Initial import

1 files changed, 1362 insertions, 0 deletions

diff --git a/drivers/tty/serial/mxs-auart.c b/drivers/tty/serial/mxs-auart.c
new file mode 100644
index 000000000..f7e5825b5
--- /dev/null
+++ b/drivers/tty/serial/mxs-auart.c
@@ -0,0 +1,1362 @@
+/*
+ * Freescale STMP37XX/STMP378X Application UART driver
+ *
+ * Author: dmitry pervushin <dimka@embeddedalley.com>
+ *
+ * Copyright 2008-2010 Freescale Semiconductor, Inc.
+ * Copyright 2008 Embedded Alley Solutions, Inc All Rights Reserved.
+ *
+ * The code contained herein is licensed under the GNU General Public
+ * License. You may obtain a copy of the GNU General Public License
+ * Version 2 or later at the following locations:
+ *
+ * http://www.opensource.org/licenses/gpl-license.html
+ * http://www.gnu.org/copyleft/gpl.html
+ */
+
+#if defined(CONFIG_SERIAL_MXS_AUART_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
+#define SUPPORT_SYSRQ
+#endif
+
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/console.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/wait.h>
+#include <linux/tty.h>
+#include <linux/tty_driver.h>
+#include <linux/tty_flip.h>
+#include <linux/serial.h>
+#include <linux/serial_core.h>
+#include <linux/platform_device.h>
+#include <linux/device.h>
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/of_device.h>
+#include <linux/dma-mapping.h>
+#include <linux/dmaengine.h>
+
+#include <asm/cacheflush.h>
+
+#include <linux/gpio.h>
+#include <linux/gpio/consumer.h>
+#include <linux/err.h>
+#include <linux/irq.h>
+#include "serial_mctrl_gpio.h"
+
+#define MXS_AUART_PORTS 5
+#define MXS_AUART_FIFO_SIZE		16
+
+#define AUART_CTRL0			0x00000000
+#define AUART_CTRL0_SET			0x00000004
+#define AUART_CTRL0_CLR			0x00000008
+#define AUART_CTRL0_TOG			0x0000000c
+#define AUART_CTRL1			0x00000010
+#define AUART_CTRL1_SET			0x00000014
+#define AUART_CTRL1_CLR			0x00000018
+#define AUART_CTRL1_TOG			0x0000001c
+#define AUART_CTRL2			0x00000020
+#define AUART_CTRL2_SET			0x00000024
+#define AUART_CTRL2_CLR			0x00000028
+#define AUART_CTRL2_TOG			0x0000002c
+#define AUART_LINECTRL			0x00000030
+#define AUART_LINECTRL_SET		0x00000034
+#define AUART_LINECTRL_CLR		0x00000038
+#define AUART_LINECTRL_TOG		0x0000003c
+#define AUART_LINECTRL2			0x00000040
+#define AUART_LINECTRL2_SET		0x00000044
+#define AUART_LINECTRL2_CLR		0x00000048
+#define AUART_LINECTRL2_TOG		0x0000004c
+#define AUART_INTR			0x00000050
+#define AUART_INTR_SET			0x00000054
+#define AUART_INTR_CLR			0x00000058
+#define AUART_INTR_TOG			0x0000005c
+#define AUART_DATA			0x00000060
+#define AUART_STAT			0x00000070
+#define AUART_DEBUG			0x00000080
+#define AUART_VERSION			0x00000090
+#define AUART_AUTOBAUD			0x000000a0
+
+#define AUART_CTRL0_SFTRST			(1 << 31)
+#define AUART_CTRL0_CLKGATE			(1 << 30)
+#define AUART_CTRL0_RXTO_ENABLE			(1 << 27)
+#define AUART_CTRL0_RXTIMEOUT(v)		(((v) & 0x7ff) << 16)
+#define AUART_CTRL0_XFER_COUNT(v)		((v) & 0xffff)
+
+#define AUART_CTRL1_XFER_COUNT(v)		((v) & 0xffff)
+
+#define AUART_CTRL2_DMAONERR			(1 << 26)
+#define AUART_CTRL2_TXDMAE			(1 << 25)
+#define AUART_CTRL2_RXDMAE			(1 << 24)
+
+#define AUART_CTRL2_CTSEN			(1 << 15)
+#define AUART_CTRL2_RTSEN			(1 << 14)
+#define AUART_CTRL2_RTS				(1 << 11)
+#define AUART_CTRL2_RXE				(1 << 9)
+#define AUART_CTRL2_TXE				(1 << 8)
+#define AUART_CTRL2_UARTEN			(1 << 0)
+
+#define AUART_LINECTRL_BAUD_DIVINT_SHIFT	16
+#define AUART_LINECTRL_BAUD_DIVINT_MASK		0xffff0000
+#define AUART_LINECTRL_BAUD_DIVINT(v)		(((v) & 0xffff) << 16)
+#define AUART_LINECTRL_BAUD_DIVFRAC_SHIFT	8
+#define AUART_LINECTRL_BAUD_DIVFRAC_MASK	0x00003f00
+#define AUART_LINECTRL_BAUD_DIVFRAC(v)		(((v) & 0x3f) << 8)
+#define AUART_LINECTRL_WLEN_MASK		0x00000060
+#define AUART_LINECTRL_WLEN(v)			(((v) & 0x3) << 5)
+#define AUART_LINECTRL_FEN			(1 << 4)
+#define AUART_LINECTRL_STP2			(1 << 3)
+#define AUART_LINECTRL_EPS			(1 << 2)
+#define AUART_LINECTRL_PEN			(1 << 1)
+#define AUART_LINECTRL_BRK			(1 << 0)
+
+#define AUART_INTR_RTIEN			(1 << 22)
+#define AUART_INTR_TXIEN			(1 << 21)
+#define AUART_INTR_RXIEN			(1 << 20)
+#define AUART_INTR_CTSMIEN			(1 << 17)
+#define AUART_INTR_RTIS				(1 << 6)
+#define AUART_INTR_TXIS				(1 << 5)
+#define AUART_INTR_RXIS				(1 << 4)
+#define AUART_INTR_CTSMIS			(1 << 1)
+
+#define AUART_STAT_BUSY				(1 << 29)
+#define AUART_STAT_CTS				(1 << 28)
+#define AUART_STAT_TXFE				(1 << 27)
+#define AUART_STAT_TXFF				(1 << 25)
+#define AUART_STAT_RXFE				(1 << 24)
+#define AUART_STAT_OERR				(1 << 19)
+#define AUART_STAT_BERR				(1 << 18)
+#define AUART_STAT_PERR				(1 << 17)
+#define AUART_STAT_FERR				(1 << 16)
+#define AUART_STAT_RXCOUNT_MASK			0xffff
+
+static struct uart_driver auart_driver;
+
+enum mxs_auart_type {
+	IMX23_AUART,
+	IMX28_AUART,
+};
+
+struct mxs_auart_port {
+	struct uart_port port;
+
+#define MXS_AUART_DMA_ENABLED	0x2
+#define MXS_AUART_DMA_TX_SYNC	2  /* bit 2 */
+#define MXS_AUART_DMA_RX_READY	3  /* bit 3 */
+#define MXS_AUART_RTSCTS	4  /* bit 4 */
+	unsigned long flags;
+	unsigned int mctrl_prev;
