ipoctal.c

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#include <linux/device.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/sched.h>
#include <linux/tty.h>
#include <linux/serial.h>
#include <linux/tty_flip.h>
#include <linux/slab.h>
#include <linux/atomic.h>
#include <linux/io.h>
#include "../ipack.h"
#include "ipoctal.h"
#include "scc2698.h"

#define IP_OCTAL_ID_SPACE_VECTOR    0x41
#define IP_OCTAL_NB_BLOCKS          4

static const struct tty_operations ipoctal_fops;

struct ipoctal_channel {
    struct ipoctal_stats        stats;
    unsigned int            nb_bytes;
    wait_queue_head_t       queue;
    spinlock_t          lock;
    unsigned int            pointer_read;
    unsigned int            pointer_write;
    atomic_t            open;
    struct tty_port         tty_port;
    union scc2698_channel __iomem   *regs;
    union scc2698_block __iomem *block_regs;
    unsigned int            board_id;
    unsigned char           *board_write;
    u8              isr_rx_rdy_mask;
    u8              isr_tx_rdy_mask;
};

struct ipoctal {
    struct ipack_device     *dev;
    unsigned int            board_id;
    struct ipoctal_channel      channel[NR_CHANNELS];
    unsigned char           write;
    struct tty_driver       *tty_drv;
};

static int ipoctal_port_activate(struct tty_port *port, struct tty_struct *tty)
{
    struct ipoctal_channel *channel;

    channel = dev_get_drvdata(tty->dev);

    iowrite8(CR_ENABLE_RX, &channel->regs->w.cr);
    return 0;
}

static int ipoctal_open(struct tty_struct *tty, struct file *file)
{
    int res;
    struct ipoctal_channel *channel;

    channel = dev_get_drvdata(tty->dev);

    if (atomic_read(&channel->open))
        return -EBUSY;

    tty->driver_data = channel;

    res = tty_port_open(&channel->tty_port, tty, file);
    if (res)
        return res;

    atomic_inc(&channel->open);
    return 0;
}

static void ipoctal_reset_stats(struct ipoctal_stats *stats)
{
    stats->tx = 0;
    stats->rx = 0;
    stats->rcv_break = 0;
    stats->framing_err = 0;
    stats->overrun_err = 0;
    stats->parity_err = 0;
}

static void ipoctal_free_channel(struct ipoctal_channel *channel)
{
    ipoctal_reset_stats(&channel->stats);
    channel->pointer_read = 0;
    channel->pointer_write = 0;
    channel->nb_bytes = 0;
}

static void ipoctal_close(struct tty_struct *tty, struct file *filp)
{
    struct ipoctal_channel *channel = tty->driver_data;

    tty_port_close(&channel->tty_port, tty, filp);

    if (atomic_dec_and_test(&channel->open))
        ipoctal_free_channel(channel);
}

static int ipoctal_get_icount(struct tty_struct *tty,
                  struct serial_icounter_struct *icount)
{
    struct ipoctal_channel *channel = tty->driver_data;

    icount->cts = 0;
    icount->dsr = 0;
    icount->rng = 0;
    icount->dcd = 0;
    icount->rx = channel->stats.rx;
    icount->tx = channel->stats.tx;
    icount->frame = channel->stats.framing_err;
    icount->parity = channel->stats.parity_err;
    icount->brk = channel->stats.rcv_break;
    return 0;
}

static void ipoctal_irq_rx(struct ipoctal_channel *channel,
               struct tty_struct *tty, u8 sr)
{
    unsigned char value;
    unsigned char flag = TTY_NORMAL;
    u8 isr;

    do {
        value = ioread8(&channel->regs->r.rhr);
        /* Error: count statistics */
        if (sr & SR_ERROR) {
            iowrite8(CR_CMD_RESET_ERR_STATUS, &channel->regs->w.cr);

            if (sr & SR_OVERRUN_ERROR) {
                channel->stats.overrun_err++;
                /* Overrun doesn't affect the current character*/
                tty_insert_flip_char(tty, 0, TTY_OVERRUN);
            }
            if (sr & SR_PARITY_ERROR) {
                channel->stats.parity_err++;
                flag = TTY_PARITY;
            }
            if (sr & SR_FRAMING_ERROR) {
                channel->stats.framing_err++;
                flag = TTY_FRAME;
            }
            if (sr & SR_RECEIVED_BREAK) {
                iowrite8(CR_CMD_RESET_BREAK_CHANGE, &channel->regs->w.cr);
                channel->stats.rcv_break++;
                flag = TTY_BREAK;
            }
        }
        tty_insert_flip_char(tty, value, flag);

