/****************************************************************************
   *
   * Driver for the IFX 6x60 spi modem.
   *
   * Copyright (C) 2008 Option International
   * Copyright (C) 2008 Filip Aben <f.aben@option.com>
   *		      Denis Joseph Barrow <d.barow@option.com>
   *		      Jan Dumon <j.dumon@option.com>
   *
   * Copyright (C) 2009, 2010 Intel Corp
   * Russ Gorby <russ.gorby@intel.com>
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License version 2 as
   * published by the Free Software Foundation.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	 See the
   * GNU General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
   * USA
   *
   * Driver modified by Intel from Option gtm501l_spi.c
   *
   * Notes
   * o	The driver currently assumes a single device only. If you need to
   *	change this then look for saved_ifx_dev and add a device lookup
   * o	The driver is intended to be big-endian safe but has never been
   *	tested that way (no suitable hardware). There are a couple of FIXME
   *	notes by areas that may need addressing
   * o	Some of the GPIO naming/setup assumptions may need revisiting if
   *	you need to use this driver for another platform.
   *
   *****************************************************************************/
  #include <linux/dma-mapping.h>
  #include <linux/module.h>
  #include <linux/termios.h>
  #include <linux/tty.h>
  #include <linux/device.h>
  #include <linux/spi/spi.h>
  #include <linux/kfifo.h>
  #include <linux/tty_flip.h>
  #include <linux/timer.h>
  #include <linux/serial.h>
  #include <linux/interrupt.h>
  #include <linux/irq.h>
  #include <linux/rfkill.h>
  #include <linux/fs.h>
  #include <linux/ip.h>
  #include <linux/dmapool.h>
  #include <linux/gpio.h>
  #include <linux/sched.h>
  #include <linux/time.h>
  #include <linux/wait.h>
  #include <linux/pm.h>
  #include <linux/pm_runtime.h>
  #include <linux/spi/ifx_modem.h>
  #include <linux/delay.h>
  #include <linux/reboot.h>
  
  #include "ifx6x60.h"
  
  #define IFX_SPI_MORE_MASK		0x10
  #define IFX_SPI_MORE_BIT		4	/* bit position in u8 */
  #define IFX_SPI_CTS_BIT			6	/* bit position in u8 */
  #define IFX_SPI_MODE			SPI_MODE_1
  #define IFX_SPI_TTY_ID			0
  #define IFX_SPI_TIMEOUT_SEC		2
  #define IFX_SPI_HEADER_0		(-1)
  #define IFX_SPI_HEADER_F		(-2)
  
  #define PO_POST_DELAY		200
  #define IFX_MDM_RST_PMU	4
  
  /* forward reference */
  static void ifx_spi_handle_srdy(struct ifx_spi_device *ifx_dev);
  static int ifx_modem_reboot_callback(struct notifier_block *nfb,
  				unsigned long event, void *data);
  static int ifx_modem_power_off(struct ifx_spi_device *ifx_dev);
  
  /* local variables */
  static int spi_bpw = 16;		/* 8, 16 or 32 bit word length */
  static struct tty_driver *tty_drv;
  static struct ifx_spi_device *saved_ifx_dev;
  static struct lock_class_key ifx_spi_key;
  
  static struct notifier_block ifx_modem_reboot_notifier_block = {
  	.notifier_call = ifx_modem_reboot_callback,
  };
  
  static int ifx_modem_power_off(struct ifx_spi_device *ifx_dev)
  {
  	gpio_set_value(IFX_MDM_RST_PMU, 1);
  	msleep(PO_POST_DELAY);
  
  	return 0;
  }
  
  static int ifx_modem_reboot_callback(struct notifier_block *nfb,
  				 unsigned long event, void *data)
  {
  	if (saved_ifx_dev)
  		ifx_modem_power_off(saved_ifx_dev);
  	else
  		pr_warn("no ifx modem active;
  ");
  
  	return NOTIFY_OK;
  }
  
  /* GPIO/GPE settings */
  
  /**
   *	mrdy_set_high		-	set MRDY GPIO
   *	@ifx: device we are controlling
   *
   */
  static inline void mrdy_set_high(struct ifx_spi_device *ifx)
  {
  	gpio_set_value(ifx->gpio.mrdy, 1);
  }
  
  /**
   *	mrdy_set_low		-	clear MRDY GPIO
   *	@ifx: device we are controlling
   *
   */
  static inline void mrdy_set_low(struct ifx_spi_device *ifx)
  {
  	gpio_set_value(ifx->gpio.mrdy, 0);
  }
  
  /**
   *	ifx_spi_power_state_set
   *	@ifx_dev: our SPI device
   *	@val: bits to set
   *
   *	Set bit in power status and signal power system if status becomes non-0
   */
  static void
  ifx_spi_power_state_set(struct ifx_spi_device *ifx_dev, unsigned char val)
  {
  	unsigned long flags;
  
  	spin_lock_irqsave(&ifx_dev->power_lock, flags);
  
  	/*
  	 * if power status is already non-0, just update, else
  	 * tell power system
  	 */
  	if (!ifx_dev->power_status)
  		pm_runtime_get(&ifx_dev->spi_dev->dev);
  	ifx_dev->power_status |= val;
  
  	spin_unlock_irqrestore(&ifx_dev->power_lock, flags);
  }
  
  /**
   *	ifx_spi_power_state_clear	-	clear power bit
   *	@ifx_dev: our SPI device
   *	@val: bits to clear
   *
   *	clear bit in power status and signal power system if status becomes 0
   */
  static void
  ifx_spi_power_state_clear(struct ifx_spi_device *ifx_dev, unsigned char val)
  {
  	unsigned long flags;
  
  	spin_lock_irqsave(&ifx_dev->power_lock, flags);
  
  	if (ifx_dev->power_status) {
  		ifx_dev->power_status &= ~val;
  		if (!ifx_dev->power_status)
  			pm_runtime_put(&ifx_dev->spi_dev->dev);
  	}
  
  	spin_unlock_irqrestore(&ifx_dev->power_lock, flags);
  }
  
  /**
   *	swap_buf_8
   *	@buf: our buffer
   *	@len : number of bytes (not words) in the buffer
   *	@end: end of buffer
   *
   *	Swap the contents of a buffer into big endian format
   */
  static inline void swap_buf_8(unsigned char *buf, int len, void *end)
  {
  	/* don't swap buffer if SPI word width is 8 bits */
  	return;
  }
  
  /**
   *	swap_buf_16
   *	@buf: our buffer
   *	@len : number of bytes (not words) in the buffer
   *	@end: end of buffer
   *
   *	Swap the contents of a buffer into big endian format
   */
  static inline void swap_buf_16(unsigned char *buf, int len, void *end)
  {
  	int n;
  
  	u16 *buf_16 = (u16 *)buf;
  	len = ((len + 1) >> 1);
  	if ((void *)&buf_16[len] > end) {
  		pr_err("swap_buf_16: swap exceeds boundary (%p > %p)!",
  		       &buf_16[len], end);
  		return;
  	}
  	for (n = 0; n < len; n++) {
  		*buf_16 = cpu_to_be16(*buf_16);
  		buf_16++;
  	}
  }
  