+	enum mxs_auart_type devtype;
+
+	struct clk *clk;
+	struct device *dev;
+
+	/* for DMA */
+	struct scatterlist tx_sgl;
+	struct dma_chan	*tx_dma_chan;
+	void *tx_dma_buf;
+
+	struct scatterlist rx_sgl;
+	struct dma_chan	*rx_dma_chan;
+	void *rx_dma_buf;
+
+	struct mctrl_gpios	*gpios;
+	int			gpio_irq[UART_GPIO_MAX];
+	bool			ms_irq_enabled;
+};
+
+static struct platform_device_id mxs_auart_devtype[] = {
+	{ .name = "mxs-auart-imx23", .driver_data = IMX23_AUART },
+	{ .name = "mxs-auart-imx28", .driver_data = IMX28_AUART },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(platform, mxs_auart_devtype);
+
+static const struct of_device_id mxs_auart_dt_ids[] = {
+	{
+		.compatible = "fsl,imx28-auart",
+		.data = &mxs_auart_devtype[IMX28_AUART]
+	}, {
+		.compatible = "fsl,imx23-auart",
+		.data = &mxs_auart_devtype[IMX23_AUART]
+	}, { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, mxs_auart_dt_ids);
+
+static inline int is_imx28_auart(struct mxs_auart_port *s)
+{
+	return s->devtype == IMX28_AUART;
+}
+
+static inline bool auart_dma_enabled(struct mxs_auart_port *s)
+{
+	return s->flags & MXS_AUART_DMA_ENABLED;
+}
+
+static void mxs_auart_stop_tx(struct uart_port *u);
+
+#define to_auart_port(u) container_of(u, struct mxs_auart_port, port)
+
+static void mxs_auart_tx_chars(struct mxs_auart_port *s);
+
+static void dma_tx_callback(void *param)
+{
+	struct mxs_auart_port *s = param;
+	struct circ_buf *xmit = &s->port.state->xmit;
+
+	dma_unmap_sg(s->dev, &s->tx_sgl, 1, DMA_TO_DEVICE);
+
+	/* clear the bit used to serialize the DMA tx. */
+	clear_bit(MXS_AUART_DMA_TX_SYNC, &s->flags);
+	smp_mb__after_atomic();
+
+	/* wake up the possible processes. */
+	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
+		uart_write_wakeup(&s->port);
+
+	mxs_auart_tx_chars(s);
+}
+
+static int mxs_auart_dma_tx(struct mxs_auart_port *s, int size)
+{
+	struct dma_async_tx_descriptor *desc;
+	struct scatterlist *sgl = &s->tx_sgl;
+	struct dma_chan *channel = s->tx_dma_chan;
+	u32 pio;
+
+	/* [1] : send PIO. Note, the first pio word is CTRL1. */
+	pio = AUART_CTRL1_XFER_COUNT(size);
+	desc = dmaengine_prep_slave_sg(channel, (struct scatterlist *)&pio,
+					1, DMA_TRANS_NONE, 0);
+	if (!desc) {
+		dev_err(s->dev, "step 1 error\n");
+		return -EINVAL;
+	}
+
+	/* [2] : set DMA buffer. */
+	sg_init_one(sgl, s->tx_dma_buf, size);
+	dma_map_sg(s->dev, sgl, 1, DMA_TO_DEVICE);
+	desc = dmaengine_prep_slave_sg(channel, sgl,
+			1, DMA_MEM_TO_DEV, DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
+	if (!desc) {
+		dev_err(s->dev, "step 2 error\n");
+		return -EINVAL;
+	}
+
+	/* [3] : submit the DMA */
+	desc->callback = dma_tx_callback;
+	desc->callback_param = s;
+	dmaengine_submit(desc);
+	dma_async_issue_pending(channel);
+	return 0;
+}
+
+static void mxs_auart_tx_chars(struct mxs_auart_port *s)
+{
+	struct circ_buf *xmit = &s->port.state->xmit;
+
+	if (auart_dma_enabled(s)) {
+		u32 i = 0;
+		int size;
+		void *buffer = s->tx_dma_buf;
+
+		if (test_and_set_bit(MXS_AUART_DMA_TX_SYNC, &s->flags))
+			return;
+
+		while (!uart_circ_empty(xmit) && !uart_tx_stopped(&s->port)) {
+			size = min_t(u32, UART_XMIT_SIZE - i,
+				     CIRC_CNT_TO_END(xmit->head,
+						     xmit->tail,
+						     UART_XMIT_SIZE));
+			memcpy(buffer + i, xmit->buf + xmit->tail, size);
+			xmit->tail = (xmit->tail + size) & (UART_XMIT_SIZE - 1);
+
+			i += size;
+			if (i >= UART_XMIT_SIZE)
+				break;
+		}
+
+		if (uart_tx_stopped(&s->port))
+			mxs_auart_stop_tx(&s->port);
+
+		if (i) {
+			mxs_auart_dma_tx(s, i);
+		} else {
+			clear_bit(MXS_AUART_DMA_TX_SYNC, &s->flags);
+			smp_mb__after_atomic();
+		}
+		return;
+	}
+
+
+	while (!(readl(s->port.membase + AUART_STAT) &
+		 AUART_STAT_TXFF)) {
+		if (s->port.x_char) {
+			s->port.icount.tx++;
+			writel(s->port.x_char,
+				     s->port.membase + AUART_DATA);
+			s->port.x_char = 0;
+			continue;
+		}
+		if (!uart_circ_empty(xmit) && !uart_tx_stopped(&s->port)) {
+			s->port.icount.tx++;
+			writel(xmit->buf[xmit->tail],
+				     s->port.membase + AUART_DATA);
+			xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
+		} else
+			break;
+	}
+	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
+		uart_write_wakeup(&s->port);
+
+	if (uart_circ_empty(&(s->port.state->xmit)))
+		writel(AUART_INTR_TXIEN,
+			     s->port.membase + AUART_INTR_CLR);
+	else
+		writel(AUART_INTR_TXIEN,
+			     s->port.membase + AUART_INTR_SET);
+
+	if (uart_tx_stopped(&s->port))
+		mxs_auart_stop_tx(&s->port);
+}
+
+static void mxs_auart_rx_char(struct mxs_auart_port *s)
+{
+	int flag;
+	u32 stat;
+	u8 c;
+
+	c = readl(s->port.membase + AUART_DATA);
+	stat = readl(s->port.membase + AUART_STAT);
+
+	flag = TTY_NORMAL;
+	s->port.icount.rx++;
+
+	if (stat & AUART_STAT_BERR) {
+		s->port.icount.brk++;
+		if (uart_handle_break(&s->port))
+			goto out;
+	} else if (stat & AUART_STAT_PERR) {
+		s->port.icount.parity++;
+	} else if (stat & AUART_STAT_FERR) {
+		s->port.icount.frame++;
+	}
+
+	/*
+	 * Mask off conditions which should be ingored.