        /* Check if there are more characters in RX FIFO
         * If there are more, the isr register for this channel
         * has enabled the RxRDY|FFULL bit.
         */
        isr = ioread8(&channel->block_regs->r.isr);
        sr = ioread8(&channel->regs->r.sr);
    } while (isr & channel->isr_rx_rdy_mask);

    tty_flip_buffer_push(tty);
}

static void ipoctal_irq_tx(struct ipoctal_channel *channel)
{
    unsigned char value;
    unsigned int *pointer_write = &channel->pointer_write;

    if (channel->nb_bytes <= 0) {
        channel->nb_bytes = 0;
        return;
    }

    value = channel->tty_port.xmit_buf[*pointer_write];
    iowrite8(value, &channel->regs->w.thr);
    channel->stats.tx++;
    (*pointer_write)++;
    *pointer_write = *pointer_write % PAGE_SIZE;
    channel->nb_bytes--;

    if ((channel->nb_bytes == 0) &&
        (waitqueue_active(&channel->queue))) {

        if (channel->board_id != IPACK1_DEVICE_ID_SBS_OCTAL_485) {
            *channel->board_write = 1;
            wake_up_interruptible(&channel->queue);
        }
    }
}

static void ipoctal_irq_channel(struct ipoctal_channel *channel)
{
    u8 isr, sr;
    struct tty_struct *tty;

    /* If there is no client, skip the check */
    if (!atomic_read(&channel->open))
        return;

    tty = tty_port_tty_get(&channel->tty_port);
    if (!tty)
        return;
    /* The HW is organized in pair of channels.  See which register we need
     * to read from */
    isr = ioread8(&channel->block_regs->r.isr);
    sr = ioread8(&channel->regs->r.sr);

    /* In case of RS-485, change from TX to RX when finishing TX.
     * Half-duplex. */
    if ((channel->board_id == IPACK1_DEVICE_ID_SBS_OCTAL_485) &&
        (sr & SR_TX_EMPTY) && (channel->nb_bytes == 0)) {
        iowrite8(CR_DISABLE_TX, &channel->regs->w.cr);
        iowrite8(CR_CMD_NEGATE_RTSN, &channel->regs->w.cr);
        iowrite8(CR_ENABLE_RX, &channel->regs->w.cr);
        *channel->board_write = 1;
        wake_up_interruptible(&channel->queue);
    }

    /* RX data */
    if ((isr & channel->isr_rx_rdy_mask) && (sr & SR_RX_READY))
        ipoctal_irq_rx(channel, tty, sr);

    /* TX of each character */
    if ((isr & channel->isr_tx_rdy_mask) && (sr & SR_TX_READY))
        ipoctal_irq_tx(channel);

    tty_flip_buffer_push(tty);
    tty_kref_put(tty);
}

static irqreturn_t ipoctal_irq_handler(void *arg)
{
    unsigned int i;
    struct ipoctal *ipoctal = (struct ipoctal *) arg;

    /* Check all channels */
    for (i = 0; i < NR_CHANNELS; i++)
        ipoctal_irq_channel(&ipoctal->channel[i]);

