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android-kvm / linux / 12d15e6f6377fe46b1f9dc51133890a732f1ae05 / . / drivers / tty / serial / sc16is7xx.c
blob: 914825e034273d7bc2676a73f608399e9dc2ac20 [file] [log] [blame]
/*
* SC16IS7xx tty serial driver - Copyright (C) 2014 GridPoint
* Author: Jon Ringle <jringle@gridpoint.com>
*
* Based on max310x.c, by Alexander Shiyan <shc_work@mail.ru>
*
* 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.
*
*/
#include <linux/bitops.h>
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/gpio.h>
#include <linux/i2c.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_device.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/uaccess.h>
#define SC16IS7XX_NAME "sc16is7xx"
/* SC16IS7XX register definitions */
#define SC16IS7XX_RHR_REG (0x00) /* RX FIFO */
#define SC16IS7XX_THR_REG (0x00) /* TX FIFO */
#define SC16IS7XX_IER_REG (0x01) /* Interrupt enable */
#define SC16IS7XX_IIR_REG (0x02) /* Interrupt Identification */
#define SC16IS7XX_FCR_REG (0x02) /* FIFO control */
#define SC16IS7XX_LCR_REG (0x03) /* Line Control */
#define SC16IS7XX_MCR_REG (0x04) /* Modem Control */
#define SC16IS7XX_LSR_REG (0x05) /* Line Status */
#define SC16IS7XX_MSR_REG (0x06) /* Modem Status */
#define SC16IS7XX_SPR_REG (0x07) /* Scratch Pad */
#define SC16IS7XX_TXLVL_REG (0x08) /* TX FIFO level */
#define SC16IS7XX_RXLVL_REG (0x09) /* RX FIFO level */
#define SC16IS7XX_IODIR_REG (0x0a) /* I/O Direction
* - only on 75x/76x
*/
#define SC16IS7XX_IOSTATE_REG (0x0b) /* I/O State
* - only on 75x/76x
*/
#define SC16IS7XX_IOINTENA_REG (0x0c) /* I/O Interrupt Enable
* - only on 75x/76x
*/
#define SC16IS7XX_IOCONTROL_REG (0x0e) /* I/O Control
* - only on 75x/76x
*/
#define SC16IS7XX_EFCR_REG (0x0f) /* Extra Features Control */
/* TCR/TLR Register set: Only if ((MCR[2] == 1) && (EFR[4] == 1)) */
#define SC16IS7XX_TCR_REG (0x06) /* Transmit control */
#define SC16IS7XX_TLR_REG (0x07) /* Trigger level */
/* Special Register set: Only if ((LCR[7] == 1) && (LCR != 0xBF)) */
#define SC16IS7XX_DLL_REG (0x00) /* Divisor Latch Low */
#define SC16IS7XX_DLH_REG (0x01) /* Divisor Latch High */
/* Enhanced Register set: Only if (LCR == 0xBF) */
#define SC16IS7XX_EFR_REG (0x02) /* Enhanced Features */
#define SC16IS7XX_XON1_REG (0x04) /* Xon1 word */
#define SC16IS7XX_XON2_REG (0x05) /* Xon2 word */
#define SC16IS7XX_XOFF1_REG (0x06) /* Xoff1 word */
#define SC16IS7XX_XOFF2_REG (0x07) /* Xoff2 word */
/* IER register bits */
#define SC16IS7XX_IER_RDI_BIT (1 << 0) /* Enable RX data interrupt */
#define SC16IS7XX_IER_THRI_BIT (1 << 1) /* Enable TX holding register
* interrupt */
#define SC16IS7XX_IER_RLSI_BIT (1 << 2) /* Enable RX line status
* interrupt */
#define SC16IS7XX_IER_MSI_BIT (1 << 3) /* Enable Modem status
* interrupt */
/* IER register bits - write only if (EFR[4] == 1) */
#define SC16IS7XX_IER_SLEEP_BIT (1 << 4) /* Enable Sleep mode */
#define SC16IS7XX_IER_XOFFI_BIT (1 << 5) /* Enable Xoff interrupt */
#define SC16IS7XX_IER_RTSI_BIT (1 << 6) /* Enable nRTS interrupt */
#define SC16IS7XX_IER_CTSI_BIT (1 << 7) /* Enable nCTS interrupt */
/* FCR register bits */
#define SC16IS7XX_FCR_FIFO_BIT (1 << 0) /* Enable FIFO */
#define SC16IS7XX_FCR_RXRESET_BIT (1 << 1) /* Reset RX FIFO */
#define SC16IS7XX_FCR_TXRESET_BIT (1 << 2) /* Reset TX FIFO */
#define SC16IS7XX_FCR_RXLVLL_BIT (1 << 6) /* RX Trigger level LSB */
#define SC16IS7XX_FCR_RXLVLH_BIT (1 << 7) /* RX Trigger level MSB */
/* FCR register bits - write only if (EFR[4] == 1) */
#define SC16IS7XX_FCR_TXLVLL_BIT (1 << 4) /* TX Trigger level LSB */
#define SC16IS7XX_FCR_TXLVLH_BIT (1 << 5) /* TX Trigger level MSB */
/* IIR register bits */
#define SC16IS7XX_IIR_NO_INT_BIT (1 << 0) /* No interrupts pending */
#define SC16IS7XX_IIR_ID_MASK 0x3e /* Mask for the interrupt ID */
#define SC16IS7XX_IIR_THRI_SRC 0x02 /* TX holding register empty */
#define SC16IS7XX_IIR_RDI_SRC 0x04 /* RX data interrupt */
#define SC16IS7XX_IIR_RLSE_SRC 0x06 /* RX line status error */
#define SC16IS7XX_IIR_RTOI_SRC 0x0c /* RX time-out interrupt */
#define SC16IS7XX_IIR_MSI_SRC 0x00 /* Modem status interrupt
* - only on 75x/76x
*/
#define SC16IS7XX_IIR_INPIN_SRC 0x30 /* Input pin change of state
