Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1700 insertions, 0 deletions

diff --git a/drivers/tty/serial/max310x.c b/drivers/tty/serial/max310x.c
new file mode 100644
index 000000000..338cb19de
--- /dev/null
+++ b/drivers/tty/serial/max310x.c
@@ -0,0 +1,1700 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ *  Maxim (Dallas) MAX3107/8/9, MAX14830 serial driver
+ *
+ *  Copyright (C) 2012-2016 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
+ */
+
+#include <linux/bitops.h>
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/gpio/driver.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/mod_devicetable.h>
+#include <linux/property.h>
+#include <linux/regmap.h>
+#include <linux/serial_core.h>
+#include <linux/serial.h>
+#include <linux/tty.h>
+#include <linux/tty_flip.h>
+#include <linux/spi/spi.h>
+#include <linux/uaccess.h>
+
+#define MAX310X_NAME			"max310x"
+#define MAX310X_MAJOR			204
+#define MAX310X_MINOR			209
+#define MAX310X_UART_NRMAX		16
+
+/* 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_REG_05			(0x05)
+#define MAX310X_SPCHR_IRQEN_REG		MAX310X_REG_05 /* Special char IRQ en */
+#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 */
+#define MAX310X_REG_1F			(0x1f)
+
+#define MAX310X_REVID_REG		MAX310X_REG_1F /* Revision ID */
+
+#define MAX310X_GLOBALIRQ_REG		MAX310X_REG_1F /* Global IRQ (RO) */
+#define MAX310X_GLOBALCMD_REG		MAX310X_REG_1F /* Global Command (WO) */
+
+/* Extended registers */
+#define MAX310X_SPI_REVID_EXTREG	MAX310X_REG_05 /* Revision ID */
+#define MAX310X_I2C_REVID_EXTREG	(0x25) /* Revision ID */
+
+/* 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 */
+
+/* IRDA register bits */
+#define MAX310X_IRDA_IRDAEN_BIT		(1 << 0) /* IRDA mode enable */
+#define MAX310X_IRDA_SIR_BIT		(1 << 1) /* SIR mode 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
+						  */
+
+/* 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 */
+
+/* Global commands */
+#define MAX310X_EXTREG_ENBL		(0xce)
+#define MAX310X_EXTREG_DSBL		(0xcd)
+
+/* Misc definitions */
+#define MAX310X_FIFO_SIZE		(128)
+#define MAX310x_REV_MASK		(0xf8)
+#define MAX310X_WRITE_BIT		0x80
+
+/* MAX3107 specific */
+#define MAX3107_REV_ID			(0xa0)
+
+/* MAX3109 specific */
+#define MAX3109_REV_ID			(0xc0)
+
+/* MAX14830 specific */
+#define MAX14830_BRGCFG_CLKDIS_BIT	(1 << 6) /* Clock Disable */
+#define MAX14830_REV_ID			(0xb0)
+
+struct max310x_if_cfg {
+	int (*extended_reg_enable)(struct device *dev, bool enable);
+
+	unsigned int rev_id_reg;
+};
+
+struct max310x_devtype {
+	struct {
+		unsigned short min;
+		unsigned short max;
+	} slave_addr;
+	char	name[9];
+	int	nr;
+	u8	mode1;
+	int	(*detect)(struct device *);
+	void	(*power)(struct uart_port *, int);
+};
+
+struct max310x_one {
+	struct uart_port	port;
+	struct work_struct	tx_work;
+	struct work_struct	md_work;
+	struct work_struct	rs_work;
+	struct regmap		*regmap;
+
+	u8 rx_buf[MAX310X_FIFO_SIZE];
+};
+#define to_max310x_port(_port) \
+	container_of(_port, struct max310x_one, port)
+
+struct max310x_port {
+	const struct max310x_devtype *devtype;
+	const struct max310x_if_cfg *if_cfg;
+	struct regmap		*regmap;
+	struct clk		*clk;
+#ifdef CONFIG_GPIOLIB
+	struct gpio_chip	gpio;
+#endif
+	struct max310x_one	p[];
+};
+
+static struct uart_driver max310x_uart = {
+	.owner		= THIS_MODULE,
+	.driver_name	= MAX310X_NAME,
+	.dev_name	= "ttyMAX",
+	.major		= MAX310X_MAJOR,
+	.minor		= MAX310X_MINOR,
+	.nr		= MAX310X_UART_NRMAX,
+};
+
+static DECLARE_BITMAP(max310x_lines, MAX310X_UART_NRMAX);
+
+static u8 max310x_port_read(struct uart_port *port, u8 reg)
+{
+	struct max310x_one *one = to_max310x_port(port);
+	unsigned int val = 0;
+
+	regmap_read(one->regmap, reg, &val);
+
+	return val;
+}
+
+static void max310x_port_write(struct uart_port *port, u8 reg, u8 val)
+{
+	struct max310x_one *one = to_max310x_port(port);
+
+	regmap_write(one->regmap, reg, val);
+}
+
+static void max310x_port_update(struct uart_port *port, u8 reg, u8 mask, u8 val)
+{
+	struct max310x_one *one = to_max310x_port(port);
+
+	regmap_update_bits(one->regmap, reg, mask, val);
+}
+
+static int max3107_detect(struct device *dev)
+{
+	struct max310x_port *s = dev_get_drvdata(dev);
+	unsigned int val = 0;
+	int ret;
+
+	ret = regmap_read(s->regmap, MAX310X_REVID_REG, &val);
+	if (ret)
+		return ret;
+
+	if (((val & MAX310x_REV_MASK) != MAX3107_REV_ID)) {
+		dev_err(dev,
+			"%s ID 0x%02x does not match\n", s->devtype->name, val);
+		return -ENODEV;
+	}
+
+	return 0;
+}
+
+static int max3108_detect(struct device *dev)
+{
+	struct max310x_port *s = dev_get_drvdata(dev);
+	unsigned int val = 0;
+	int ret;
+
+	/* MAX3108 have not REV ID register, we just check default value
+	 * from clocksource register to make sure everything works.
