ifx6x60.c

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/****************************************************************************
 *
 * Driver for the IFX 6x60 spi modem.
 *
 * Copyright (C) 2008 Option International
 * Copyright (C) 2008 Filip Aben <[email protected]>
 *            Denis Joseph Barrow <[email protected]>
 *            Jan Dumon <[email protected]>
 *
 * Copyright (C) 2009, 2010 Intel Corp
 * Russ Gorby <[email protected]>
 *
 * 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 "ifx6x60.h"

#define IFX_SPI_MORE_MASK       0x10
#define IFX_SPI_MORE_BIT        12  /* bit position in u16 */
#define IFX_SPI_CTS_BIT         13  /* bit position in u16 */
#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)

/* forward reference */
static void ifx_spi_handle_srdy(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;

/* GPIO/GPE settings */

static inline void mrdy_set_high(struct ifx_spi_device *ifx)
{
    gpio_set_value(ifx->gpio.mrdy, 1);
}

static inline void mrdy_set_low(struct ifx_spi_device *ifx)
{
    gpio_set_value(ifx->gpio.mrdy, 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);
}

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);
}

static inline void swap_buf(u16 *buf, int len, void *end)
{
    int n;

    len = ((len + 1) >> 1);
    if ((void *)&buf[len] > end) {
        pr_err("swap_buf: swap exceeds boundary (%p > %p)!",
               &buf[len], end);
        return;
    }
    for (n = 0; n < len; n++) {
        *buf = cpu_to_be16(*buf);
        buf++;
    }
}

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)) {
            ifx_dev->spi_timer.expires =
                jiffies + IFX_SPI_TIMEOUT_SEC*HZ;
            add_timer(&ifx_dev->spi_timer);

        }
    }
    ifx_spi_power_state_set(ifx_dev, IFX_SPI_POWER_DATA_PENDING);
    mrdy_set_high(ifx_dev);
}

static void ifx_spi_ttyhangup(struct ifx_spi_device *ifx_dev)
{
    struct tty_port *pport = &ifx_dev->tty_port;
    struct tty_struct *tty = tty_port_tty_get(pport);
    if (tty) {
        tty_hangup(tty);
        tty_kref_put(tty);
    }
}

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 ***");
    ifx_spi_ttyhangup(ifx_dev);
    mrdy_set_low(ifx_dev);
    clear_bit(IFX_SPI_STATE_TIMER_PENDING, &ifx_dev->flags);
}

/* char/tty operations */

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;
}

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;
}

static int ifx_spi_open(struct tty_struct *tty, struct file *filp)
{
    return tty_port_open(&saved_ifx_dev->tty_port, tty, filp);
}

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 ? */
}

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;
}

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;
}

static void ifx_spi_wakeup_serial(struct ifx_spi_device *ifx_dev)
{
    struct tty_struct *tty;

    tty = tty_port_tty_get(&ifx_dev->tty_port);
    if (!tty)
        return;
    tty_wakeup(tty);
    tty_kref_put(tty);
}

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;
    memset(tx_buffer, 0, IFX_SPI_TRANSFER_SIZE);

    /* 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 */
                ifx_spi_wakeup_serial(ifx_dev);
            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 */
    swap_buf((u16 *)(ifx_dev->tx_buffer), tx_count,
        &ifx_dev->tx_buffer[IFX_SPI_TRANSFER_SIZE]);
    return tx_count;
}

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;
    int tx_count = kfifo_in_locked(&ifx_dev->tx_fifo, tmp_buf, count,
                   &ifx_dev->fifo_lock);
    mrdy_assert(ifx_dev);
    return tx_count;
}

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);
}

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);
}

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);
}

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);

    /* put port data into this tty */
    tty->driver_data = ifx_dev;

    /* allows flip string push from int context */
    tty->low_latency = 1;

    return 0;
}

static void ifx_port_shutdown(struct tty_port *port)
{
    struct ifx_spi_device *ifx_dev =
        container_of(port, struct ifx_spi_device, tty_port);

    mrdy_set_low(ifx_dev);
    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,
};

static void ifx_spi_insert_flip_string(struct ifx_spi_device *ifx_dev,
                    unsigned char *chars, size_t size)
{
    struct tty_struct *tty = tty_port_tty_get(&ifx_dev->tty_port);
    if (!tty)
        return;
    tty_insert_flip_string(tty, chars, size);
    tty_flip_buffer_push(tty);
    tty_kref_put(tty);
}

static void ifx_spi_complete(void *ctx)
{
    struct ifx_spi_device *ifx_dev = ctx;
    struct tty_struct *tty;
    struct tty_ldisc *ldisc = NULL;
    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 */
        swap_buf((u16 *)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);
        swap_buf((u16 *)(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 = tty_port_tty_get(&ifx_dev->tty_port);
            if (tty) {
                ldisc = tty_ldisc_ref(tty);
                if (ldisc) {
                    ldisc->ops->write_wakeup(tty);
                    tty_ldisc_deref(ldisc);
                }
                tty_kref_put(tty);
            }
        }
    }
}

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)) {
        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 = spi_bpw;

        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;
}

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);
    kfifo_free(&ifx_dev->tx_fifo);
}

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_ret;
    }
    return 0;

error_ret:
    ifx_spi_free_port(ifx_dev);
    return ret;
}

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_sync(&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);
}

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;
}

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  */
            ifx_spi_ttyhangup(ifx_dev);
        }
    } 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;
}

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);
}

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;
}

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 = (struct ifx_modem_platform_data *)spi->dev.platform_data;
    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;
    }

    /* 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\n",
            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;
}

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;
}

static void ifx_spi_spi_shutdown(struct spi_device *spi)
{
}

/*
 * various suspends and resumes have nothing to do
 * no hardware to save state for
 */

static int ifx_spi_spi_suspend(struct spi_device *spi, pm_message_t msg)
{
    return 0;
}

static int ifx_spi_spi_resume(struct spi_device *spi)
{
    return 0;
}

static int ifx_spi_pm_suspend(struct device *dev)
{
    return 0;
}

static int ifx_spi_pm_resume(struct device *dev)
{
    return 0;
}

static int ifx_spi_pm_runtime_resume(struct device *dev)
{
    return 0;
}

static int ifx_spi_pm_runtime_suspend(struct device *dev)
{
    return 0;
}

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 = __devexit_p(ifx_spi_spi_remove),
    .suspend = ifx_spi_spi_suspend,
    .resume = ifx_spi_spi_resume,
    .id_table = ifx_id_table
};

static void __exit ifx_spi_exit(void)
{
    /* unregister */
    tty_unregister_driver(tty_drv);
    spi_unregister_driver((void *)&ifx_spi_driver);
}

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);
        put_tty_driver(tty_drv);
        return result;
    }

    result = spi_register_driver((void *)&ifx_spi_driver);
    if (result) {
        pr_err("%s: spi_register_driver failed(%d)",
            DRVNAME, result);
        tty_unregister_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");