* - only on 75x/76x
*/
#define SC16IS7XX_IIR_XOFFI_SRC 0x10 /* Received Xoff */
#define SC16IS7XX_IIR_CTSRTS_SRC 0x20 /* nCTS,nRTS change of state
* from active (LOW)
* to inactive (HIGH)
*/
/* LCR register bits */
#define SC16IS7XX_LCR_LENGTH0_BIT (1 << 0) /* Word length bit 0 */
#define SC16IS7XX_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 SC16IS7XX_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 SC16IS7XX_LCR_PARITY_BIT (1 << 3) /* Parity bit enable */
#define SC16IS7XX_LCR_EVENPARITY_BIT (1 << 4) /* Even parity bit enable */
#define SC16IS7XX_LCR_FORCEPARITY_BIT (1 << 5) /* 9-bit multidrop parity */
#define SC16IS7XX_LCR_TXBREAK_BIT (1 << 6) /* TX break enable */
#define SC16IS7XX_LCR_DLAB_BIT (1 << 7) /* Divisor Latch enable */
#define SC16IS7XX_LCR_WORD_LEN_5 (0x00)
#define SC16IS7XX_LCR_WORD_LEN_6 (0x01)
#define SC16IS7XX_LCR_WORD_LEN_7 (0x02)
#define SC16IS7XX_LCR_WORD_LEN_8 (0x03)
#define SC16IS7XX_LCR_CONF_MODE_A SC16IS7XX_LCR_DLAB_BIT /* Special
* reg set */
#define SC16IS7XX_LCR_CONF_MODE_B 0xBF /* Enhanced
* reg set */
/* MCR register bits */
#define SC16IS7XX_MCR_DTR_BIT (1 << 0) /* DTR complement
* - only on 75x/76x
*/
#define SC16IS7XX_MCR_RTS_BIT (1 << 1) /* RTS complement */
#define SC16IS7XX_MCR_TCRTLR_BIT (1 << 2) /* TCR/TLR register enable */
#define SC16IS7XX_MCR_LOOP_BIT (1 << 4) /* Enable loopback test mode */
#define SC16IS7XX_MCR_XONANY_BIT (1 << 5) /* Enable Xon Any
* - write enabled
* if (EFR[4] == 1)
*/
#define SC16IS7XX_MCR_IRDA_BIT (1 << 6) /* Enable IrDA mode
* - write enabled
* if (EFR[4] == 1)
*/
#define SC16IS7XX_MCR_CLKSEL_BIT (1 << 7) /* Divide clock by 4
* - write enabled
* if (EFR[4] == 1)
*/
/* LSR register bits */
#define SC16IS7XX_LSR_DR_BIT (1 << 0) /* Receiver data ready */
#define SC16IS7XX_LSR_OE_BIT (1 << 1) /* Overrun Error */
#define SC16IS7XX_LSR_PE_BIT (1 << 2) /* Parity Error */
#define SC16IS7XX_LSR_FE_BIT (1 << 3) /* Frame Error */
#define SC16IS7XX_LSR_BI_BIT (1 << 4) /* Break Interrupt */
#define SC16IS7XX_LSR_BRK_ERROR_MASK 0x1E /* BI, FE, PE, OE bits */
#define SC16IS7XX_LSR_THRE_BIT (1 << 5) /* TX holding register empty */
#define SC16IS7XX_LSR_TEMT_BIT (1 << 6) /* Transmitter empty */
#define SC16IS7XX_LSR_FIFOE_BIT (1 << 7) /* Fifo Error */
/* MSR register bits */
#define SC16IS7XX_MSR_DCTS_BIT (1 << 0) /* Delta CTS Clear To Send */
#define SC16IS7XX_MSR_DDSR_BIT (1 << 1) /* Delta DSR Data Set Ready
* or (IO4)
* - only on 75x/76x
*/
#define SC16IS7XX_MSR_DRI_BIT (1 << 2) /* Delta RI Ring Indicator
* or (IO7)
* - only on 75x/76x
*/
#define SC16IS7XX_MSR_DCD_BIT (1 << 3) /* Delta CD Carrier Detect
* or (IO6)
* - only on 75x/76x
*/
#define SC16IS7XX_MSR_CTS_BIT (1 << 0) /* CTS */
#define SC16IS7XX_MSR_DSR_BIT (1 << 1) /* DSR (IO4)
* - only on 75x/76x
*/
#define SC16IS7XX_MSR_RI_BIT (1 << 2) /* RI (IO7)
* - only on 75x/76x
*/
#define SC16IS7XX_MSR_CD_BIT (1 << 3) /* CD (IO6)
* - only on 75x/76x
*/
#define SC16IS7XX_MSR_DELTA_MASK 0x0F /* Any of the delta bits! */
/*
* TCR register bits
* TCR trigger levels are available from 0 to 60 characters with a granularity
* of four.
* The programmer must program the TCR such that TCR[3:0] > TCR[7:4]. There is
* no built-in hardware check to make sure this condition is met. Also, the TCR
* must be programmed with this condition before auto RTS or software flow
* control is enabled to avoid spurious operation of the device.
*/
#define SC16IS7XX_TCR_RX_HALT(words) ((((words) / 4) & 0x0f) << 0)
#define SC16IS7XX_TCR_RX_RESUME(words) ((((words) / 4) & 0x0f) << 4)
/*
* TLR register bits
* If TLR[3:0] or TLR[7:4] are logical 0, the selectable trigger levels via the
* FIFO Control Register (FCR) are used for the transmit and receive FIFO
* trigger levels. Trigger levels from 4 characters to 60 characters are
* available with a granularity of four.
*
* When the trigger level setting in TLR is zero, the SC16IS740/750/760 uses the
* trigger level setting defined in FCR. If TLR has non-zero trigger level value
* the trigger level defined in FCR is discarded. This applies to both transmit
* FIFO and receive FIFO trigger level setting.
*
* When TLR is used for RX trigger level control, FCR[7:6] should be left at the
* default state, that is, '00'.