+	 */
+	ret = regmap_read(s->regmap, MAX310X_CLKSRC_REG, &val);
+	if (ret)
+		return ret;
+
+	if (val != (MAX310X_CLKSRC_EXTCLK_BIT | MAX310X_CLKSRC_PLLBYP_BIT)) {
+		dev_err(dev, "%s not present\n", s->devtype->name);
+		return -ENODEV;
+	}
+
+	return 0;
+}
+
+static int max3109_detect(struct device *dev)
+{
+	struct max310x_port *s = dev_get_drvdata(dev);
+	unsigned int val = 0;
+	int ret;
+
+	ret = s->if_cfg->extended_reg_enable(dev, true);
+	if (ret)
+		return ret;
+
+	regmap_read(s->regmap, s->if_cfg->rev_id_reg, &val);
+	s->if_cfg->extended_reg_enable(dev, false);
+	if (((val & MAX310x_REV_MASK) != MAX3109_REV_ID)) {
+		dev_err(dev,
+			"%s ID 0x%02x does not match\n", s->devtype->name, val);
+		return -ENODEV;
+	}
+
+	return 0;
+}
+
+static void max310x_power(struct uart_port *port, int on)
+{
+	max310x_port_update(port, MAX310X_MODE1_REG,
+			    MAX310X_MODE1_FORCESLEEP_BIT,
+			    on ? 0 : MAX310X_MODE1_FORCESLEEP_BIT);
+	if (on)
+		msleep(50);
+}
+
+static int max14830_detect(struct device *dev)
+{
+	struct max310x_port *s = dev_get_drvdata(dev);
+	unsigned int val = 0;
+	int ret;
+
+	ret = s->if_cfg->extended_reg_enable(dev, true);
+	if (ret)
+		return ret;
+	
+	regmap_read(s->regmap, s->if_cfg->rev_id_reg, &val);
+	s->if_cfg->extended_reg_enable(dev, false);
+	if (((val & MAX310x_REV_MASK) != MAX14830_REV_ID)) {
+		dev_err(dev,
+			"%s ID 0x%02x does not match\n", s->devtype->name, val);
+		return -ENODEV;
+	}
+
+	return 0;
+}
+
+static void max14830_power(struct uart_port *port, int on)
+{
+	max310x_port_update(port, MAX310X_BRGCFG_REG,
+			    MAX14830_BRGCFG_CLKDIS_BIT,
+			    on ? 0 : MAX14830_BRGCFG_CLKDIS_BIT);
+	if (on)
+		msleep(50);
+}
+
+static const struct max310x_devtype max3107_devtype = {
+	.name	= "MAX3107",
+	.nr	= 1,
+	.mode1	= MAX310X_MODE1_AUTOSLEEP_BIT | MAX310X_MODE1_IRQSEL_BIT,
+	.detect	= max3107_detect,
+	.power	= max310x_power,
+	.slave_addr	= {
+		.min = 0x2c,
+		.max = 0x2f,
+	},
+};
+
+static const struct max310x_devtype max3108_devtype = {
+	.name	= "MAX3108",
+	.nr	= 1,
+	.mode1	= MAX310X_MODE1_AUTOSLEEP_BIT,
+	.detect	= max3108_detect,
+	.power	= max310x_power,
+	.slave_addr	= {
+		.min = 0x60,
+		.max = 0x6f,
+	},
+};
+
+static const struct max310x_devtype max3109_devtype = {
+	.name	= "MAX3109",
+	.nr	= 2,
+	.mode1	= MAX310X_MODE1_AUTOSLEEP_BIT,
+	.detect	= max3109_detect,
+	.power	= max310x_power,
+	.slave_addr	= {
+		.min = 0x60,
+		.max = 0x6f,
+	},
+};
+
+static const struct max310x_devtype max14830_devtype = {
+	.name	= "MAX14830",
+	.nr	= 4,
+	.mode1	= MAX310X_MODE1_IRQSEL_BIT,
+	.detect	= max14830_detect,
+	.power	= max14830_power,
+	.slave_addr	= {
+		.min = 0x60,
+		.max = 0x6f,
+	},
+};
+
+static bool max310x_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:
+		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:
+	case MAX310X_BRGDIVLSB_REG:
+	case MAX310X_REG_05:
+	case MAX310X_REG_1F:
+		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 bool max310x_reg_noinc(struct device *dev, unsigned int reg)
+{
+	return reg == MAX310X_RHR_REG;
+}
+
+static int max310x_set_baud(struct uart_port *port, int baud)
+{
+	unsigned int mode = 0, div = 0, frac = 0, c = 0, F = 0;
+
+	/*
+	 * Calculate the integer divisor first. Select a proper mode
+	 * in case if the requested baud is too high for the pre-defined
+	 * clocks frequency.
+	 */
+	div = port->uartclk / baud;
+	if (div < 8) {
+		/* Mode x4 */
+		c = 4;
+		mode = MAX310X_BRGCFG_4XMODE_BIT;
+	} else if (div < 16) {
+		/* Mode x2 */
+		c = 8;
+		mode = MAX310X_BRGCFG_2XMODE_BIT;
+	} else {
+		c = 16;
+	}
+
+	/* Calculate the divisor in accordance with the fraction coefficient */
+	div /= c;
+	F = c*baud;
+
+	/* Calculate the baud rate fraction */
+	if (div > 0)
+		frac = (16*(port->uartclk % F)) / F;
+	else
+		div = 1;
+
+	max310x_port_write(port, MAX310X_BRGDIVMSB_REG, div >> 8);
+	max310x_port_write(port, MAX310X_BRGDIVLSB_REG, div);
+	max310x_port_write(port, MAX310X_BRGCFG_REG, frac | mode);
+
+	/* Return the actual baud rate we just programmed */
+	return (16*port->uartclk) / (c*(16*div + frac));
+}
+
+static int max310x_update_best_err(unsigned long f, long *besterr)
+{
+	/* Use baudrate 115200 for calculate error */
+	long err = f % (460800 * 16);
+
+	if ((*besterr < 0) || (*besterr > err)) {
+		*besterr = err;
+		return 0;
+	}
+
+	return 1;
+}
+
+static u32 max310x_set_ref_clk(struct device *dev, struct max310x_port *s,
+			       unsigned long freq, bool xtal)
+{
+	unsigned int div, clksrc, pllcfg = 0;
+	long besterr = -1;
+	unsigned long fdiv, fmul, bestfreq = freq;
+
+	/* First, update error without PLL */
+	max310x_update_best_err(freq, &besterr);
+
+	/* Try all possible PLL dividers */
+	for (div = 1; (div <= 63) && besterr; div++) {
+		fdiv = DIV_ROUND_CLOSEST(freq, 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 */
+	clksrc = MAX310X_CLKSRC_EXTCLK_BIT | (xtal ? MAX310X_CLKSRC_CRYST_BIT : 0);
+
+	/* 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);
+
+	/* Wait for crystal */
+	if (xtal) {
+		unsigned int val;
+		msleep(10);
+		regmap_read(s->regmap, MAX310X_STS_IRQSTS_REG, &val);
+		if (!(val & MAX310X_STS_CLKREADY_BIT)) {
+			dev_warn(dev, "clock is not stable yet\n");
+		}
+	}
+
+	return bestfreq;
+}
+
+static void max310x_batch_write(struct uart_port *port, u8 *txbuf, unsigned int len)
+{
+	struct max310x_one *one = to_max310x_port(port);
+
+	regmap_noinc_write(one->regmap, MAX310X_THR_REG, txbuf, len);
+}
+
+static void max310x_batch_read(struct uart_port *port, u8 *rxbuf, unsigned int len)
+{
+	struct max310x_one *one = to_max310x_port(port);
+
+	regmap_noinc_read(one->regmap, MAX310X_RHR_REG, rxbuf, len);
+}
+
+static void max310x_handle_rx(struct uart_port *port, unsigned int rxlen)
+{
+	struct max310x_one *one = to_max310x_port(port);
+	unsigned int sts, ch, flag, i;
+
+	if (port->read_status_mask == MAX310X_LSR_RXOVR_BIT) {
+		/* We are just reading, happily ignoring any error conditions.