  /**
   *	swap_buf_32
   *	@buf: our buffer
   *	@len : number of bytes (not words) in the buffer
   *	@end: end of buffer
   *
   *	Swap the contents of a buffer into big endian format
   */
  static inline void swap_buf_32(unsigned char *buf, int len, void *end)
  {
  	int n;
  
  	u32 *buf_32 = (u32 *)buf;
  	len = (len + 3) >> 2;
  
  	if ((void *)&buf_32[len] > end) {
  		pr_err("swap_buf_32: swap exceeds boundary (%p > %p)!
  ",
  		       &buf_32[len], end);
  		return;
  	}
  	for (n = 0; n < len; n++) {
  		*buf_32 = cpu_to_be32(*buf_32);
  		buf_32++;
  	}
  }
  
  /**
   *	mrdy_assert		-	assert MRDY line
   *	@ifx_dev: our SPI device
   *
   *	Assert mrdy and set timer to wait for SRDY interrupt, if SRDY is low
   *	now.
   *
   *	FIXME: Can SRDY even go high as we are running this code ?
   */
  static void mrdy_assert(struct ifx_spi_device *ifx_dev)
  {
  	int val = gpio_get_value(ifx_dev->gpio.srdy);
  	if (!val) {
  		if (!test_and_set_bit(IFX_SPI_STATE_TIMER_PENDING,
  				      &ifx_dev->flags)) {
  			mod_timer(&ifx_dev->spi_timer,jiffies + IFX_SPI_TIMEOUT_SEC*HZ);
  
  		}
  	}
  	ifx_spi_power_state_set(ifx_dev, IFX_SPI_POWER_DATA_PENDING);
  	mrdy_set_high(ifx_dev);
  }
  
  /**
   *	ifx_spi_timeout		-	SPI timeout
   *	@arg: our SPI device
   *
   *	The SPI has timed out: hang up the tty. Users will then see a hangup
   *	and error events.
   */
  static void ifx_spi_timeout(unsigned long arg)
  {
  	struct ifx_spi_device *ifx_dev = (struct ifx_spi_device *)arg;
  
  	dev_warn(&ifx_dev->spi_dev->dev, "*** SPI Timeout ***");
  	tty_port_tty_hangup(&ifx_dev->tty_port, false);
  	mrdy_set_low(ifx_dev);
  	clear_bit(IFX_SPI_STATE_TIMER_PENDING, &ifx_dev->flags);
  }
  
  /* char/tty operations */
  
  /**
   *	ifx_spi_tiocmget	-	get modem lines
   *	@tty: our tty device
   *	@filp: file handle issuing the request
   *
   *	Map the signal state into Linux modem flags and report the value
   *	in Linux terms
   */
  static int ifx_spi_tiocmget(struct tty_struct *tty)
  {
  	unsigned int value;
  	struct ifx_spi_device *ifx_dev = tty->driver_data;
  
  	value =
  	(test_bit(IFX_SPI_RTS, &ifx_dev->signal_state) ? TIOCM_RTS : 0) |
  	(test_bit(IFX_SPI_DTR, &ifx_dev->signal_state) ? TIOCM_DTR : 0) |
  	(test_bit(IFX_SPI_CTS, &ifx_dev->signal_state) ? TIOCM_CTS : 0) |
  	(test_bit(IFX_SPI_DSR, &ifx_dev->signal_state) ? TIOCM_DSR : 0) |
  	(test_bit(IFX_SPI_DCD, &ifx_dev->signal_state) ? TIOCM_CAR : 0) |
  	(test_bit(IFX_SPI_RI, &ifx_dev->signal_state) ? TIOCM_RNG : 0);
  	return value;
  }
  
  /**
   *	ifx_spi_tiocmset	-	set modem bits
   *	@tty: the tty structure
   *	@set: bits to set
   *	@clear: bits to clear
   *
   *	The IFX6x60 only supports DTR and RTS. Set them accordingly
   *	and flag that an update to the modem is needed.
   *
   *	FIXME: do we need to kick the tranfers when we do this ?
   */
  static int ifx_spi_tiocmset(struct tty_struct *tty,
  			    unsigned int set, unsigned int clear)
  {
  	struct ifx_spi_device *ifx_dev = tty->driver_data;
  
  	if (set & TIOCM_RTS)
  		set_bit(IFX_SPI_RTS, &ifx_dev->signal_state);
  	if (set & TIOCM_DTR)
  		set_bit(IFX_SPI_DTR, &ifx_dev->signal_state);
  	if (clear & TIOCM_RTS)
  		clear_bit(IFX_SPI_RTS, &ifx_dev->signal_state);
  	if (clear & TIOCM_DTR)
  		clear_bit(IFX_SPI_DTR, &ifx_dev->signal_state);
  
  	set_bit(IFX_SPI_UPDATE, &ifx_dev->signal_state);
  	return 0;
  }
  
  /**
   *	ifx_spi_open	-	called on tty open
   *	@tty: our tty device
   *	@filp: file handle being associated with the tty
   *
   *	Open the tty interface. We let the tty_port layer do all the work
   *	for us.
   *
   *	FIXME: Remove single device assumption and saved_ifx_dev
   */
  static int ifx_spi_open(struct tty_struct *tty, struct file *filp)
  {
  	return tty_port_open(&saved_ifx_dev->tty_port, tty, filp);
  }
  
  /**
   *	ifx_spi_close	-	called when our tty closes
   *	@tty: the tty being closed
   *	@filp: the file handle being closed
   *
   *	Perform the close of the tty. We use the tty_port layer to do all
   *	our hard work.
   */
  static void ifx_spi_close(struct tty_struct *tty, struct file *filp)
  {
  	struct ifx_spi_device *ifx_dev = tty->driver_data;
  	tty_port_close(&ifx_dev->tty_port, tty, filp);
  	/* FIXME: should we do an ifx_spi_reset here ? */
  }
  
  /**
   *	ifx_decode_spi_header	-	decode received header
   *	@buffer: the received data
   *	@length: decoded length
   *	@more: decoded more flag
   *	@received_cts: status of cts we received
   *
   *	Note how received_cts is handled -- if header is all F it is left
   *	the same as it was, if header is all 0 it is set to 0 otherwise it is
   *	taken from the incoming header.
   *
   *	FIXME: endianness
   */
  static int ifx_spi_decode_spi_header(unsigned char *buffer, int *length,
  			unsigned char *more, unsigned char *received_cts)
  {
  	u16 h1;
  	u16 h2;
  	u16 *in_buffer = (u16 *)buffer;
  
  	h1 = *in_buffer;
  	h2 = *(in_buffer+1);
  
  	if (h1 == 0 && h2 == 0) {
  		*received_cts = 0;
  		return IFX_SPI_HEADER_0;
  	} else if (h1 == 0xffff && h2 == 0xffff) {
  		/* spi_slave_cts remains as it was */
  		return IFX_SPI_HEADER_F;
  	}
  
