text: /*
   *
   *  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/slab.h>
  #include <linux/device.h>
  #include <linux/module.h>
  #include <linux/serial_core.h>
  #include <linux/serial.h>
  #include <linux/spi/spi.h>
  #include <linux/freezer.h>
  #include <linux/tty.h>
  #include <linux/tty_flip.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 && !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.state) {
  		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.state->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) {
  			tty_flip_buffer_push(&s->port.state->port);
  			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)
  		tty_flip_buffer_push(&s->port.state->port);
  }
  
  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;
  
  	dev_dbg(&s->spi->dev, "%s\n", __func__);
  
  	cflag = termios->c_cflag;
  	param_new = 0;
  	param_mask = 0;
  
  	baud = tty_termios_baud_rate(termios);
  	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_termios_encode_baud_rate(termios, 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.state->port.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_freezable_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;
  	}
  
  	if (s->loopback) {
  		u16 tx, rx;
  		tx = 0x4001;
  		max3100_sr(s, tx, &rx);
  	}
  
  	if (s->max3100_hw_suspend)
  		s->max3100_hw_suspend(0);
  	s->conf_commit = 1;
  	max3100_dowork(s);
  	/* wait for clock to settle */
  	msleep(50);
  
  	max3100_enable_ms(&s->port);
  
  	return 0;
  }
  
  static const char *max3100_type(struct uart_port *port)
  {
  	struct max3100_port *s = container_of(port,
  					      struct max3100_port,
  					      port);
  
  	dev_dbg(&s->spi->dev, "%s\n", __func__);
  
  	return s->port.type == PORT_MAX3100 ? "MAX3100" : NULL;
  }
  
  static void max3100_release_port(struct uart_port *port)
  {
  	struct max3100_port *s = container_of(port,
  					      struct max3100_port,
  					      port);
  
  	dev_dbg(&s->spi->dev, "%s\n", __func__);
  }
  
  static void max3100_config_port(struct uart_port *port, int flags)
  {
  	struct max3100_port *s = container_of(port,
  					      struct max3100_port,
  					      port);
  
  	dev_dbg(&s->spi->dev, "%s\n", __func__);
  
  	if (flags & UART_CONFIG_TYPE)
  		s->port.type = PORT_MAX3100;
  }
  
  static int max3100_verify_port(struct uart_port *port,
  			       struct serial_struct *ser)
  {
  	struct max3100_port *s = container_of(port,
  					      struct max3100_port,
  					      port);
  	int ret = -EINVAL;
  
  	dev_dbg(&s->spi->dev, "%s\n", __func__);
  
  	if (ser->type == PORT_UNKNOWN || ser->type == PORT_MAX3100)
  		ret = 0;
  	return ret;
  }
  
  static void max3100_stop_tx(struct uart_port *port)
  {
  	struct max3100_port *s = container_of(port,
  					      struct max3100_port,
  					      port);
  
  	dev_dbg(&s->spi->dev, "%s\n", __func__);
  }
  
  static int max3100_request_port(struct uart_port *port)
  {
  	struct max3100_port *s = container_of(port,
  					      struct max3100_port,
  					      port);
  
  	dev_dbg(&s->spi->dev, "%s\n", __func__);
  	return 0;
  }
  
  static void max3100_break_ctl(struct uart_port *port, int break_state)
  {
  	struct max3100_port *s = container_of(port,
  					      struct max3100_port,
  					      port);
  
  	dev_dbg(&s->spi->dev, "%s\n", __func__);
  }
  
  static struct uart_ops max3100_ops = {
  	.tx_empty	= max3100_tx_empty,
  	.set_mctrl	= max3100_set_mctrl,
  	.get_mctrl	= max3100_get_mctrl,
  	.stop_tx        = max3100_stop_tx,
  	.start_tx	= max3100_start_tx,
  	.stop_rx	= max3100_stop_rx,
  	.enable_ms      = max3100_enable_ms,
  	.break_ctl      = max3100_break_ctl,
  	.startup	= max3100_startup,
  	.shutdown	= max3100_shutdown,
  	.set_termios	= max3100_set_termios,
  	.type		= max3100_type,
  	.release_port   = max3100_release_port,
  	.request_port   = max3100_request_port,
  	.config_port	= max3100_config_port,
  	.verify_port	= max3100_verify_port,
  };
  
  static struct uart_driver max3100_uart_driver = {
  	.owner          = THIS_MODULE,
  	.driver_name    = "ttyMAX",
  	.dev_name       = "ttyMAX",
  	.major          = MAX3100_MAJOR,
  	.minor          = MAX3100_MINOR,
  	.nr             = MAX_MAX3100,
  };
  static int uart_driver_registered;
  
  static int max3100_probe(struct spi_device *spi)
  {
  	int i, retval;
  	struct plat_max3100 *pdata;
  	u16 tx, rx;
  
  	mutex_lock(&max3100s_lock);
  
  	if (!uart_driver_registered) {
  		uart_driver_registered = 1;
  		retval = uart_register_driver(&max3100_uart_driver);
  		if (retval) {
  			printk(KERN_ERR "Couldn't register max3100 uart driver\n");
  			mutex_unlock(&max3100s_lock);
  			return retval;
  		}
  	}
  
  	for (i = 0; i < MAX_MAX3100; i++)
  		if (!max3100s[i])
  			break;
  	if (i == MAX_MAX3100) {
  		dev_warn(&spi->dev, "too many MAX3100 chips\n");
  		mutex_unlock(&max3100s_lock);
  		return -ENOMEM;
  	}
  