+	 */
+	stat &= s->port.read_status_mask;
+
+	if (stat & AUART_STAT_BERR) {
+		flag = TTY_BREAK;
+	} else if (stat & AUART_STAT_PERR)
+		flag = TTY_PARITY;
+	else if (stat & AUART_STAT_FERR)
+		flag = TTY_FRAME;
+
+	if (stat & AUART_STAT_OERR)
+		s->port.icount.overrun++;
+
+	if (uart_handle_sysrq_char(&s->port, c))
+		goto out;
+
+	uart_insert_char(&s->port, stat, AUART_STAT_OERR, c, flag);
+out:
+	writel(stat, s->port.membase + AUART_STAT);
+}
+
+static void mxs_auart_rx_chars(struct mxs_auart_port *s)
+{
+	u32 stat = 0;
+
+	for (;;) {
+		stat = readl(s->port.membase + AUART_STAT);
+		if (stat & AUART_STAT_RXFE)
+			break;
+		mxs_auart_rx_char(s);
+	}
+
+	writel(stat, s->port.membase + AUART_STAT);
+	tty_flip_buffer_push(&s->port.state->port);
+}
+
+static int mxs_auart_request_port(struct uart_port *u)
+{
+	return 0;
+}
+
+static int mxs_auart_verify_port(struct uart_port *u,
+				    struct serial_struct *ser)
+{
+	if (u->type != PORT_UNKNOWN && u->type != PORT_IMX)
+		return -EINVAL;
+	return 0;
+}
+
+static void mxs_auart_config_port(struct uart_port *u, int flags)
+{
+}
+
+static const char *mxs_auart_type(struct uart_port *u)
+{
+	struct mxs_auart_port *s = to_auart_port(u);
+
+	return dev_name(s->dev);
+}
+
+static void mxs_auart_release_port(struct uart_port *u)
+{
+}
+
+static void mxs_auart_set_mctrl(struct uart_port *u, unsigned mctrl)
+{
+	struct mxs_auart_port *s = to_auart_port(u);
+
+	u32 ctrl = readl(u->membase + AUART_CTRL2);
+
+	ctrl &= ~(AUART_CTRL2_RTSEN | AUART_CTRL2_RTS);
+	if (mctrl & TIOCM_RTS) {
+		if (uart_cts_enabled(u))
+			ctrl |= AUART_CTRL2_RTSEN;
+		else
+			ctrl |= AUART_CTRL2_RTS;
+	}
+
+	writel(ctrl, u->membase + AUART_CTRL2);
+
+	mctrl_gpio_set(s->gpios, mctrl);
+}
+
+#define MCTRL_ANY_DELTA        (TIOCM_RI | TIOCM_DSR | TIOCM_CD | TIOCM_CTS)
+static u32 mxs_auart_modem_status(struct mxs_auart_port *s, u32 mctrl)
+{
+	u32 mctrl_diff;
+
+	mctrl_diff = mctrl ^ s->mctrl_prev;
+	s->mctrl_prev = mctrl;
+	if (mctrl_diff & MCTRL_ANY_DELTA && s->ms_irq_enabled &&
+						s->port.state != NULL) {
+		if (mctrl_diff & TIOCM_RI)
+			s->port.icount.rng++;
+		if (mctrl_diff & TIOCM_DSR)
+			s->port.icount.dsr++;
+		if (mctrl_diff & TIOCM_CD)
+			uart_handle_dcd_change(&s->port, mctrl & TIOCM_CD);
+		if (mctrl_diff & TIOCM_CTS)
+			uart_handle_cts_change(&s->port, mctrl & TIOCM_CTS);
+
+		wake_up_interruptible(&s->port.state->port.delta_msr_wait);
+	}
+	return mctrl;
+}
+
+static u32 mxs_auart_get_mctrl(struct uart_port *u)
+{
+	struct mxs_auart_port *s = to_auart_port(u);
+	u32 stat = readl(u->membase + AUART_STAT);
+	u32 mctrl = 0;
+
+	if (stat & AUART_STAT_CTS)
+		mctrl |= TIOCM_CTS;
+
+	return mctrl_gpio_get(s->gpios, &mctrl);
+}
+
+/*
+ * Enable modem status interrupts
+ */
+static void mxs_auart_enable_ms(struct uart_port *port)
+{
+	struct mxs_auart_port *s = to_auart_port(port);
+
+	/*
+	 * Interrupt should not be enabled twice
+	 */
+	if (s->ms_irq_enabled)
+		return;
+
+	s->ms_irq_enabled = true;
+
+	if (s->gpio_irq[UART_GPIO_CTS] >= 0)
+		enable_irq(s->gpio_irq[UART_GPIO_CTS]);
+	/* TODO: enable AUART_INTR_CTSMIEN otherwise */
+
+	if (s->gpio_irq[UART_GPIO_DSR] >= 0)
+		enable_irq(s->gpio_irq[UART_GPIO_DSR]);
+
+	if (s->gpio_irq[UART_GPIO_RI] >= 0)
+		enable_irq(s->gpio_irq[UART_GPIO_RI]);
+
+	if (s->gpio_irq[UART_GPIO_DCD] >= 0)
+		enable_irq(s->gpio_irq[UART_GPIO_DCD]);
+}
+
+/*
+ * Disable modem status interrupts
+ */
+static void mxs_auart_disable_ms(struct uart_port *port)
+{
+	struct mxs_auart_port *s = to_auart_port(port);
+
+	/*
+	 * Interrupt should not be disabled twice
+	 */
+	if (!s->ms_irq_enabled)
+		return;
+
+	s->ms_irq_enabled = false;
+
+	if (s->gpio_irq[UART_GPIO_CTS] >= 0)
+		disable_irq(s->gpio_irq[UART_GPIO_CTS]);
+	/* TODO: disable AUART_INTR_CTSMIEN otherwise */
+
+	if (s->gpio_irq[UART_GPIO_DSR] >= 0)
+		disable_irq(s->gpio_irq[UART_GPIO_DSR]);
+
+	if (s->gpio_irq[UART_GPIO_RI] >= 0)