*/
#define SC16IS7XX_TLR_TX_TRIGGER(words) ((((words) / 4) & 0x0f) << 0)
#define SC16IS7XX_TLR_RX_TRIGGER(words) ((((words) / 4) & 0x0f) << 4)
/* IOControl register bits (Only 750/760) */
#define SC16IS7XX_IOCONTROL_LATCH_BIT (1 << 0) /* Enable input latching */
#define SC16IS7XX_IOCONTROL_GPIO_BIT (1 << 1) /* Enable GPIO[7:4] */
#define SC16IS7XX_IOCONTROL_SRESET_BIT (1 << 3) /* Software Reset */
/* EFCR register bits */
#define SC16IS7XX_EFCR_9BIT_MODE_BIT (1 << 0) /* Enable 9-bit or Multidrop
* mode (RS485) */
#define SC16IS7XX_EFCR_RXDISABLE_BIT (1 << 1) /* Disable receiver */
#define SC16IS7XX_EFCR_TXDISABLE_BIT (1 << 2) /* Disable transmitter */
#define SC16IS7XX_EFCR_AUTO_RS485_BIT (1 << 4) /* Auto RS485 RTS direction */
#define SC16IS7XX_EFCR_RTS_INVERT_BIT (1 << 5) /* RTS output inversion */
#define SC16IS7XX_EFCR_IRDA_MODE_BIT (1 << 7) /* IrDA mode
* 0 = rate upto 115.2 kbit/s
* - Only 750/760
* 1 = rate upto 1.152 Mbit/s
* - Only 760
*/
/* EFR register bits */
#define SC16IS7XX_EFR_AUTORTS_BIT (1 << 6) /* Auto RTS flow ctrl enable */
#define SC16IS7XX_EFR_AUTOCTS_BIT (1 << 7) /* Auto CTS flow ctrl enable */
#define SC16IS7XX_EFR_XOFF2_DETECT_BIT (1 << 5) /* Enable Xoff2 detection */
#define SC16IS7XX_EFR_ENABLE_BIT (1 << 4) /* Enable enhanced functions
* and writing to IER[7:4],
* FCR[5:4], MCR[7:5]
*/
#define SC16IS7XX_EFR_SWFLOW3_BIT (1 << 3) /* SWFLOW bit 3 */
#define SC16IS7XX_EFR_SWFLOW2_BIT (1 << 2) /* SWFLOW bit 2
*
* SWFLOW bits 3 & 2 table:
* 00 -> no transmitter flow
* control
* 01 -> transmitter generates
* XON2 and XOFF2
* 10 -> transmitter generates
* XON1 and XOFF1
* 11 -> transmitter generates
* XON1, XON2, XOFF1 and
* XOFF2
*/
#define SC16IS7XX_EFR_SWFLOW1_BIT (1 << 1) /* SWFLOW bit 2 */
#define SC16IS7XX_EFR_SWFLOW0_BIT (1 << 0) /* SWFLOW bit 3
*
* SWFLOW bits 3 & 2 table:
* 00 -> no received flow
* control
* 01 -> receiver compares
* XON2 and XOFF2
* 10 -> receiver compares
* XON1 and XOFF1
* 11 -> receiver compares
* XON1, XON2, XOFF1 and
* XOFF2
*/
/* Misc definitions */
#define SC16IS7XX_FIFO_SIZE (64)
#define SC16IS7XX_REG_SHIFT 2
struct sc16is7xx_devtype {
char name[10];
int nr_gpio;
int nr_uart;
};
struct sc16is7xx_one {
struct uart_port port;
struct work_struct tx_work;
struct work_struct md_work;
struct serial_rs485 rs485;
};
struct sc16is7xx_port {
struct uart_driver uart;
struct sc16is7xx_devtype *devtype;
struct regmap *regmap;
struct mutex mutex;
struct clk *clk;
#ifdef CONFIG_GPIOLIB
struct gpio_chip gpio;
#endif
unsigned char buf[SC16IS7XX_FIFO_SIZE];
struct sc16is7xx_one p[0];
};
#define to_sc16is7xx_one(p,e) ((container_of((p), struct sc16is7xx_one, e)))
static u8 sc16is7xx_port_read(struct uart_port *port, u8 reg)
{
struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
unsigned int val = 0;
regmap_read(s->regmap,
(reg << SC16IS7XX_REG_SHIFT) | port->line, &val);
return val;
}
static void sc16is7xx_port_write(struct uart_port *port, u8 reg, u8 val)
{
struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
regmap_write(s->regmap,
(reg << SC16IS7XX_REG_SHIFT) | port->line, val);
}
static void sc16is7xx_port_update(struct uart_port *port, u8 reg,
u8 mask, u8 val)
{
struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
regmap_update_bits(s->regmap,
(reg << SC16IS7XX_REG_SHIFT) | port->line,
mask, val);
}
static void sc16is7xx_power(struct uart_port *port, int on)
{
sc16is7xx_port_update(port, SC16IS7XX_IER_REG,
SC16IS7XX_IER_SLEEP_BIT,
on ? 0 : SC16IS7XX_IER_SLEEP_BIT);
}
static const struct sc16is7xx_devtype sc16is74x_devtype = {
.name = "SC16IS74X",
.nr_gpio = 0,
.nr_uart = 1,
};
static const struct sc16is7xx_devtype sc16is750_devtype = {
.name = "SC16IS750",
.nr_gpio = 8,
.nr_uart = 1,
};
static const struct sc16is7xx_devtype sc16is752_devtype = {
.name = "SC16IS752",
.nr_gpio = 8,
.nr_uart = 2,
};
static const struct sc16is7xx_devtype sc16is760_devtype = {
.name = "SC16IS760",