  	*length = h1 & 0xfff;	/* upper bits of byte are flags */
  	*more = (buffer[1] >> IFX_SPI_MORE_BIT) & 1;
  	*received_cts = (buffer[3] >> IFX_SPI_CTS_BIT) & 1;
  	return 0;
  }
  
  /**
   *	ifx_setup_spi_header	-	set header fields
   *	@txbuffer: pointer to start of SPI buffer
   *	@tx_count: bytes
   *	@more: indicate if more to follow
   *
   *	Format up an SPI header for a transfer
   *
   *	FIXME: endianness?
   */
  static void ifx_spi_setup_spi_header(unsigned char *txbuffer, int tx_count,
  					unsigned char more)
  {
  	*(u16 *)(txbuffer) = tx_count;
  	*(u16 *)(txbuffer+2) = IFX_SPI_PAYLOAD_SIZE;
  	txbuffer[1] |= (more << IFX_SPI_MORE_BIT) & IFX_SPI_MORE_MASK;
  }
  
  /**
   *	ifx_spi_prepare_tx_buffer	-	prepare transmit frame
   *	@ifx_dev: our SPI device
   *
   *	The transmit buffr needs a header and various other bits of
   *	information followed by as much data as we can pull from the FIFO
   *	and transfer. This function formats up a suitable buffer in the
   *	ifx_dev->tx_buffer
   *
   *	FIXME: performance - should we wake the tty when the queue is half
   *			     empty ?
   */
  static int ifx_spi_prepare_tx_buffer(struct ifx_spi_device *ifx_dev)
  {
  	int temp_count;
  	int queue_length;
  	int tx_count;
  	unsigned char *tx_buffer;
  
  	tx_buffer = ifx_dev->tx_buffer;
  
  	/* make room for required SPI header */
  	tx_buffer += IFX_SPI_HEADER_OVERHEAD;
  	tx_count = IFX_SPI_HEADER_OVERHEAD;
  
  	/* clear to signal no more data if this turns out to be the
  	 * last buffer sent in a sequence */
  	ifx_dev->spi_more = 0;
  
  	/* if modem cts is set, just send empty buffer */
  	if (!ifx_dev->spi_slave_cts) {
  		/* see if there's tx data */
  		queue_length = kfifo_len(&ifx_dev->tx_fifo);
  		if (queue_length != 0) {
  			/* data to mux -- see if there's room for it */
  			temp_count = min(queue_length, IFX_SPI_PAYLOAD_SIZE);
  			temp_count = kfifo_out_locked(&ifx_dev->tx_fifo,
  					tx_buffer, temp_count,
  					&ifx_dev->fifo_lock);
  
  			/* update buffer pointer and data count in message */
  			tx_buffer += temp_count;
  			tx_count += temp_count;
  			if (temp_count == queue_length)
  				/* poke port to get more data */
  				tty_port_tty_wakeup(&ifx_dev->tty_port);
  			else /* more data in port, use next SPI message */
  				ifx_dev->spi_more = 1;
  		}
  	}
  	/* have data and info for header -- set up SPI header in buffer */
  	/* spi header needs payload size, not entire buffer size */
  	ifx_spi_setup_spi_header(ifx_dev->tx_buffer,
  					tx_count-IFX_SPI_HEADER_OVERHEAD,
  					ifx_dev->spi_more);
  	/* swap actual data in the buffer */
  	ifx_dev->swap_buf((ifx_dev->tx_buffer), tx_count,
  		&ifx_dev->tx_buffer[IFX_SPI_TRANSFER_SIZE]);
  	return tx_count;
  }
  
  /**
   *	ifx_spi_write		-	line discipline write
   *	@tty: our tty device
   *	@buf: pointer to buffer to write (kernel space)
   *	@count: size of buffer
   *
   *	Write the characters we have been given into the FIFO. If the device
   *	is not active then activate it, when the SRDY line is asserted back
   *	this will commence I/O
   */
  static int ifx_spi_write(struct tty_struct *tty, const unsigned char *buf,
  			 int count)
  {
  	struct ifx_spi_device *ifx_dev = tty->driver_data;
  	unsigned char *tmp_buf = (unsigned char *)buf;
  	unsigned long flags;
  	bool is_fifo_empty;
  	int tx_count;
  
  	spin_lock_irqsave(&ifx_dev->fifo_lock, flags);
  	is_fifo_empty = kfifo_is_empty(&ifx_dev->tx_fifo);
  	tx_count = kfifo_in(&ifx_dev->tx_fifo, tmp_buf, count);
  	spin_unlock_irqrestore(&ifx_dev->fifo_lock, flags);
  	if (is_fifo_empty)
  		mrdy_assert(ifx_dev);
  
  	return tx_count;
  }
  
  /**
   *	ifx_spi_chars_in_buffer	-	line discipline helper
   *	@tty: our tty device
   *
   *	Report how much data we can accept before we drop bytes. As we use
   *	a simple FIFO this is nice and easy.
   */
  static int ifx_spi_write_room(struct tty_struct *tty)
  {
  	struct ifx_spi_device *ifx_dev = tty->driver_data;
  	return IFX_SPI_FIFO_SIZE - kfifo_len(&ifx_dev->tx_fifo);
  }
  
  /**
   *	ifx_spi_chars_in_buffer	-	line discipline helper
   *	@tty: our tty device
   *
   *	Report how many characters we have buffered. In our case this is the
   *	number of bytes sitting in our transmit FIFO.
   */
  static int ifx_spi_chars_in_buffer(struct tty_struct *tty)
  {
  	struct ifx_spi_device *ifx_dev = tty->driver_data;
  	return kfifo_len(&ifx_dev->tx_fifo);
  }
  
  /**
   *	ifx_port_hangup
   *	@port: our tty port
   *
   *	tty port hang up. Called when tty_hangup processing is invoked either
   *	by loss of carrier, or by software (eg vhangup). Serialized against
   *	activate/shutdown by the tty layer.
   */
  static void ifx_spi_hangup(struct tty_struct *tty)
  {
  	struct ifx_spi_device *ifx_dev = tty->driver_data;
  	tty_port_hangup(&ifx_dev->tty_port);
  }
  
  /**
   *	ifx_port_activate
   *	@port: our tty port
   *
   *	tty port activate method - called for first open. Serialized
   *	with hangup and shutdown by the tty layer.
   */
  static int ifx_port_activate(struct tty_port *port, struct tty_struct *tty)
  {
  	struct ifx_spi_device *ifx_dev =
  		container_of(port, struct ifx_spi_device, tty_port);
  
  	/* clear any old data; can't do this in 'close' */
  	kfifo_reset(&ifx_dev->tx_fifo);
  