+		 * Break condition, parity checking, framing errors -- they
+		 * are all ignored. That means that we can do a batch-read.
+		 *
+		 * There is a small opportunity for race if the RX FIFO
+		 * overruns while we're reading the buffer; the datasheets says
+		 * that the LSR register applies to the "current" character.
+		 * That's also the reason why we cannot do batched reads when
+		 * asked to check the individual statuses.
+		 * */
+
+		sts = max310x_port_read(port, MAX310X_LSR_IRQSTS_REG);
+		max310x_batch_read(port, one->rx_buf, rxlen);
+
+		port->icount.rx += rxlen;
+		flag = TTY_NORMAL;
+		sts &= port->read_status_mask;
+
+		if (sts & MAX310X_LSR_RXOVR_BIT) {
+			dev_warn_ratelimited(port->dev, "Hardware RX FIFO overrun\n");
+			port->icount.overrun++;
+		}
+
+		for (i = 0; i < (rxlen - 1); ++i)
+			uart_insert_char(port, sts, 0, one->rx_buf[i], flag);
+
+		/*
+		 * Handle the overrun case for the last character only, since
+		 * the RxFIFO overflow happens after it is pushed to the FIFO
+		 * tail.
+		 */
+		uart_insert_char(port, sts, MAX310X_LSR_RXOVR_BIT,
+				 one->rx_buf[rxlen-1], flag);
+
+	} else {
+		if (unlikely(rxlen >= port->fifosize)) {
+			dev_warn_ratelimited(port->dev, "Possible RX FIFO overrun\n");
+			port->icount.buf_overrun++;
+			/* Ensure sanity of RX level */
+			rxlen = port->fifosize;
+		}
+
+		while (rxlen--) {
+			ch = max310x_port_read(port, MAX310X_RHR_REG);
+			sts = max310x_port_read(port, MAX310X_LSR_IRQSTS_REG);
+
+			sts &= MAX310X_LSR_RXPAR_BIT | MAX310X_LSR_FRERR_BIT |
+			       MAX310X_LSR_RXOVR_BIT | MAX310X_LSR_RXBRK_BIT;
+
+			port->icount.rx++;
+			flag = TTY_NORMAL;
+
+			if (unlikely(sts)) {
+				if (sts & MAX310X_LSR_RXBRK_BIT) {
+					port->icount.brk++;
+					if (uart_handle_break(port))
+						continue;
+				} else if (sts & MAX310X_LSR_RXPAR_BIT)
+					port->icount.parity++;
+				else if (sts & MAX310X_LSR_FRERR_BIT)
+					port->icount.frame++;
+				else if (sts & MAX310X_LSR_RXOVR_BIT)
+					port->icount.overrun++;
+
+				sts &= 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(port, ch))
+				continue;
+
+			if (sts & port->ignore_status_mask)
+				continue;
+
+			uart_insert_char(port, sts, MAX310X_LSR_RXOVR_BIT, ch, flag);
+		}
+	}
+
+	tty_flip_buffer_push(&port->state->port);
+}
+
+static void max310x_handle_tx(struct uart_port *port)
+{
+	struct circ_buf *xmit = &port->state->xmit;
+	unsigned int txlen, to_send, until_end;
+
+	if (unlikely(port->x_char)) {
+		max310x_port_write(port, MAX310X_THR_REG, port->x_char);
+		port->icount.tx++;
+		port->x_char = 0;
+		return;
+	}
+
+	if (uart_circ_empty(xmit) || uart_tx_stopped(port))
+		return;
+
+	/* Get length of data pending in circular buffer */
+	to_send = uart_circ_chars_pending(xmit);
+	until_end = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE);
+	if (likely(to_send)) {
+		/* Limit to size of TX FIFO */
+		txlen = max310x_port_read(port, MAX310X_TXFIFOLVL_REG);
+		txlen = port->fifosize - txlen;
+		to_send = (to_send > txlen) ? txlen : to_send;
+
+		if (until_end < to_send) {
+			/* It's a circ buffer -- wrap around.
