serial: New serial driver MAX310X

This driver is a replacement for a MAX3107 driver with a lot of
improvements and new features.
The main differences from the old version:
- Using the regmap.
- Using devm_XXX-related functions.
- The use of threaded IRQ with IRQF_ONESHOT flag allows the driver to
  the hardware that supports only level IRQ.
- Improved error handling of serial port, improved FIFO handling,
  improved hardware & software flow control.
- Advanced flags allows turn on RS-485 mode (Auto direction control).
- Ability to load multiple instances of drivers.
- Added support for MAX3108.
- GPIO support.
- Driver is quite ready for adding I2C support and support other ICs
  with compatible registers set (MAX3109, MAX14830).

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/tty/serial/max310x.c b/drivers/tty/serial/max310x.c
new file mode 100644
index 0000000..534e448
--- /dev/null
+++ b/drivers/tty/serial/max310x.c
@@ -0,0 +1,1259 @@
+/*
+ *  Maxim (Dallas) MAX3107/8 serial driver
+ *
+ *  Copyright (C) 2012 Alexander Shiyan <shc_work@mail.ru>
+ *
+ *  Based on max3100.c, by Christian Pellegrin <chripell@evolware.org>
+ *  Based on max3110.c, by Feng Tang <feng.tang@intel.com>
+ *  Based on max3107.c, by Aavamobile
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ */
+
+/* TODO: MAX3109 support (Dual) */
+/* TODO: MAX14830 support (Quad) */
+
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/serial_core.h>
+#include <linux/serial.h>
+#include <linux/tty.h>
+#include <linux/tty_flip.h>
+#include <linux/regmap.h>
+#include <linux/gpio.h>
+#include <linux/spi/spi.h>
+#include <linux/platform_data/max310x.h>
+
+#define MAX310X_MAJOR			204
+#define MAX310X_MINOR			209
+
+/* MAX310X register definitions */
+#define MAX310X_RHR_REG			(0x00) /* RX FIFO */
+#define MAX310X_THR_REG			(0x00) /* TX FIFO */
+#define MAX310X_IRQEN_REG		(0x01) /* IRQ enable */
+#define MAX310X_IRQSTS_REG		(0x02) /* IRQ status */
+#define MAX310X_LSR_IRQEN_REG		(0x03) /* LSR IRQ enable */
+#define MAX310X_LSR_IRQSTS_REG		(0x04) /* LSR IRQ status */
+#define MAX310X_SPCHR_IRQEN_REG		(0x05) /* Special char IRQ enable */
+#define MAX310X_SPCHR_IRQSTS_REG	(0x06) /* Special char IRQ status */
+#define MAX310X_STS_IRQEN_REG		(0x07) /* Status IRQ enable */
+#define MAX310X_STS_IRQSTS_REG		(0x08) /* Status IRQ status */
+#define MAX310X_MODE1_REG		(0x09) /* MODE1 */
+#define MAX310X_MODE2_REG		(0x0a) /* MODE2 */
+#define MAX310X_LCR_REG			(0x0b) /* LCR */
+#define MAX310X_RXTO_REG		(0x0c) /* RX timeout */
+#define MAX310X_HDPIXDELAY_REG		(0x0d) /* Auto transceiver delays */
+#define MAX310X_IRDA_REG		(0x0e) /* IRDA settings */
+#define MAX310X_FLOWLVL_REG		(0x0f) /* Flow control levels */
+#define MAX310X_FIFOTRIGLVL_REG		(0x10) /* FIFO IRQ trigger levels */
+#define MAX310X_TXFIFOLVL_REG		(0x11) /* TX FIFO level */
+#define MAX310X_RXFIFOLVL_REG		(0x12) /* RX FIFO level */
+#define MAX310X_FLOWCTRL_REG		(0x13) /* Flow control */
+#define MAX310X_XON1_REG		(0x14) /* XON1 character */
+#define MAX310X_XON2_REG		(0x15) /* XON2 character */
+#define MAX310X_XOFF1_REG		(0x16) /* XOFF1 character */
+#define MAX310X_XOFF2_REG		(0x17) /* XOFF2 character */
+#define MAX310X_GPIOCFG_REG		(0x18) /* GPIO config */
+#define MAX310X_GPIODATA_REG		(0x19) /* GPIO data */
+#define MAX310X_PLLCFG_REG		(0x1a) /* PLL config */
+#define MAX310X_BRGCFG_REG		(0x1b) /* Baud rate generator conf */
+#define MAX310X_BRGDIVLSB_REG		(0x1c) /* Baud rate divisor LSB */
+#define MAX310X_BRGDIVMSB_REG		(0x1d) /* Baud rate divisor MSB */
+#define MAX310X_CLKSRC_REG		(0x1e) /* Clock source */
+/* Only present in MAX3107 */
+#define MAX3107_REVID_REG		(0x1f) /* Revision identification */
+
+/* IRQ register bits */
+#define MAX310X_IRQ_LSR_BIT		(1 << 0) /* LSR interrupt */
+#define MAX310X_IRQ_SPCHR_BIT		(1 << 1) /* Special char interrupt */
+#define MAX310X_IRQ_STS_BIT		(1 << 2) /* Status interrupt */
+#define MAX310X_IRQ_RXFIFO_BIT		(1 << 3) /* RX FIFO interrupt */
+#define MAX310X_IRQ_TXFIFO_BIT		(1 << 4) /* TX FIFO interrupt */
+#define MAX310X_IRQ_TXEMPTY_BIT		(1 << 5) /* TX FIFO empty interrupt */
+#define MAX310X_IRQ_RXEMPTY_BIT		(1 << 6) /* RX FIFO empty interrupt */
+#define MAX310X_IRQ_CTS_BIT		(1 << 7) /* CTS interrupt */
+
+/* LSR register bits */
+#define MAX310X_LSR_RXTO_BIT		(1 << 0) /* RX timeout */
+#define MAX310X_LSR_RXOVR_BIT		(1 << 1) /* RX overrun */
+#define MAX310X_LSR_RXPAR_BIT		(1 << 2) /* RX parity error */
+#define MAX310X_LSR_FRERR_BIT		(1 << 3) /* Frame error */
+#define MAX310X_LSR_RXBRK_BIT		(1 << 4) /* RX break */
+#define MAX310X_LSR_RXNOISE_BIT		(1 << 5) /* RX noise */
+#define MAX310X_LSR_CTS_BIT		(1 << 7) /* CTS pin state */
+
+/* Special character register bits */
+#define MAX310X_SPCHR_XON1_BIT		(1 << 0) /* XON1 character */
+#define MAX310X_SPCHR_XON2_BIT		(1 << 1) /* XON2 character */
+#define MAX310X_SPCHR_XOFF1_BIT		(1 << 2) /* XOFF1 character */
+#define MAX310X_SPCHR_XOFF2_BIT		(1 << 3) /* XOFF2 character */