    /* Clear the IPack device interrupt */
    readw(ipoctal->dev->int_space.address + ACK_INT_REQ0);
    readw(ipoctal->dev->int_space.address + ACK_INT_REQ1);

    return IRQ_HANDLED;
}

static int ipoctal_check_model(struct ipack_device *dev, unsigned char *id)
{
    unsigned char manufacturerID;
    unsigned char board_id;


    manufacturerID = ioread8(dev->id_space.address + IPACK_IDPROM_OFFSET_MANUFACTURER_ID);
    if (manufacturerID != IPACK1_VENDOR_ID_SBS)
        return -ENODEV;
    board_id = ioread8(dev->id_space.address + IPACK_IDPROM_OFFSET_MODEL);
    switch (board_id) {
    case IPACK1_DEVICE_ID_SBS_OCTAL_232:
    case IPACK1_DEVICE_ID_SBS_OCTAL_422:
    case IPACK1_DEVICE_ID_SBS_OCTAL_485:
        *id = board_id;
        break;
    default:
        return -ENODEV;
    }

    return 0;
}

static const struct tty_port_operations ipoctal_tty_port_ops = {
    .dtr_rts = NULL,
    .activate = ipoctal_port_activate,
};

static int ipoctal_inst_slot(struct ipoctal *ipoctal, unsigned int bus_nr,
                 unsigned int slot)
{
    int res = 0;
    int i;
    struct tty_driver *tty;
    char name[20];
    unsigned char board_id;
    struct ipoctal_channel *channel;
    union scc2698_channel __iomem *chan_regs;
    union scc2698_block __iomem *block_regs;

    res = ipoctal->dev->bus->ops->map_space(ipoctal->dev, 0,
                        IPACK_ID_SPACE);
    if (res) {
        dev_err(&ipoctal->dev->dev,
            "Unable to map slot [%d:%d] ID space!\n",
            bus_nr, slot);
        return res;
    }

    res = ipoctal_check_model(ipoctal->dev, &board_id);
    if (res) {
        ipoctal->dev->bus->ops->unmap_space(ipoctal->dev,
                            IPACK_ID_SPACE);
        goto out_unregister_id_space;
    }
    ipoctal->board_id = board_id;

    res = ipoctal->dev->bus->ops->map_space(ipoctal->dev, 0,
                        IPACK_IO_SPACE);
    if (res) {
        dev_err(&ipoctal->dev->dev,
            "Unable to map slot [%d:%d] IO space!\n",
            bus_nr, slot);
        goto out_unregister_id_space;
    }

    res = ipoctal->dev->bus->ops->map_space(ipoctal->dev, 0,
                        IPACK_INT_SPACE);
    if (res) {
        dev_err(&ipoctal->dev->dev,
            "Unable to map slot [%d:%d] INT space!\n",
            bus_nr, slot);
        goto out_unregister_io_space;
    }

    res = ipoctal->dev->bus->ops->map_space(ipoctal->dev,
                       0x8000, IPACK_MEM_SPACE);
    if (res) {
        dev_err(&ipoctal->dev->dev,
            "Unable to map slot [%d:%d] MEM space!\n",
            bus_nr, slot);
        goto out_unregister_int_space;
    }

    /* Save the virtual address to access the registers easily */
    chan_regs =
        (union scc2698_channel __iomem *) ipoctal->dev->io_space.address;
    block_regs =
        (union scc2698_block __iomem *) ipoctal->dev->io_space.address;

    /* Disable RX and TX before touching anything */
    for (i = 0; i < NR_CHANNELS ; i++) {
        struct ipoctal_channel *channel = &ipoctal->channel[i];
        channel->regs = chan_regs + i;
        channel->block_regs = block_regs + (i >> 1);
        channel->board_write = &ipoctal->write;
        channel->board_id = ipoctal->board_id;
        if (i & 1) {
            channel->isr_tx_rdy_mask = ISR_TxRDY_B;
            channel->isr_rx_rdy_mask = ISR_RxRDY_FFULL_B;
        } else {
            channel->isr_tx_rdy_mask = ISR_TxRDY_A;
            channel->isr_rx_rdy_mask = ISR_RxRDY_FFULL_A;
        }

        iowrite8(CR_DISABLE_RX | CR_DISABLE_TX, &channel->regs->w.cr);
        iowrite8(CR_CMD_RESET_RX, &channel->regs->w.cr);
        iowrite8(CR_CMD_RESET_TX, &channel->regs->w.cr);
        iowrite8(MR1_CHRL_8_BITS | MR1_ERROR_CHAR | MR1_RxINT_RxRDY,
             &channel->regs->w.mr); /* mr1 */
        iowrite8(0, &channel->regs->w.mr); /* mr2 */
        iowrite8(TX_CLK_9600  | RX_CLK_9600, &channel->regs->w.csr);
    }