+		disable_irq(s->gpio_irq[UART_GPIO_RI]);
+
+	if (s->gpio_irq[UART_GPIO_DCD] >= 0)
+		disable_irq(s->gpio_irq[UART_GPIO_DCD]);
+}
+
+static int mxs_auart_dma_prep_rx(struct mxs_auart_port *s);
+static void dma_rx_callback(void *arg)
+{
+	struct mxs_auart_port *s = (struct mxs_auart_port *) arg;
+	struct tty_port *port = &s->port.state->port;
+	int count;
+	u32 stat;
+
+	dma_unmap_sg(s->dev, &s->rx_sgl, 1, DMA_FROM_DEVICE);
+
+	stat = readl(s->port.membase + AUART_STAT);
+	stat &= ~(AUART_STAT_OERR | AUART_STAT_BERR |
+			AUART_STAT_PERR | AUART_STAT_FERR);
+
+	count = stat & AUART_STAT_RXCOUNT_MASK;
+	tty_insert_flip_string(port, s->rx_dma_buf, count);
+
+	writel(stat, s->port.membase + AUART_STAT);
+	tty_flip_buffer_push(port);
+
+	/* start the next DMA for RX. */
+	mxs_auart_dma_prep_rx(s);
+}
+
+static int mxs_auart_dma_prep_rx(struct mxs_auart_port *s)
+{
+	struct dma_async_tx_descriptor *desc;
+	struct scatterlist *sgl = &s->rx_sgl;
+	struct dma_chan *channel = s->rx_dma_chan;
+	u32 pio[1];
+
+	/* [1] : send PIO */
+	pio[0] = AUART_CTRL0_RXTO_ENABLE
+		| AUART_CTRL0_RXTIMEOUT(0x80)
+		| AUART_CTRL0_XFER_COUNT(UART_XMIT_SIZE);
+	desc = dmaengine_prep_slave_sg(channel, (struct scatterlist *)pio,
+					1, DMA_TRANS_NONE, 0);
+	if (!desc) {
+		dev_err(s->dev, "step 1 error\n");
+		return -EINVAL;
+	}
+
+	/* [2] : send DMA request */
+	sg_init_one(sgl, s->rx_dma_buf, UART_XMIT_SIZE);
+	dma_map_sg(s->dev, sgl, 1, DMA_FROM_DEVICE);
+	desc = dmaengine_prep_slave_sg(channel, sgl, 1, DMA_DEV_TO_MEM,
+					DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
+	if (!desc) {
+		dev_err(s->dev, "step 2 error\n");
+		return -1;
+	}
+
+	/* [3] : submit the DMA, but do not issue it. */
+	desc->callback = dma_rx_callback;
+	desc->callback_param = s;
+	dmaengine_submit(desc);
+	dma_async_issue_pending(channel);
+	return 0;
+}
+
+static void mxs_auart_dma_exit_channel(struct mxs_auart_port *s)
+{
+	if (s->tx_dma_chan) {
+		dma_release_channel(s->tx_dma_chan);
+		s->tx_dma_chan = NULL;
+	}
+	if (s->rx_dma_chan) {
+		dma_release_channel(s->rx_dma_chan);
+		s->rx_dma_chan = NULL;
+	}
+
+	kfree(s->tx_dma_buf);
+	kfree(s->rx_dma_buf);
+	s->tx_dma_buf = NULL;
+	s->rx_dma_buf = NULL;
+}
+
+static void mxs_auart_dma_exit(struct mxs_auart_port *s)
+{
+
+	writel(AUART_CTRL2_TXDMAE | AUART_CTRL2_RXDMAE | AUART_CTRL2_DMAONERR,
+		s->port.membase + AUART_CTRL2_CLR);
+
+	mxs_auart_dma_exit_channel(s);
+	s->flags &= ~MXS_AUART_DMA_ENABLED;
+	clear_bit(MXS_AUART_DMA_TX_SYNC, &s->flags);
+	clear_bit(MXS_AUART_DMA_RX_READY, &s->flags);
+}
+
+static int mxs_auart_dma_init(struct mxs_auart_port *s)
+{
+	if (auart_dma_enabled(s))
+		return 0;
+
+	/* init for RX */
+	s->rx_dma_chan = dma_request_slave_channel(s->dev, "rx");
+	if (!s->rx_dma_chan)
+		goto err_out;
+	s->rx_dma_buf = kzalloc(UART_XMIT_SIZE, GFP_KERNEL | GFP_DMA);
+	if (!s->rx_dma_buf)
+		goto err_out;
+
+	/* init for TX */
+	s->tx_dma_chan = dma_request_slave_channel(s->dev, "tx");
+	if (!s->tx_dma_chan)
+		goto err_out;
+	s->tx_dma_buf = kzalloc(UART_XMIT_SIZE, GFP_KERNEL | GFP_DMA);
+	if (!s->tx_dma_buf)
+		goto err_out;
+
+	/* set the flags */
+	s->flags |= MXS_AUART_DMA_ENABLED;
+	dev_dbg(s->dev, "enabled the DMA support.");
+
+	/* The DMA buffer is now the FIFO the TTY subsystem can use */
+	s->port.fifosize = UART_XMIT_SIZE;
+
+	return 0;
+
+err_out:
+	mxs_auart_dma_exit_channel(s);
+	return -EINVAL;
+
+}
+
+#define RTS_AT_AUART()	IS_ERR_OR_NULL(mctrl_gpio_to_gpiod(s->gpios,	\
+							UART_GPIO_RTS))
+#define CTS_AT_AUART()	IS_ERR_OR_NULL(mctrl_gpio_to_gpiod(s->gpios,	\
+							UART_GPIO_CTS))
+static void mxs_auart_settermios(struct uart_port *u,
+				 struct ktermios *termios,
+				 struct ktermios *old)
+{
+	struct mxs_auart_port *s = to_auart_port(u);
+	u32 bm, ctrl, ctrl2, div;
+	unsigned int cflag, baud;
+
+	cflag = termios->c_cflag;
+
+	ctrl = AUART_LINECTRL_FEN;
+	ctrl2 = readl(u->membase + AUART_CTRL2);
+
