart_port *efm32_uart_ports[5];
+
+#ifdef CONFIG_SERIAL_EFM32_UART_CONSOLE
+static void efm32_uart_console_putchar(struct uart_port *port, int ch)
+{
+	struct efm32_uart_port *efm_port = to_efm_port(port);
+	unsigned int timeout = 0x400;
+	u32 status;
+
+	while (1) {
+		status = efm32_uart_read32(efm_port, UARTn_STATUS);
+
+		if (status & UARTn_STATUS_TXBL)
+			break;
+		if (!timeout--)
+			return;
+	}
+	efm32_uart_write32(efm_port, ch, UARTn_TXDATA);
+}
+
+static void efm32_uart_console_write(struct console *co, const char *s,
+		unsigned int count)
+{
+	struct efm32_uart_port *efm_port = efm32_uart_ports[co->index];
+	u32 status = efm32_uart_read32(efm_port, UARTn_STATUS);
+	unsigned int timeout = 0x400;
+
+	if (!(status & UARTn_STATUS_TXENS))
+		efm32_uart_write32(efm_port, UARTn_CMD_TXEN, UARTn_CMD);
+
+	uart_console_write(&efm_port->port, s, count,
+			efm32_uart_console_putchar);
+
+	/* Wait for the transmitter to become empty */
+	while (1) {
+		u32 status = efm32_uart_read32(efm_port, UARTn_STATUS);
+		if (status & UARTn_STATUS_TXC)
+			break;
+		if (!timeout--)
+			break;
+	}
+
+	if (!(status & UARTn_STATUS_TXENS))
+		efm32_uart_write32(efm_port, UARTn_CMD_TXDIS, UARTn_CMD);
+}
+
+static void efm32_uart_console_get_options(struct efm32_uart_port *efm_port,
+		int *baud, int *parity, int *bits)
+{
+	u32 ctrl = efm32_uart_read32(efm_port, UARTn_CTRL);
+	u32 route, clkdiv, frame;
+
+	if (ctrl & UARTn_CTRL_SYNC)
+		/* not operating in async mode */
+		return;
+
+	route = efm32_uart_read32(efm_port, UARTn_ROUTE);
+	if (!(route & UARTn_ROUTE_TXPEN))
+		/* tx pin not routed */
+		return;
+
+	clkdiv = efm32_uart_read32(efm_port, UARTn_CLKDIV);
+
+	*baud = DIV_ROUND_CLOSEST(4 * efm_port->port.uartclk,
+			16 * (4 + (clkdiv >> 6)));
+
+	frame = efm32_uart_read32(efm_port, UARTn_FRAME);
+	if (frame & UARTn_FRAME_PARITY_ODD)
+		*parity = 'o';
+	else if (frame & UARTn_FRAME_PARITY_EVEN)
+		*parity = 'e';
+	else
+		*parity = 'n';
+
+	*bits = (frame & UARTn_FRAME_DATABITS__MASK) -
+			UARTn_FRAME_DATABITS(4) + 4;
+
+	efm_debug(efm_port, "get_opts: options=%d%c%d\n",
+			*baud, *parity, *bits);
+}
+
+static int efm32_uart_console_setup(struct console *co, char *options)
+{
+	struct efm32_uart_port *efm_port;
+	int baud = 115200;
+	int bits = 8;
+	int parity = 'n';
+	int flow = 'n';
+	int ret;
+
+	if (co->index < 0 || co->index >= ARRAY_SIZE(efm32_uart_ports)) {
+		unsigned i;
+		for (i = 0; i < ARRAY_SIZE(efm32_uart_ports); ++i) {
+			if (efm32_uart_ports[i]) {
+				pr_warn("efm32-console: fall back to console index %u (from %hhi)\n",
+						i, co->index);
+				co->index = i;
+				break;
+			}
+		}
+	}
+
+	efm_port = efm32_uart_ports[co->index];
+	if (!efm_port) {
+		pr_warn("efm32-console: No port at %d\n", co->index);
+		return -ENODEV;
+	}
+
+	ret = clk_prepare(efm_port->clk);
+	if (ret) {