  	max3100s[i] = kzalloc(sizeof(struct max3100_port), GFP_KERNEL);
  	if (!max3100s[i]) {
  		dev_warn(&spi->dev,
  			 "kmalloc for max3100 structure %d failed!\n", i);
  		mutex_unlock(&max3100s_lock);
  		return -ENOMEM;
  	}
  	max3100s[i]->spi = spi;
  	max3100s[i]->irq = spi->irq;
  	spin_lock_init(&max3100s[i]->conf_lock);
  	spi_set_drvdata(spi, max3100s[i]);
  	pdata = spi->dev.platform_data;
  	max3100s[i]->crystal = pdata->crystal;
  	max3100s[i]->loopback = pdata->loopback;
  	max3100s[i]->poll_time = pdata->poll_time * HZ / 1000;
  	if (pdata->poll_time > 0 && max3100s[i]->poll_time == 0)
  		max3100s[i]->poll_time = 1;
  	max3100s[i]->max3100_hw_suspend = pdata->max3100_hw_suspend;
  	max3100s[i]->minor = i;
  	init_timer(&max3100s[i]->timer);
  	max3100s[i]->timer.function = max3100_timeout;
  	max3100s[i]->timer.data = (unsigned long) max3100s[i];
  
  	dev_dbg(&spi->dev, "%s: adding port %d\n", __func__, i);
  	max3100s[i]->port.irq = max3100s[i]->irq;
  	max3100s[i]->port.uartclk = max3100s[i]->crystal ? 3686400 : 1843200;
  	max3100s[i]->port.fifosize = 16;
  	max3100s[i]->port.ops = &max3100_ops;
  	max3100s[i]->port.flags = UPF_SKIP_TEST | UPF_BOOT_AUTOCONF;
  	max3100s[i]->port.line = i;
  	max3100s[i]->port.type = PORT_MAX3100;
  	max3100s[i]->port.dev = &spi->dev;
  	retval = uart_add_one_port(&max3100_uart_driver, &max3100s[i]->port);
  	if (retval < 0)
  		dev_warn(&spi->dev,
  			 "uart_add_one_port failed for line %d with error %d\n",
  			 i, retval);
  
  	/* set shutdown mode to save power. Will be woken-up on open */
  	if (max3100s[i]->max3100_hw_suspend)
  		max3100s[i]->max3100_hw_suspend(1);
  	else {
  		tx = MAX3100_WC | MAX3100_SHDN;
  		max3100_sr(max3100s[i], tx, &rx);
  	}
  	mutex_unlock(&max3100s_lock);
  	return 0;
  }
  
  static int max3100_remove(struct spi_device *spi)
  {
  	struct max3100_port *s = spi_get_drvdata(spi);
  	int i;
  
  	mutex_lock(&max3100s_lock);
  
  	/* find out the index for the chip we are removing */
  	for (i = 0; i < MAX_MAX3100; i++)
  		if (max3100s[i] == s) {
  			dev_dbg(&spi->dev, "%s: removing port %d\n", __func__, i);
  			uart_remove_one_port(&max3100_uart_driver, &max3100s[i]->port);
  			kfree(max3100s[i]);
  			max3100s[i] = NULL;
  			break;
  		}
  
  	WARN_ON(i == MAX_MAX3100);
  	
  	/* check if this is the last chip we have */
  	for (i = 0; i < MAX_MAX3100; i++)
  		if (max3100s[i]) {
  			mutex_unlock(&max3100s_lock);
  			return 0;
  		}
  	pr_debug("removing max3100 driver\n");
  	uart_unregister_driver(&max3100_uart_driver);
  
  	mutex_unlock(&max3100s_lock);
  	return 0;
  }
  
  #ifdef CONFIG_PM_SLEEP
  
  static int max3100_suspend(struct device *dev)
  {
  	struct max3100_port *s = dev_get_drvdata(dev);
  
  	dev_dbg(&s->spi->dev, "%s\n", __func__);
  
  	disable_irq(s->irq);
  
  	s->suspending = 1;
  	uart_suspend_port(&max3100_uart_driver, &s->port);
  
  	if (s->max3100_hw_suspend)
  		s->max3100_hw_suspend(1);
  	else {
  		/* no HW suspend, so do SW one */
  		u16 tx, rx;
  
  		tx = MAX3100_WC | MAX3100_SHDN;
  		max3100_sr(s, tx, &rx);
  	}
  	return 0;
  }
  
  static int max3100_resume(struct device *dev)
  {
  	struct max3100_port *s = dev_get_drvdata(dev);
  
  	dev_dbg(&s->spi->dev, "%s\n", __func__);
  
  	if (s->max3100_hw_suspend)
  		s->max3100_hw_suspend(0);
  	uart_resume_port(&max3100_uart_driver, &s->port);
  	s->suspending = 0;
  
  	enable_irq(s->irq);
  
  	s->conf_commit = 1;
  	if (s->workqueue)
  		max3100_dowork(s);
  
  	return 0;
  }
  
  static SIMPLE_DEV_PM_OPS(max3100_pm_ops, max3100_suspend, max3100_resume);
  #define MAX3100_PM_OPS (&max3100_pm_ops)
  
  #else
  #define MAX3100_PM_OPS NULL
  #endif
  
  static struct spi_driver max3100_driver = {
  	.driver = {
  		.name		= "max3100",
  		.owner		= THIS_MODULE,
  		.pm		= MAX3100_PM_OPS,
  	},
  	.probe		= max3100_probe,
  	.remove		= max3100_remove,
  };
  
  module_spi_driver(max3100_driver);
  
  MODULE_DESCRIPTION("MAX3100 driver");
  MODULE_AUTHOR("Christian Pellegrin <chripell@evolware.org>");
  MODULE_LICENSE("GPL");
  MODULE_ALIAS("spi:max3100");
  