+	/* byte size */
+	switch (cflag & CSIZE) {
+	case CS5:
+		bm = 0;
+		break;
+	case CS6:
+		bm = 1;
+		break;
+	case CS7:
+		bm = 2;
+		break;
+	case CS8:
+		bm = 3;
+		break;
+	default:
+		return;
+	}
+
+	ctrl |= AUART_LINECTRL_WLEN(bm);
+
+	/* parity */
+	if (cflag & PARENB) {
+		ctrl |= AUART_LINECTRL_PEN;
+		if ((cflag & PARODD) == 0)
+			ctrl |= AUART_LINECTRL_EPS;
+	}
+
+	u->read_status_mask = 0;
+
+	if (termios->c_iflag & INPCK)
+		u->read_status_mask |= AUART_STAT_PERR;
+	if (termios->c_iflag & (IGNBRK | BRKINT | PARMRK))
+		u->read_status_mask |= AUART_STAT_BERR;
+
+	/*
+	 * Characters to ignore
+	 */
+	u->ignore_status_mask = 0;
+	if (termios->c_iflag & IGNPAR)
+		u->ignore_status_mask |= AUART_STAT_PERR;
+	if (termios->c_iflag & IGNBRK) {
+		u->ignore_status_mask |= AUART_STAT_BERR;
+		/*
+		 * If we're ignoring parity and break indicators,
+		 * ignore overruns too (for real raw support).
+		 */
+		if (termios->c_iflag & IGNPAR)
+			u->ignore_status_mask |= AUART_STAT_OERR;
+	}
+
+	/*
+	 * ignore all characters if CREAD is not set
+	 */
+	if (cflag & CREAD)
+		ctrl2 |= AUART_CTRL2_RXE;
+	else
+		ctrl2 &= ~AUART_CTRL2_RXE;
+
+	/* figure out the stop bits requested */
+	if (cflag & CSTOPB)
+		ctrl |= AUART_LINECTRL_STP2;
+
+	/* figure out the hardware flow control settings */
+	ctrl2 &= ~(AUART_CTRL2_CTSEN | AUART_CTRL2_RTSEN);
+	if (cflag & CRTSCTS) {
+		/*
+		 * The DMA has a bug(see errata:2836) in mx23.
+		 * So we can not implement the DMA for auart in mx23,
+		 * we can only implement the DMA support for auart
+		 * in mx28.
+		 */
+		if (is_imx28_auart(s)
+				&& test_bit(MXS_AUART_RTSCTS, &s->flags)) {
+			if (!mxs_auart_dma_init(s))
+				/* enable DMA tranfer */
+				ctrl2 |= AUART_CTRL2_TXDMAE | AUART_CTRL2_RXDMAE
+				       | AUART_CTRL2_DMAONERR;
+		}
+		/* Even if RTS is GPIO line RTSEN can be enabled because
+		 * the pinctrl configuration decides about RTS pin function */
+		ctrl2 |= AUART_CTRL2_RTSEN;
+		if (CTS_AT_AUART())
+			ctrl2 |= AUART_CTRL2_CTSEN;
+	}
+
+	/* set baud rate */
+	baud = uart_get_baud_rate(u, termios, old, 0, u->uartclk);
+	div = u->uartclk * 32 / baud;
+	ctrl |= AUART_LINECTRL_BAUD_DIVFRAC(div & 0x3F);
+	ctrl |= AUART_LINECTRL_BAUD_DIVINT(div >> 6);
+
+	writel(ctrl, u->membase + AUART_LINECTRL);
+	writel(ctrl2, u->membase + AUART_CTRL2);
+
+	uart_update_timeout(u, termios->c_cflag, baud);
+
+	/* prepare for the DMA RX. */
+	if (auart_dma_enabled(s) &&
+		!test_and_set_bit(MXS_AUART_DMA_RX_READY, &s->flags)) {
+		if (!mxs_auart_dma_prep_rx(s)) {
+			/* Disable the normal RX interrupt. */
+			writel(AUART_INTR_RXIEN | AUART_INTR_RTIEN,
+					u->membase + AUART_INTR_CLR);
+		} else {
+			mxs_auart_dma_exit(s);
+			dev_err(s->dev, "We can not start up the DMA.\n");
+		}
+	}
+
+	/* CTS flow-control and modem-status interrupts */
+	if (UART_ENABLE_MS(u, termios->c_cflag))
+		mxs_auart_enable_ms(u);
+	else
+		mxs_auart_disable_ms(u);
+}
+
+static void mxs_auart_set_ldisc(struct uart_port *port,
+				struct ktermios *termios)
+{
+	if (termios->c_line == N_PPS) {
+		port->flags |= UPF_HARDPPS_CD;
+		mxs_auart_enable_ms(port);
+	} else {
+		port->flags &= ~UPF_HARDPPS_CD;
+	}
+}
+
+static irqreturn_t mxs_auart_irq_handle(int irq, void *context)
+{
+	u32 istat;
+	struct mxs_auart_port *s = context;
+	u32 mctrl_temp = s->mctrl_prev;
+	u32 stat = readl(s->port.membase + AUART_STAT);
+
+	istat = readl(s->port.membase + AUART_INTR);
+
+	/* ack irq */
+	writel(istat & (AUART_INTR_RTIS
+		| AUART_INTR_TXIS
+		| AUART_INTR_RXIS
+		| AUART_INTR_CTSMIS),
+			s->port.membase + AUART_INTR_CLR);
+
+	/*
+	 * Dealing with GPIO interrupt
+	 */
+	if (irq == s->gpio_irq[UART_GPIO_CTS] ||
+	    irq == s->gpio_irq[UART_GPIO_DCD] ||
+	    irq == s->gpio_irq[UART_GPIO_DSR] ||
+	    irq == s->gpio_irq[UART_GPIO_RI])
+		mxs_auart_modem_status(s,
+				mctrl_gpio_get(s->gpios, &mctrl_temp));
+
+	if (istat & AUART_INTR_CTSMIS) {
