telit_spi.c

/****************************************************************************
 *
 * Driver for Telit UE910/HE910 SPI modems.
 *
 * 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>
 *
 * Copyright (C) 2015 ActiGraph, LLC
 * Judge Maygarden <judge.maygarden@actigraphcorp.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
 * Driver modified by ActiGraph from Intel ifx6x60.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/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/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/delay.h>
#include <linux/reboot.h>
#include <linux/of_gpio.h>

#include "telit_spi.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

/* 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 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)
{
    printk(KERN_INFO "%s(0x%p)\n", __func__, ifx_dev);

    gpio_set_value(ifx_dev->gpio.on, 0);
    msleep(3000);
    gpio_set_value(ifx_dev->gpio.power, 0);
    msleep(PO_POST_DELAY);

    return 0;
}

static int ifx_modem_reboot_callback(struct notifier_block *nfb,
                 unsigned long event, void *data)
{
    printk(KERN_INFO "%s(0x%p, %ld, 0x%p)\n", __func__, nfb, event, data);

    if (saved_ifx_dev)
        ifx_modem_power_off(saved_ifx_dev);
    else
        pr_warn("no ifx modem active;\n");

    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)!\n",
               &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;

    printk(KERN_INFO "%s(0x%p, 0x%p, %d)\n", __func__, tty, buf, 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 = 0;
    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;

    printk(KERN_INFO "%s(0x%08lX)\n", __func__, 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)) {

        printk(KERN_INFO "\t%s:%d\n", __func__, __LINE__);
        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.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
         */
        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) {
            printk(KERN_INFO "\t%s:%d\n", __func__, __LINE__);
            clear_bit(IFX_SPI_STATE_IO_IN_PROGRESS,
                  &ifx_dev->flags);
            tasklet_schedule(&ifx_dev->io_work_tasklet);
            return;
        }

    } else {
        printk(KERN_INFO "\t%s:%d\n", __func__, __LINE__);
        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;

    printk(KERN_INFO "%s(%d, 0x%p)\n", __func__, irq, 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.status);
    int solreset = test_bit(MR_START, &ifx_dev->mdm_reset_state);

    printk(KERN_INFO "%s(%d, 0x%p)\n", __func__, irq, dev);
    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);
    kfree(ifx_dev->tx_buffer);
    kfree(ifx_dev->rx_buffer);
}

/**
 *  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.shutdown, 1);
    gpio_set_value(ifx_dev->gpio.on, 1);
    gpio_set_value(ifx_dev->gpio.power, 1);
    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);
    }
    if (0 == gpio_get_value(ifx_dev->gpio.status)) {
        gpio_set_value(ifx_dev->gpio.on, 0);
        msleep(5000);
        gpio_set_value(ifx_dev->gpio.on, 1);
    }
    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);
    } else {
        msleep(1000);
    }

    ifx_dev->mdm_reset_state = 0;
    return ret;
}

/**
 *  ifx_spi_spi_probe   -   probe callback
 *  @spi: our possible matching SPI device
 *
 *  Probe for a xE910 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_spi_device *ifx_dev;

    printk(KERN_INFO "%s(0x%p)\n", __func__, spi);
    printk(KERN_INFO "\tmax_speed_hz = %d\n", spi->max_speed_hz);
    printk(KERN_INFO "\tchip_select = %d\n", spi->chip_select);
    printk(KERN_INFO "\tbits_per_word = %d\n", spi->bits_per_word);
    printk(KERN_INFO "\tmode = %d\n", spi->mode);
    printk(KERN_INFO "\tirq = %d\n", spi->irq);
    printk(KERN_INFO "\tmodalias = %s\n", spi->modalias);
    printk(KERN_INFO "\tcs_gpio = %d\n", spi->cs_gpio);

    if (saved_ifx_dev) {
        dev_dbg(&spi->dev, "ignoring subsequent detection");
        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->use_dma = 1;

    /* initialize spi mode, etc */
    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 buffers */
    ifx_dev->tx_buffer = kmalloc(IFX_SPI_TRANSFER_SIZE, GFP_KERNEL);
    if (!ifx_dev->tx_buffer) {
        dev_err(&spi->dev, "TX buffer allocation failed");
        ret = -ENOMEM;
        goto error_ret;
    }
    ifx_dev->rx_buffer = kmalloc(IFX_SPI_TRANSFER_SIZE, GFP_KERNEL);
    if (!ifx_dev->rx_buffer) {
        dev_err(&spi->dev, "RX buffer allocation failed");
        ret = -ENOMEM;
        goto error_ret1;
    }