.nr_gpio = 8,
.nr_uart = 1,
};
static const struct sc16is7xx_devtype sc16is762_devtype = {
.name = "SC16IS762",
.nr_gpio = 8,
.nr_uart = 2,
};
static bool sc16is7xx_regmap_volatile(struct device *dev, unsigned int reg)
{
switch (reg >> SC16IS7XX_REG_SHIFT) {
case SC16IS7XX_RHR_REG:
case SC16IS7XX_IIR_REG:
case SC16IS7XX_LSR_REG:
case SC16IS7XX_MSR_REG:
case SC16IS7XX_TXLVL_REG:
case SC16IS7XX_RXLVL_REG:
case SC16IS7XX_IOSTATE_REG:
return true;
default:
break;
}
return false;
}
static bool sc16is7xx_regmap_precious(struct device *dev, unsigned int reg)
{
switch (reg >> SC16IS7XX_REG_SHIFT) {
case SC16IS7XX_RHR_REG:
return true;
default:
break;
}
return false;
}
static int sc16is7xx_set_baud(struct uart_port *port, int baud)
{
struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
u8 lcr;
u8 prescaler = 0;
unsigned long clk = port->uartclk, div = clk / 16 / baud;
if (div > 0xffff) {
prescaler = SC16IS7XX_MCR_CLKSEL_BIT;
div /= 4;
}
lcr = sc16is7xx_port_read(port, SC16IS7XX_LCR_REG);
/* Open the LCR divisors for configuration */
sc16is7xx_port_write(port, SC16IS7XX_LCR_REG,
SC16IS7XX_LCR_CONF_MODE_B);
/* Enable enhanced features */
regcache_cache_bypass(s->regmap, true);
sc16is7xx_port_write(port, SC16IS7XX_EFR_REG,
SC16IS7XX_EFR_ENABLE_BIT);
regcache_cache_bypass(s->regmap, false);
/* Put LCR back to the normal mode */
sc16is7xx_port_write(port, SC16IS7XX_LCR_REG, lcr);
sc16is7xx_port_update(port, SC16IS7XX_MCR_REG,
SC16IS7XX_MCR_CLKSEL_BIT,
prescaler);
/* Open the LCR divisors for configuration */
sc16is7xx_port_write(port, SC16IS7XX_LCR_REG,
SC16IS7XX_LCR_CONF_MODE_A);
/* Write the new divisor */
regcache_cache_bypass(s->regmap, true);
sc16is7xx_port_write(port, SC16IS7XX_DLH_REG, div / 256);
sc16is7xx_port_write(port, SC16IS7XX_DLL_REG, div % 256);
regcache_cache_bypass(s->regmap, false);
/* Put LCR back to the normal mode */
sc16is7xx_port_write(port, SC16IS7XX_LCR_REG, lcr);
return DIV_ROUND_CLOSEST(clk / 16, div);
}
static void sc16is7xx_handle_rx(struct uart_port *port, unsigned int rxlen,
unsigned int iir)
{
struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
unsigned int lsr = 0, ch, flag, bytes_read, i;
bool read_lsr = (iir == SC16IS7XX_IIR_RLSE_SRC) ? true : false;
if (unlikely(rxlen >= sizeof(s->buf))) {
dev_warn_ratelimited(port->dev,
"Port %i: Possible RX FIFO overrun: %d\n",
port->line, rxlen);
port->icount.buf_overrun++;
/* Ensure sanity of RX level */
rxlen = sizeof(s->buf);
}
while (rxlen) {
/* Only read lsr if there are possible errors in FIFO */
if (read_lsr) {
lsr = sc16is7xx_port_read(port, SC16IS7XX_LSR_REG);
if (!(lsr & SC16IS7XX_LSR_FIFOE_BIT))
read_lsr = false; /* No errors left in FIFO */
} else
lsr = 0;
if (read_lsr) {
s->buf[0] = sc16is7xx_port_read(port, SC16IS7XX_RHR_REG);
bytes_read = 1;
} else {
regcache_cache_bypass(s->regmap, true);
regmap_raw_read(s->regmap, SC16IS7XX_RHR_REG,
s->buf, rxlen);
regcache_cache_bypass(s->regmap, false);
bytes_read = rxlen;
}
lsr &= SC16IS7XX_LSR_BRK_ERROR_MASK;
port->icount.rx++;
flag = TTY_NORMAL;
if (unlikely(lsr)) {
if (lsr & SC16IS7XX_LSR_BI_BIT) {
port->icount.brk++;
if (uart_handle_break(port))
continue;
} else if (lsr & SC16IS7XX_LSR_PE_BIT)
port->icount.parity++;
else if (lsr & SC16IS7XX_LSR_FE_BIT)
port->icount.frame++;
else if (lsr & SC16IS7XX_LSR_OE_BIT)
port->icount.overrun++;
lsr &= port->read_status_mask;
if (lsr & SC16IS7XX_LSR_BI_BIT)
flag = TTY_BREAK;
else if (lsr & SC16IS7XX_LSR_PE_BIT)
flag = TTY_PARITY;
else if (lsr & SC16IS7XX_LSR_FE_BIT)
flag = TTY_FRAME;
else if (lsr & SC16IS7XX_LSR_OE_BIT)
flag = TTY_OVERRUN;
}
for (i = 0; i < bytes_read; ++i) {
ch = s->buf[i];
if (uart_handle_sysrq_char(port, ch))
continue;
if (lsr & port->ignore_status_mask)
continue;
uart_insert_char(port, lsr, SC16IS7XX_LSR_OE_BIT, ch,
flag);
}
rxlen -= bytes_read;
}
tty_flip_buffer_push(&port->state->port);
}
static void sc16is7xx_handle_tx(struct uart_port *port)
{
struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
struct circ_buf *xmit = &port->state->xmit;
unsigned int txlen, to_send, i;
if (unlikely(port->x_char)) {
sc16is7xx_port_write(port, SC16IS7XX_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);
if (likely(to_send)) {
/* Limit to size of TX FIFO */
txlen = sc16is7xx_port_read(port, SC16IS7XX_TXLVL_REG);
to_send = (to_send > txlen) ? txlen : to_send;
/* Add data to send */
port->icount.tx += to_send;
/* Convert to linear buffer */
for (i = 0; i < to_send; ++i) {
s->buf[i] = xmit->buf[xmit->tail];
xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
}
regcache_cache_bypass(s->regmap, true);
regmap_raw_write(s->regmap, SC16IS7XX_THR_REG, s->buf, to_send);
regcache_cache_bypass(s->regmap, false);
}
if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
uart_write_wakeup(port);
}
static void sc16is7xx_port_irq(struct sc16is7xx_port *s, int portno)
{
struct uart_port *port = &s->p[portno].port;
do {
unsigned int iir, msr, rxlen;
iir = sc16is7xx_port_read(port, SC16IS7XX_IIR_REG);
if (iir & SC16IS7XX_IIR_NO_INT_BIT)
break;
iir &= SC16IS7XX_IIR_ID_MASK;
switch (iir) {
case SC16IS7XX_IIR_RDI_SRC:
case SC16IS7XX_IIR_RLSE_SRC:
case SC16IS7XX_IIR_RTOI_SRC:
case SC16IS7XX_IIR_XOFFI_SRC:
rxlen = sc16is7xx_port_read(port, SC16IS7XX_RXLVL_REG);
if (rxlen)
sc16is7xx_handle_rx(port, rxlen, iir);
break;
case SC16IS7XX_IIR_CTSRTS_SRC:
msr = sc16is7xx_port_read(port, SC16IS7XX_MSR_REG);
uart_handle_cts_change(port,
!!(msr & SC16IS7XX_MSR_CTS_BIT));
break;
case SC16IS7XX_IIR_THRI_SRC:
mutex_lock(&s->mutex);
sc16is7xx_handle_tx(port);
mutex_unlock(&s->mutex);
break;
default:
dev_err_ratelimited(port->dev,
"Port %i: Unexpected interrupt: %x",
port->line, iir);
break;
}
} while (1);
}
static irqreturn_t sc16is7xx_ist(int irq, void *dev_id)
{
struct sc16is7xx_port *s = (struct sc16is7xx_port *)dev_id;
int i;
for (i = 0; i < s->uart.nr; ++i)
sc16is7xx_port_irq(s, i);
return IRQ_HANDLED;
}
static void sc16is7xx_wq_proc(struct work_struct *ws)
{
struct sc16is7xx_one *one = to_sc16is7xx_one(ws, tx_work);
struct sc16is7xx_port *s = dev_get_drvdata(one->port.dev);
mutex_lock(&s->mutex);
sc16is7xx_handle_tx(&one->port);
mutex_unlock(&s->mutex);
}
static void sc16is7xx_stop_tx(struct uart_port* port)
{
struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
struct circ_buf *xmit = &one->port.state->xmit;
/* handle rs485 */
if (one->rs485.flags & SER_RS485_ENABLED) {
/* do nothing if current tx not yet completed */
int lsr = sc16is7xx_port_read(port, SC16IS7XX_LSR_REG);
if (!(lsr & SC16IS7XX_LSR_TEMT_BIT))
return;
if (uart_circ_empty(xmit) &&
(one->rs485.delay_rts_after_send > 0))
mdelay(one->rs485.delay_rts_after_send);
}
sc16is7xx_port_update(port, SC16IS7XX_IER_REG,
SC16IS7XX_IER_THRI_BIT,
0);
}
static void sc16is7xx_stop_rx(struct uart_port* port)
{
struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
one->port.read_status_mask &= ~SC16IS7XX_LSR_DR_BIT;
sc16is7xx_port_update(port, SC16IS7XX_IER_REG,
SC16IS7XX_LSR_DR_BIT,
0);
}
static void sc16is7xx_start_tx(struct uart_port *port)
{
struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
/* handle rs485 */
if ((one->rs485.flags & SER_RS485_ENABLED) &&
(one->rs485.delay_rts_before_send > 0)) {
mdelay(one->rs485.delay_rts_before_send);
}
if (!work_pending(&one->tx_work))
schedule_work(&one->tx_work);
}
static unsigned int sc16is7xx_tx_empty(struct uart_port *port)
{
unsigned int lvl, lsr;
lvl = sc16is7xx_port_read(port, SC16IS7XX_TXLVL_REG);
lsr = sc16is7xx_port_read(port, SC16IS7XX_LSR_REG);
return ((lsr & SC16IS7XX_LSR_THRE_BIT) && !lvl) ? TIOCSER_TEMT : 0;
}
static unsigned int sc16is7xx_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 sc16is7xx_md_proc(struct work_struct *ws)
{
struct sc16is7xx_one *one = to_sc16is7xx_one(ws, md_work);
sc16is7xx_port_update(&one->port, SC16IS7XX_MCR_REG,
SC16IS7XX_MCR_LOOP_BIT,
(one->port.mctrl & TIOCM_LOOP) ?
