Commit 7831d56b authored by Alan Cox's avatar Alan Cox Committed by Linus Torvalds
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tty: MAX3100



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Signed-off-by: default avatarAlan "I'm hiding" Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 3a709703
/*
*
* Copyright (C) 2008 Christian Pellegrin <chripell@evolware.org>
*
* 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.
*
*
* Notes: the MAX3100 doesn't provide an interrupt on CTS so we have
* to use polling for flow control. TX empty IRQ is unusable, since
* writing conf clears FIFO buffer and we cannot have this interrupt
* always asking us for attention.
*
* Example platform data:
static struct plat_max3100 max3100_plat_data = {
.loopback = 0,
.crystal = 0,
.poll_time = 100,
};
static struct spi_board_info spi_board_info[] = {
{
.modalias = "max3100",
.platform_data = &max3100_plat_data,
.irq = IRQ_EINT12,
.max_speed_hz = 5*1000*1000,
.chip_select = 0,
},
};
* The initial minor number is 209 in the low-density serial port:
* mknod /dev/ttyMAX0 c 204 209
*/
#define MAX3100_MAJOR 204
#define MAX3100_MINOR 209
/* 4 MAX3100s should be enough for everyone */
#define MAX_MAX3100 4
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/serial_core.h>
#include <linux/serial.h>
#include <linux/spi/spi.h>
#include <linux/freezer.h>
#include <linux/serial_max3100.h>
#define MAX3100_C (1<<14)
#define MAX3100_D (0<<14)
#define MAX3100_W (1<<15)
#define MAX3100_RX (0<<15)
#define MAX3100_WC (MAX3100_W | MAX3100_C)
#define MAX3100_RC (MAX3100_RX | MAX3100_C)
#define MAX3100_WD (MAX3100_W | MAX3100_D)
#define MAX3100_RD (MAX3100_RX | MAX3100_D)
#define MAX3100_CMD (3 << 14)
#define MAX3100_T (1<<14)
#define MAX3100_R (1<<15)
#define MAX3100_FEN (1<<13)
#define MAX3100_SHDN (1<<12)
#define MAX3100_TM (1<<11)
#define MAX3100_RM (1<<10)
#define MAX3100_PM (1<<9)
#define MAX3100_RAM (1<<8)
#define MAX3100_IR (1<<7)
#define MAX3100_ST (1<<6)
#define MAX3100_PE (1<<5)
#define MAX3100_L (1<<4)
#define MAX3100_BAUD (0xf)
#define MAX3100_TE (1<<10)
#define MAX3100_RAFE (1<<10)
#define MAX3100_RTS (1<<9)
#define MAX3100_CTS (1<<9)
#define MAX3100_PT (1<<8)
#define MAX3100_DATA (0xff)
#define MAX3100_RT (MAX3100_R | MAX3100_T)
#define MAX3100_RTC (MAX3100_RT | MAX3100_CTS | MAX3100_RAFE)
/* the following simulate a status reg for ignore_status_mask */
#define MAX3100_STATUS_PE 1
#define MAX3100_STATUS_FE 2
#define MAX3100_STATUS_OE 4
struct max3100_port {
struct uart_port port;
struct spi_device *spi;
int cts; /* last CTS received for flow ctrl */
int tx_empty; /* last TX empty bit */
spinlock_t conf_lock; /* shared data */
int conf_commit; /* need to make changes */
int conf; /* configuration for the MAX31000
* (bits 0-7, bits 8-11 are irqs) */
int rts_commit; /* need to change rts */
int rts; /* rts status */
int baud; /* current baud rate */
int parity; /* keeps track if we should send parity */
#define MAX3100_PARITY_ON 1
#define MAX3100_PARITY_ODD 2
#define MAX3100_7BIT 4
int rx_enabled; /* if we should rx chars */
int irq; /* irq assigned to the max3100 */
int minor; /* minor number */
int crystal; /* 1 if 3.6864Mhz crystal 0 for 1.8432 */
int loopback; /* 1 if we are in loopback mode */
/* for handling irqs: need workqueue since we do spi_sync */
struct workqueue_struct *workqueue;