    for (i = 0; i < IP_OCTAL_NB_BLOCKS; i++) {
        iowrite8(ACR_BRG_SET2, &block_regs[i].w.acr);
        iowrite8(OPCR_MPP_OUTPUT | OPCR_MPOa_RTSN | OPCR_MPOb_RTSN,
             &block_regs[i].w.opcr);
        iowrite8(IMR_TxRDY_A | IMR_RxRDY_FFULL_A | IMR_DELTA_BREAK_A |
             IMR_TxRDY_B | IMR_RxRDY_FFULL_B | IMR_DELTA_BREAK_B,
             &block_regs[i].w.imr);
    }

    /*
     * IP-OCTAL has different addresses to copy its IRQ vector.
     * Depending of the carrier these addresses are accesible or not.
     * More info in the datasheet.
     */
    ipoctal->dev->bus->ops->request_irq(ipoctal->dev,
                       ipoctal_irq_handler, ipoctal);
    /* Dummy write */
    iowrite8(1, ipoctal->dev->mem_space.address + 1);

    /* Register the TTY device */

    /* Each IP-OCTAL channel is a TTY port */
    tty = alloc_tty_driver(NR_CHANNELS);

    if (!tty) {
        res = -ENOMEM;
        goto out_unregister_slot_unmap;
    }

    /* Fill struct tty_driver with ipoctal data */
    tty->owner = THIS_MODULE;
    tty->driver_name = KBUILD_MODNAME;
    sprintf(name, KBUILD_MODNAME ".%d.%d.", bus_nr, slot);
    tty->name = name;
    tty->major = 0;

    tty->minor_start = 0;
    tty->type = TTY_DRIVER_TYPE_SERIAL;
    tty->subtype = SERIAL_TYPE_NORMAL;
    tty->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV;
    tty->init_termios = tty_std_termios;
    tty->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL | CLOCAL;
    tty->init_termios.c_ispeed = 9600;
    tty->init_termios.c_ospeed = 9600;

    tty_set_operations(tty, &ipoctal_fops);
    res = tty_register_driver(tty);
    if (res) {
        dev_err(&ipoctal->dev->dev, "Can't register tty driver.\n");
        put_tty_driver(tty);
        goto out_unregister_slot_unmap;
    }

    /* Save struct tty_driver for use it when uninstalling the device */
    ipoctal->tty_drv = tty;

    for (i = 0; i < NR_CHANNELS; i++) {
        struct device *tty_dev;

        channel = &ipoctal->channel[i];
        tty_port_init(&channel->tty_port);
        tty_port_alloc_xmit_buf(&channel->tty_port);
        channel->tty_port.ops = &ipoctal_tty_port_ops;

        ipoctal_reset_stats(&channel->stats);
        channel->nb_bytes = 0;
        init_waitqueue_head(&channel->queue);

        spin_lock_init(&channel->lock);
        channel->pointer_read = 0;
        channel->pointer_write = 0;
        tty_dev = tty_port_register_device(&channel->tty_port, tty, i, NULL);
        if (IS_ERR(tty_dev)) {
            dev_err(&ipoctal->dev->dev, "Failed to register tty device.\n");
            continue;
        }
        dev_set_drvdata(tty_dev, channel);

        /*
         * Enable again the RX. TX will be enabled when
         * there is something to send
         */
        iowrite8(CR_ENABLE_RX, &channel->regs->w.cr);
    }

    return 0;

out_unregister_slot_unmap:
    ipoctal->dev->bus->ops->unmap_space(ipoctal->dev, IPACK_ID_SPACE);
out_unregister_int_space:
    ipoctal->dev->bus->ops->unmap_space(ipoctal->dev, IPACK_INT_SPACE);
out_unregister_io_space:
    ipoctal->dev->bus->ops->unmap_space(ipoctal->dev, IPACK_IO_SPACE);
out_unregister_id_space:
    ipoctal->dev->bus->ops->unmap_space(ipoctal->dev, IPACK_MEM_SPACE);
    return res;
}

static inline int ipoctal_copy_write_buffer(struct ipoctal_channel *channel,
                        const unsigned char *buf,
                        int count)
{
    unsigned long flags;
    int i;
    unsigned int *pointer_read = &channel->pointer_read;

