/*
 * SPI bus via the Blackfin SPORT peripheral
 *
 * Enter bugs at http://blackfin.uclinux.org/
 *
 * Copyright 2009-2011 Analog Devices Inc.
 *
 * Licensed under the GPL-2 or later.
 */

#include <linux/module.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/gpio.h>
#include <linux/io.h>
#include <linux/ioport.h>
#include <linux/irq.h>
#include <linux/errno.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/spi/spi.h>
#include <linux/workqueue.h>

#include <asm/portmux.h>
#include <asm/bfin5xx_spi.h>
#include <asm/blackfin.h>
#include <asm/bfin_sport.h>
#include <asm/cacheflush.h>

#define DRV_NAME        "bfin-sport-spi"
#define DRV_DESC        "SPI bus via the Blackfin SPORT"

MODULE_AUTHOR("Cliff Cai");
MODULE_DESCRIPTION(DRV_DESC);
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:bfin-sport-spi");

enum bfin_sport_spi_state {
        START_STATE,
        RUNNING_STATE,
        DONE_STATE,
        ERROR_STATE,
};

struct bfin_sport_spi_master_data;

struct bfin_sport_transfer_ops {
        void (*write) (struct bfin_sport_spi_master_data *);
        void (*read) (struct bfin_sport_spi_master_data *);
        void (*duplex) (struct bfin_sport_spi_master_data *);
};

struct bfin_sport_spi_master_data {
        /* Driver model hookup */
        struct device *dev;

        /* SPI framework hookup */
        struct spi_master *master;

        /* Regs base of SPI controller */
        struct sport_register __iomem *regs;
        int err_irq;

        /* Pin request list */
        u16 *pin_req;

        /* Driver message queue */
        struct workqueue_struct *workqueue;
        struct work_struct pump_messages;
        spinlock_t lock;
        struct list_head queue;
        int busy;
        bool run;

        /* Message Transfer pump */
        struct tasklet_struct pump_transfers;

        /* Current message transfer state info */
        enum bfin_sport_spi_state state;
        struct spi_message *cur_msg;
        struct spi_transfer *cur_transfer;
        struct bfin_sport_spi_slave_data *cur_chip;
        union {
                void *tx;
                u8 *tx8;
                u16 *tx16;
        };
        void *tx_end;
        union {
                void *rx;
                u8 *rx8;
                u16 *rx16;
        };
        void *rx_end;

        int cs_change;
        struct bfin_sport_transfer_ops *ops;
};

struct bfin_sport_spi_slave_data {
        u16 ctl_reg;
        u16 baud;
        u16 cs_chg_udelay;      /* Some devices require > 255usec delay */
        u32 cs_gpio;
        u16 idle_tx_val;
        struct bfin_sport_transfer_ops *ops;
};

static void
bfin_sport_spi_enable(struct bfin_sport_spi_master_data *drv_data)
{
        bfin_write_or(&drv_data->regs->tcr1, TSPEN);
        bfin_write_or(&drv_data->regs->rcr1, TSPEN);
        SSYNC();
}

static void
bfin_sport_spi_disable(struct bfin_sport_spi_master_data *drv_data)
{
        bfin_write_and(&drv_data->regs->tcr1, ~TSPEN);
        bfin_write_and(&drv_data->regs->rcr1, ~TSPEN);
        SSYNC();
}

/* Caculate the SPI_BAUD register value based on input HZ */
static u16
bfin_sport_hz_to_spi_baud(u32 speed_hz)
{
        u_long clk, sclk = get_sclk();
        int div = (sclk / (2 * speed_hz)) - 1;

        if (div < 0)
                div = 0;

        clk = sclk / (2 * (div + 1));

        if (clk > speed_hz)
                div++;

        return div;
}

/* Chip select operation functions for cs_change flag */
static void
bfin_sport_spi_cs_active(struct bfin_sport_spi_slave_data *chip)
{
        gpio_direction_output(chip->cs_gpio, 0);
}

static void
bfin_sport_spi_cs_deactive(struct bfin_sport_spi_slave_data *chip)
{
        gpio_direction_output(chip->cs_gpio, 1);
        /* Move delay here for consistency */
        if (chip->cs_chg_udelay)
                udelay(chip->cs_chg_udelay);
}

static void
bfin_sport_spi_stat_poll_complete(struct bfin_sport_spi_master_data *drv_data)
{
        unsigned long timeout = jiffies + HZ;
        while (!(bfin_read(&drv_data->regs->stat) & RXNE)) {
                if (!time_before(jiffies, timeout))
                        break;
        }
}