SC16IS7XX_MCR_LOOP_BIT : 0);
}
static void sc16is7xx_set_mctrl(struct uart_port *port, unsigned int mctrl)
{
struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
schedule_work(&one->md_work);
}
static void sc16is7xx_break_ctl(struct uart_port *port, int break_state)
{
sc16is7xx_port_update(port, SC16IS7XX_LCR_REG,
SC16IS7XX_LCR_TXBREAK_BIT,
break_state ? SC16IS7XX_LCR_TXBREAK_BIT : 0);
}
static void sc16is7xx_set_termios(struct uart_port *port,
struct ktermios *termios,
struct ktermios *old)
{
struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
unsigned int lcr, flow = 0;
int baud;
/* Mask termios capabilities we don't support */
termios->c_cflag &= ~CMSPAR;
/* Word size */
switch (termios->c_cflag & CSIZE) {
case CS5:
lcr = SC16IS7XX_LCR_WORD_LEN_5;
break;
case CS6:
lcr = SC16IS7XX_LCR_WORD_LEN_6;
break;
case CS7:
lcr = SC16IS7XX_LCR_WORD_LEN_7;
break;
case CS8:
lcr = SC16IS7XX_LCR_WORD_LEN_8;
break;
default:
lcr = SC16IS7XX_LCR_WORD_LEN_8;
termios->c_cflag &= ~CSIZE;
termios->c_cflag |= CS8;
break;
}
/* Parity */
if (termios->c_cflag & PARENB) {
lcr |= SC16IS7XX_LCR_PARITY_BIT;
if (!(termios->c_cflag & PARODD))
lcr |= SC16IS7XX_LCR_EVENPARITY_BIT;
}
/* Stop bits */
if (termios->c_cflag & CSTOPB)
lcr |= SC16IS7XX_LCR_STOPLEN_BIT; /* 2 stops */
/* Set read status mask */
port->read_status_mask = SC16IS7XX_LSR_OE_BIT;
if (termios->c_iflag & INPCK)
port->read_status_mask |= SC16IS7XX_LSR_PE_BIT |
SC16IS7XX_LSR_FE_BIT;
if (termios->c_iflag & (BRKINT | PARMRK))
port->read_status_mask |= SC16IS7XX_LSR_BI_BIT;
/* Set status ignore mask */
port->ignore_status_mask = 0;
if (termios->c_iflag & IGNBRK)
port->ignore_status_mask |= SC16IS7XX_LSR_BI_BIT;
if (!(termios->c_cflag & CREAD))
port->ignore_status_mask |= SC16IS7XX_LSR_BRK_ERROR_MASK;
sc16is7xx_port_write(port, SC16IS7XX_LCR_REG,
SC16IS7XX_LCR_CONF_MODE_B);
/* Configure flow control */
regcache_cache_bypass(s->regmap, true);
sc16is7xx_port_write(port, SC16IS7XX_XON1_REG, termios->c_cc[VSTART]);
sc16is7xx_port_write(port, SC16IS7XX_XOFF1_REG, termios->c_cc[VSTOP]);
if (termios->c_cflag & CRTSCTS)
flow |= SC16IS7XX_EFR_AUTOCTS_BIT |
SC16IS7XX_EFR_AUTORTS_BIT;
if (termios->c_iflag & IXON)
flow |= SC16IS7XX_EFR_SWFLOW3_BIT;
if (termios->c_iflag & IXOFF)
flow |= SC16IS7XX_EFR_SWFLOW1_BIT;
sc16is7xx_port_write(port, SC16IS7XX_EFR_REG, flow);
regcache_cache_bypass(s->regmap, false);
/* Update LCR register */
sc16is7xx_port_write(port, SC16IS7XX_LCR_REG, lcr);
/* Get baud rate generator configuration */
baud = uart_get_baud_rate(port, termios, old,
port->uartclk / 16 / 4 / 0xffff,
port->uartclk / 16);
/* Setup baudrate generator */
baud = sc16is7xx_set_baud(port, baud);
/* Update timeout according to new baud rate */
uart_update_timeout(port, termios->c_cflag, baud);
}
#if defined(TIOCSRS485) && defined(TIOCGRS485)
static void sc16is7xx_config_rs485(struct uart_port *port,
struct serial_rs485 *rs485)
{
struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
one->rs485 = *rs485;
if (one->rs485.flags & SER_RS485_ENABLED) {
sc16is7xx_port_update(port, SC16IS7XX_EFCR_REG,
SC16IS7XX_EFCR_AUTO_RS485_BIT,
SC16IS7XX_EFCR_AUTO_RS485_BIT);
} else {
sc16is7xx_port_update(port, SC16IS7XX_EFCR_REG,
SC16IS7XX_EFCR_AUTO_RS485_BIT,
0);
}
}
#endif
static int sc16is7xx_ioctl(struct uart_port *port, unsigned int cmd,
unsigned long arg)
{
#if defined(TIOCSRS485) && defined(TIOCGRS485)
struct serial_rs485 rs485;
switch (cmd) {
case TIOCSRS485:
if (copy_from_user(&rs485, (void __user *)arg, sizeof(rs485)))
return -EFAULT;
sc16is7xx_config_rs485(port, &rs485);
return 0;
case TIOCGRS485:
if (copy_to_user((void __user *)arg,
&(to_sc16is7xx_one(port, port)->rs485),
sizeof(rs485)))
return -EFAULT;
return 0;
default:
break;
}
#endif
return -ENOIOCTLCMD;
}
static int sc16is7xx_startup(struct uart_port *port)
{
struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
unsigned int val;
sc16is7xx_power(port, 1);
/* Reset FIFOs*/
val = SC16IS7XX_FCR_RXRESET_BIT | SC16IS7XX_FCR_TXRESET_BIT;
sc16is7xx_port_write(port, SC16IS7XX_FCR_REG, val);
udelay(5);
sc16is7xx_port_write(port, SC16IS7XX_FCR_REG,
SC16IS7XX_FCR_FIFO_BIT);
/* Enable EFR */
sc16is7xx_port_write(port, SC16IS7XX_LCR_REG,
SC16IS7XX_LCR_CONF_MODE_B);
regcache_cache_bypass(s->regmap, true);
/* Enable write access to enhanced features and internal clock div */
sc16is7xx_port_write(port, SC16IS7XX_EFR_REG,
SC16IS7XX_EFR_ENABLE_BIT);
/* Enable TCR/TLR */
sc16is7xx_port_update(port, SC16IS7XX_MCR_REG,
SC16IS7XX_MCR_TCRTLR_BIT,
SC16IS7XX_MCR_TCRTLR_BIT);
/* Configure flow control levels */
/* Flow control halt level 48, resume level 24 */