+			 * We could do that in one SPI transaction, but meh. */
+			max310x_batch_write(port, xmit->buf + xmit->tail, until_end);
+			max310x_batch_write(port, xmit->buf, to_send - until_end);
+		} else {
+			max310x_batch_write(port, xmit->buf + xmit->tail, to_send);
+		}
+
+		/* Add data to send */
+		port->icount.tx += to_send;
+		xmit->tail = (xmit->tail + to_send) & (UART_XMIT_SIZE - 1);
+	}
+
+	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
+		uart_write_wakeup(port);
+}
+
+static void max310x_start_tx(struct uart_port *port)
+{
+	struct max310x_one *one = to_max310x_port(port);
+
+	schedule_work(&one->tx_work);
+}
+
+static irqreturn_t max310x_port_irq(struct max310x_port *s, int portno)
+{
+	struct uart_port *port = &s->p[portno].port;
+	irqreturn_t res = IRQ_NONE;
+
+	do {
+		unsigned int ists, lsr, rxlen;
+
+		/* Read IRQ status & RX FIFO level */
+		ists = max310x_port_read(port, MAX310X_IRQSTS_REG);
+		rxlen = max310x_port_read(port, MAX310X_RXFIFOLVL_REG);
+		if (!ists && !rxlen)
+			break;
+
+		res = IRQ_HANDLED;
+
+		if (ists & MAX310X_IRQ_CTS_BIT) {
+			lsr = max310x_port_read(port, MAX310X_LSR_IRQSTS_REG);
+			uart_handle_cts_change(port,
+					       !!(lsr & MAX310X_LSR_CTS_BIT));
+		}
+		if (rxlen)
+			max310x_handle_rx(port, rxlen);
+		if (ists & MAX310X_IRQ_TXEMPTY_BIT)
+			max310x_start_tx(port);
+	} while (1);
+	return res;
+}
+
+static irqreturn_t max310x_ist(int irq, void *dev_id)
+{
+	struct max310x_port *s = (struct max310x_port *)dev_id;
+	bool handled = false;
+
+	if (s->devtype->nr > 1) {
+		do {
+			unsigned int val = ~0;
+
+			WARN_ON_ONCE(regmap_read(s->regmap,
+						 MAX310X_GLOBALIRQ_REG, &val));
+			val = ((1 << s->devtype->nr) - 1) & ~val;
+			if (!val)
+				break;
+			if (max310x_port_irq(s, fls(val) - 1) == IRQ_HANDLED)
+				handled = true;
+		} while (1);
+	} else {
+		if (max310x_port_irq(s, 0) == IRQ_HANDLED)
+			handled = true;
+	}
+
+	return IRQ_RETVAL(handled);
+}
+
+static void max310x_tx_proc(struct work_struct *ws)
+{
+	struct max310x_one *one = container_of(ws, struct max310x_one, tx_work);
+
+	max310x_handle_tx(&one->port);
+}
+
+static unsigned int max310x_tx_empty(struct uart_port *port)
+{
+	u8 lvl = max310x_port_read(port, MAX310X_TXFIFOLVL_REG);
+
+	return lvl ? 0 : TIOCSER_TEMT;
+}
+
+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_md_proc(struct work_struct *ws)
+{
+	struct max310x_one *one = container_of(ws, struct max310x_one, md_work);
+
+	max310x_port_update(&one->port, MAX310X_MODE2_REG,
+			    MAX310X_MODE2_LOOPBACK_BIT,
+			    (one->port.mctrl & TIOCM_LOOP) ?
+			    MAX310X_MODE2_LOOPBACK_BIT : 0);
+}
+
+static void max310x_set_mctrl(struct uart_port *port, unsigned int mctrl)
+{
+	struct max310x_one *one = to_max310x_port(port);
+
+	schedule_work(&one->md_work);
+}
+
+static void max310x_break_ctl(struct uart_port *port, int break_state)
+{
+	max310x_port_update(port, MAX310X_LCR_REG,
+			    MAX310X_LCR_TXBREAK_BIT,
+			    break_state ? MAX310X_LCR_TXBREAK_BIT : 0);
+}
+
+static void max310x_set_termios(struct uart_port *port,
+				struct ktermios *termios,
+				const struct ktermios *old)
+{
+	unsigned int lcr = 0, flow = 0;
+	int baud;
+
+	/* Mask termios capabilities we don't support */
+	termios->c_cflag &= ~CMSPAR;
+
+	/* Word size */
+	switch (termios->c_cflag & CSIZE) {
+	case CS5:
+		break;
+	case CS6:
+		lcr = MAX310X_LCR_LENGTH0_BIT;
+		break;
+	case CS7:
+		lcr = MAX310X_LCR_LENGTH1_BIT;
+		break;
+	case CS8:
+	default:
+		lcr = MAX310X_LCR_LENGTH1_BIT | MAX310X_LCR_LENGTH0_BIT;
+		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 */
+	max310x_port_write(port, 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 & (IGNBRK | 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 */
+	max310x_port_write(port, MAX310X_XON1_REG, termios->c_cc[VSTART]);
+	max310x_port_write(port, MAX310X_XOFF1_REG, termios->c_cc[VSTOP]);
+
+	/* Disable transmitter before enabling AutoCTS or auto transmitter
+	 * flow control
+	 */
+	if (termios->c_cflag & CRTSCTS || termios->c_iflag & IXOFF) {
+		max310x_port_update(port, MAX310X_MODE1_REG,
+				    MAX310X_MODE1_TXDIS_BIT,
+				    MAX310X_MODE1_TXDIS_BIT);
+	}
+
+	port->status &= ~(UPSTAT_AUTOCTS | UPSTAT_AUTORTS | UPSTAT_AUTOXOFF);
+
+	if (termios->c_cflag & CRTSCTS) {
+		/* Enable AUTORTS and AUTOCTS */
+		port->status |= UPSTAT_AUTOCTS | UPSTAT_AUTORTS;
+		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) {
+		port->status |= UPSTAT_AUTOXOFF;
+		flow |= MAX310X_FLOWCTRL_SWFLOW1_BIT |
+			MAX310X_FLOWCTRL_SWFLOWEN_BIT;
+	}
+	max310x_port_write(port, MAX310X_FLOWCTRL_REG, flow);
+
+	/* Enable transmitter after disabling AutoCTS and auto transmitter