  	/* clear any flag which may be set in port shutdown procedure */
  	clear_bit(IFX_SPI_STATE_IO_IN_PROGRESS, &ifx_dev->flags);
  	clear_bit(IFX_SPI_STATE_IO_READY, &ifx_dev->flags);
  
  	/* put port data into this tty */
  	tty->driver_data = ifx_dev;
  
  	/* allows flip string push from int context */
  	port->low_latency = 1;
  
  	/* set flag to allows data transfer */
  	set_bit(IFX_SPI_STATE_IO_AVAILABLE, &ifx_dev->flags);
  
  	return 0;
  }
  
  /**
   *	ifx_port_shutdown
   *	@port: our tty port
   *
   *	tty port shutdown method - called for last port close. Serialized
   *	with hangup and activate by the tty layer.
   */
  static void ifx_port_shutdown(struct tty_port *port)
  {
  	struct ifx_spi_device *ifx_dev =
  		container_of(port, struct ifx_spi_device, tty_port);
  
  	clear_bit(IFX_SPI_STATE_IO_AVAILABLE, &ifx_dev->flags);
  	mrdy_set_low(ifx_dev);
  	del_timer(&ifx_dev->spi_timer);
  	clear_bit(IFX_SPI_STATE_TIMER_PENDING, &ifx_dev->flags);
  	tasklet_kill(&ifx_dev->io_work_tasklet);
  }
  
  static const struct tty_port_operations ifx_tty_port_ops = {
  	.activate = ifx_port_activate,
  	.shutdown = ifx_port_shutdown,
  };
  
  static const struct tty_operations ifx_spi_serial_ops = {
  	.open = ifx_spi_open,
  	.close = ifx_spi_close,
  	.write = ifx_spi_write,
  	.hangup = ifx_spi_hangup,
  	.write_room = ifx_spi_write_room,
  	.chars_in_buffer = ifx_spi_chars_in_buffer,
  	.tiocmget = ifx_spi_tiocmget,
  	.tiocmset = ifx_spi_tiocmset,
  };
  
  /**
   *	ifx_spi_insert_fip_string	-	queue received data
   *	@ifx_ser: our SPI device
   *	@chars: buffer we have received
   *	@size: number of chars reeived
   *
   *	Queue bytes to the tty assuming the tty side is currently open. If
   *	not the discard the data.
   */
  static void ifx_spi_insert_flip_string(struct ifx_spi_device *ifx_dev,
  				    unsigned char *chars, size_t size)
  {
  	tty_insert_flip_string(&ifx_dev->tty_port, chars, size);
  	tty_flip_buffer_push(&ifx_dev->tty_port);
  }
  
  /**
   *	ifx_spi_complete	-	SPI transfer completed
   *	@ctx: our SPI device
   *
   *	An SPI transfer has completed. Process any received data and kick off
   *	any further transmits we can commence.
   */
  static void ifx_spi_complete(void *ctx)
  {
  	struct ifx_spi_device *ifx_dev = ctx;
  	int length;
  	int actual_length;
  	unsigned char more;
  	unsigned char cts;
  	int local_write_pending = 0;
  	int queue_length;
  	int srdy;
  	int decode_result;
  
  	mrdy_set_low(ifx_dev);
  
  	if (!ifx_dev->spi_msg.status) {
  		/* check header validity, get comm flags */
  		ifx_dev->swap_buf(ifx_dev->rx_buffer, IFX_SPI_HEADER_OVERHEAD,
  			&ifx_dev->rx_buffer[IFX_SPI_HEADER_OVERHEAD]);
  		decode_result = ifx_spi_decode_spi_header(ifx_dev->rx_buffer,
  				&length, &more, &cts);
  		if (decode_result == IFX_SPI_HEADER_0) {
  			dev_dbg(&ifx_dev->spi_dev->dev,
  				"ignore input: invalid header 0");
  			ifx_dev->spi_slave_cts = 0;
  			goto complete_exit;
  		} else if (decode_result == IFX_SPI_HEADER_F) {
  			dev_dbg(&ifx_dev->spi_dev->dev,
  				"ignore input: invalid header F");
  			goto complete_exit;
  		}
  
  		ifx_dev->spi_slave_cts = cts;
  
  		actual_length = min((unsigned int)length,
  					ifx_dev->spi_msg.actual_length);
  		ifx_dev->swap_buf(
  			(ifx_dev->rx_buffer + IFX_SPI_HEADER_OVERHEAD),
  			 actual_length,
  			 &ifx_dev->rx_buffer[IFX_SPI_TRANSFER_SIZE]);
  		ifx_spi_insert_flip_string(
  			ifx_dev,
  			ifx_dev->rx_buffer + IFX_SPI_HEADER_OVERHEAD,
  			(size_t)actual_length);
  	} else {
  		dev_dbg(&ifx_dev->spi_dev->dev, "SPI transfer error %d",
  		       ifx_dev->spi_msg.status);
  	}
  
  complete_exit:
  	if (ifx_dev->write_pending) {
  		ifx_dev->write_pending = 0;
  		local_write_pending = 1;
  	}
  
  	clear_bit(IFX_SPI_STATE_IO_IN_PROGRESS, &(ifx_dev->flags));
  
  	queue_length = kfifo_len(&ifx_dev->tx_fifo);
  	srdy = gpio_get_value(ifx_dev->gpio.srdy);
  	if (!srdy)
  		ifx_spi_power_state_clear(ifx_dev, IFX_SPI_POWER_SRDY);
  
  	/* schedule output if there is more to do */
  	if (test_and_clear_bit(IFX_SPI_STATE_IO_READY, &ifx_dev->flags))
  		tasklet_schedule(&ifx_dev->io_work_tasklet);
  	else {
  		if (more || ifx_dev->spi_more || queue_length > 0 ||
  			local_write_pending) {
  			if (ifx_dev->spi_slave_cts) {
  				if (more)
  					mrdy_assert(ifx_dev);
  			} else
  				mrdy_assert(ifx_dev);
  		} else {
  			/*
  			 * poke line discipline driver if any for more data
  			 * may or may not get more data to write
  			 * for now, say not busy
  			 */
  			ifx_spi_power_state_clear(ifx_dev,
  						  IFX_SPI_POWER_DATA_PENDING);
  			tty_port_tty_wakeup(&ifx_dev->tty_port);
  		}
  	}
  }
  
  /**
   *	ifx_spio_io		-	I/O tasklet
   *	@data: our SPI device
   *
   *	Queue data for transmission if possible and then kick off the
   *	transfer.
   */
  static void ifx_spi_io(unsigned long data)
  {
  	int retval;
  	struct ifx_spi_device *ifx_dev = (struct ifx_spi_device *) data;
  
  	if (!test_and_set_bit(IFX_SPI_STATE_IO_IN_PROGRESS, &ifx_dev->flags) &&
  		test_bit(IFX_SPI_STATE_IO_AVAILABLE, &ifx_dev->flags)) {
  		if (ifx_dev->gpio.unack_srdy_int_nb > 0)
  			ifx_dev->gpio.unack_srdy_int_nb--;
  
  		ifx_spi_prepare_tx_buffer(ifx_dev);
  
  		spi_message_init(&ifx_dev->spi_msg);
  		INIT_LIST_HEAD(&ifx_dev->spi_msg.queue);
  
  		ifx_dev->spi_msg.context = ifx_dev;
  		ifx_dev->spi_msg.complete = ifx_spi_complete;
  