+		dev_warn(efm_port->port.dev,
+				"console: clk_prepare failed: %d\n", ret);
+		return ret;
+	}
+
+	efm_port->port.uartclk = clk_get_rate(efm_port->clk);
+
+	if (options)
+		uart_parse_options(options, &baud, &parity, &bits, &flow);
+	else
+		efm32_uart_console_get_options(efm_port,
+				&baud, &parity, &bits);
+
+	return uart_set_options(&efm_port->port, co, baud, parity, bits, flow);
+}
+
+static struct uart_driver efm32_uart_reg;
+
+static struct console efm32_uart_console = {
+	.name = DEV_NAME,
+	.write = efm32_uart_console_write,
+	.device = uart_console_device,
+	.setup = efm32_uart_console_setup,
+	.flags = CON_PRINTBUFFER,
+	.index = -1,
+	.data = &efm32_uart_reg,
+};
+
+#else
+#define efm32_uart_console (*(struct console *)NULL)
+#endif /* ifdef CONFIG_SERIAL_EFM32_UART_CONSOLE / else */
+
+static struct uart_driver efm32_uart_reg = {
+	.owner = THIS_MODULE,
+	.driver_name = DRIVER_NAME,
+	.dev_name = DEV_NAME,
+	.nr = ARRAY_SIZE(efm32_uart_ports),
+	.cons = &efm32_uart_console,
+};
+
+static int efm32_uart_probe_dt(struct platform_device *pdev,
+		struct efm32_uart_port *efm_port)
+{
+	struct device_node *np = pdev->dev.of_node;
+	int ret;
+
+	if (!np)
+		return 1;
+
+	ret = of_alias_get_id(np, "serial");
+	if (ret < 0) {
+		dev_err(&pdev->dev, "failed to get alias id: %d\n", ret);
+		return ret;
+	} else {
+		efm_port->port.line = ret;
+		return 0;
+	}
+
+}
+
+static int __devinit efm32_uart_probe(struct platform_device *pdev)
+{
+	struct efm32_uart_port *efm_port;
+	struct resource *res;
+	int ret;
+
+	efm_port = kzalloc(sizeof(*efm_port), GFP_KERNEL);
+	if (!efm_port) {
+		dev_dbg(&pdev->dev, "failed to allocate private data\n");
+		return -ENOMEM;
+	}
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res) {
+		ret = -ENODEV;
+		dev_dbg(&pdev->dev, "failed to determine base address\n");
+		goto err_get_base;
+	}
+
+	if (resource_size(res) < 60) {
+		ret = -EINVAL;
+		dev_dbg(&pdev->dev, "memory resource too small\n");
+		goto err_too_small;
+	}
+
+	ret = platform_get_irq(pdev, 0);
+	if (ret <= 0) {
+		dev_dbg(&pdev->dev, "failed to get rx irq\n");
+		goto err_get_rxirq;
+	}
+
+	efm_port->port.irq = ret;
+
+	ret = platform_get_irq(pdev, 1);
+	if (ret <= 0)
+		ret = efm_port->port.irq + 1;
+
+	efm_port->txirq = ret;
+
+	efm_port->port.dev = &pdev->dev;
+	efm_port->port.mapbase = res->start;
+	efm_port->port.type = PORT_EFMUART;
+	efm_port->port.iotype = UPIO_MEM32;
+	efm_port->port.fifosize = 2;
+	efm_port->port.ops = &efm32_uart_pops;
+	efm_port->port.flags = UPF_BOOT_AUTOCONF;
+
+	ret = efm32_uart_probe_dt(pdev, efm_port);
+	if (ret > 0)
+		/* not created by device tree */
+		efm_port->port.line = pdev->id;
+
+	if (efm_port->port.line >= 0 &&
+			efm_port->port.line < ARRAY_SIZE(efm32_uart_ports))
+		efm32_uart_ports[efm_port->port.line] = efm_port;
+