struct work_struct work;
/* set to 1 to make the workhandler exit as soon as possible */
int force_end_work;
/* need to know we are suspending to avoid deadlock on workqueue */
int suspending;
/* hook for suspending MAX3100 via dedicated pin */
void (*max3100_hw_suspend) (int suspend);
/* poll time (in ms) for ctrl lines */
int poll_time;
/* and its timer */
struct timer_list timer;
};
static struct max3100_port *max3100s[MAX_MAX3100]; /* the chips */
static DEFINE_MUTEX(max3100s_lock); /* race on probe */
static int max3100_do_parity(struct max3100_port *s, u16 c)
{
int parity;
if (s->parity & MAX3100_PARITY_ODD)
parity = 1;
else
parity = 0;
if (s->parity & MAX3100_7BIT)
c &= 0x7f;
else
c &= 0xff;
parity = parity ^ (hweight8(c) & 1);
return parity;
}
static int max3100_check_parity(struct max3100_port *s, u16 c)
{
return max3100_do_parity(s, c) == ((c >> 8) & 1);
}
static void max3100_calc_parity(struct max3100_port *s, u16 *c)
{
if (s->parity & MAX3100_7BIT)
*c &= 0x7f;
else
*c &= 0xff;
if (s->parity & MAX3100_PARITY_ON)
*c |= max3100_do_parity(s, *c) << 8;
}
static void max3100_work(struct work_struct *w);
static void max3100_dowork(struct max3100_port *s)
{
if (!s->force_end_work && !work_pending(&s->work) &&
!freezing(current) && !s->suspending)
queue_work(s->workqueue, &s->work);
}
static void max3100_timeout(unsigned long data)
{
struct max3100_port *s = (struct max3100_port *)data;
if (s->port.info) {
max3100_dowork(s);
mod_timer(&s->timer, jiffies + s->poll_time);
}
}
static int max3100_sr(struct max3100_port *s, u16 tx, u16 *rx)
{
struct spi_message message;
u16 etx, erx;
int status;
struct spi_transfer tran = {
.tx_buf = &etx,
.rx_buf = &erx,
.len = 2,
};
etx = cpu_to_be16(tx);
spi_message_init(&message);
spi_message_add_tail(&tran, &message);
status = spi_sync(s->spi, &message);
if (status) {
dev_warn(&s->spi->dev, "error while calling spi_sync\n");
return -EIO;
}
*rx = be16_to_cpu(erx);
s->tx_empty = (*rx & MAX3100_T) > 0;
dev_dbg(&s->spi->dev, "%04x - %04x\n", tx, *rx);
return 0;
}
static int max3100_handlerx(struct max3100_port *s, u16 rx)
{
unsigned int ch, flg, status = 0;
int ret = 0, cts;
if (rx & MAX3100_R && s->rx_enabled) {
dev_dbg(&s->spi->dev, "%s\n", __func__);
ch = rx & (s->parity & MAX3100_7BIT ? 0x7f : 0xff);
if (rx & MAX3100_RAFE) {
s->port.icount.frame++;
flg = TTY_FRAME;
status |= MAX3100_STATUS_FE;
} else {
if (s->parity & MAX3100_PARITY_ON) {
if (max3100_check_parity(s, rx)) {
s->port.icount.rx++;
flg = TTY_NORMAL;
} else {
s->port.icount.parity++;
flg = TTY_PARITY;
status |= MAX3100_STATUS_PE;
}
} else {
s->port.icount.rx++;
flg = TTY_NORMAL;
}
}
uart_insert_char(&s->port, status, MAX3100_STATUS_OE, ch, flg);
ret = 1;
}
cts = (rx & MAX3100_CTS) > 0;
if (s->cts != cts) {
s->cts = cts;
uart_handle_cts_change(&s->port, cts ? TIOCM_CTS : 0);
}
return ret;
}
static void max3100_work(struct work_struct *w)
{
struct max3100_port *s = container_of(w, struct max3100_port, work);
int rxchars;
u16 tx, rx;
int conf, cconf, rts, crts;
struct circ_buf *xmit = &s->port.info->xmit;
dev_dbg(&s->spi->dev, "%s\n", __func__);
rxchars = 0;
do {
spin_lock(&s->conf_lock);
conf = s->conf;
cconf = s->conf_commit;
s->conf_commit = 0;
rts = s->rts;
crts = s->rts_commit;
s->rts_commit = 0;
spin_unlock(&s->conf_lock);
if (cconf)
max3100_sr(s, MAX3100_WC | conf, &rx);
if (crts) {