+#define MAX310X_SPCHR_BREAK_BIT		(1 << 4) /* RX break */
+#define MAX310X_SPCHR_MULTIDROP_BIT	(1 << 5) /* 9-bit multidrop addr char */
+
+/* Status register bits */
+#define MAX310X_STS_GPIO0_BIT		(1 << 0) /* GPIO 0 interrupt */
+#define MAX310X_STS_GPIO1_BIT		(1 << 1) /* GPIO 1 interrupt */
+#define MAX310X_STS_GPIO2_BIT		(1 << 2) /* GPIO 2 interrupt */
+#define MAX310X_STS_GPIO3_BIT		(1 << 3) /* GPIO 3 interrupt */
+#define MAX310X_STS_CLKREADY_BIT	(1 << 5) /* Clock ready */
+#define MAX310X_STS_SLEEP_BIT		(1 << 6) /* Sleep interrupt */
+
+/* MODE1 register bits */
+#define MAX310X_MODE1_RXDIS_BIT		(1 << 0) /* RX disable */
+#define MAX310X_MODE1_TXDIS_BIT		(1 << 1) /* TX disable */
+#define MAX310X_MODE1_TXHIZ_BIT		(1 << 2) /* TX pin three-state */
+#define MAX310X_MODE1_RTSHIZ_BIT	(1 << 3) /* RTS pin three-state */
+#define MAX310X_MODE1_TRNSCVCTRL_BIT	(1 << 4) /* Transceiver ctrl enable */
+#define MAX310X_MODE1_FORCESLEEP_BIT	(1 << 5) /* Force sleep mode */
+#define MAX310X_MODE1_AUTOSLEEP_BIT	(1 << 6) /* Auto sleep enable */
+#define MAX310X_MODE1_IRQSEL_BIT	(1 << 7) /* IRQ pin enable */
+
+/* MODE2 register bits */
+#define MAX310X_MODE2_RST_BIT		(1 << 0) /* Chip reset */
+#define MAX310X_MODE2_FIFORST_BIT	(1 << 1) /* FIFO reset */
+#define MAX310X_MODE2_RXTRIGINV_BIT	(1 << 2) /* RX FIFO INT invert */
+#define MAX310X_MODE2_RXEMPTINV_BIT	(1 << 3) /* RX FIFO empty INT invert */
+#define MAX310X_MODE2_SPCHR_BIT		(1 << 4) /* Special chr detect enable */
+#define MAX310X_MODE2_LOOPBACK_BIT	(1 << 5) /* Internal loopback enable */
+#define MAX310X_MODE2_MULTIDROP_BIT	(1 << 6) /* 9-bit multidrop enable */
+#define MAX310X_MODE2_ECHOSUPR_BIT	(1 << 7) /* ECHO suppression enable */
+
+/* LCR register bits */
+#define MAX310X_LCR_LENGTH0_BIT		(1 << 0) /* Word length bit 0 */
+#define MAX310X_LCR_LENGTH1_BIT		(1 << 1) /* Word length bit 1
+						  *
+						  * Word length bits table:
+						  * 00 -> 5 bit words
+						  * 01 -> 6 bit words
+						  * 10 -> 7 bit words
+						  * 11 -> 8 bit words
+						  */
+#define MAX310X_LCR_STOPLEN_BIT		(1 << 2) /* STOP length bit
+						  *
+						  * STOP length bit table:
+						  * 0 -> 1 stop bit
+						  * 1 -> 1-1.5 stop bits if
+						  *      word length is 5,
+						  *      2 stop bits otherwise
+						  */
+#define MAX310X_LCR_PARITY_BIT		(1 << 3) /* Parity bit enable */
+#define MAX310X_LCR_EVENPARITY_BIT	(1 << 4) /* Even parity bit enable */
+#define MAX310X_LCR_FORCEPARITY_BIT	(1 << 5) /* 9-bit multidrop parity */
+#define MAX310X_LCR_TXBREAK_BIT		(1 << 6) /* TX break enable */
+#define MAX310X_LCR_RTS_BIT		(1 << 7) /* RTS pin control */
+#define MAX310X_LCR_WORD_LEN_5		(0x00)
+#define MAX310X_LCR_WORD_LEN_6		(0x01)
+#define MAX310X_LCR_WORD_LEN_7		(0x02)
+#define MAX310X_LCR_WORD_LEN_8		(0x03)
+
+/* IRDA register bits */
+#define MAX310X_IRDA_IRDAEN_BIT		(1 << 0) /* IRDA mode enable */
+#define MAX310X_IRDA_SIR_BIT		(1 << 1) /* SIR mode enable */
+#define MAX310X_IRDA_SHORTIR_BIT	(1 << 2) /* Short SIR mode enable */
+#define MAX310X_IRDA_MIR_BIT		(1 << 3) /* MIR mode enable */
+#define MAX310X_IRDA_RXINV_BIT		(1 << 4) /* RX logic inversion enable */
+#define MAX310X_IRDA_TXINV_BIT		(1 << 5) /* TX logic inversion enable */
+
+/* Flow control trigger level register masks */
+#define MAX310X_FLOWLVL_HALT_MASK	(0x000f) /* Flow control halt level */
+#define MAX310X_FLOWLVL_RES_MASK	(0x00f0) /* Flow control resume level */
+#define MAX310X_FLOWLVL_HALT(words)	((words / 8) & 0x0f)
+#define MAX310X_FLOWLVL_RES(words)	(((words / 8) & 0x0f) << 4)
+
+/* FIFO interrupt trigger level register masks */
+#define MAX310X_FIFOTRIGLVL_TX_MASK	(0x0f) /* TX FIFO trigger level */
+#define MAX310X_FIFOTRIGLVL_RX_MASK	(0xf0) /* RX FIFO trigger level */
+#define MAX310X_FIFOTRIGLVL_TX(words)	((words / 8) & 0x0f)
+#define MAX310X_FIFOTRIGLVL_RX(words)	(((words / 8) & 0x0f) << 4)
+
+/* Flow control register bits */
+#define MAX310X_FLOWCTRL_AUTORTS_BIT	(1 << 0) /* Auto RTS flow ctrl enable */
+#define MAX310X_FLOWCTRL_AUTOCTS_BIT	(1 << 1) /* Auto CTS flow ctrl enable */
+#define MAX310X_FLOWCTRL_GPIADDR_BIT	(1 << 2) /* Enables that GPIO inputs
+						  * are used in conjunction with
+						  * XOFF2 for definition of
+						  * special character */
+#define MAX310X_FLOWCTRL_SWFLOWEN_BIT	(1 << 3) /* Auto SW flow ctrl enable */
+#define MAX310X_FLOWCTRL_SWFLOW0_BIT	(1 << 4) /* SWFLOW bit 0 */
+#define MAX310X_FLOWCTRL_SWFLOW1_BIT	(1 << 5) /* SWFLOW bit 1
+						  *
+						  * SWFLOW bits 1 & 0 table:
+						  * 00 -> no transmitter flow
+						  *       control
+						  * 01 -> receiver compares
+						  *       XON2 and XOFF2
+						  *       and controls
+						  *       transmitter
+						  * 10 -> receiver compares
+						  *       XON1 and XOFF1
+						  *       and controls
+						  *       transmitter
+						  * 11 -> receiver compares
+						  *       XON1, XON2, XOFF1 and
+						  *       XOFF2 and controls