    /* Copy the bytes from the user buffer to the internal one */
    for (i = 0; i < count; i++) {
        if (i <= (PAGE_SIZE - channel->nb_bytes)) {
            spin_lock_irqsave(&channel->lock, flags);
            channel->tty_port.xmit_buf[*pointer_read] = buf[i];
            *pointer_read = (*pointer_read + 1) % PAGE_SIZE;
            channel->nb_bytes++;
            spin_unlock_irqrestore(&channel->lock, flags);
        } else {
            break;
        }
    }
    return i;
}

static int ipoctal_write_tty(struct tty_struct *tty,
                 const unsigned char *buf, int count)
{
    struct ipoctal_channel *channel = tty->driver_data;
    unsigned int char_copied;

    char_copied = ipoctal_copy_write_buffer(channel, buf, count);

    /* As the IP-OCTAL 485 only supports half duplex, do it manually */
    if (channel->board_id == IPACK1_DEVICE_ID_SBS_OCTAL_485) {
        iowrite8(CR_DISABLE_RX, &channel->regs->w.cr);
        iowrite8(CR_CMD_ASSERT_RTSN, &channel->regs->w.cr);
    }

    /*
     * Send a packet and then disable TX to avoid failure after several send
     * operations
     */
    iowrite8(CR_ENABLE_TX, &channel->regs->w.cr);
    wait_event_interruptible(channel->queue, *channel->board_write);
    iowrite8(CR_DISABLE_TX, &channel->regs->w.cr);

    *channel->board_write = 0;
    return char_copied;
}

static int ipoctal_write_room(struct tty_struct *tty)
{
    struct ipoctal_channel *channel = tty->driver_data;

    return PAGE_SIZE - channel->nb_bytes;
}

static int ipoctal_chars_in_buffer(struct tty_struct *tty)
{
    struct ipoctal_channel *channel = tty->driver_data;

    return channel->nb_bytes;
}

static void ipoctal_set_termios(struct tty_struct *tty,
                struct ktermios *old_termios)
{
    unsigned int cflag;
    unsigned char mr1 = 0;
    unsigned char mr2 = 0;
    unsigned char csr = 0;
    struct ipoctal_channel *channel = tty->driver_data;
    speed_t baud;

    cflag = tty->termios.c_cflag;

    /* Disable and reset everything before change the setup */
    iowrite8(CR_DISABLE_RX | CR_DISABLE_TX, &channel->regs->w.cr);
    iowrite8(CR_CMD_RESET_RX, &channel->regs->w.cr);
    iowrite8(CR_CMD_RESET_TX, &channel->regs->w.cr);
    iowrite8(CR_CMD_RESET_ERR_STATUS, &channel->regs->w.cr);
    iowrite8(CR_CMD_RESET_MR, &channel->regs->w.cr);

    /* Set Bits per chars */
    switch (cflag & CSIZE) {
    case CS6:
        mr1 |= MR1_CHRL_6_BITS;
        break;
    case CS7:
        mr1 |= MR1_CHRL_7_BITS;
        break;
    case CS8:
    default:
        mr1 |= MR1_CHRL_8_BITS;
        /* By default, select CS8 */
        tty->termios.c_cflag = (cflag & ~CSIZE) | CS8;
        break;
    }

    /* Set Parity */
    if (cflag & PARENB)
        if (cflag & PARODD)
            mr1 |= MR1_PARITY_ON | MR1_PARITY_ODD;
        else
            mr1 |= MR1_PARITY_ON | MR1_PARITY_EVEN;
    else
        mr1 |= MR1_PARITY_OFF;

    /* Mark or space parity is not supported */
    tty->termios.c_cflag &= ~CMSPAR;