+	ret = uart_add_one_port(&efm32_uart_reg, &efm_port->port);
+	if (ret) {
+		dev_dbg(&pdev->dev, "failed to add port: %d\n", ret);
+
+		if (pdev->id >= 0 && pdev->id < ARRAY_SIZE(efm32_uart_ports))
+			efm32_uart_ports[pdev->id] = NULL;
+err_get_rxirq:
+err_too_small:
+err_get_base:
+		kfree(efm_port);
+	} else {
+		platform_set_drvdata(pdev, efm_port);
+		dev_dbg(&pdev->dev, "\\o/\n");
+	}
+
+	return ret;
+}
+
+static int __devexit efm32_uart_remove(struct platform_device *pdev)
+{
+	struct efm32_uart_port *efm_port = platform_get_drvdata(pdev);
+
+	platform_set_drvdata(pdev, NULL);
+
+	uart_remove_one_port(&efm32_uart_reg, &efm_port->port);
+
+	if (pdev->id >= 0 && pdev->id < ARRAY_SIZE(efm32_uart_ports))
+		efm32_uart_ports[pdev->id] = NULL;
+
+	kfree(efm_port);
+
+	return 0;
+}
+
+static struct of_device_id efm32_uart_dt_ids[] = {
+	{
+		.compatible = "efm32,uart",
+	}, {
+		/* sentinel */
+	}
+};
+MODULE_DEVICE_TABLE(of, efm32_uart_dt_ids);
+
+static struct platform_driver efm32_uart_driver = {
+	.probe = efm32_uart_probe,
+	.remove = __devexit_p(efm32_uart_remove),
+
+	.driver = {
+		.name = DRIVER_NAME,
+		.owner = THIS_MODULE,
+		.of_match_table = efm32_uart_dt_ids,
+	},
+};
+
+static int __init efm32_uart_init(void)
+{
+	int ret;
+
+	ret = uart_register_driver(&efm32_uart_reg);
+	if (ret)
+		return ret;
+
+	ret = platform_driver_register(&efm32_uart_driver);
+	if (ret)
+		uart_unregister_driver(&efm32_uart_reg);
+
+	pr_info("EFM32 UART/USART driver\n");
+
+	return ret;
+}
+module_init(efm32_uart_init);
+
+static void __exit efm32_uart_exit(void)
+{
+	platform_driver_unregister(&efm32_uart_driver);
+	uart_unregister_driver(&efm32_uart_reg);
+}
+
+MODULE_AUTHOR("Uwe Kleine-Koenig <u.kleine-koenig@...gutronix.de>");
+MODULE_DESCRIPTION("EFM32 UART/USART driver");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:" DRIVER_NAME);
diff --git a/include/linux/platform_data/efm32-uart.h b/include/linux/platform_data/efm32-uart.h
new file mode 100644
index 0000000..ed0e975
--- /dev/null
+++ b/include/linux/platform_data/efm32-uart.h
@@ -0,0 +1,18 @@
+/*
+ *
+ *
+ */
+#ifndef __LINUX_PLATFORM_DATA_EFM32_UART_H__
+#define __LINUX_PLATFORM_DATA_EFM32_UART_H__
+
+#include <linux/types.h>
+
+/**
+ * struct efm32_uart_pdata
+ * @location: pinmux location for the I/O pins (to be written to the ROUTE
+ * 	register)
+ */
+struct efm32_uart_pdata {
+	u8 location;
+};
+#endif /* ifndef __LINUX_PLATFORM_DATA_EFM32_UART_H__ */
diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
index c91ace7..585bfd0 100644
--- a/include/linux/serial_core.h
+++ b/include/linux/serial_core.h
@@ -210,6 +210,8 @@
 /* Atheros AR933X SoC */
 #define PORT_AR933X	99
 
+/* Energy Micro efm32 SoC */
+#define PORT_EFMUART   100
 
 #ifdef __KERNEL__
 
-- 
1.7.8.3

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