+	 * flow control
+	 */
+	if (!(termios->c_cflag & CRTSCTS) && !(termios->c_iflag & IXOFF)) {
+		max310x_port_update(port, MAX310X_MODE1_REG,
+				    MAX310X_MODE1_TXDIS_BIT,
+				    0);
+	}
+
+	/* Get baud rate generator configuration */
+	baud = uart_get_baud_rate(port, termios, old,
+				  port->uartclk / 16 / 0xffff,
+				  port->uartclk / 4);
+
+	/* Setup baudrate generator */
+	baud = max310x_set_baud(port, baud);
+
+	/* Update timeout according to new baud rate */
+	uart_update_timeout(port, termios->c_cflag, baud);
+}
+
+static void max310x_rs_proc(struct work_struct *ws)
+{
+	struct max310x_one *one = container_of(ws, struct max310x_one, rs_work);
+	unsigned int delay, mode1 = 0, mode2 = 0;
+
+	delay = (one->port.rs485.delay_rts_before_send << 4) |
+		one->port.rs485.delay_rts_after_send;
+	max310x_port_write(&one->port, MAX310X_HDPIXDELAY_REG, delay);
+
+	if (one->port.rs485.flags & SER_RS485_ENABLED) {
+		mode1 = MAX310X_MODE1_TRNSCVCTRL_BIT;
+
+		if (!(one->port.rs485.flags & SER_RS485_RX_DURING_TX))
+			mode2 = MAX310X_MODE2_ECHOSUPR_BIT;
+	}
+
+	max310x_port_update(&one->port, MAX310X_MODE1_REG,
+			MAX310X_MODE1_TRNSCVCTRL_BIT, mode1);
+	max310x_port_update(&one->port, MAX310X_MODE2_REG,
+			MAX310X_MODE2_ECHOSUPR_BIT, mode2);
+}
+
+static int max310x_rs485_config(struct uart_port *port, struct ktermios *termios,
+				struct serial_rs485 *rs485)
+{
+	struct max310x_one *one = to_max310x_port(port);
+
+	if ((rs485->delay_rts_before_send > 0x0f) ||
+	    (rs485->delay_rts_after_send > 0x0f))
+		return -ERANGE;
+
+	port->rs485 = *rs485;
+
+	schedule_work(&one->rs_work);
+
+	return 0;
+}
+
+static int max310x_startup(struct uart_port *port)
+{
+	struct max310x_port *s = dev_get_drvdata(port->dev);
+	unsigned int val;
+
+	s->devtype->power(port, 1);
+
+	/* Configure MODE1 register */
+	max310x_port_update(port, MAX310X_MODE1_REG,
+			    MAX310X_MODE1_TRNSCVCTRL_BIT, 0);
+
+	/* Configure MODE2 register & Reset FIFOs*/
+	val = MAX310X_MODE2_RXEMPTINV_BIT | MAX310X_MODE2_FIFORST_BIT;
+	max310x_port_write(port, MAX310X_MODE2_REG, val);
+	max310x_port_update(port, MAX310X_MODE2_REG,
+			    MAX310X_MODE2_FIFORST_BIT, 0);
+
+	/* Configure mode1/mode2 to have rs485/rs232 enabled at startup */
+	val = (clamp(port->rs485.delay_rts_before_send, 0U, 15U) << 4) |
+		clamp(port->rs485.delay_rts_after_send, 0U, 15U);
+	max310x_port_write(port, MAX310X_HDPIXDELAY_REG, val);
+
+	if (port->rs485.flags & SER_RS485_ENABLED) {
+		max310x_port_update(port, MAX310X_MODE1_REG,
+				    MAX310X_MODE1_TRNSCVCTRL_BIT,
+				    MAX310X_MODE1_TRNSCVCTRL_BIT);
+
+		if (!(port->rs485.flags & SER_RS485_RX_DURING_TX))
+			max310x_port_update(port, MAX310X_MODE2_REG,
+					    MAX310X_MODE2_ECHOSUPR_BIT,
+					    MAX310X_MODE2_ECHOSUPR_BIT);
+	}
+
+	/* Configure flow control levels */
+	/* Flow control halt level 96, resume level 48 */
+	max310x_port_write(port, MAX310X_FLOWLVL_REG,
+			   MAX310X_FLOWLVL_RES(48) | MAX310X_FLOWLVL_HALT(96));
+
+	/* Clear IRQ status register */
+	max310x_port_read(port, MAX310X_IRQSTS_REG);
+
+	/* Enable RX, TX, CTS change interrupts */
+	val = MAX310X_IRQ_RXEMPTY_BIT | MAX310X_IRQ_TXEMPTY_BIT;
+	max310x_port_write(port, MAX310X_IRQEN_REG, val | MAX310X_IRQ_CTS_BIT);
+
+	return 0;
+}
+
+static void max310x_shutdown(struct uart_port *port)
+{
+	struct max310x_port *s = dev_get_drvdata(port->dev);
+
+	/* Disable all interrupts */
+	max310x_port_write(port, MAX310X_IRQEN_REG, 0);
+
+	s->devtype->power(port, 0);
+}
+
+static const char *max310x_type(struct uart_port *port)
+{
+	struct max310x_port *s = dev_get_drvdata(port->dev);
+
+	return (port->type == PORT_MAX310X) ? s->devtype->name : NULL;
+}
+
+static int max310x_request_port(struct uart_port *port)
+{
+	/* Do nothing */
+	return 0;
+}
+
+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 *s)
+{
+	if ((s->type != PORT_UNKNOWN) && (s->type != PORT_MAX310X))
+		return -EINVAL;
+	if (s->irq != port->irq)
+		return -EINVAL;
+
+	return 0;
+}
+
+static void max310x_null_void(struct uart_port *port)
+{
+	/* Do nothing */
+}
+
+static const struct uart_ops max310x_ops = {
+	.tx_empty	= max310x_tx_empty,
+	.set_mctrl	= max310x_set_mctrl,
+	.get_mctrl	= max310x_get_mctrl,
+	.stop_tx	= max310x_null_void,
+	.start_tx	= max310x_start_tx,
+	.stop_rx	= max310x_null_void,
+	.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_null_void,
+	.config_port	= max310x_config_port,
+	.verify_port	= max310x_verify_port,
+};
+
+static int __maybe_unused max310x_suspend(struct device *dev)
+{
+	struct max310x_port *s = dev_get_drvdata(dev);
+	int i;
+
+	for (i = 0; i < s->devtype->nr; i++) {
+		uart_suspend_port(&max310x_uart, &s->p[i].port);