    /* Set stop bits */
    if (cflag & CSTOPB)
        mr2 |= MR2_STOP_BITS_LENGTH_2;
    else
        mr2 |= MR2_STOP_BITS_LENGTH_1;

    /* Set the flow control */
    switch (channel->board_id) {
    case IPACK1_DEVICE_ID_SBS_OCTAL_232:
        if (cflag & CRTSCTS) {
            mr1 |= MR1_RxRTS_CONTROL_ON;
            mr2 |= MR2_TxRTS_CONTROL_OFF | MR2_CTS_ENABLE_TX_ON;
        } else {
            mr1 |= MR1_RxRTS_CONTROL_OFF;
            mr2 |= MR2_TxRTS_CONTROL_OFF | MR2_CTS_ENABLE_TX_OFF;
        }
        break;
    case IPACK1_DEVICE_ID_SBS_OCTAL_422:
        mr1 |= MR1_RxRTS_CONTROL_OFF;
        mr2 |= MR2_TxRTS_CONTROL_OFF | MR2_CTS_ENABLE_TX_OFF;
        break;
    case IPACK1_DEVICE_ID_SBS_OCTAL_485:
        mr1 |= MR1_RxRTS_CONTROL_OFF;
        mr2 |= MR2_TxRTS_CONTROL_ON | MR2_CTS_ENABLE_TX_OFF;
        break;
    default:
        return;
        break;
    }

    baud = tty_get_baud_rate(tty);
    tty_termios_encode_baud_rate(&tty->termios, baud, baud);

    /* Set baud rate */
    switch (baud) {
    case 75:
        csr |= TX_CLK_75 | RX_CLK_75;
        break;
    case 110:
        csr |= TX_CLK_110 | RX_CLK_110;
        break;
    case 150:
        csr |= TX_CLK_150 | RX_CLK_150;
        break;
    case 300:
        csr |= TX_CLK_300 | RX_CLK_300;
        break;
    case 600:
        csr |= TX_CLK_600 | RX_CLK_600;
        break;
    case 1200:
        csr |= TX_CLK_1200 | RX_CLK_1200;
        break;
    case 1800:
        csr |= TX_CLK_1800 | RX_CLK_1800;
        break;
    case 2000:
        csr |= TX_CLK_2000 | RX_CLK_2000;
        break;
    case 2400:
        csr |= TX_CLK_2400 | RX_CLK_2400;
        break;
    case 4800:
        csr |= TX_CLK_4800  | RX_CLK_4800;
        break;
    case 9600:
        csr |= TX_CLK_9600  | RX_CLK_9600;
        break;
    case 19200:
        csr |= TX_CLK_19200 | RX_CLK_19200;
        break;
    case 38400:
    default:
        csr |= TX_CLK_38400 | RX_CLK_38400;
        /* In case of default, we establish 38400 bps */
        tty_termios_encode_baud_rate(&tty->termios, 38400, 38400);
        break;
    }

    mr1 |= MR1_ERROR_CHAR;
    mr1 |= MR1_RxINT_RxRDY;

    /* Write the control registers */
    iowrite8(mr1, &channel->regs->w.mr);
    iowrite8(mr2, &channel->regs->w.mr);
    iowrite8(csr, &channel->regs->w.csr);

    /* Enable again the RX */
    iowrite8(CR_ENABLE_RX, &channel->regs->w.cr);
}

static void ipoctal_hangup(struct tty_struct *tty)
{
    unsigned long flags;
    struct ipoctal_channel *channel = tty->driver_data;

    if (channel == NULL)
        return;

    spin_lock_irqsave(&channel->lock, flags);
    channel->nb_bytes = 0;
    channel->pointer_read = 0;
    channel->pointer_write = 0;
    spin_unlock_irqrestore(&channel->lock, flags);

    tty_port_hangup(&channel->tty_port);

    iowrite8(CR_DISABLE_RX | CR_DISABLE_TX, &channel->regs->w.cr);
    iowrite8(CR_CMD_RESET_RX, &channel->regs->w.cr);
    iowrite8(CR_CMD_RESET_TX, &channel->regs->w.cr);
    iowrite8(CR_CMD_RESET_ERR_STATUS, &channel->regs->w.cr);
    iowrite8(CR_CMD_RESET_MR, &channel->regs->w.cr);