max3100_sr(s, MAX3100_WD | MAX3100_TE |
(s->rts ? MAX3100_RTS : 0), &rx);
rxchars += max3100_handlerx(s, rx);
}
max3100_sr(s, MAX3100_RD, &rx);
rxchars += max3100_handlerx(s, rx);
if (rx & MAX3100_T) {
tx = 0xffff;
if (s->port.x_char) {
tx = s->port.x_char;
s->port.icount.tx++;
s->port.x_char = 0;
} else if (!uart_circ_empty(xmit) &&
!uart_tx_stopped(&s->port)) {
tx = xmit->buf[xmit->tail];
xmit->tail = (xmit->tail + 1) &
(UART_XMIT_SIZE - 1);
s->port.icount.tx++;
}
if (tx != 0xffff) {
max3100_calc_parity(s, &tx);
tx |= MAX3100_WD | (s->rts ? MAX3100_RTS : 0);
max3100_sr(s, tx, &rx);
rxchars += max3100_handlerx(s, rx);
}
}
if (rxchars > 16 && s->port.info->port.tty != NULL) {
tty_flip_buffer_push(s->port.info->port.tty);
rxchars = 0;
}
if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
uart_write_wakeup(&s->port);
} while (!s->force_end_work &&
!freezing(current) &&
((rx & MAX3100_R) ||
(!uart_circ_empty(xmit) &&
!uart_tx_stopped(&s->port))));
if (rxchars > 0 && s->port.info->port.tty != NULL)
tty_flip_buffer_push(s->port.info->port.tty);
}
static irqreturn_t max3100_irq(int irqno, void *dev_id)
{
struct max3100_port *s = dev_id;
dev_dbg(&s->spi->dev, "%s\n", __func__);
max3100_dowork(s);
return IRQ_HANDLED;
}
static void max3100_enable_ms(struct uart_port *port)
{
struct max3100_port *s = container_of(port,
struct max3100_port,
port);
if (s->poll_time > 0)
mod_timer(&s->timer, jiffies);
dev_dbg(&s->spi->dev, "%s\n", __func__);
}
static void max3100_start_tx(struct uart_port *port)
{
struct max3100_port *s = container_of(port,
struct max3100_port,
port);
dev_dbg(&s->spi->dev, "%s\n", __func__);
max3100_dowork(s);
}
static void max3100_stop_rx(struct uart_port *port)
{
struct max3100_port *s = container_of(port,
struct max3100_port,
port);
dev_dbg(&s->spi->dev, "%s\n", __func__);
s->rx_enabled = 0;
spin_lock(&s->conf_lock);
s->conf &= ~MAX3100_RM;
s->conf_commit = 1;
spin_unlock(&s->conf_lock);
max3100_dowork(s);
}
static unsigned int max3100_tx_empty(struct uart_port *port)
{
struct max3100_port *s = container_of(port,
struct max3100_port,
port);
dev_dbg(&s->spi->dev, "%s\n", __func__);
/* may not be truly up-to-date */
max3100_dowork(s);
return s->tx_empty;
}
static unsigned int max3100_get_mctrl(struct uart_port *port)
{
struct max3100_port *s = container_of(port,
struct max3100_port,
port);
dev_dbg(&s->spi->dev, "%s\n", __func__);
/* may not be truly up-to-date */
max3100_dowork(s);
/* always assert DCD and DSR since these lines are not wired */
return (s->cts ? TIOCM_CTS : 0) | TIOCM_DSR | TIOCM_CAR;
}
static void max3100_set_mctrl(struct uart_port *port, unsigned int mctrl)
{
struct max3100_port *s = container_of(port,
struct max3100_port,
port);
int rts;
dev_dbg(&s->spi->dev, "%s\n", __func__);
rts = (mctrl & TIOCM_RTS) > 0;
spin_lock(&s->conf_lock);
if (s->rts != rts) {
s->rts = rts;
s->rts_commit = 1;
max3100_dowork(s);
}
spin_unlock(&s->conf_lock);
}
static void
max3100_set_termios(struct uart_port *port, struct ktermios *termios,
struct ktermios *old)
{
struct max3100_port *s = container_of(port,
struct max3100_port,
port);
int baud = 0;
unsigned cflag;
u32 param_new, param_mask, parity = 0;
struct tty_struct *tty = s->port.info->port.tty;
dev_dbg(&s->spi->dev, "%s\n", __func__);
if (!tty)
return;
cflag = termios->c_cflag;
param_new = 0;
param_mask = 0;