+		s->devtype->power(&s->p[i].port, 0);
+	}
+
+	return 0;
+}
+
+static int __maybe_unused max310x_resume(struct device *dev)
+{
+	struct max310x_port *s = dev_get_drvdata(dev);
+	int i;
+
+	for (i = 0; i < s->devtype->nr; i++) {
+		s->devtype->power(&s->p[i].port, 1);
+		uart_resume_port(&max310x_uart, &s->p[i].port);
+	}
+
+	return 0;
+}
+
+static SIMPLE_DEV_PM_OPS(max310x_pm_ops, max310x_suspend, max310x_resume);
+
+#ifdef CONFIG_GPIOLIB
+static int max310x_gpio_get(struct gpio_chip *chip, unsigned offset)
+{
+	unsigned int val;
+	struct max310x_port *s = gpiochip_get_data(chip);
+	struct uart_port *port = &s->p[offset / 4].port;
+
+	val = max310x_port_read(port, MAX310X_GPIODATA_REG);
+
+	return !!((val >> 4) & (1 << (offset % 4)));
+}
+
+static void max310x_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
+{
+	struct max310x_port *s = gpiochip_get_data(chip);
+	struct uart_port *port = &s->p[offset / 4].port;
+
+	max310x_port_update(port, MAX310X_GPIODATA_REG, 1 << (offset % 4),
+			    value ? 1 << (offset % 4) : 0);
+}
+
+static int max310x_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
+{
+	struct max310x_port *s = gpiochip_get_data(chip);
+	struct uart_port *port = &s->p[offset / 4].port;
+
+	max310x_port_update(port, MAX310X_GPIOCFG_REG, 1 << (offset % 4), 0);
+
+	return 0;
+}
+
+static int max310x_gpio_direction_output(struct gpio_chip *chip,
+					 unsigned offset, int value)
+{
+	struct max310x_port *s = gpiochip_get_data(chip);
+	struct uart_port *port = &s->p[offset / 4].port;
+
+	max310x_port_update(port, MAX310X_GPIODATA_REG, 1 << (offset % 4),
+			    value ? 1 << (offset % 4) : 0);
+	max310x_port_update(port, MAX310X_GPIOCFG_REG, 1 << (offset % 4),
+			    1 << (offset % 4));
+
+	return 0;
+}
+
+static int max310x_gpio_set_config(struct gpio_chip *chip, unsigned int offset,
+				   unsigned long config)
+{
+	struct max310x_port *s = gpiochip_get_data(chip);
+	struct uart_port *port = &s->p[offset / 4].port;
+
+	switch (pinconf_to_config_param(config)) {
+	case PIN_CONFIG_DRIVE_OPEN_DRAIN:
+		max310x_port_update(port, MAX310X_GPIOCFG_REG,
+				1 << ((offset % 4) + 4),
+				1 << ((offset % 4) + 4));
+		return 0;
+	case PIN_CONFIG_DRIVE_PUSH_PULL:
+		max310x_port_update(port, MAX310X_GPIOCFG_REG,
+				1 << ((offset % 4) + 4), 0);
+		return 0;
+	default:
+		return -ENOTSUPP;
+	}
+}
+#endif
+
+static const struct serial_rs485 max310x_rs485_supported = {
+	.flags = SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | SER_RS485_RX_DURING_TX,
+	.delay_rts_before_send = 1,
+	.delay_rts_after_send = 1,
+};
+
+static int max310x_probe(struct device *dev, const struct max310x_devtype *devtype,
+			 const struct max310x_if_cfg *if_cfg,
+			 struct regmap *regmaps[], int irq)
+{
+	int i, ret, fmin, fmax, freq;
+	struct max310x_port *s;
+	u32 uartclk = 0;
+	bool xtal;
+
+	for (i = 0; i < devtype->nr; i++)
+		if (IS_ERR(regmaps[i]))
+			return PTR_ERR(regmaps[i]);
+
+	/* Alloc port structure */
+	s = devm_kzalloc(dev, struct_size(s, p, devtype->nr), GFP_KERNEL);
+	if (!s) {
+		dev_err(dev, "Error allocating port structure\n");
+		return -ENOMEM;
+	}
+
+	/* Always ask for fixed clock rate from a property. */
+	device_property_read_u32(dev, "clock-frequency", &uartclk);
+
+	xtal = device_property_match_string(dev, "clock-names", "osc") < 0;
+	if (xtal)
+		s->clk = devm_clk_get_optional(dev, "xtal");
+	else
+		s->clk = devm_clk_get_optional(dev, "osc");
+	if (IS_ERR(s->clk))
+		return PTR_ERR(s->clk);
+
+	ret = clk_prepare_enable(s->clk);
+	if (ret)
+		return ret;
+
+	freq = clk_get_rate(s->clk);
+	if (freq == 0)
+		freq = uartclk;
+	if (freq == 0) {
+		dev_err(dev, "Cannot get clock rate\n");
+		ret = -EINVAL;
+		goto out_clk;
+	}
+
+	if (xtal) {
+		fmin = 1000000;
+		fmax = 4000000;
+	} else {
+		fmin = 500000;
+		fmax = 35000000;
+	}
+
+	/* Check frequency limits */
+	if (freq < fmin || freq > fmax) {
+		ret = -ERANGE;
+		goto out_clk;
+	}
+
+	s->regmap = regmaps[0];
+	s->devtype = devtype;
+	s->if_cfg = if_cfg;
+	dev_set_drvdata(dev, s);
+
+	/* Check device to ensure we are talking to what we expect */
+	ret = devtype->detect(dev);
+	if (ret)
+		goto out_clk;
+
+	for (i = 0; i < devtype->nr; i++) {
+		/* Reset port */
+		regmap_write(regmaps[i], MAX310X_MODE2_REG,
+			     MAX310X_MODE2_RST_BIT);
+		/* Clear port reset */
+		regmap_write(regmaps[i], MAX310X_MODE2_REG, 0);
+
+		/* Wait for port startup */
+		do {
+			regmap_read(regmaps[i], MAX310X_BRGDIVLSB_REG, &ret);
+		} while (ret != 0x01);
+
+		regmap_write(regmaps[i], MAX310X_MODE1_REG, devtype->mode1);
+	}
+
+	uartclk = max310x_set_ref_clk(dev, s, freq, xtal);