  		/* set up our spi transfer */
  		/* note len is BYTES, not transfers */
  		ifx_dev->spi_xfer.len = IFX_SPI_TRANSFER_SIZE;
  		ifx_dev->spi_xfer.cs_change = 0;
  		ifx_dev->spi_xfer.speed_hz = ifx_dev->spi_dev->max_speed_hz;
  		/* ifx_dev->spi_xfer.speed_hz = 390625; */
  		ifx_dev->spi_xfer.bits_per_word =
  			ifx_dev->spi_dev->bits_per_word;
  
  		ifx_dev->spi_xfer.tx_buf = ifx_dev->tx_buffer;
  		ifx_dev->spi_xfer.rx_buf = ifx_dev->rx_buffer;
  
  		/*
  		 * setup dma pointers
  		 */
  		if (ifx_dev->use_dma) {
  			ifx_dev->spi_msg.is_dma_mapped = 1;
  			ifx_dev->tx_dma = ifx_dev->tx_bus;
  			ifx_dev->rx_dma = ifx_dev->rx_bus;
  			ifx_dev->spi_xfer.tx_dma = ifx_dev->tx_dma;
  			ifx_dev->spi_xfer.rx_dma = ifx_dev->rx_dma;
  		} else {
  			ifx_dev->spi_msg.is_dma_mapped = 0;
  			ifx_dev->tx_dma = (dma_addr_t)0;
  			ifx_dev->rx_dma = (dma_addr_t)0;
  			ifx_dev->spi_xfer.tx_dma = (dma_addr_t)0;
  			ifx_dev->spi_xfer.rx_dma = (dma_addr_t)0;
  		}
  
  		spi_message_add_tail(&ifx_dev->spi_xfer, &ifx_dev->spi_msg);
  
  		/* Assert MRDY. This may have already been done by the write
  		 * routine.
  		 */
  		mrdy_assert(ifx_dev);
  
  		retval = spi_async(ifx_dev->spi_dev, &ifx_dev->spi_msg);
  		if (retval) {
  			clear_bit(IFX_SPI_STATE_IO_IN_PROGRESS,
  				  &ifx_dev->flags);
  			tasklet_schedule(&ifx_dev->io_work_tasklet);
  			return;
  		}
  	} else
  		ifx_dev->write_pending = 1;
  }
  
  /**
   *	ifx_spi_free_port	-	free up the tty side
   *	@ifx_dev: IFX device going away
   *
   *	Unregister and free up a port when the device goes away
   */
  static void ifx_spi_free_port(struct ifx_spi_device *ifx_dev)
  {
  	if (ifx_dev->tty_dev)
  		tty_unregister_device(tty_drv, ifx_dev->minor);
  	tty_port_destroy(&ifx_dev->tty_port);
  	kfifo_free(&ifx_dev->tx_fifo);
  }
  
  /**
   *	ifx_spi_create_port	-	create a new port
   *	@ifx_dev: our spi device
   *
   *	Allocate and initialise the tty port that goes with this interface
   *	and add it to the tty layer so that it can be opened.
   */
  static int ifx_spi_create_port(struct ifx_spi_device *ifx_dev)
  {
  	int ret = 0;
  	struct tty_port *pport = &ifx_dev->tty_port;
  
  	spin_lock_init(&ifx_dev->fifo_lock);
  	lockdep_set_class_and_subclass(&ifx_dev->fifo_lock,
  		&ifx_spi_key, 0);
  
  	if (kfifo_alloc(&ifx_dev->tx_fifo, IFX_SPI_FIFO_SIZE, GFP_KERNEL)) {
  		ret = -ENOMEM;
  		goto error_ret;
  	}
  
  	tty_port_init(pport);
  	pport->ops = &ifx_tty_port_ops;
  	ifx_dev->minor = IFX_SPI_TTY_ID;
  	ifx_dev->tty_dev = tty_port_register_device(pport, tty_drv,
  			ifx_dev->minor, &ifx_dev->spi_dev->dev);
  	if (IS_ERR(ifx_dev->tty_dev)) {
  		dev_dbg(&ifx_dev->spi_dev->dev,
  			"%s: registering tty device failed", __func__);
  		ret = PTR_ERR(ifx_dev->tty_dev);
  		goto error_port;
  	}
  	return 0;
  
  error_port:
  	tty_port_destroy(pport);
  error_ret:
  	ifx_spi_free_port(ifx_dev);
  	return ret;
  }
  
  /**
   *	ifx_spi_handle_srdy		-	handle SRDY
   *	@ifx_dev: device asserting SRDY
   *
   *	Check our device state and see what we need to kick off when SRDY
   *	is asserted. This usually means killing the timer and firing off the
   *	I/O processing.
   */
  static void ifx_spi_handle_srdy(struct ifx_spi_device *ifx_dev)
  {
  	if (test_bit(IFX_SPI_STATE_TIMER_PENDING, &ifx_dev->flags)) {
  		del_timer(&ifx_dev->spi_timer);
  		clear_bit(IFX_SPI_STATE_TIMER_PENDING, &ifx_dev->flags);
  	}
  
  	ifx_spi_power_state_set(ifx_dev, IFX_SPI_POWER_SRDY);
  
  	if (!test_bit(IFX_SPI_STATE_IO_IN_PROGRESS, &ifx_dev->flags))
  		tasklet_schedule(&ifx_dev->io_work_tasklet);
  	else
  		set_bit(IFX_SPI_STATE_IO_READY, &ifx_dev->flags);
  }
  
  /**
   *	ifx_spi_srdy_interrupt	-	SRDY asserted
   *	@irq: our IRQ number
   *	@dev: our ifx device
   *
   *	The modem asserted SRDY. Handle the srdy event
   */
  static irqreturn_t ifx_spi_srdy_interrupt(int irq, void *dev)
  {
  	struct ifx_spi_device *ifx_dev = dev;
  	ifx_dev->gpio.unack_srdy_int_nb++;
  	ifx_spi_handle_srdy(ifx_dev);
  	return IRQ_HANDLED;
  }
  