+						  *       transmitter
+						  */
+#define MAX310X_FLOWCTRL_SWFLOW2_BIT	(1 << 6) /* SWFLOW bit 2 */
+#define MAX310X_FLOWCTRL_SWFLOW3_BIT	(1 << 7) /* SWFLOW bit 3
+						  *
+						  * SWFLOW bits 3 & 2 table:
+						  * 00 -> no received flow
+						  *       control
+						  * 01 -> transmitter generates
+						  *       XON2 and XOFF2
+						  * 10 -> transmitter generates
+						  *       XON1 and XOFF1
+						  * 11 -> transmitter generates
+						  *       XON1, XON2, XOFF1 and
+						  *       XOFF2
+						  */
+
+/* GPIO configuration register bits */
+#define MAX310X_GPIOCFG_GP0OUT_BIT	(1 << 0) /* GPIO 0 output enable */
+#define MAX310X_GPIOCFG_GP1OUT_BIT	(1 << 1) /* GPIO 1 output enable */
+#define MAX310X_GPIOCFG_GP2OUT_BIT	(1 << 2) /* GPIO 2 output enable */
+#define MAX310X_GPIOCFG_GP3OUT_BIT	(1 << 3) /* GPIO 3 output enable */
+#define MAX310X_GPIOCFG_GP0OD_BIT	(1 << 4) /* GPIO 0 open-drain enable */
+#define MAX310X_GPIOCFG_GP1OD_BIT	(1 << 5) /* GPIO 1 open-drain enable */
+#define MAX310X_GPIOCFG_GP2OD_BIT	(1 << 6) /* GPIO 2 open-drain enable */
+#define MAX310X_GPIOCFG_GP3OD_BIT	(1 << 7) /* GPIO 3 open-drain enable */
+
+/* GPIO DATA register bits */
+#define MAX310X_GPIODATA_GP0OUT_BIT	(1 << 0) /* GPIO 0 output value */
+#define MAX310X_GPIODATA_GP1OUT_BIT	(1 << 1) /* GPIO 1 output value */
+#define MAX310X_GPIODATA_GP2OUT_BIT	(1 << 2) /* GPIO 2 output value */
+#define MAX310X_GPIODATA_GP3OUT_BIT	(1 << 3) /* GPIO 3 output value */
+#define MAX310X_GPIODATA_GP0IN_BIT	(1 << 4) /* GPIO 0 input value */
+#define MAX310X_GPIODATA_GP1IN_BIT	(1 << 5) /* GPIO 1 input value */
+#define MAX310X_GPIODATA_GP2IN_BIT	(1 << 6) /* GPIO 2 input value */
+#define MAX310X_GPIODATA_GP3IN_BIT	(1 << 7) /* GPIO 3 input value */
+
+/* PLL configuration register masks */
+#define MAX310X_PLLCFG_PREDIV_MASK	(0x3f) /* PLL predivision value */
+#define MAX310X_PLLCFG_PLLFACTOR_MASK	(0xc0) /* PLL multiplication factor */
+
+/* Baud rate generator configuration register bits */
+#define MAX310X_BRGCFG_2XMODE_BIT	(1 << 4) /* Double baud rate */
+#define MAX310X_BRGCFG_4XMODE_BIT	(1 << 5) /* Quadruple baud rate */
+
+/* Clock source register bits */
+#define MAX310X_CLKSRC_CRYST_BIT	(1 << 1) /* Crystal osc enable */
+#define MAX310X_CLKSRC_PLL_BIT		(1 << 2) /* PLL enable */
+#define MAX310X_CLKSRC_PLLBYP_BIT	(1 << 3) /* PLL bypass */
+#define MAX310X_CLKSRC_EXTCLK_BIT	(1 << 4) /* External clock enable */
+#define MAX310X_CLKSRC_CLK2RTS_BIT	(1 << 7) /* Baud clk to RTS pin */
+
+/* Misc definitions */
+#define MAX310X_FIFO_SIZE		(128)
+
+/* MAX3107 specific */
+#define MAX3107_REV_ID			(0xa0)
+#define MAX3107_REV_MASK		(0xfe)
+
+/* IRQ status bits definitions */
+#define MAX310X_IRQ_TX			(MAX310X_IRQ_TXFIFO_BIT | \
+					 MAX310X_IRQ_TXEMPTY_BIT)
+#define MAX310X_IRQ_RX			(MAX310X_IRQ_RXFIFO_BIT | \
+					 MAX310X_IRQ_RXEMPTY_BIT)
+
+/* Supported chip types */
+enum {
+	MAX310X_TYPE_MAX3107	= 3107,
+	MAX310X_TYPE_MAX3108	= 3108,
+};
+
+struct max310x_port {
+	struct uart_driver	uart;
+	struct uart_port	port;
+
+	const char		*name;
+	int			uartclk;
+
+	unsigned int		nr_gpio;
+#ifdef CONFIG_GPIOLIB
+	struct gpio_chip	gpio;
+#endif
+
+	struct regmap		*regmap;
+	struct regmap_config	regcfg;
+
+	struct workqueue_struct	*wq;
+	struct work_struct	tx_work;
+
+	struct mutex		max310x_mutex;
+
+	struct max310x_pdata	*pdata;
+};
+
+static bool max3107_8_reg_writeable(struct device *dev, unsigned int reg)
+{
+	switch (reg) {
+	case MAX310X_IRQSTS_REG:
+	case MAX310X_LSR_IRQSTS_REG:
+	case MAX310X_SPCHR_IRQSTS_REG:
+	case MAX310X_STS_IRQSTS_REG:
+	case MAX310X_TXFIFOLVL_REG:
+	case MAX310X_RXFIFOLVL_REG:
+	case MAX3107_REVID_REG: /* Only available on MAX3107 */
+		return false;
+	default:
+		break;
+	}
+
+	return true;
+}
+
+static bool max310x_reg_volatile(struct device *dev, unsigned int reg)
+{
+	switch (reg) {
+	case MAX310X_RHR_REG:
+	case MAX310X_IRQSTS_REG:
+	case MAX310X_LSR_IRQSTS_REG:
+	case MAX310X_SPCHR_IRQSTS_REG:
+	case MAX310X_STS_IRQSTS_REG:
+	case MAX310X_TXFIFOLVL_REG:
+	case MAX310X_RXFIFOLVL_REG:
+	case MAX310X_GPIODATA_REG:
+		return true;
+	default:
+		break;
+	}
+
+	return false;
+}
+
+static bool max310x_reg_precious(struct device *dev, unsigned int reg)
+{
+	switch (reg) {
+	case MAX310X_RHR_REG:
+	case MAX310X_IRQSTS_REG:
+	case MAX310X_SPCHR_IRQSTS_REG:
+	case MAX310X_STS_IRQSTS_REG:
+		return true;
+	default:
+		break;
+	}
+
+	return false;
+}
+
+static void max310x_set_baud(struct max310x_port *s, int baud)
+{
+	unsigned int mode = 0, div = s->uartclk / baud;
+
+	if (!(div / 16)) {
+		/* Mode x2 */
+		mode = MAX310X_BRGCFG_2XMODE_BIT;
+		div = (s->uartclk * 2) / baud;
+	}
+
+	if (!(div / 16)) {
+		/* Mode x4 */
+		mode = MAX310X_BRGCFG_4XMODE_BIT;
+		div = (s->uartclk * 4) / baud;
+	}
+
+	regmap_write(s->regmap, MAX310X_BRGDIVMSB_REG,
+		     ((div / 16) >> 8) & 0xff);
+	regmap_write(s->regmap, MAX310X_BRGDIVLSB_REG, (div / 16) & 0xff);
+	regmap_write(s->regmap, MAX310X_BRGCFG_REG, (div % 16) | mode);