+	dev_dbg(dev, "Reference clock set to %i Hz\n", uartclk);
+
+	for (i = 0; i < devtype->nr; i++) {
+		unsigned int line;
+
+		line = find_first_zero_bit(max310x_lines, MAX310X_UART_NRMAX);
+		if (line == MAX310X_UART_NRMAX) {
+			ret = -ERANGE;
+			goto out_uart;
+		}
+
+		/* Initialize port data */
+		s->p[i].port.line	= line;
+		s->p[i].port.dev	= dev;
+		s->p[i].port.irq	= irq;
+		s->p[i].port.type	= PORT_MAX310X;
+		s->p[i].port.fifosize	= MAX310X_FIFO_SIZE;
+		s->p[i].port.flags	= UPF_FIXED_TYPE | UPF_LOW_LATENCY;
+		s->p[i].port.iotype	= UPIO_PORT;
+		s->p[i].port.iobase	= i;
+		s->p[i].port.membase	= (void __iomem *)~0;
+		s->p[i].port.uartclk	= uartclk;
+		s->p[i].port.rs485_config = max310x_rs485_config;
+		s->p[i].port.rs485_supported = max310x_rs485_supported;
+		s->p[i].port.ops	= &max310x_ops;
+		s->p[i].regmap		= regmaps[i];
+
+		/* Disable all interrupts */
+		max310x_port_write(&s->p[i].port, MAX310X_IRQEN_REG, 0);
+		/* Clear IRQ status register */
+		max310x_port_read(&s->p[i].port, MAX310X_IRQSTS_REG);
+		/* Initialize queue for start TX */
+		INIT_WORK(&s->p[i].tx_work, max310x_tx_proc);
+		/* Initialize queue for changing LOOPBACK mode */
+		INIT_WORK(&s->p[i].md_work, max310x_md_proc);
+		/* Initialize queue for changing RS485 mode */
+		INIT_WORK(&s->p[i].rs_work, max310x_rs_proc);
+
+		/* Register port */
+		ret = uart_add_one_port(&max310x_uart, &s->p[i].port);
+		if (ret) {
+			s->p[i].port.dev = NULL;
+			goto out_uart;
+		}
+		set_bit(line, max310x_lines);
+
+		/* Go to suspend mode */
+		devtype->power(&s->p[i].port, 0);
+	}
+
+#ifdef CONFIG_GPIOLIB
+	/* Setup GPIO cotroller */
+	s->gpio.owner		= THIS_MODULE;
+	s->gpio.parent		= dev;
+	s->gpio.label		= devtype->name;
+	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.set_config	= max310x_gpio_set_config;
+	s->gpio.base		= -1;
+	s->gpio.ngpio		= devtype->nr * 4;
+	s->gpio.can_sleep	= 1;
+	ret = devm_gpiochip_add_data(dev, &s->gpio, s);
+	if (ret)
+		goto out_uart;
+#endif
+
+	/* Setup interrupt */
+	ret = devm_request_threaded_irq(dev, irq, NULL, max310x_ist,
+					IRQF_ONESHOT | IRQF_SHARED, dev_name(dev), s);
+	if (!ret)
+		return 0;
+
+	dev_err(dev, "Unable to reguest IRQ %i\n", irq);
+
+out_uart:
+	for (i = 0; i < devtype->nr; i++) {
+		if (s->p[i].port.dev) {
+			uart_remove_one_port(&max310x_uart, &s->p[i].port);
+			clear_bit(s->p[i].port.line, max310x_lines);
+		}
+	}
+
+out_clk:
+	clk_disable_unprepare(s->clk);
+
+	return ret;
+}
+
+static void max310x_remove(struct device *dev)
+{
+	struct max310x_port *s = dev_get_drvdata(dev);
+	int i;
+
+	for (i = 0; i < s->devtype->nr; i++) {
+		cancel_work_sync(&s->p[i].tx_work);
+		cancel_work_sync(&s->p[i].md_work);
+		cancel_work_sync(&s->p[i].rs_work);
+		uart_remove_one_port(&max310x_uart, &s->p[i].port);
+		clear_bit(s->p[i].port.line, max310x_lines);
+		s->devtype->power(&s->p[i].port, 0);
+	}
+
+	clk_disable_unprepare(s->clk);
+}
+
+static const struct of_device_id __maybe_unused max310x_dt_ids[] = {
+	{ .compatible = "maxim,max3107",	.data = &max3107_devtype, },
+	{ .compatible = "maxim,max3108",	.data = &max3108_devtype, },
+	{ .compatible = "maxim,max3109",	.data = &max3109_devtype, },
+	{ .compatible = "maxim,max14830",	.data = &max14830_devtype },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, max310x_dt_ids);
+
+static struct regmap_config regcfg = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	.write_flag_mask = MAX310X_WRITE_BIT,
+	.cache_type = REGCACHE_RBTREE,
+	.max_register = MAX310X_REG_1F,
+	.writeable_reg = max310x_reg_writeable,
+	.volatile_reg = max310x_reg_volatile,
+	.precious_reg = max310x_reg_precious,
+	.writeable_noinc_reg = max310x_reg_noinc,
+	.readable_noinc_reg = max310x_reg_noinc,
+	.max_raw_read = MAX310X_FIFO_SIZE,
+	.max_raw_write = MAX310X_FIFO_SIZE,
+};
+
+#ifdef CONFIG_SPI_MASTER
+static int max310x_spi_extended_reg_enable(struct device *dev, bool enable)
+{
+	struct max310x_port *s = dev_get_drvdata(dev);
+
+	return regmap_write(s->regmap, MAX310X_GLOBALCMD_REG,
+			    enable ? MAX310X_EXTREG_ENBL : MAX310X_EXTREG_DSBL);
+}
+
+static const struct max310x_if_cfg __maybe_unused max310x_spi_if_cfg = {
+	.extended_reg_enable = max310x_spi_extended_reg_enable,
+	.rev_id_reg = MAX310X_SPI_REVID_EXTREG,
+};
+
+static int max310x_spi_probe(struct spi_device *spi)
+{
+	const struct max310x_devtype *devtype;
+	struct regmap *regmaps[4];
+	unsigned int i;
+	int ret;
+
+	/* Setup SPI bus */
+	spi->bits_per_word	= 8;
+	spi->mode		= spi->mode ? : SPI_MODE_0;
+	spi->max_speed_hz	= spi->max_speed_hz ? : 26000000;
+	ret = spi_setup(spi);
+	if (ret)
+		return ret;
+
+	devtype = device_get_match_data(&spi->dev);