  /**
   *	ifx_spi_reset_interrupt	-	Modem has changed reset state
   *	@irq: interrupt number
   *	@dev: our device pointer
   *
   *	The modem has either entered or left reset state. Check the GPIO
   *	line to see which.
   *
   *	FIXME: review locking on MR_INPROGRESS versus
   *	parallel unsolicited reset/solicited reset
   */
  static irqreturn_t ifx_spi_reset_interrupt(int irq, void *dev)
  {
  	struct ifx_spi_device *ifx_dev = dev;
  	int val = gpio_get_value(ifx_dev->gpio.reset_out);
  	int solreset = test_bit(MR_START, &ifx_dev->mdm_reset_state);
  
  	if (val == 0) {
  		/* entered reset */
  		set_bit(MR_INPROGRESS, &ifx_dev->mdm_reset_state);
  		if (!solreset) {
  			/* unsolicited reset  */
  			tty_port_tty_hangup(&ifx_dev->tty_port, false);
  		}
  	} else {
  		/* exited reset */
  		clear_bit(MR_INPROGRESS, &ifx_dev->mdm_reset_state);
  		if (solreset) {
  			set_bit(MR_COMPLETE, &ifx_dev->mdm_reset_state);
  			wake_up(&ifx_dev->mdm_reset_wait);
  		}
  	}
  	return IRQ_HANDLED;
  }
  
  /**
   *	ifx_spi_free_device - free device
   *	@ifx_dev: device to free
   *
   *	Free the IFX device
   */
  static void ifx_spi_free_device(struct ifx_spi_device *ifx_dev)
  {
  	ifx_spi_free_port(ifx_dev);
  	dma_free_coherent(&ifx_dev->spi_dev->dev,
  				IFX_SPI_TRANSFER_SIZE,
  				ifx_dev->tx_buffer,
  				ifx_dev->tx_bus);
  	dma_free_coherent(&ifx_dev->spi_dev->dev,
  				IFX_SPI_TRANSFER_SIZE,
  				ifx_dev->rx_buffer,
  				ifx_dev->rx_bus);
  }
  
  /**
   *	ifx_spi_reset	-	reset modem
   *	@ifx_dev: modem to reset
   *
   *	Perform a reset on the modem
   */
  static int ifx_spi_reset(struct ifx_spi_device *ifx_dev)
  {
  	int ret;
  	/*
  	 * set up modem power, reset
  	 *
  	 * delays are required on some platforms for the modem
  	 * to reset properly
  	 */
  	set_bit(MR_START, &ifx_dev->mdm_reset_state);
  	gpio_set_value(ifx_dev->gpio.po, 0);
  	gpio_set_value(ifx_dev->gpio.reset, 0);
  	msleep(25);
  	gpio_set_value(ifx_dev->gpio.reset, 1);
  	msleep(1);
  	gpio_set_value(ifx_dev->gpio.po, 1);
  	msleep(1);
  	gpio_set_value(ifx_dev->gpio.po, 0);
  	ret = wait_event_timeout(ifx_dev->mdm_reset_wait,
  				 test_bit(MR_COMPLETE,
  					  &ifx_dev->mdm_reset_state),
  				 IFX_RESET_TIMEOUT);
  	if (!ret)
  		dev_warn(&ifx_dev->spi_dev->dev, "Modem reset timeout: (state:%lx)",
  			 ifx_dev->mdm_reset_state);
  
  	ifx_dev->mdm_reset_state = 0;
  	return ret;
  }
  
  /**
   *	ifx_spi_spi_probe	-	probe callback
   *	@spi: our possible matching SPI device
   *
   *	Probe for a 6x60 modem on SPI bus. Perform any needed device and
   *	GPIO setup.
   *
   *	FIXME:
   *	-	Support for multiple devices
   *	-	Split out MID specific GPIO handling eventually
   */
  
  static int ifx_spi_spi_probe(struct spi_device *spi)
  {
  	int ret;
  	int srdy;
  	struct ifx_modem_platform_data *pl_data;
  	struct ifx_spi_device *ifx_dev;
  
  	if (saved_ifx_dev) {
  		dev_dbg(&spi->dev, "ignoring subsequent detection");
  		return -ENODEV;
  	}
  
  	pl_data = dev_get_platdata(&spi->dev);
  	if (!pl_data) {
  		dev_err(&spi->dev, "missing platform data!");
  		return -ENODEV;
  	}
  
  	/* initialize structure to hold our device variables */
  	ifx_dev = kzalloc(sizeof(struct ifx_spi_device), GFP_KERNEL);
  	if (!ifx_dev) {
  		dev_err(&spi->dev, "spi device allocation failed");
  		return -ENOMEM;
  	}
  	saved_ifx_dev = ifx_dev;
  	ifx_dev->spi_dev = spi;
  	clear_bit(IFX_SPI_STATE_IO_IN_PROGRESS, &ifx_dev->flags);
  	spin_lock_init(&ifx_dev->write_lock);
  	spin_lock_init(&ifx_dev->power_lock);
  	ifx_dev->power_status = 0;
  	init_timer(&ifx_dev->spi_timer);
  	ifx_dev->spi_timer.function = ifx_spi_timeout;
  	ifx_dev->spi_timer.data = (unsigned long)ifx_dev;
  	ifx_dev->modem = pl_data->modem_type;
  	ifx_dev->use_dma = pl_data->use_dma;
  	ifx_dev->max_hz = pl_data->max_hz;
  	/* initialize spi mode, etc */
  	spi->max_speed_hz = ifx_dev->max_hz;
  	spi->mode = IFX_SPI_MODE | (SPI_LOOP & spi->mode);
  	spi->bits_per_word = spi_bpw;
  	ret = spi_setup(spi);
  	if (ret) {
  		dev_err(&spi->dev, "SPI setup wasn't successful %d", ret);
  		return -ENODEV;
  	}
  
  	/* init swap_buf function according to word width configuration */
  	if (spi->bits_per_word == 32)
  		ifx_dev->swap_buf = swap_buf_32;
  	else if (spi->bits_per_word == 16)
  		ifx_dev->swap_buf = swap_buf_16;
  	else
  		ifx_dev->swap_buf = swap_buf_8;
  
  	/* ensure SPI protocol flags are initialized to enable transfer */
  	ifx_dev->spi_more = 0;
  	ifx_dev->spi_slave_cts = 0;
  
  	/*initialize transfer and dma buffers */
  	ifx_dev->tx_buffer = dma_alloc_coherent(ifx_dev->spi_dev->dev.parent,
  				IFX_SPI_TRANSFER_SIZE,
  				&ifx_dev->tx_bus,
  				GFP_KERNEL);
  	if (!ifx_dev->tx_buffer) {
  		dev_err(&spi->dev, "DMA-TX buffer allocation failed");
  		ret = -ENOMEM;
  		goto error_ret;
  	}
  	ifx_dev->rx_buffer = dma_alloc_coherent(ifx_dev->spi_dev->dev.parent,
  				IFX_SPI_TRANSFER_SIZE,
  				&ifx_dev->rx_bus,
  				GFP_KERNEL);
  	if (!ifx_dev->rx_buffer) {
  		dev_err(&spi->dev, "DMA-RX buffer allocation failed");
  		ret = -ENOMEM;
  		goto error_ret;
  	}
  