+}
+
+static void max310x_wait_pll(struct max310x_port *s)
+{
+	int tryes = 1000;
+
+	/* Wait for PLL only if crystal is used */
+	if (!(s->pdata->driver_flags & MAX310X_EXT_CLK)) {
+		unsigned int sts = 0;
+
+		while (tryes--) {
+			regmap_read(s->regmap, MAX310X_STS_IRQSTS_REG, &sts);
+			if (sts & MAX310X_STS_CLKREADY_BIT)
+				break;
+		}
+	}
+}
+
+static int __devinit max310x_update_best_err(unsigned long f, long *besterr)
+{
+	/* Use baudrate 115200 for calculate error */
+	long err = f % (115200 * 16);
+
+	if ((*besterr < 0) || (*besterr > err)) {
+		*besterr = err;
+		return 0;
+	}
+
+	return 1;
+}
+
+static int __devinit max310x_set_ref_clk(struct max310x_port *s)
+{
+	unsigned int div, clksrc, pllcfg = 0;
+	long besterr = -1;
+	unsigned long fdiv, fmul, bestfreq = s->pdata->frequency;
+
+	/* First, update error without PLL */
+	max310x_update_best_err(s->pdata->frequency, &besterr);
+
+	/* Try all possible PLL dividers */
+	for (div = 1; (div <= 63) && besterr; div++) {
+		fdiv = DIV_ROUND_CLOSEST(s->pdata->frequency, div);
+
+		/* Try multiplier 6 */
+		fmul = fdiv * 6;
+		if ((fdiv >= 500000) && (fdiv <= 800000))
+			if (!max310x_update_best_err(fmul, &besterr)) {
+				pllcfg = (0 << 6) | div;
+				bestfreq = fmul;
+			}
+		/* Try multiplier 48 */
+		fmul = fdiv * 48;
+		if ((fdiv >= 850000) && (fdiv <= 1200000))
+			if (!max310x_update_best_err(fmul, &besterr)) {
+				pllcfg = (1 << 6) | div;
+				bestfreq = fmul;
+			}
+		/* Try multiplier 96 */
+		fmul = fdiv * 96;
+		if ((fdiv >= 425000) && (fdiv <= 1000000))
+			if (!max310x_update_best_err(fmul, &besterr)) {
+				pllcfg = (2 << 6) | div;
+				bestfreq = fmul;
+			}
+		/* Try multiplier 144 */
+		fmul = fdiv * 144;
+		if ((fdiv >= 390000) && (fdiv <= 667000))
+			if (!max310x_update_best_err(fmul, &besterr)) {
+				pllcfg = (3 << 6) | div;
+				bestfreq = fmul;
+			}
+	}
+
+	/* Configure clock source */
+	if (s->pdata->driver_flags & MAX310X_EXT_CLK)
+		clksrc = MAX310X_CLKSRC_EXTCLK_BIT;
+	else
+		clksrc = MAX310X_CLKSRC_CRYST_BIT;
+
+	/* Configure PLL */
+	if (pllcfg) {
+		clksrc |= MAX310X_CLKSRC_PLL_BIT;
+		regmap_write(s->regmap, MAX310X_PLLCFG_REG, pllcfg);
+	} else
+		clksrc |= MAX310X_CLKSRC_PLLBYP_BIT;
+
+	regmap_write(s->regmap, MAX310X_CLKSRC_REG, clksrc);
+
+	if (pllcfg)
+		max310x_wait_pll(s);
+
+	dev_dbg(s->port.dev, "Reference clock set to %lu Hz\n", bestfreq);
+
+	return (int)bestfreq;
+}
+
+static void max310x_handle_rx(struct max310x_port *s, unsigned int rxlen)
+{
+	unsigned int sts = 0, ch = 0, flag;
+	struct tty_struct *tty = tty_port_tty_get(&s->port.state->port);
+
+	if (!tty)
+		return;
+
+	if (unlikely(rxlen >= MAX310X_FIFO_SIZE)) {
+		dev_warn(s->port.dev, "Possible RX FIFO overrun %d\n", rxlen);
+		/* Ensure sanity of RX level */
+		rxlen = MAX310X_FIFO_SIZE;
+	}
+
+	dev_dbg(s->port.dev, "RX Len = %u\n", rxlen);
+
+	while (rxlen--) {
+		regmap_read(s->regmap, MAX310X_RHR_REG, &ch);
+		regmap_read(s->regmap, MAX310X_LSR_IRQSTS_REG, &sts);
+
+		sts &= MAX310X_LSR_RXPAR_BIT | MAX310X_LSR_FRERR_BIT |
+		       MAX310X_LSR_RXOVR_BIT | MAX310X_LSR_RXBRK_BIT;
+
+		s->port.icount.rx++;
+		flag = TTY_NORMAL;
+
+		if (unlikely(sts)) {
+			if (sts & MAX310X_LSR_RXBRK_BIT) {
+				s->port.icount.brk++;
+				if (uart_handle_break(&s->port))
+					continue;
+			} else if (sts & MAX310X_LSR_RXPAR_BIT)
+				s->port.icount.parity++;
+			else if (sts & MAX310X_LSR_FRERR_BIT)
+				s->port.icount.frame++;
+			else if (sts & MAX310X_LSR_RXOVR_BIT)
+				s->port.icount.overrun++;
+
+			sts &= s->port.read_status_mask;
+			if (sts & MAX310X_LSR_RXBRK_BIT)
+				flag = TTY_BREAK;
+			else if (sts & MAX310X_LSR_RXPAR_BIT)
+				flag = TTY_PARITY;
+			else if (sts & MAX310X_LSR_FRERR_BIT)
+				flag = TTY_FRAME;
+			else if (sts & MAX310X_LSR_RXOVR_BIT)
+				flag = TTY_OVERRUN;
+		}
+
+		if (uart_handle_sysrq_char(s->port, ch))
+			continue;
+
+		if (sts & s->port.ignore_status_mask)
+			continue;
+
+		uart_insert_char(&s->port, sts, MAX310X_LSR_RXOVR_BIT,
+				 ch, flag);
+	}
+
+	tty_flip_buffer_push(tty);
+
+	tty_kref_put(tty);
+}
+
+static void max310x_handle_tx(struct max310x_port *s)
+{
+	struct circ_buf *xmit = &s->port.state->xmit;
+	unsigned int txlen = 0, to_send;
+
+	if (unlikely(s->port.x_char)) {
+		regmap_write(s->regmap, MAX310X_THR_REG, s->port.x_char);
+		s->port.icount.tx++;
+		s->port.x_char = 0;
+		return;
+	}
+
+	if (uart_circ_empty(xmit) || uart_tx_stopped(&s->port))
+		return;
+
+	/* Get length of data pending in circular buffer */
+	to_send = uart_circ_chars_pending(xmit);
+	if (likely(to_send)) {
+		/* Limit to size of TX FIFO */
+		regmap_read(s->regmap, MAX310X_TXFIFOLVL_REG, &txlen);
+		txlen = MAX310X_FIFO_SIZE - txlen;
+		to_send = (to_send > txlen) ? txlen : to_send;
+
+		dev_dbg(s->port.dev, "TX Len = %u\n", to_send);
+
+		/* Add data to send */
+		s->port.icount.tx += to_send;
+		while (to_send--) {
+			regmap_write(s->regmap, MAX310X_THR_REG,
+				     xmit->buf[xmit->tail]);