+		if (CTS_AT_AUART() && s->ms_irq_enabled)
+			uart_handle_cts_change(&s->port,
+					stat & AUART_STAT_CTS);
+		writel(AUART_INTR_CTSMIS,
+				s->port.membase + AUART_INTR_CLR);
+		istat &= ~AUART_INTR_CTSMIS;
+	}
+
+	if (istat & (AUART_INTR_RTIS | AUART_INTR_RXIS)) {
+		if (!auart_dma_enabled(s))
+			mxs_auart_rx_chars(s);
+		istat &= ~(AUART_INTR_RTIS | AUART_INTR_RXIS);
+	}
+
+	if (istat & AUART_INTR_TXIS) {
+		mxs_auart_tx_chars(s);
+		istat &= ~AUART_INTR_TXIS;
+	}
+
+	return IRQ_HANDLED;
+}
+
+static void mxs_auart_reset(struct uart_port *u)
+{
+	int i;
+	unsigned int reg;
+
+	writel(AUART_CTRL0_SFTRST, u->membase + AUART_CTRL0_CLR);
+
+	for (i = 0; i < 10000; i++) {
+		reg = readl(u->membase + AUART_CTRL0);
+		if (!(reg & AUART_CTRL0_SFTRST))
+			break;
+		udelay(3);
+	}
+	writel(AUART_CTRL0_CLKGATE, u->membase + AUART_CTRL0_CLR);
+}
+
+static int mxs_auart_startup(struct uart_port *u)
+{
+	int ret;
+	struct mxs_auart_port *s = to_auart_port(u);
+
+	ret = clk_prepare_enable(s->clk);
+	if (ret)
+		return ret;
+
+	writel(AUART_CTRL0_CLKGATE, u->membase + AUART_CTRL0_CLR);
+
+	writel(AUART_CTRL2_UARTEN, u->membase + AUART_CTRL2_SET);
+
+	writel(AUART_INTR_RXIEN | AUART_INTR_RTIEN | AUART_INTR_CTSMIEN,
+			u->membase + AUART_INTR);
+
+	/* Reset FIFO size (it could have changed if DMA was enabled) */
+	u->fifosize = MXS_AUART_FIFO_SIZE;
+
+	/*
+	 * Enable fifo so all four bytes of a DMA word are written to
+	 * output (otherwise, only the LSB is written, ie. 1 in 4 bytes)
+	 */
+	writel(AUART_LINECTRL_FEN, u->membase + AUART_LINECTRL_SET);
+
+	/* get initial status of modem lines */
+	mctrl_gpio_get(s->gpios, &s->mctrl_prev);
+
+	s->ms_irq_enabled = false;
+	return 0;
+}
+
+static void mxs_auart_shutdown(struct uart_port *u)
+{
+	struct mxs_auart_port *s = to_auart_port(u);
+
+	mxs_auart_disable_ms(u);
+
+	if (auart_dma_enabled(s))
+		mxs_auart_dma_exit(s);
+
+	writel(AUART_CTRL2_UARTEN, u->membase + AUART_CTRL2_CLR);
+
+	writel(AUART_INTR_RXIEN | AUART_INTR_RTIEN | AUART_INTR_CTSMIEN,
+			u->membase + AUART_INTR_CLR);
+
+	writel(AUART_CTRL0_CLKGATE, u->membase + AUART_CTRL0_SET);
+
+	clk_disable_unprepare(s->clk);
+}
+
+static unsigned int mxs_auart_tx_empty(struct uart_port *u)
+{
+	if ((readl(u->membase + AUART_STAT) &
+		 (AUART_STAT_TXFE | AUART_STAT_BUSY)) == AUART_STAT_TXFE)
+		return TIOCSER_TEMT;
+
+	return 0;
+}
+
+static void mxs_auart_start_tx(struct uart_port *u)
+{
+	struct mxs_auart_port *s = to_auart_port(u);
+
+	/* enable transmitter */
+	writel(AUART_CTRL2_TXE, u->membase + AUART_CTRL2_SET);
+
+	mxs_auart_tx_chars(s);
+}
+
+static void mxs_auart_stop_tx(struct uart_port *u)
+{
+	writel(AUART_CTRL2_TXE, u->membase + AUART_CTRL2_CLR);
+}
+
+static void mxs_auart_stop_rx(struct uart_port *u)
+{
+	writel(AUART_CTRL2_RXE, u->membase + AUART_CTRL2_CLR);
+}
+
+static void mxs_auart_break_ctl(struct uart_port *u, int ctl)
+{
+	if (ctl)
+		writel(AUART_LINECTRL_BRK,
+			     u->membase + AUART_LINECTRL_SET);
+	else
+		writel(AUART_LINECTRL_BRK,
+			     u->membase + AUART_LINECTRL_CLR);
+}
+
+static struct uart_ops mxs_auart_ops = {
+	.tx_empty       = mxs_auart_tx_empty,
+	.start_tx       = mxs_auart_start_tx,
+	.stop_tx	= mxs_auart_stop_tx,
+	.stop_rx	= mxs_auart_stop_rx,
+	.enable_ms      = mxs_auart_enable_ms,
+	.break_ctl      = mxs_auart_break_ctl,
+	.set_mctrl	= mxs_auart_set_mctrl,
+	.get_mctrl      = mxs_auart_get_mctrl,
+	.startup	= mxs_auart_startup,
+	.shutdown       = mxs_auart_shutdown,
+	.set_termios    = mxs_auart_settermios,
+	.set_ldisc      = mxs_auart_set_ldisc,
+	.type	   	= mxs_auart_type,
+	.release_port   = mxs_auart_release_port,
+	.request_port   = mxs_auart_request_port,
+	.config_port    = mxs_auart_config_port,
+	.verify_port    = mxs_auart_verify_port,
+};
+
+static struct mxs_auart_port *auart_port[MXS_AUART_PORTS];
+
+#ifdef CONFIG_SERIAL_MXS_AUART_CONSOLE
+static void mxs_auart_console_putchar(struct uart_port *port, int ch)