  	/* initialize waitq for modem reset */
  	init_waitqueue_head(&ifx_dev->mdm_reset_wait);
  
  	spi_set_drvdata(spi, ifx_dev);
  	tasklet_init(&ifx_dev->io_work_tasklet, ifx_spi_io,
  						(unsigned long)ifx_dev);
  
  	set_bit(IFX_SPI_STATE_PRESENT, &ifx_dev->flags);
  
  	/* create our tty port */
  	ret = ifx_spi_create_port(ifx_dev);
  	if (ret != 0) {
  		dev_err(&spi->dev, "create default tty port failed");
  		goto error_ret;
  	}
  
  	ifx_dev->gpio.reset = pl_data->rst_pmu;
  	ifx_dev->gpio.po = pl_data->pwr_on;
  	ifx_dev->gpio.mrdy = pl_data->mrdy;
  	ifx_dev->gpio.srdy = pl_data->srdy;
  	ifx_dev->gpio.reset_out = pl_data->rst_out;
  
  	dev_info(&spi->dev, "gpios %d, %d, %d, %d, %d",
  		 ifx_dev->gpio.reset, ifx_dev->gpio.po, ifx_dev->gpio.mrdy,
  		 ifx_dev->gpio.srdy, ifx_dev->gpio.reset_out);
  
  	/* Configure gpios */
  	ret = gpio_request(ifx_dev->gpio.reset, "ifxModem");
  	if (ret < 0) {
  		dev_err(&spi->dev, "Unable to allocate GPIO%d (RESET)",
  			ifx_dev->gpio.reset);
  		goto error_ret;
  	}
  	ret += gpio_direction_output(ifx_dev->gpio.reset, 0);
  	ret += gpio_export(ifx_dev->gpio.reset, 1);
  	if (ret) {
  		dev_err(&spi->dev, "Unable to configure GPIO%d (RESET)",
  			ifx_dev->gpio.reset);
  		ret = -EBUSY;
  		goto error_ret2;
  	}
  
  	ret = gpio_request(ifx_dev->gpio.po, "ifxModem");
  	ret += gpio_direction_output(ifx_dev->gpio.po, 0);
  	ret += gpio_export(ifx_dev->gpio.po, 1);
  	if (ret) {
  		dev_err(&spi->dev, "Unable to configure GPIO%d (ON)",
  			ifx_dev->gpio.po);
  		ret = -EBUSY;
  		goto error_ret3;
  	}
  
  	ret = gpio_request(ifx_dev->gpio.mrdy, "ifxModem");
  	if (ret < 0) {
  		dev_err(&spi->dev, "Unable to allocate GPIO%d (MRDY)",
  			ifx_dev->gpio.mrdy);
  		goto error_ret3;
  	}
  	ret += gpio_export(ifx_dev->gpio.mrdy, 1);
  	ret += gpio_direction_output(ifx_dev->gpio.mrdy, 0);
  	if (ret) {
  		dev_err(&spi->dev, "Unable to configure GPIO%d (MRDY)",
  			ifx_dev->gpio.mrdy);
  		ret = -EBUSY;
  		goto error_ret4;
  	}
  
  	ret = gpio_request(ifx_dev->gpio.srdy, "ifxModem");
  	if (ret < 0) {
  		dev_err(&spi->dev, "Unable to allocate GPIO%d (SRDY)",
  			ifx_dev->gpio.srdy);
  		ret = -EBUSY;
  		goto error_ret4;
  	}
  	ret += gpio_export(ifx_dev->gpio.srdy, 1);
  	ret += gpio_direction_input(ifx_dev->gpio.srdy);
  	if (ret) {
  		dev_err(&spi->dev, "Unable to configure GPIO%d (SRDY)",
  			ifx_dev->gpio.srdy);
  		ret = -EBUSY;
  		goto error_ret5;
  	}
  
  	ret = gpio_request(ifx_dev->gpio.reset_out, "ifxModem");
  	if (ret < 0) {
  		dev_err(&spi->dev, "Unable to allocate GPIO%d (RESET_OUT)",
  			ifx_dev->gpio.reset_out);
  		goto error_ret5;
  	}
  	ret += gpio_export(ifx_dev->gpio.reset_out, 1);
  	ret += gpio_direction_input(ifx_dev->gpio.reset_out);
  	if (ret) {
  		dev_err(&spi->dev, "Unable to configure GPIO%d (RESET_OUT)",
  			ifx_dev->gpio.reset_out);
  		ret = -EBUSY;
  		goto error_ret6;
  	}
  
  	ret = request_irq(gpio_to_irq(ifx_dev->gpio.reset_out),
  			  ifx_spi_reset_interrupt,
  			  IRQF_TRIGGER_RISING|IRQF_TRIGGER_FALLING, DRVNAME,
  		(void *)ifx_dev);
  	if (ret) {
  		dev_err(&spi->dev, "Unable to get irq %x
  ",
  			gpio_to_irq(ifx_dev->gpio.reset_out));
  		goto error_ret6;
  	}
  
  	ret = ifx_spi_reset(ifx_dev);
  
  	ret = request_irq(gpio_to_irq(ifx_dev->gpio.srdy),
  			  ifx_spi_srdy_interrupt,
  			  IRQF_TRIGGER_RISING, DRVNAME,
  			  (void *)ifx_dev);
  	if (ret) {
  		dev_err(&spi->dev, "Unable to get irq %x",
  			gpio_to_irq(ifx_dev->gpio.srdy));
  		goto error_ret7;
  	}
  
  	/* set pm runtime power state and register with power system */
  	pm_runtime_set_active(&spi->dev);
  	pm_runtime_enable(&spi->dev);
  
  	/* handle case that modem is already signaling SRDY */
  	/* no outgoing tty open at this point, this just satisfies the
  	 * modem's read and should reset communication properly
  	 */
  	srdy = gpio_get_value(ifx_dev->gpio.srdy);
  
  	if (srdy) {
  		mrdy_assert(ifx_dev);
  		ifx_spi_handle_srdy(ifx_dev);
  	} else
  		mrdy_set_low(ifx_dev);
  	return 0;
  
  error_ret7:
  	free_irq(gpio_to_irq(ifx_dev->gpio.reset_out), (void *)ifx_dev);
  error_ret6:
  	gpio_free(ifx_dev->gpio.srdy);
  error_ret5:
  	gpio_free(ifx_dev->gpio.mrdy);
  error_ret4:
  	gpio_free(ifx_dev->gpio.reset);
  error_ret3:
  	gpio_free(ifx_dev->gpio.po);
  error_ret2:
  	gpio_free(ifx_dev->gpio.reset_out);
  error_ret:
  	ifx_spi_free_device(ifx_dev);
  	saved_ifx_dev = NULL;
  	return ret;
  }
  