+			xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
+		};
+	}
+
+	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
+		uart_write_wakeup(&s->port);
+}
+
+static irqreturn_t max310x_ist(int irq, void *dev_id)
+{
+	struct max310x_port *s = (struct max310x_port *)dev_id;
+	unsigned int ists = 0, lsr = 0, rxlen = 0;
+
+	mutex_lock(&s->max310x_mutex);
+
+	for (;;) {
+		/* Read IRQ status & RX FIFO level */
+		regmap_read(s->regmap, MAX310X_IRQSTS_REG, &ists);
+		regmap_read(s->regmap, MAX310X_LSR_IRQSTS_REG, &lsr);
+		regmap_read(s->regmap, MAX310X_RXFIFOLVL_REG, &rxlen);
+		if (!ists && !(lsr & MAX310X_LSR_RXTO_BIT) && !rxlen)
+			break;
+
+		dev_dbg(s->port.dev, "IRQ status: 0x%02x\n", ists);
+
+		if (rxlen)
+			max310x_handle_rx(s, rxlen);
+		if (ists & MAX310X_IRQ_TX)
+			max310x_handle_tx(s);
+		if (ists & MAX310X_IRQ_CTS_BIT)
+			uart_handle_cts_change(&s->port,
+					       !!(lsr & MAX310X_LSR_CTS_BIT));
+	}
+
+	mutex_unlock(&s->max310x_mutex);
+
+	return IRQ_HANDLED;
+}
+
+static void max310x_wq_proc(struct work_struct *ws)
+{
+	struct max310x_port *s = container_of(ws, struct max310x_port, tx_work);
+
+	mutex_lock(&s->max310x_mutex);
+	max310x_handle_tx(s);
+	mutex_unlock(&s->max310x_mutex);
+}
+
+static void max310x_start_tx(struct uart_port *port)
+{
+	struct max310x_port *s = container_of(port, struct max310x_port, port);
+
+	queue_work(s->wq, &s->tx_work);
+}
+
+static void max310x_stop_tx(struct uart_port *port)
+{
+	/* Do nothing */
+}
+
+static void max310x_stop_rx(struct uart_port *port)
+{
+	/* Do nothing */
+}
+
+static unsigned int max310x_tx_empty(struct uart_port *port)
+{
+	unsigned int val = 0;
+	struct max310x_port *s = container_of(port, struct max310x_port, port);
+
+	mutex_lock(&s->max310x_mutex);
+	regmap_read(s->regmap, MAX310X_TXFIFOLVL_REG, &val);
+	mutex_unlock(&s->max310x_mutex);
+
+	return val ? 0 : TIOCSER_TEMT;
+}
+
+static void max310x_enable_ms(struct uart_port *port)
+{
+	/* Modem status not supported */
+}
+
+static unsigned int max310x_get_mctrl(struct uart_port *port)
+{
+	/* DCD and DSR are not wired and CTS/RTS is handled automatically
+	 * so just indicate DSR and CAR asserted
+	 */
+	return TIOCM_DSR | TIOCM_CAR;
+}
+
+static void max310x_set_mctrl(struct uart_port *port, unsigned int mctrl)
+{
+	/* DCD and DSR are not wired and CTS/RTS is hadnled automatically
+	 * so do nothing
+	 */
+}
+
+static void max310x_break_ctl(struct uart_port *port, int break_state)
+{
+	struct max310x_port *s = container_of(port, struct max310x_port, port);
+
+	mutex_lock(&s->max310x_mutex);
+	regmap_update_bits(s->regmap, MAX310X_LCR_REG,
+			   MAX310X_LCR_TXBREAK_BIT,
+			   break_state ? MAX310X_LCR_TXBREAK_BIT : 0);
+	mutex_unlock(&s->max310x_mutex);
+}
+
+static void max310x_set_termios(struct uart_port *port,
+				struct ktermios *termios,
+				struct ktermios *old)
+{
+	struct max310x_port *s = container_of(port, struct max310x_port, port);
+	unsigned int lcr, flow = 0;
+	int baud;
+
+	mutex_lock(&s->max310x_mutex);
+
+	/* Mask termios capabilities we don't support */
+	termios->c_cflag &= ~CMSPAR;
+	termios->c_iflag &= ~IXANY;
+
+	/* Word size */
+	switch (termios->c_cflag & CSIZE) {
+	case CS5:
+		lcr = MAX310X_LCR_WORD_LEN_5;
+		break;
+	case CS6:
+		lcr = MAX310X_LCR_WORD_LEN_6;
+		break;
+	case CS7:
+		lcr = MAX310X_LCR_WORD_LEN_7;
+		break;
+	case CS8:
+	default:
+		lcr = MAX310X_LCR_WORD_LEN_8;
+		break;
+	}
+
+	/* Parity */
+	if (termios->c_cflag & PARENB) {
+		lcr |= MAX310X_LCR_PARITY_BIT;
+		if (!(termios->c_cflag & PARODD))
+			lcr |= MAX310X_LCR_EVENPARITY_BIT;
+	}
+
+	/* Stop bits */
+	if (termios->c_cflag & CSTOPB)
+		lcr |= MAX310X_LCR_STOPLEN_BIT; /* 2 stops */
+
+	/* Update LCR register */
+	regmap_write(s->regmap, MAX310X_LCR_REG, lcr);
+
+	/* Set read status mask */
+	port->read_status_mask = MAX310X_LSR_RXOVR_BIT;
+	if (termios->c_iflag & INPCK)
+		port->read_status_mask |= MAX310X_LSR_RXPAR_BIT |
+					  MAX310X_LSR_FRERR_BIT;
+	if (termios->c_iflag & (BRKINT | PARMRK))
+		port->read_status_mask |= MAX310X_LSR_RXBRK_BIT;
+
+	/* Set status ignore mask */
+	port->ignore_status_mask = 0;
+	if (termios->c_iflag & IGNBRK)
+		port->ignore_status_mask |= MAX310X_LSR_RXBRK_BIT;
+	if (!(termios->c_cflag & CREAD))
+		port->ignore_status_mask |= MAX310X_LSR_RXPAR_BIT |
+					    MAX310X_LSR_RXOVR_BIT |
+					    MAX310X_LSR_FRERR_BIT |
+					    MAX310X_LSR_RXBRK_BIT;
+
+	/* Configure flow control */
+	regmap_write(s->regmap, MAX310X_XON1_REG, termios->c_cc[VSTART]);
+	regmap_write(s->regmap, MAX310X_XOFF1_REG, termios->c_cc[VSTOP]);
+	if (termios->c_cflag & CRTSCTS)
+		flow |= MAX310X_FLOWCTRL_AUTOCTS_BIT |
+			MAX310X_FLOWCTRL_AUTORTS_BIT;
+	if (termios->c_iflag & IXON)
+		flow |= MAX310X_FLOWCTRL_SWFLOW3_BIT |
+			MAX310X_FLOWCTRL_SWFLOWEN_BIT;
+	if (termios->c_iflag & IXOFF)
+		flow |= MAX310X_FLOWCTRL_SWFLOW1_BIT |
+			MAX310X_FLOWCTRL_SWFLOWEN_BIT;
+	regmap_write(s->regmap, MAX310X_FLOWCTRL_REG, flow);