baud = tty_get_baud_rate(tty);
param_new = s->conf & MAX3100_BAUD;
switch (baud) {
case 300:
if (s->crystal)
baud = s->baud;
else
param_new = 15;
break;
case 600:
param_new = 14 + s->crystal;
break;
case 1200:
param_new = 13 + s->crystal;
break;
case 2400:
param_new = 12 + s->crystal;
break;
case 4800:
param_new = 11 + s->crystal;
break;
case 9600:
param_new = 10 + s->crystal;
break;
case 19200:
param_new = 9 + s->crystal;
break;
case 38400:
param_new = 8 + s->crystal;
break;
case 57600:
param_new = 1 + s->crystal;
break;
case 115200:
param_new = 0 + s->crystal;
break;
case 230400:
if (s->crystal)
param_new = 0;
else
baud = s->baud;
break;
default:
baud = s->baud;
}
tty_encode_baud_rate(tty, baud, baud);
s->baud = baud;
param_mask |= MAX3100_BAUD;
if ((cflag & CSIZE) == CS8) {
param_new &= ~MAX3100_L;
parity &= ~MAX3100_7BIT;
} else {
param_new |= MAX3100_L;
parity |= MAX3100_7BIT;
cflag = (cflag & ~CSIZE) | CS7;
}
param_mask |= MAX3100_L;
if (cflag & CSTOPB)
param_new |= MAX3100_ST;
else
param_new &= ~MAX3100_ST;
param_mask |= MAX3100_ST;
if (cflag & PARENB) {
param_new |= MAX3100_PE;
parity |= MAX3100_PARITY_ON;
} else {
param_new &= ~MAX3100_PE;
parity &= ~MAX3100_PARITY_ON;
}
param_mask |= MAX3100_PE;
if (cflag & PARODD)
parity |= MAX3100_PARITY_ODD;
else
parity &= ~MAX3100_PARITY_ODD;
/* mask termios capabilities we don't support */
cflag &= ~CMSPAR;
termios->c_cflag = cflag;
s->port.ignore_status_mask = 0;
if (termios->c_iflag & IGNPAR)
s->port.ignore_status_mask |=
MAX3100_STATUS_PE | MAX3100_STATUS_FE |
MAX3100_STATUS_OE;
/* we are sending char from a workqueue so enable */
s->port.info->port.tty->low_latency = 1;
if (s->poll_time > 0)
del_timer_sync(&s->timer);
uart_update_timeout(port, termios->c_cflag, baud);
spin_lock(&s->conf_lock);
s->conf = (s->conf & ~param_mask) | (param_new & param_mask);
s->conf_commit = 1;
s->parity = parity;
spin_unlock(&s->conf_lock);
max3100_dowork(s);
if (UART_ENABLE_MS(&s->port, termios->c_cflag))
max3100_enable_ms(&s->port);
}
static void max3100_shutdown(struct uart_port *port)
{
struct max3100_port *s = container_of(port,
struct max3100_port,
port);
dev_dbg(&s->spi->dev, "%s\n", __func__);
if (s->suspending)
return;
s->force_end_work = 1;
if (s->poll_time > 0)
del_timer_sync(&s->timer);
if (s->workqueue) {
flush_workqueue(s->workqueue);
destroy_workqueue(s->workqueue);
s->workqueue = NULL;
}
if (s->irq)
free_irq(s->irq, s);
/* set shutdown mode to save power */
if (s->max3100_hw_suspend)
s->max3100_hw_suspend(1);
else {
u16 tx, rx;
tx = MAX3100_WC | MAX3100_SHDN;
max3100_sr(s, tx, &rx);
}
}
static int max3100_startup(struct uart_port *port)
{
struct max3100_port *s = container_of(port,
struct max3100_port,
port);
char b[12];
dev_dbg(&s->spi->dev, "%s\n", __func__);
s->conf = MAX3100_RM;
s->baud = s->crystal ? 230400 : 115200;
s->rx_enabled = 1;
if (s->suspending)
return 0;
s->force_end_work = 0;
s->parity = 0;
s->rts = 0;
sprintf(b, "max3100-%d", s->minor);
s->workqueue = create_freezeable_workqueue(b);
if (!s->workqueue) {
dev_warn(&s->spi->dev, "cannot create workqueue\n");
return -EBUSY;
}
INIT_WORK(&s->work, max3100_work);
if (request_irq(s->irq, max3100_irq,
IRQF_TRIGGER_FALLING, "max3100", s) < 0) {
dev_warn(&s->spi->dev, "cannot allocate irq %d\n", s->irq);
s->irq = 0;
destroy_workqueue(s->workqueue);
s->workqueue = NULL;
return -EBUSY;
}