sc16is7xx_port_write(port, SC16IS7XX_TCR_REG,
SC16IS7XX_TCR_RX_RESUME(24) |
SC16IS7XX_TCR_RX_HALT(48));
regcache_cache_bypass(s->regmap, false);
/* Now, initialize the UART */
sc16is7xx_port_write(port, SC16IS7XX_LCR_REG, SC16IS7XX_LCR_WORD_LEN_8);
/* Enable the Rx and Tx FIFO */
sc16is7xx_port_update(port, SC16IS7XX_EFCR_REG,
SC16IS7XX_EFCR_RXDISABLE_BIT |
SC16IS7XX_EFCR_TXDISABLE_BIT,
0);
/* Enable RX, TX, CTS change interrupts */
val = SC16IS7XX_IER_RDI_BIT | SC16IS7XX_IER_THRI_BIT |
SC16IS7XX_IER_CTSI_BIT;
sc16is7xx_port_write(port, SC16IS7XX_IER_REG, val);
return 0;
}
static void sc16is7xx_shutdown(struct uart_port *port)
{
/* Disable all interrupts */
sc16is7xx_port_write(port, SC16IS7XX_IER_REG, 0);
/* Disable TX/RX */
sc16is7xx_port_write(port, SC16IS7XX_EFCR_REG,
SC16IS7XX_EFCR_RXDISABLE_BIT |
SC16IS7XX_EFCR_TXDISABLE_BIT);
sc16is7xx_power(port, 0);
}
static const char *sc16is7xx_type(struct uart_port *port)
{
struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
return (port->type == PORT_SC16IS7XX) ? s->devtype->name : NULL;
}
static int sc16is7xx_request_port(struct uart_port *port)
{
/* Do nothing */
return 0;
}
static void sc16is7xx_config_port(struct uart_port *port, int flags)
{
if (flags & UART_CONFIG_TYPE)
port->type = PORT_SC16IS7XX;
}
static int sc16is7xx_verify_port(struct uart_port *port,
struct serial_struct *s)
{
if ((s->type != PORT_UNKNOWN) && (s->type != PORT_SC16IS7XX))
return -EINVAL;
if (s->irq != port->irq)
return -EINVAL;
return 0;
}
static void sc16is7xx_pm(struct uart_port *port, unsigned int state,
unsigned int oldstate)
{
sc16is7xx_power(port, (state == UART_PM_STATE_ON) ? 1 : 0);
}
static void sc16is7xx_null_void(struct uart_port *port)
{
/* Do nothing */
}
static const struct uart_ops sc16is7xx_ops = {
.tx_empty = sc16is7xx_tx_empty,
.set_mctrl = sc16is7xx_set_mctrl,
.get_mctrl = sc16is7xx_get_mctrl,
.stop_tx = sc16is7xx_stop_tx,
.start_tx = sc16is7xx_start_tx,
.stop_rx = sc16is7xx_stop_rx,
.break_ctl = sc16is7xx_break_ctl,
.startup = sc16is7xx_startup,
.shutdown = sc16is7xx_shutdown,
.set_termios = sc16is7xx_set_termios,
.type = sc16is7xx_type,
.request_port = sc16is7xx_request_port,
.release_port = sc16is7xx_null_void,
.config_port = sc16is7xx_config_port,
.verify_port = sc16is7xx_verify_port,
.ioctl = sc16is7xx_ioctl,
.pm = sc16is7xx_pm,
};
#ifdef CONFIG_GPIOLIB
static int sc16is7xx_gpio_get(struct gpio_chip *chip, unsigned offset)
{
unsigned int val;
struct sc16is7xx_port *s = container_of(chip, struct sc16is7xx_port,
gpio);
struct uart_port *port = &s->p[0].port;
val = sc16is7xx_port_read(port, SC16IS7XX_IOSTATE_REG);
return !!(val & BIT(offset));
}
static void sc16is7xx_gpio_set(struct gpio_chip *chip, unsigned offset, int val)
{
struct sc16is7xx_port *s = container_of(chip, struct sc16is7xx_port,
gpio);
struct uart_port *port = &s->p[0].port;
sc16is7xx_port_update(port, SC16IS7XX_IOSTATE_REG, BIT(offset),
val ? BIT(offset) : 0);
}
static int sc16is7xx_gpio_direction_input(struct gpio_chip *chip,
unsigned offset)
{
struct sc16is7xx_port *s = container_of(chip, struct sc16is7xx_port,
gpio);
struct uart_port *port = &s->p[0].port;
sc16is7xx_port_update(port, SC16IS7XX_IODIR_REG, BIT(offset), 0);
return 0;
}
static int sc16is7xx_gpio_direction_output(struct gpio_chip *chip,
unsigned offset, int val)
{
struct sc16is7xx_port *s = container_of(chip, struct sc16is7xx_port,
gpio);
struct uart_port *port = &s->p[0].port;
sc16is7xx_port_update(port, SC16IS7XX_IOSTATE_REG, BIT(offset),
val ? BIT(offset) : 0);
sc16is7xx_port_update(port, SC16IS7XX_IODIR_REG, BIT(offset),
BIT(offset));
return 0;
}
#endif
static int sc16is7xx_probe(struct device *dev,
struct sc16is7xx_devtype *devtype,
struct regmap *regmap, int irq, unsigned long flags)
{
unsigned long freq, *pfreq = dev_get_platdata(dev);
struct clk *clk;
int i, ret;
struct sc16is7xx_port *s;
if (IS_ERR(regmap))
return PTR_ERR(regmap);
/* Alloc port structure */
s = devm_kzalloc(dev, sizeof(*s) +
sizeof(struct sc16is7xx_one) * devtype->nr_uart,
GFP_KERNEL);
if (!s) {
dev_err(dev, "Error allocating port structure\n");
return -ENOMEM;
}
clk = devm_clk_get(dev, NULL);
if (IS_ERR(clk)) {
if (pfreq)
freq = *pfreq;
else
return PTR_ERR(clk);
} else {
freq = clk_get_rate(clk);
}
s->regmap = regmap;
s->devtype = devtype;
dev_set_drvdata(dev, s);
/* Register UART driver */
s->uart.owner = THIS_MODULE;
s->uart.dev_name = "ttySC";
s->uart.nr = devtype->nr_uart;
ret = uart_register_driver(&s->uart);
if (ret) {
dev_err(dev, "Registering UART driver failed\n");
goto out_clk;
}
#ifdef CONFIG_GPIOLIB
if (devtype->nr_gpio) {