+
+	/* Get baud rate generator configuration */
+	baud = uart_get_baud_rate(port, termios, old,
+				  port->uartclk / 16 / 0xffff,
+				  port->uartclk / 4);
+
+	/* Setup baudrate generator */
+	max310x_set_baud(s, baud);
+
+	/* Update timeout according to new baud rate */
+	uart_update_timeout(port, termios->c_cflag, baud);
+
+	mutex_unlock(&s->max310x_mutex);
+}
+
+static int max310x_startup(struct uart_port *port)
+{
+	unsigned int val, line = port->line;
+	struct max310x_port *s = container_of(port, struct max310x_port, port);
+
+	if (s->pdata->suspend)
+		s->pdata->suspend(0);
+
+	mutex_lock(&s->max310x_mutex);
+
+	/* Configure baud rate, 9600 as default */
+	max310x_set_baud(s, 9600);
+
+	/* Configure LCR register, 8N1 mode by default */
+	val = MAX310X_LCR_WORD_LEN_8;
+	regmap_write(s->regmap, MAX310X_LCR_REG, val);
+
+	/* Configure MODE1 register */
+	regmap_update_bits(s->regmap, MAX310X_MODE1_REG,
+			   MAX310X_MODE1_TRNSCVCTRL_BIT,
+			   (s->pdata->uart_flags[line] & MAX310X_AUTO_DIR_CTRL)
+			   ? MAX310X_MODE1_TRNSCVCTRL_BIT : 0);
+
+	/* Configure MODE2 register */
+	val = MAX310X_MODE2_RXEMPTINV_BIT;
+	if (s->pdata->uart_flags[line] & MAX310X_LOOPBACK)
+		val |= MAX310X_MODE2_LOOPBACK_BIT;
+	if (s->pdata->uart_flags[line] & MAX310X_ECHO_SUPRESS)
+		val |= MAX310X_MODE2_ECHOSUPR_BIT;
+
+	/* Reset FIFOs */
+	val |= MAX310X_MODE2_FIFORST_BIT;
+	regmap_write(s->regmap, MAX310X_MODE2_REG, val);
+
+	/* Configure FIFO trigger level register */
+	/* RX FIFO trigger for 16 words, TX FIFO trigger for 64 words */
+	val = MAX310X_FIFOTRIGLVL_RX(16) | MAX310X_FIFOTRIGLVL_TX(64);
+	regmap_write(s->regmap, MAX310X_FIFOTRIGLVL_REG, val);
+
+	/* Configure flow control levels */
+	/* Flow control halt level 96, resume level 48 */
+	val = MAX310X_FLOWLVL_RES(48) | MAX310X_FLOWLVL_HALT(96);
+	regmap_write(s->regmap, MAX310X_FLOWLVL_REG, val);
+
+	/* Clear timeout register */
+	regmap_write(s->regmap, MAX310X_RXTO_REG, 0);
+
+	/* Configure LSR interrupt enable register */
+	/* Enable RX timeout interrupt */
+	val = MAX310X_LSR_RXTO_BIT;
+	regmap_write(s->regmap, MAX310X_LSR_IRQEN_REG, val);
+
+	/* Clear FIFO reset */
+	regmap_update_bits(s->regmap, MAX310X_MODE2_REG,
+			   MAX310X_MODE2_FIFORST_BIT, 0);
+
+	/* Clear IRQ status register by reading it */
+	regmap_read(s->regmap, MAX310X_IRQSTS_REG, &val);
+
+	/* Configure interrupt enable register */
+	/* Enable CTS change interrupt */
+	val = MAX310X_IRQ_CTS_BIT;
+	/* Enable RX, TX interrupts */
+	val |= MAX310X_IRQ_RX | MAX310X_IRQ_TX;
+	regmap_write(s->regmap, MAX310X_IRQEN_REG, val);
+
+	mutex_unlock(&s->max310x_mutex);
+
+	return 0;
+}
+
+static void max310x_shutdown(struct uart_port *port)
+{
+	struct max310x_port *s = container_of(port, struct max310x_port, port);
+
+	/* Disable all interrupts */
+	mutex_lock(&s->max310x_mutex);
+	regmap_write(s->regmap, MAX310X_IRQEN_REG, 0);
+	mutex_unlock(&s->max310x_mutex);
+
+	if (s->pdata->suspend)
+		s->pdata->suspend(1);
+}
+
+static const char *max310x_type(struct uart_port *port)
+{
+	struct max310x_port *s = container_of(port, struct max310x_port, port);
+
+	return (port->type == PORT_MAX310X) ? s->name : NULL;
+}
+
+static int max310x_request_port(struct uart_port *port)
+{
+	/* Do nothing */
+	return 0;
+}
+
+static void max310x_release_port(struct uart_port *port)
+{
+	/* Do nothing */
+}
+
+static void max310x_config_port(struct uart_port *port, int flags)
+{
+	if (flags & UART_CONFIG_TYPE)
+		port->type = PORT_MAX310X;
+}
+
+static int max310x_verify_port(struct uart_port *port, struct serial_struct *ser)
+{
+	if ((ser->type == PORT_UNKNOWN) || (ser->type == PORT_MAX310X))
+		return 0;
+	if (ser->irq == port->irq)
+		return 0;
+
+	return -EINVAL;
+}
+
+static struct uart_ops max310x_ops = {
+	.tx_empty	= max310x_tx_empty,
+	.set_mctrl	= max310x_set_mctrl,
+	.get_mctrl	= max310x_get_mctrl,
+	.stop_tx	= max310x_stop_tx,
+	.start_tx	= max310x_start_tx,
+	.stop_rx	= max310x_stop_rx,
+	.enable_ms	= max310x_enable_ms,
+	.break_ctl	= max310x_break_ctl,
+	.startup	= max310x_startup,
+	.shutdown	= max310x_shutdown,
+	.set_termios	= max310x_set_termios,
+	.type		= max310x_type,
+	.request_port	= max310x_request_port,
+	.release_port	= max310x_release_port,
+	.config_port	= max310x_config_port,
+	.verify_port	= max310x_verify_port,
+};
+
+static int max310x_suspend(struct spi_device *spi, pm_message_t state)
+{
+	int ret;
+	struct max310x_port *s = dev_get_drvdata(&spi->dev);
+
+	dev_dbg(&spi->dev, "Suspend\n");
+
+	ret = uart_suspend_port(&s->uart, &s->port);
+
+	mutex_lock(&s->max310x_mutex);
+
+	/* Enable sleep mode */
+	regmap_update_bits(s->regmap, MAX310X_MODE1_REG,
+			   MAX310X_MODE1_FORCESLEEP_BIT,
+			   MAX310X_MODE1_FORCESLEEP_BIT);
+
+	mutex_unlock(&s->max310x_mutex);
+
+	if (s->pdata->suspend)
+		s->pdata->suspend(1);
+
+	return ret;
+}
+
+static int max310x_resume(struct spi_device *spi)
+{
+	struct max310x_port *s = dev_get_drvdata(&spi->dev);
+
+	dev_dbg(&spi->dev, "Resume\n");