    clear_bit(ASYNCB_INITIALIZED, &channel->tty_port.flags);
    wake_up_interruptible(&channel->tty_port.open_wait);
}

static const struct tty_operations ipoctal_fops = {
    .ioctl =        NULL,
    .open =         ipoctal_open,
    .close =        ipoctal_close,
    .write =        ipoctal_write_tty,
    .set_termios =      ipoctal_set_termios,
    .write_room =       ipoctal_write_room,
    .chars_in_buffer =  ipoctal_chars_in_buffer,
    .get_icount =       ipoctal_get_icount,
    .hangup =       ipoctal_hangup,
};

static int ipoctal_probe(struct ipack_device *dev)
{
    int res;
    struct ipoctal *ipoctal;

    ipoctal = kzalloc(sizeof(struct ipoctal), GFP_KERNEL);
    if (ipoctal == NULL)
        return -ENOMEM;

    ipoctal->dev = dev;
    res = ipoctal_inst_slot(ipoctal, dev->bus_nr, dev->slot);
    if (res)
        goto out_uninst;

    dev_set_drvdata(&dev->dev, ipoctal);
    return 0;

out_uninst:
    kfree(ipoctal);
    return res;
}

static void __ipoctal_remove(struct ipoctal *ipoctal)
{
    int i;

    ipoctal->dev->bus->ops->free_irq(ipoctal->dev);

    for (i = 0; i < NR_CHANNELS; i++) {
        struct ipoctal_channel *channel = &ipoctal->channel[i];
        tty_unregister_device(ipoctal->tty_drv, i);
        tty_port_free_xmit_buf(&channel->tty_port);
    }

    tty_unregister_driver(ipoctal->tty_drv);
    put_tty_driver(ipoctal->tty_drv);
    ipoctal->dev->bus->ops->unmap_space(ipoctal->dev, IPACK_MEM_SPACE);
    ipoctal->dev->bus->ops->unmap_space(ipoctal->dev, IPACK_INT_SPACE);
    ipoctal->dev->bus->ops->unmap_space(ipoctal->dev, IPACK_IO_SPACE);
    ipoctal->dev->bus->ops->unmap_space(ipoctal->dev, IPACK_ID_SPACE);
    kfree(ipoctal);
}

static void ipoctal_remove(struct ipack_device *idev)
{
    __ipoctal_remove(dev_get_drvdata(&idev->dev));
}

static DEFINE_IPACK_DEVICE_TABLE(ipoctal_ids) = {
    { IPACK_DEVICE(IPACK_ID_VERSION_1, IPACK1_VENDOR_ID_SBS,
            IPACK1_DEVICE_ID_SBS_OCTAL_232) },
    { IPACK_DEVICE(IPACK_ID_VERSION_1, IPACK1_VENDOR_ID_SBS,
            IPACK1_DEVICE_ID_SBS_OCTAL_422) },
    { IPACK_DEVICE(IPACK_ID_VERSION_1, IPACK1_VENDOR_ID_SBS,
            IPACK1_DEVICE_ID_SBS_OCTAL_485) },
    { 0, },
};

MODULE_DEVICE_TABLE(ipack, ipoctal_ids);

static const struct ipack_driver_ops ipoctal_drv_ops = {
    .probe  = ipoctal_probe,
    .remove = ipoctal_remove,
};

static struct ipack_driver driver = {
    .ops      = &ipoctal_drv_ops,
    .id_table = ipoctal_ids,
};

static int __init ipoctal_init(void)
{
    return ipack_driver_register(&driver, THIS_MODULE, KBUILD_MODNAME);
}

static void __exit ipoctal_exit(void)
{
    ipack_driver_unregister(&driver);
}

MODULE_DESCRIPTION("IP-Octal 232, 422 and 485 device driver");
MODULE_LICENSE("GPL");

module_init(ipoctal_init);
module_exit(ipoctal_exit);