    /* 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.power = of_get_named_gpio(spi->dev.of_node, "modem-power", 0);
    ifx_dev->gpio.shutdown = of_get_named_gpio(spi->dev.of_node, "modem-shutdown", 0);
    ifx_dev->gpio.on = of_get_named_gpio(spi->dev.of_node, "modem-on", 0);
    ifx_dev->gpio.mrdy = of_get_named_gpio(spi->dev.of_node, "modem-mrdy", 0);
    ifx_dev->gpio.srdy = of_get_named_gpio(spi->dev.of_node, "modem-srdy", 0);
    ifx_dev->gpio.status = of_get_named_gpio(spi->dev.of_node, "modem-status", 0);

    dev_info(&spi->dev, "gpios %d, %d, %d, %d, %d, %d",
         ifx_dev->gpio.power, ifx_dev->gpio.shutdown, ifx_dev->gpio.on,
         ifx_dev->gpio.mrdy, ifx_dev->gpio.srdy, ifx_dev->gpio.status);

    /* Configure gpios */
    ret = gpio_request(ifx_dev->gpio.power, "ifxModem");
    if (ret < 0) {
        dev_err(&spi->dev, "Unable to allocate GPIO%d (RESET)",
            ifx_dev->gpio.power);
        goto error_ret;
    }
    ret += gpio_direction_output(ifx_dev->gpio.power, 0);
    ret += gpio_export(ifx_dev->gpio.power, 1);
    if (ret) {
        dev_err(&spi->dev, "Unable to configure GPIO%d (RESET)",
            ifx_dev->gpio.power);
        ret = -EBUSY;
        goto error_ret2;
    }

    ret = gpio_request(ifx_dev->gpio.shutdown, "ifxModem");
    if (ret < 0) {
        dev_err(&spi->dev, "Unable to allocate GPIO%d (RESET)",
            ifx_dev->gpio.shutdown);
        goto error_ret;
    }
    ret += gpio_direction_output(ifx_dev->gpio.shutdown, 0);
    ret += gpio_export(ifx_dev->gpio.shutdown, 1);
    if (ret) {
        dev_err(&spi->dev, "Unable to configure GPIO%d (RESET)",
            ifx_dev->gpio.shutdown);
        ret = -EBUSY;
        goto error_ret2;
    }

    ret = gpio_request(ifx_dev->gpio.on, "ifxModem");
    ret += gpio_direction_output(ifx_dev->gpio.on, 0);
    ret += gpio_export(ifx_dev->gpio.on, 1);
    if (ret) {
        dev_err(&spi->dev, "Unable to configure GPIO%d (ON)",
            ifx_dev->gpio.on);
        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.status, "ifxModem");
    if (ret < 0) {
        dev_err(&spi->dev, "Unable to allocate GPIO%d (RESET_OUT)",
            ifx_dev->gpio.status);
        goto error_ret5;
    }
    ret += gpio_export(ifx_dev->gpio.status, 1);
    ret += gpio_direction_input(ifx_dev->gpio.status);
    if (ret) {
        dev_err(&spi->dev, "Unable to configure GPIO%d (RESET_OUT)",
            ifx_dev->gpio.status);
        ret = -EBUSY;
        goto error_ret6;
    }

    ret = request_irq(gpio_to_irq(ifx_dev->gpio.status),
              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\n",
            gpio_to_irq(ifx_dev->gpio.status));
        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.status), (void *)ifx_dev);
    gpio_free(ifx_dev->gpio.status);
error_ret6:
    gpio_free(ifx_dev->gpio.srdy);
error_ret5:
    gpio_free(ifx_dev->gpio.mrdy);
error_ret4:
    gpio_free(ifx_dev->gpio.on);
error_ret3:
    gpio_free(ifx_dev->gpio.shutdown);
    gpio_free(ifx_dev->gpio.power);
error_ret2:
    kfree(ifx_dev->rx_buffer);
error_ret1:
    kfree(ifx_dev->tx_buffer);
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);

    pm_runtime_disable(&spi->dev);

    /* stop activity */
    tasklet_kill(&ifx_dev->io_work_tasklet);

    /* free irq */
    free_irq(gpio_to_irq(ifx_dev->gpio.status), (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.shutdown);
    gpio_free(ifx_dev->gpio.on);
    gpio_free(ifx_dev->gpio.status);

    /* 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 of_device_id telit_spi_dt_ids[] = {
    { .compatible = "linux,telit_spi" },
    { }
};
MODULE_DEVICE_TABLE(of, telit_spi_dt_ids);

/* spi operations */
static struct spi_driver ifx_spi_driver = {
    .driver = {
        .name = DRVNAME,
        .owner = THIS_MODULE,
        .of_match_table = of_match_ptr(telit_spi_dt_ids),
        .pm = &ifx_spi_pm
    },
    .probe = ifx_spi_spi_probe,
    .shutdown = ifx_spi_spi_shutdown,
    .remove = ifx_spi_spi_remove,
};

/**
 *  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("ActiGraph");
MODULE_DESCRIPTION("Telit HE910/UE910 spi driver");
MODULE_LICENSE("GPL");
MODULE_INFO(Version, "0.1-telit_spi");