+
+	if (s->pdata->suspend)
+		s->pdata->suspend(0);
+
+	mutex_lock(&s->max310x_mutex);
+
+	/* Disable sleep mode */
+	regmap_update_bits(s->regmap, MAX310X_MODE1_REG,
+			   MAX310X_MODE1_FORCESLEEP_BIT,
+			   0);
+
+	max310x_wait_pll(s);
+
+	mutex_unlock(&s->max310x_mutex);
+
+	return uart_resume_port(&s->uart, &s->port);
+}
+
+#ifdef CONFIG_GPIOLIB
+static int max310x_gpio_get(struct gpio_chip *chip, unsigned offset)
+{
+	unsigned int val = 0;
+	struct max310x_port *s = container_of(chip, struct max310x_port, gpio);
+
+	mutex_lock(&s->max310x_mutex);
+	regmap_read(s->regmap, MAX310X_GPIODATA_REG, &val);
+	mutex_unlock(&s->max310x_mutex);
+
+	return !!((val >> 4) & (1 << offset));
+}
+
+static void max310x_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
+{
+	struct max310x_port *s = container_of(chip, struct max310x_port, gpio);
+
+	mutex_lock(&s->max310x_mutex);
+	regmap_update_bits(s->regmap, MAX310X_GPIODATA_REG, 1 << offset, value ?
+							    1 << offset : 0);
+	mutex_unlock(&s->max310x_mutex);
+}
+
+static int max310x_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
+{
+	struct max310x_port *s = container_of(chip, struct max310x_port, gpio);
+
+	mutex_lock(&s->max310x_mutex);
+
+	regmap_update_bits(s->regmap, MAX310X_GPIOCFG_REG, 1 << offset, 0);
+
+	mutex_unlock(&s->max310x_mutex);
+
+	return 0;
+}
+
+static int max310x_gpio_direction_output(struct gpio_chip *chip,
+					 unsigned offset, int value)
+{
+	struct max310x_port *s = container_of(chip, struct max310x_port, gpio);
+
+	mutex_lock(&s->max310x_mutex);
+
+	regmap_update_bits(s->regmap, MAX310X_GPIOCFG_REG, 1 << offset,
+							   1 << offset);
+	regmap_update_bits(s->regmap, MAX310X_GPIODATA_REG, 1 << offset, value ?
+							    1 << offset : 0);
+
+	mutex_unlock(&s->max310x_mutex);
+
+	return 0;
+}
+#endif
+
+/* Generic platform data */
+static struct max310x_pdata generic_plat_data = {
+	.driver_flags	= MAX310X_EXT_CLK,
+	.uart_flags[0]	= MAX310X_ECHO_SUPRESS,
+	.frequency	= 26000000,
+};
+
+static int __devinit max310x_probe(struct spi_device *spi)
+{
+	struct max310x_port *s;
+	struct device *dev = &spi->dev;
+	int chiptype = spi_get_device_id(spi)->driver_data;
+	struct max310x_pdata *pdata = dev->platform_data;
+	unsigned int val = 0;
+	int ret;
+
+	/* Check for IRQ */
+	if (spi->irq <= 0) {
+		dev_err(dev, "No IRQ specified\n");
+		return -ENOTSUPP;
+	}
+
+	/* Alloc port structure */
+	s = devm_kzalloc(dev, sizeof(struct max310x_port), GFP_KERNEL);
+	if (!s) {
+		dev_err(dev, "Error allocating port structure\n");
+		return -ENOMEM;
+	}
+	dev_set_drvdata(dev, s);
+
+	if (!pdata) {
+		dev_warn(dev, "No platform data supplied, using defaults\n");
+		pdata = &generic_plat_data;
+	}
+	s->pdata = pdata;
+
+	/* Individual chip settings */
+	switch (chiptype) {
+	case MAX310X_TYPE_MAX3107:
+		s->name = "MAX3107";
+		s->nr_gpio = 4;
+		s->uart.nr = 1;
+		s->regcfg.max_register = 0x1f;
+		break;
+	case MAX310X_TYPE_MAX3108:
+		s->name = "MAX3108";
+		s->nr_gpio = 4;
+		s->uart.nr = 1;
+		s->regcfg.max_register = 0x1e;
+		break;
+	default:
+		dev_err(dev, "Unsupported chip type %i\n", chiptype);
+		return -ENOTSUPP;
+	}
+
+	/* Check input frequency */
+	if ((pdata->driver_flags & MAX310X_EXT_CLK) &&
+	   ((pdata->frequency < 500000) || (pdata->frequency > 35000000)))
+		goto err_freq;
+	/* Check frequency for quartz */
+	if (!(pdata->driver_flags & MAX310X_EXT_CLK) &&
+	   ((pdata->frequency < 1000000) || (pdata->frequency > 4000000)))
+		goto err_freq;
+
+	mutex_init(&s->max310x_mutex);
+
+	/* Setup SPI bus */
+	spi->mode		= SPI_MODE_0;
+	spi->bits_per_word	= 8;
+	spi->max_speed_hz	= 26000000;
+	spi_setup(spi);
+
+	/* Setup regmap */
+	s->regcfg.reg_bits		= 8;
+	s->regcfg.val_bits		= 8;
+	s->regcfg.read_flag_mask	= 0x00;
+	s->regcfg.write_flag_mask	= 0x80;
+	s->regcfg.cache_type		= REGCACHE_RBTREE;
+	s->regcfg.writeable_reg		= max3107_8_reg_writeable;
+	s->regcfg.volatile_reg		= max310x_reg_volatile;
+	s->regcfg.precious_reg		= max310x_reg_precious;
+	s->regmap = devm_regmap_init_spi(spi, &s->regcfg);
+	if (IS_ERR(s->regmap)) {
+		ret = PTR_ERR(s->regmap);
+		dev_err(dev, "Failed to initialize register map\n");
+		goto err_out;
+	}
+
+	/* Reset chip & check SPI function */
+	ret = regmap_write(s->regmap, MAX310X_MODE2_REG, MAX310X_MODE2_RST_BIT);
+	if (ret) {
+		dev_err(dev, "SPI transfer failed\n");
+		goto err_out;
+	}
+	/* Clear chip reset */
+	regmap_write(s->regmap, MAX310X_MODE2_REG, 0);
+
+	switch (chiptype) {
+	case MAX310X_TYPE_MAX3107:
+		/* Check REV ID to ensure we are talking to what we expect */
+		regmap_read(s->regmap, MAX3107_REVID_REG, &val);
+		if (((val & MAX3107_REV_MASK) != MAX3107_REV_ID)) {
+			dev_err(dev, "%s ID 0x%02x does not match\n",
+				s->name, val);
+			ret = -ENODEV;
+			goto err_out;
+		}
+		break;
+	case MAX310X_TYPE_MAX3108:
+		/* MAX3108 have not REV ID register, we just check default value
+		 * from clocksource register to make sure everything works.