/* Setup GPIO cotroller */
s->gpio.owner = THIS_MODULE;
s->gpio.dev = dev;
s->gpio.label = dev_name(dev);
s->gpio.direction_input = sc16is7xx_gpio_direction_input;
s->gpio.get = sc16is7xx_gpio_get;
s->gpio.direction_output = sc16is7xx_gpio_direction_output;
s->gpio.set = sc16is7xx_gpio_set;
s->gpio.base = -1;
s->gpio.ngpio = devtype->nr_gpio;
s->gpio.can_sleep = 1;
ret = gpiochip_add(&s->gpio);
if (ret)
goto out_uart;
}
#endif
mutex_init(&s->mutex);
for (i = 0; i < devtype->nr_uart; ++i) {
/* Initialize port data */
s->p[i].port.line = i;
s->p[i].port.dev = dev;
s->p[i].port.irq = irq;
s->p[i].port.type = PORT_SC16IS7XX;
s->p[i].port.fifosize = SC16IS7XX_FIFO_SIZE;
s->p[i].port.flags = UPF_FIXED_TYPE | UPF_LOW_LATENCY;
s->p[i].port.iotype = UPIO_PORT;
s->p[i].port.uartclk = freq;
s->p[i].port.ops = &sc16is7xx_ops;
/* Disable all interrupts */
sc16is7xx_port_write(&s->p[i].port, SC16IS7XX_IER_REG, 0);
/* Disable TX/RX */
sc16is7xx_port_write(&s->p[i].port, SC16IS7XX_EFCR_REG,
SC16IS7XX_EFCR_RXDISABLE_BIT |
SC16IS7XX_EFCR_TXDISABLE_BIT);
/* Initialize queue for start TX */
INIT_WORK(&s->p[i].tx_work, sc16is7xx_wq_proc);
/* Initialize queue for changing mode */
INIT_WORK(&s->p[i].md_work, sc16is7xx_md_proc);
/* Register port */
uart_add_one_port(&s->uart, &s->p[i].port);
/* Go to suspend mode */
sc16is7xx_power(&s->p[i].port, 0);
}
/* Setup interrupt */
ret = devm_request_threaded_irq(dev, irq, NULL, sc16is7xx_ist,
IRQF_ONESHOT | flags, dev_name(dev), s);
if (!ret)
return 0;
mutex_destroy(&s->mutex);
#ifdef CONFIG_GPIOLIB
if (devtype->nr_gpio)
WARN_ON(gpiochip_remove(&s->gpio));
out_uart:
#endif
uart_unregister_driver(&s->uart);
out_clk:
if (!IS_ERR(s->clk))
clk_disable_unprepare(s->clk);
return ret;
}
static int sc16is7xx_remove(struct device *dev)
{
struct sc16is7xx_port *s = dev_get_drvdata(dev);
int i, ret = 0;
#ifdef CONFIG_GPIOLIB
if (s->devtype->nr_gpio) {
ret = gpiochip_remove(&s->gpio);
if (ret)
return ret;
}
#endif
for (i = 0; i < s->uart.nr; i++) {
cancel_work_sync(&s->p[i].tx_work);
cancel_work_sync(&s->p[i].md_work);
uart_remove_one_port(&s->uart, &s->p[i].port);
sc16is7xx_power(&s->p[i].port, 0);
}
mutex_destroy(&s->mutex);
uart_unregister_driver(&s->uart);
if (!IS_ERR(s->clk))
clk_disable_unprepare(s->clk);
return ret;
}
static const struct of_device_id __maybe_unused sc16is7xx_dt_ids[] = {
{ .compatible = "nxp,sc16is740", .data = &sc16is74x_devtype, },
{ .compatible = "nxp,sc16is741", .data = &sc16is74x_devtype, },
{ .compatible = "nxp,sc16is750", .data = &sc16is750_devtype, },
{ .compatible = "nxp,sc16is752", .data = &sc16is752_devtype, },
{ .compatible = "nxp,sc16is760", .data = &sc16is760_devtype, },
{ .compatible = "nxp,sc16is762", .data = &sc16is762_devtype, },
{ }
};
MODULE_DEVICE_TABLE(of, sc16is7xx_dt_ids);
static struct regmap_config regcfg = {
.reg_bits = 7,
.pad_bits = 1,
.val_bits = 8,
.cache_type = REGCACHE_RBTREE,
.volatile_reg = sc16is7xx_regmap_volatile,
.precious_reg = sc16is7xx_regmap_precious,
};
static int sc16is7xx_i2c_probe(struct i2c_client *i2c,
const struct i2c_device_id *id)
{
struct sc16is7xx_devtype *devtype;
unsigned long flags = 0;
struct regmap *regmap;
if (i2c->dev.of_node) {
const struct of_device_id *of_id =
of_match_device(sc16is7xx_dt_ids, &i2c->dev);
devtype = (struct sc16is7xx_devtype *)of_id->data;
} else {
devtype = (struct sc16is7xx_devtype *)id->driver_data;
flags = IRQF_TRIGGER_FALLING;
}
regcfg.max_register = (0xf << SC16IS7XX_REG_SHIFT) |
(devtype->nr_uart - 1);
regmap = devm_regmap_init_i2c(i2c, &regcfg);
return sc16is7xx_probe(&i2c->dev, devtype, regmap, i2c->irq, flags);
}
static int sc16is7xx_i2c_remove(struct i2c_client *client)
{
return sc16is7xx_remove(&client->dev);
}
static const struct i2c_device_id sc16is7xx_i2c_id_table[] = {
{ "sc16is74x", (kernel_ulong_t)&sc16is74x_devtype, },
{ "sc16is750", (kernel_ulong_t)&sc16is750_devtype, },
{ "sc16is752", (kernel_ulong_t)&sc16is752_devtype, },
{ "sc16is760", (kernel_ulong_t)&sc16is760_devtype, },
{ "sc16is762", (kernel_ulong_t)&sc16is762_devtype, },
{ }
};
MODULE_DEVICE_TABLE(i2c, sc16is7xx_i2c_id_table);
static struct i2c_driver sc16is7xx_i2c_uart_driver = {
.driver = {
.name = SC16IS7XX_NAME,
.owner = THIS_MODULE,
.of_match_table = of_match_ptr(sc16is7xx_dt_ids),
},
.probe = sc16is7xx_i2c_probe,
.remove = sc16is7xx_i2c_remove,
.id_table = sc16is7xx_i2c_id_table,
};
module_i2c_driver(sc16is7xx_i2c_uart_driver);
MODULE_ALIAS("i2c:sc16is7xx");
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Jon Ringle <jringle@gridpoint.com>");
MODULE_DESCRIPTION("SC16IS7XX serial driver");