+{
+	unsigned int to = 1000;
+
+	while (readl(port->membase + AUART_STAT) & AUART_STAT_TXFF) {
+		if (!to--)
+			break;
+		udelay(1);
+	}
+
+	writel(ch, port->membase + AUART_DATA);
+}
+
+static void
+auart_console_write(struct console *co, const char *str, unsigned int count)
+{
+	struct mxs_auart_port *s;
+	struct uart_port *port;
+	unsigned int old_ctrl0, old_ctrl2;
+	unsigned int to = 20000;
+
+	if (co->index >= MXS_AUART_PORTS || co->index < 0)
+		return;
+
+	s = auart_port[co->index];
+	port = &s->port;
+
+	clk_enable(s->clk);
+
+	/* First save the CR then disable the interrupts */
+	old_ctrl2 = readl(port->membase + AUART_CTRL2);
+	old_ctrl0 = readl(port->membase + AUART_CTRL0);
+
+	writel(AUART_CTRL0_CLKGATE,
+		     port->membase + AUART_CTRL0_CLR);
+	writel(AUART_CTRL2_UARTEN | AUART_CTRL2_TXE,
+		     port->membase + AUART_CTRL2_SET);
+
+	uart_console_write(port, str, count, mxs_auart_console_putchar);
+
+	/* Finally, wait for transmitter to become empty ... */
+	while (readl(port->membase + AUART_STAT) & AUART_STAT_BUSY) {
+		udelay(1);
+		if (!to--)
+			break;
+	}
+
+	/*
+	 * ... and restore the TCR if we waited long enough for the transmitter
+	 * to be idle. This might keep the transmitter enabled although it is
+	 * unused, but that is better than to disable it while it is still
+	 * transmitting.
+	 */
+	if (!(readl(port->membase + AUART_STAT) & AUART_STAT_BUSY)) {
+		writel(old_ctrl0, port->membase + AUART_CTRL0);
+		writel(old_ctrl2, port->membase + AUART_CTRL2);
+	}
+
+	clk_disable(s->clk);
+}
+
+static void __init
+auart_console_get_options(struct uart_port *port, int *baud,
+			  int *parity, int *bits)
+{
+	unsigned int lcr_h, quot;
+
+	if (!(readl(port->membase + AUART_CTRL2) & AUART_CTRL2_UARTEN))
+		return;
+
+	lcr_h = readl(port->membase + AUART_LINECTRL);
+
+	*parity = 'n';
+	if (lcr_h & AUART_LINECTRL_PEN) {
+		if (lcr_h & AUART_LINECTRL_EPS)
+			*parity = 'e';
+		else
+			*parity = 'o';
+	}
+
+	if ((lcr_h & AUART_LINECTRL_WLEN_MASK) == AUART_LINECTRL_WLEN(2))
+		*bits = 7;
+	else
+		*bits = 8;
+
+	quot = ((readl(port->membase + AUART_LINECTRL)
+			& AUART_LINECTRL_BAUD_DIVINT_MASK))
+			    >> (AUART_LINECTRL_BAUD_DIVINT_SHIFT - 6);
+	quot |= ((readl(port->membase + AUART_LINECTRL)
+			& AUART_LINECTRL_BAUD_DIVFRAC_MASK))
+				>> AUART_LINECTRL_BAUD_DIVFRAC_SHIFT;
+	if (quot == 0)
+		quot = 1;
+
+	*baud = (port->uartclk << 2) / quot;
+}
+
+static int __init
+auart_console_setup(struct console *co, char *options)
+{
+	struct mxs_auart_port *s;
+	int baud = 9600;
+	int bits = 8;
+	int parity = 'n';
+	int flow = 'n';
+	int ret;
+
+	/*
+	 * Check whether an invalid uart number has been specified, and
+	 * if so, search for the first available port that does have
+	 * console support.
+	 */
+	if (co->index == -1 || co->index >= ARRAY_SIZE(auart_port))
+		co->index = 0;
+	s = auart_port[co->index];
+	if (!s)
+		return -ENODEV;
+
+	ret = clk_prepare_enable(s->clk);
+	if (ret)
+		return ret;
+
+	if (options)
+		uart_parse_options(options, &baud, &parity, &bits, &flow);
+	else
+		auart_console_get_options(&s->port, &baud, &parity, &bits);
+
+	ret = uart_set_options(&s->port, co, baud, parity, bits, flow);
+
+	clk_disable_unprepare(s->clk);
+
+	return ret;
+}
+
+static struct console auart_console = {
+	.name		= "ttyAPP",
+	.write		= auart_console_write,
+	.device		= uart_console_device,
+	.setup		= auart_console_setup,
+	.flags		= CON_PRINTBUFFER,
+	.index		= -1,
+	.data		= &auart_driver,
+};
+#endif
+
+static struct uart_driver auart_driver = {
+	.owner		= THIS_MODULE,
+	.driver_name	= "ttyAPP",
+	.dev_name	= "ttyAPP",
+	.major		= 0,
+	.minor		= 0,
+	.nr		= MXS_AUART_PORTS,
+#ifdef CONFIG_SERIAL_MXS_AUART_CONSOLE
+	.cons =		&auart_console,
+#endif
+};
+
+/*
+ * This function returns 1 if pdev isn't a device instatiated by dt, 0 if it
+ * could successfully get all information from dt or a negative errno.