+	if (!devtype)
+		devtype = (struct max310x_devtype *)spi_get_device_id(spi)->driver_data;
+
+	for (i = 0; i < devtype->nr; i++) {
+		u8 port_mask = i * 0x20;
+		regcfg.read_flag_mask = port_mask;
+		regcfg.write_flag_mask = port_mask | MAX310X_WRITE_BIT;
+		regmaps[i] = devm_regmap_init_spi(spi, &regcfg);
+	}
+
+	return max310x_probe(&spi->dev, devtype, &max310x_spi_if_cfg, regmaps, spi->irq);
+}
+
+static void max310x_spi_remove(struct spi_device *spi)
+{
+	max310x_remove(&spi->dev);
+}
+
+static const struct spi_device_id max310x_id_table[] = {
+	{ "max3107",	(kernel_ulong_t)&max3107_devtype, },
+	{ "max3108",	(kernel_ulong_t)&max3108_devtype, },
+	{ "max3109",	(kernel_ulong_t)&max3109_devtype, },
+	{ "max14830",	(kernel_ulong_t)&max14830_devtype, },
+	{ }
+};
+MODULE_DEVICE_TABLE(spi, max310x_id_table);
+
+static struct spi_driver max310x_spi_driver = {
+	.driver = {
+		.name		= MAX310X_NAME,
+		.of_match_table	= max310x_dt_ids,
+		.pm		= &max310x_pm_ops,
+	},
+	.probe		= max310x_spi_probe,
+	.remove		= max310x_spi_remove,
+	.id_table	= max310x_id_table,
+};
+#endif
+
+#ifdef CONFIG_I2C
+static int max310x_i2c_extended_reg_enable(struct device *dev, bool enable)
+{
+	return 0;
+}
+
+static struct regmap_config regcfg_i2c = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	.cache_type = REGCACHE_RBTREE,
+	.writeable_reg = max310x_reg_writeable,
+	.volatile_reg = max310x_reg_volatile,
+	.precious_reg = max310x_reg_precious,
+	.max_register = MAX310X_I2C_REVID_EXTREG,
+	.writeable_noinc_reg = max310x_reg_noinc,
+	.readable_noinc_reg = max310x_reg_noinc,
+	.max_raw_read = MAX310X_FIFO_SIZE,
+	.max_raw_write = MAX310X_FIFO_SIZE,
+};
+
+static const struct max310x_if_cfg max310x_i2c_if_cfg = {
+	.extended_reg_enable = max310x_i2c_extended_reg_enable,
+	.rev_id_reg = MAX310X_I2C_REVID_EXTREG,
+};
+
+static unsigned short max310x_i2c_slave_addr(unsigned short addr,
+					     unsigned int nr)
+{
+	/*
+	 * For MAX14830 and MAX3109, the slave address depends on what the
+	 * A0 and A1 pins are tied to.
+	 * See Table I2C Address Map of the datasheet.
+	 * Based on that table, the following formulas were determined.
+	 * UART1 - UART0 = 0x10
+	 * UART2 - UART1 = 0x20 + 0x10
+	 * UART3 - UART2 = 0x10
+	 */
+
+	addr -= nr * 0x10;
+
+	if (nr >= 2)
+		addr -= 0x20;
+
+	return addr;
+}
+
+static int max310x_i2c_probe(struct i2c_client *client)
+{
+	const struct max310x_devtype *devtype =
+			device_get_match_data(&client->dev);
+	struct i2c_client *port_client;
+	struct regmap *regmaps[4];
+	unsigned int i;
+	u8 port_addr;
+
+	if (client->addr < devtype->slave_addr.min ||
+		client->addr > devtype->slave_addr.max)
+		return dev_err_probe(&client->dev, -EINVAL,
+				     "Slave addr 0x%x outside of range [0x%x, 0x%x]\n",
+				     client->addr, devtype->slave_addr.min,
+				     devtype->slave_addr.max);
+
+	regmaps[0] = devm_regmap_init_i2c(client, &regcfg_i2c);
+
+	for (i = 1; i < devtype->nr; i++) {
+		port_addr = max310x_i2c_slave_addr(client->addr, i);
+		port_client = devm_i2c_new_dummy_device(&client->dev,
+							client->adapter,
+							port_addr);
+
+		regmaps[i] = devm_regmap_init_i2c(port_client, &regcfg_i2c);
+	}
+
+	return max310x_probe(&client->dev, devtype, &max310x_i2c_if_cfg,
+			     regmaps, client->irq);
+}
+
+static void max310x_i2c_remove(struct i2c_client *client)
+{
+	max310x_remove(&client->dev);
+}
+
+static struct i2c_driver max310x_i2c_driver = {
+	.driver = {
+		.name		= MAX310X_NAME,
+		.of_match_table	= max310x_dt_ids,
+		.pm		= &max310x_pm_ops,
+	},
+	.probe_new	= max310x_i2c_probe,
+	.remove		= max310x_i2c_remove,
+};
+#endif
+
+static int __init max310x_uart_init(void)
+{
+	int ret;
+
+	bitmap_zero(max310x_lines, MAX310X_UART_NRMAX);
+
+	ret = uart_register_driver(&max310x_uart);
+	if (ret)
+		return ret;
+
+#ifdef CONFIG_SPI_MASTER
+	ret = spi_register_driver(&max310x_spi_driver);
+	if (ret)
+		goto err_spi_register;
+#endif
+
+#ifdef CONFIG_I2C
+	ret = i2c_add_driver(&max310x_i2c_driver);
+	if (ret)
+		goto err_i2c_register;
+#endif
+
+	return 0;
+
+#ifdef CONFIG_I2C
+err_i2c_register:
+	spi_unregister_driver(&max310x_spi_driver);
+#endif
+
+err_spi_register:
+	uart_unregister_driver(&max310x_uart);
+
+	return ret;
+}
+module_init(max310x_uart_init);
+
+static void __exit max310x_uart_exit(void)
+{
+#ifdef CONFIG_I2C
+	i2c_del_driver(&max310x_i2c_driver);
+#endif
+
+#ifdef CONFIG_SPI_MASTER
+	spi_unregister_driver(&max310x_spi_driver);
+#endif
+
+	uart_unregister_driver(&max310x_uart);
+}
+module_exit(max310x_uart_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Alexander Shiyan <shc_work@mail.ru>");
+MODULE_DESCRIPTION("MAX310X serial driver");