max310x.c
/*
* 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 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 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;
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(&s->port.state->port);
}
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,
};
#ifdef CONFIG_PM_SLEEP
static int max310x_suspend(struct device *dev)
{
int ret;
struct max310x_port *s = dev_get_drvdata(dev);
dev_dbg(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 device *dev)
{
struct max310x_port *s = dev_get_drvdata(dev);
dev_dbg(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);
}
static SIMPLE_DEV_PM_OPS(max310x_pm_ops, max310x_suspend, max310x_resume);
#define MAX310X_PM_OPS (&max310x_pm_ops)
#else
#define MAX310X_PM_OPS NULL
#endif
#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 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;
s->gpio.can_sleep = 1;
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);
return ret;
}
static int max310x_remove(struct spi_device *spi)
{
struct device *dev = &spi->dev;
struct max310x_port *s = dev_get_drvdata(dev);
int ret = 0;
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) {
ret = gpiochip_remove(&s->gpio);
if (ret)
dev_err(dev, "Failed to remove gpio chip: %d\n", ret);
}
#endif
dev_set_drvdata(dev, NULL);
if (s->pdata->suspend)
s->pdata->suspend(1);
if (s->pdata->exit)
s->pdata->exit();
return ret;
}
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,
.pm = MAX310X_PM_OPS,
},
.probe = max310x_probe,
.remove = max310x_remove,
.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");