+		 */
+		regmap_read(s->regmap, MAX310X_CLKSRC_REG, &val);
+		if (val != (MAX310X_CLKSRC_EXTCLK_BIT |
+			    MAX310X_CLKSRC_PLLBYP_BIT)) {
+			dev_err(dev, "%s not present\n", s->name);
+			ret = -ENODEV;
+			goto err_out;
+		}
+		break;
+	}
+
+	/* Board specific configure */
+	if (pdata->init)
+		pdata->init();
+	if (pdata->suspend)
+		pdata->suspend(0);
+
+	/* Calculate referecne clock */
+	s->uartclk = max310x_set_ref_clk(s);
+
+	/* Disable all interrupts */
+	regmap_write(s->regmap, MAX310X_IRQEN_REG, 0);
+
+	/* Setup MODE1 register */
+	val = MAX310X_MODE1_IRQSEL_BIT; /* Enable IRQ pin */
+	if (pdata->driver_flags & MAX310X_AUTOSLEEP)
+		val = MAX310X_MODE1_AUTOSLEEP_BIT;
+	regmap_write(s->regmap, MAX310X_MODE1_REG, val);
+
+	/* Setup interrupt */
+	ret = devm_request_threaded_irq(dev, spi->irq, NULL, max310x_ist,
+					IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
+					dev_name(dev), s);
+	if (ret) {
+		dev_err(dev, "Unable to reguest IRQ %i\n", spi->irq);
+		goto err_out;
+	}
+
+	/* Register UART driver */
+	s->uart.owner		= THIS_MODULE;
+	s->uart.driver_name	= dev_name(dev);
+	s->uart.dev_name	= "ttyMAX";
+	s->uart.major		= MAX310X_MAJOR;
+	s->uart.minor		= MAX310X_MINOR;
+	ret = uart_register_driver(&s->uart);
+	if (ret) {
+		dev_err(dev, "Registering UART driver failed\n");
+		goto err_out;
+	}
+
+	/* Initialize workqueue for start TX */
+	s->wq = create_freezable_workqueue(dev_name(dev));
+	INIT_WORK(&s->tx_work, max310x_wq_proc);
+
+	/* Initialize UART port data */
+	s->port.line		= 0;
+	s->port.dev		= dev;
+	s->port.irq		= spi->irq;
+	s->port.type		= PORT_MAX310X;
+	s->port.fifosize	= MAX310X_FIFO_SIZE;
+	s->port.flags		= UPF_SKIP_TEST | UPF_FIXED_TYPE;
+	s->port.iotype		= UPIO_PORT;
+	s->port.membase		= (void __iomem *)0xffffffff; /* Bogus value */
+	s->port.uartclk		= s->uartclk;
+	s->port.ops		= &max310x_ops;
+	uart_add_one_port(&s->uart, &s->port);
+
+#ifdef CONFIG_GPIOLIB
+	/* Setup GPIO cotroller */
+	if (pdata->gpio_base) {
+		s->gpio.owner		= THIS_MODULE;
+		s->gpio.dev		= dev;
+		s->gpio.label		= dev_name(dev);
+		s->gpio.direction_input	= max310x_gpio_direction_input;
+		s->gpio.get		= max310x_gpio_get;
+		s->gpio.direction_output= max310x_gpio_direction_output;
+		s->gpio.set		= max310x_gpio_set;
+		s->gpio.base		= pdata->gpio_base;
+		s->gpio.ngpio		= s->nr_gpio;
+		if (gpiochip_add(&s->gpio)) {
+			/* Indicate that we should not call gpiochip_remove */
+			s->gpio.base = 0;
+		}
+	} else
+		dev_info(dev, "GPIO support not enabled\n");
+#endif
+
+	/* Go to suspend mode */
+	if (pdata->suspend)
+		pdata->suspend(1);
+
+	return 0;
+
+err_freq:
+	dev_err(dev, "Frequency parameter incorrect\n");
+	ret = -EINVAL;
+
+err_out:
+	dev_set_drvdata(dev, NULL);
+	devm_kfree(dev, s);
+
+	return ret;
+}
+
+static int __devexit max310x_remove(struct spi_device *spi)
+{
+	struct device *dev = &spi->dev;
+	struct max310x_port *s = dev_get_drvdata(dev);
+
+	dev_dbg(dev, "Removing port\n");
+
+	devm_free_irq(dev, s->port.irq, s);
+
+	destroy_workqueue(s->wq);
+
+	uart_remove_one_port(&s->uart, &s->port);
+
+	uart_unregister_driver(&s->uart);
+
+#ifdef CONFIG_GPIOLIB
+	if (s->pdata->gpio_base)
+		gpiochip_remove(&s->gpio);
+#endif
+
+	dev_set_drvdata(dev, NULL);
+
+	if (s->pdata->suspend)
+		s->pdata->suspend(1);
+	if (s->pdata->exit)
+		s->pdata->exit();
+
+	devm_kfree(dev, s);
+
+	return 0;
+}
+
+static const struct spi_device_id max310x_id_table[] = {
+	{ "max3107",	MAX310X_TYPE_MAX3107 },
+	{ "max3108",	MAX310X_TYPE_MAX3108 },
+};
+MODULE_DEVICE_TABLE(spi, max310x_id_table);
+
+static struct spi_driver max310x_driver = {
+	.driver = {
+		.name	= "max310x",
+		.owner	= THIS_MODULE,
+	},
+	.probe		= max310x_probe,
+	.remove		= __devexit_p(max310x_remove),
+	.suspend	= max310x_suspend,
+	.resume		= max310x_resume,
+	.id_table	= max310x_id_table,
+};
+module_spi_driver(max310x_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Alexander Shiyan <shc_work@mail.ru>");
+MODULE_DESCRIPTION("MAX310X serial driver");