+ */
+static int serial_mxs_probe_dt(struct mxs_auart_port *s,
+		struct platform_device *pdev)
+{
+	struct device_node *np = pdev->dev.of_node;
+	int ret;
+
+	if (!np)
+		/* no device tree device */
+		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;
+	}
+	s->port.line = ret;
+
+	if (of_get_property(np, "fsl,uart-has-rtscts", NULL))
+		set_bit(MXS_AUART_RTSCTS, &s->flags);
+
+	return 0;
+}
+
+static int mxs_auart_init_gpios(struct mxs_auart_port *s, struct device *dev)
+{
+	enum mctrl_gpio_idx i;
+	struct gpio_desc *gpiod;
+
+	s->gpios = mctrl_gpio_init(dev, 0);
+	if (IS_ERR(s->gpios))
+		return PTR_ERR(s->gpios);
+
+	/* Block (enabled before) DMA option if RTS or CTS is GPIO line */
+	if (!RTS_AT_AUART() || !CTS_AT_AUART()) {
+		if (test_bit(MXS_AUART_RTSCTS, &s->flags))
+			dev_warn(dev,
+				 "DMA and flow control via gpio may cause some problems. DMA disabled!\n");
+		clear_bit(MXS_AUART_RTSCTS, &s->flags);
+	}
+
+	for (i = 0; i < UART_GPIO_MAX; i++) {
+		gpiod = mctrl_gpio_to_gpiod(s->gpios, i);
+		if (gpiod && (gpiod_get_direction(gpiod) == GPIOF_DIR_IN))
+			s->gpio_irq[i] = gpiod_to_irq(gpiod);
+		else
+			s->gpio_irq[i] = -EINVAL;
+	}
+
+	return 0;
+}
+
+static void mxs_auart_free_gpio_irq(struct mxs_auart_port *s)
+{
+	enum mctrl_gpio_idx i;
+
+	for (i = 0; i < UART_GPIO_MAX; i++)
+		if (s->gpio_irq[i] >= 0)
+			free_irq(s->gpio_irq[i], s);
+}
+
+static int mxs_auart_request_gpio_irq(struct mxs_auart_port *s)
+{
+	int *irq = s->gpio_irq;
+	enum mctrl_gpio_idx i;
+	int err = 0;
+
+	for (i = 0; (i < UART_GPIO_MAX) && !err; i++) {
+		if (irq[i] < 0)
+			continue;
+
+		irq_set_status_flags(irq[i], IRQ_NOAUTOEN);
+		err = request_irq(irq[i], mxs_auart_irq_handle,
+				IRQ_TYPE_EDGE_BOTH, dev_name(s->dev), s);
+		if (err)
+			dev_err(s->dev, "%s - Can't get %d irq\n",
+				__func__, irq[i]);
+	}
+
+	/*
+	 * If something went wrong, rollback.
+	 */
+	while (err && (--i >= 0))
+		if (irq[i] >= 0)
+			free_irq(irq[i], s);
+
+	return err;
+}
+
+static int mxs_auart_probe(struct platform_device *pdev)
+{
+	const struct of_device_id *of_id =
+			of_match_device(mxs_auart_dt_ids, &pdev->dev);
+	struct mxs_auart_port *s;
+	u32 version;
+	int ret, irq;
+	struct resource *r;
+
+	s = devm_kzalloc(&pdev->dev, sizeof(*s), GFP_KERNEL);
+	if (!s)
+		return -ENOMEM;
+
+	ret = serial_mxs_probe_dt(s, pdev);
+	if (ret > 0)
+		s->port.line = pdev->id < 0 ? 0 : pdev->id;
+	else if (ret < 0)
+		return ret;
+
+	if (of_id) {
+		pdev->id_entry = of_id->data;
+		s->devtype = pdev->id_entry->driver_data;
+	}
+
+	s->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(s->clk))
+		return PTR_ERR(s->clk);
+
+	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!r)
+		return -ENXIO;
+
+
+	s->port.mapbase = r->start;
+	s->port.membase = ioremap(r->start, resource_size(r));
+	s->port.ops = &mxs_auart_ops;
+	s->port.iotype = UPIO_MEM;
+	s->port.fifosize = MXS_AUART_FIFO_SIZE;
+	s->port.uartclk = clk_get_rate(s->clk);
+	s->port.type = PORT_IMX;
+	s->port.dev = s->dev = &pdev->dev;
+
+	s->mctrl_prev = 0;
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0)
+		return irq;
+
+	s->port.irq = irq;
+	ret = devm_request_irq(&pdev->dev, irq, mxs_auart_irq_handle, 0,
+			       dev_name(&pdev->dev), s);
+	if (ret)
+		return ret;
+
+	platform_set_drvdata(pdev, s);
+
+	ret = mxs_auart_init_gpios(s, &pdev->dev);
+	if (ret) {
+		dev_err(&pdev->dev, "Failed to initialize GPIOs.\n");
+		return ret;
+	}
+
+	/*
+	 * Get the GPIO lines IRQ
+	 */
+	ret = mxs_auart_request_gpio_irq(s);
+	if (ret)
+		return ret;
+
+	auart_port[s->port.line] = s;
+
+	mxs_auart_reset(&s->port);
+
+	ret = uart_add_one_port(&auart_driver, &s->port);
+	if (ret)
+		goto out_free_gpio_irq;
+
+	version = readl(s->port.membase + AUART_VERSION);
+	dev_info(&pdev->dev, "Found APPUART %d.%d.%d\n",
+	       (version >> 24) & 0xff,
+	       (version >> 16) & 0xff, version & 0xffff);
+
+	return 0;
+
+out_free_gpio_irq:
+	mxs_auart_free_gpio_irq(s);
+	auart_port[pdev->id] = NULL;
+	return ret;
+}
+
+static int mxs_auart_remove(struct platform_device *pdev)
+{
+	struct mxs_auart_port *s = platform_get_drvdata(pdev);
+
+	uart_remove_one_port(&auart_driver, &s->port);
+	auart_port[pdev->id] = NULL;
+	mxs_auart_free_gpio_irq(s);
+
+	return 0;
+}
+
+static struct platform_driver mxs_auart_driver = {
+	.probe = mxs_auart_probe,
+	.remove = mxs_auart_remove,
+	.driver = {
+		.name = "mxs-auart",
+		.of_match_table = mxs_auart_dt_ids,
+	},
+};
+
+static int __init mxs_auart_init(void)
+{
+	int r;
+
+	r = uart_register_driver(&auart_driver);
+	if (r)
+		goto out;
+
+	r = platform_driver_register(&mxs_auart_driver);
+	if (r)
+		goto out_err;
+
+	return 0;
+out_err:
+	uart_unregister_driver(&auart_driver);
+out:
+	return r;
+}
+
+static void __exit mxs_auart_exit(void)
+{
+	platform_driver_unregister(&mxs_auart_driver);
+	uart_unregister_driver(&auart_driver);
+}
+
+module_init(mxs_auart_init);
+module_exit(mxs_auart_exit);
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Freescale MXS application uart driver");
+MODULE_ALIAS("platform:mxs-auart");