  /**
   *	ifx_spi_spi_remove	-	SPI device was removed
   *	@spi: SPI device
   *
   *	FIXME: We should be shutting the device down here not in
   *	the module unload path.
   */
  
  static int ifx_spi_spi_remove(struct spi_device *spi)
  {
  	struct ifx_spi_device *ifx_dev = spi_get_drvdata(spi);
  	/* stop activity */
  	tasklet_kill(&ifx_dev->io_work_tasklet);
  	/* free irq */
  	free_irq(gpio_to_irq(ifx_dev->gpio.reset_out), (void *)ifx_dev);
  	free_irq(gpio_to_irq(ifx_dev->gpio.srdy), (void *)ifx_dev);
  
  	gpio_free(ifx_dev->gpio.srdy);
  	gpio_free(ifx_dev->gpio.mrdy);
  	gpio_free(ifx_dev->gpio.reset);
  	gpio_free(ifx_dev->gpio.po);
  	gpio_free(ifx_dev->gpio.reset_out);
  
  	/* free allocations */
  	ifx_spi_free_device(ifx_dev);
  
  	saved_ifx_dev = NULL;
  	return 0;
  }
  
  /**
   *	ifx_spi_spi_shutdown	-	called on SPI shutdown
   *	@spi: SPI device
   *
   *	No action needs to be taken here
   */
  
  static void ifx_spi_spi_shutdown(struct spi_device *spi)
  {
  	struct ifx_spi_device *ifx_dev = spi_get_drvdata(spi);
  
  	ifx_modem_power_off(ifx_dev);
  }
  
  /*
   * various suspends and resumes have nothing to do
   * no hardware to save state for
   */
  
  /**
   *	ifx_spi_pm_suspend	-	suspend modem on system suspend
   *	@dev: device being suspended
   *
   *	Suspend the modem. No action needed on Intel MID platforms, may
   *	need extending for other systems.
   */
  static int ifx_spi_pm_suspend(struct device *dev)
  {
  	return 0;
  }
  
  /**
   *	ifx_spi_pm_resume	-	resume modem on system resume
   *	@dev: device being suspended
   *
   *	Allow the modem to resume. No action needed.
   *
   *	FIXME: do we need to reset anything here ?
   */
  static int ifx_spi_pm_resume(struct device *dev)
  {
  	return 0;
  }
  
  /**
   *	ifx_spi_pm_runtime_resume	-	suspend modem
   *	@dev: device being suspended
   *
   *	Allow the modem to resume. No action needed.
   */
  static int ifx_spi_pm_runtime_resume(struct device *dev)
  {
  	return 0;
  }
  
  /**
   *	ifx_spi_pm_runtime_suspend	-	suspend modem
   *	@dev: device being suspended
   *
   *	Allow the modem to suspend and thus suspend to continue up the
   *	device tree.
   */
  static int ifx_spi_pm_runtime_suspend(struct device *dev)
  {
  	return 0;
  }
  
  /**
   *	ifx_spi_pm_runtime_idle		-	check if modem idle
   *	@dev: our device
   *
   *	Check conditions and queue runtime suspend if idle.
   */
  static int ifx_spi_pm_runtime_idle(struct device *dev)
  {
  	struct spi_device *spi = to_spi_device(dev);
  	struct ifx_spi_device *ifx_dev = spi_get_drvdata(spi);
  
  	if (!ifx_dev->power_status)
  		pm_runtime_suspend(dev);
  
  	return 0;
  }
  
  static const struct dev_pm_ops ifx_spi_pm = {
  	.resume = ifx_spi_pm_resume,
  	.suspend = ifx_spi_pm_suspend,
  	.runtime_resume = ifx_spi_pm_runtime_resume,
  	.runtime_suspend = ifx_spi_pm_runtime_suspend,
  	.runtime_idle = ifx_spi_pm_runtime_idle
  };
  
  static const struct spi_device_id ifx_id_table[] = {
  	{"ifx6160", 0},
  	{"ifx6260", 0},
  	{ }
  };
  MODULE_DEVICE_TABLE(spi, ifx_id_table);
  
  /* spi operations */
  static struct spi_driver ifx_spi_driver = {
  	.driver = {
  		.name = DRVNAME,
  		.pm = &ifx_spi_pm,
  		.owner = THIS_MODULE},
  	.probe = ifx_spi_spi_probe,
  	.shutdown = ifx_spi_spi_shutdown,
  	.remove = ifx_spi_spi_remove,
  	.id_table = ifx_id_table
  };
  
  /**
   *	ifx_spi_exit	-	module exit
   *
   *	Unload the module.
   */
  
  static void __exit ifx_spi_exit(void)
  {
  	/* unregister */
  	tty_unregister_driver(tty_drv);
  	put_tty_driver(tty_drv);
  	spi_unregister_driver((void *)&ifx_spi_driver);
  	unregister_reboot_notifier(&ifx_modem_reboot_notifier_block);
  }
  
  /**
   *	ifx_spi_init		-	module entry point
   *
   *	Initialise the SPI and tty interfaces for the IFX SPI driver
   *	We need to initialize upper-edge spi driver after the tty
   *	driver because otherwise the spi probe will race
   */
  
  static int __init ifx_spi_init(void)
  {
  	int result;
  
  	tty_drv = alloc_tty_driver(1);
  	if (!tty_drv) {
  		pr_err("%s: alloc_tty_driver failed", DRVNAME);
  		return -ENOMEM;
  	}
  
  	tty_drv->driver_name = DRVNAME;
  	tty_drv->name = TTYNAME;
  	tty_drv->minor_start = IFX_SPI_TTY_ID;
  	tty_drv->type = TTY_DRIVER_TYPE_SERIAL;
  	tty_drv->subtype = SERIAL_TYPE_NORMAL;
  	tty_drv->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV;
  	tty_drv->init_termios = tty_std_termios;
  
  	tty_set_operations(tty_drv, &ifx_spi_serial_ops);
  
  	result = tty_register_driver(tty_drv);
  	if (result) {
  		pr_err("%s: tty_register_driver failed(%d)",
  			DRVNAME, result);
  		goto err_free_tty;
  	}
  
  	result = spi_register_driver((void *)&ifx_spi_driver);
  	if (result) {
  		pr_err("%s: spi_register_driver failed(%d)",
  			DRVNAME, result);
  		goto err_unreg_tty;
  	}
  
  	result = register_reboot_notifier(&ifx_modem_reboot_notifier_block);
  	if (result) {
  		pr_err("%s: register ifx modem reboot notifier failed(%d)",
  			DRVNAME, result);
  		goto err_unreg_spi;
  	}
  
  	return 0;
  err_unreg_spi:
  	spi_unregister_driver((void *)&ifx_spi_driver);
  err_unreg_tty:
  	tty_unregister_driver(tty_drv);
  err_free_tty:
  	put_tty_driver(tty_drv);
  
  	return result;
  }
  
  module_init(ifx_spi_init);
  module_exit(ifx_spi_exit);
  
  MODULE_AUTHOR("Intel");
  MODULE_DESCRIPTION("IFX6x60 spi driver");
  MODULE_LICENSE("GPL");
  MODULE_INFO(Version, "0.1-IFX6x60");