static void
bfin_sport_spi_u8_writer(struct bfin_sport_spi_master_data *drv_data)
{
        u16 dummy;

        while (drv_data->tx < drv_data->tx_end) {
                bfin_write(&drv_data->regs->tx16, *drv_data->tx8++);
                bfin_sport_spi_stat_poll_complete(drv_data);
                dummy = bfin_read(&drv_data->regs->rx16);
        }
}

static void
bfin_sport_spi_u8_reader(struct bfin_sport_spi_master_data *drv_data)
{
        u16 tx_val = drv_data->cur_chip->idle_tx_val;

        while (drv_data->rx < drv_data->rx_end) {
                bfin_write(&drv_data->regs->tx16, tx_val);
                bfin_sport_spi_stat_poll_complete(drv_data);
                *drv_data->rx8++ = bfin_read(&drv_data->regs->rx16);
        }
}

static void
bfin_sport_spi_u8_duplex(struct bfin_sport_spi_master_data *drv_data)
{
        while (drv_data->rx < drv_data->rx_end) {
                bfin_write(&drv_data->regs->tx16, *drv_data->tx8++);
                bfin_sport_spi_stat_poll_complete(drv_data);
                *drv_data->rx8++ = bfin_read(&drv_data->regs->rx16);
        }
}

static struct bfin_sport_transfer_ops bfin_sport_transfer_ops_u8 = {
        .write  = bfin_sport_spi_u8_writer,
        .read   = bfin_sport_spi_u8_reader,
        .duplex = bfin_sport_spi_u8_duplex,
};

static void
bfin_sport_spi_u16_writer(struct bfin_sport_spi_master_data *drv_data)
{
        u16 dummy;

        while (drv_data->tx < drv_data->tx_end) {
                bfin_write(&drv_data->regs->tx16, *drv_data->tx16++);
                bfin_sport_spi_stat_poll_complete(drv_data);
                dummy = bfin_read(&drv_data->regs->rx16);
        }
}

static void
bfin_sport_spi_u16_reader(struct bfin_sport_spi_master_data *drv_data)
{
        u16 tx_val = drv_data->cur_chip->idle_tx_val;

        while (drv_data->rx < drv_data->rx_end) {
                bfin_write(&drv_data->regs->tx16, tx_val);
                bfin_sport_spi_stat_poll_complete(drv_data);
                *drv_data->rx16++ = bfin_read(&drv_data->regs->rx16);
        }
}

static void
bfin_sport_spi_u16_duplex(struct bfin_sport_spi_master_data *drv_data)
{
        while (drv_data->rx < drv_data->rx_end) {
                bfin_write(&drv_data->regs->tx16, *drv_data->tx16++);
                bfin_sport_spi_stat_poll_complete(drv_data);
                *drv_data->rx16++ = bfin_read(&drv_data->regs->rx16);
        }
}

static struct bfin_sport_transfer_ops bfin_sport_transfer_ops_u16 = {
        .write  = bfin_sport_spi_u16_writer,
        .read   = bfin_sport_spi_u16_reader,
        .duplex = bfin_sport_spi_u16_duplex,
};

/* stop controller and re-config current chip */
static void
bfin_sport_spi_restore_state(struct bfin_sport_spi_master_data *drv_data)
{
        struct bfin_sport_spi_slave_data *chip = drv_data->cur_chip;

        bfin_sport_spi_disable(drv_data);
        dev_dbg(drv_data->dev, "restoring spi ctl state\n");

        bfin_write(&drv_data->regs->tcr1, chip->ctl_reg);
        bfin_write(&drv_data->regs->tclkdiv, chip->baud);
        SSYNC();

        bfin_write(&drv_data->regs->rcr1, chip->ctl_reg & ~(ITCLK | ITFS));
        SSYNC();

        bfin_sport_spi_cs_active(chip);
}

/* test if there is more transfer to be done */
static enum bfin_sport_spi_state
bfin_sport_spi_next_transfer(struct bfin_sport_spi_master_data *drv_data)
{
        struct spi_message *msg = drv_data->cur_msg;
        struct spi_transfer *trans = drv_data->cur_transfer;

        /* Move to next transfer */
        if (trans->transfer_list.next != &msg->transfers) {
                drv_data->cur_transfer =
                    list_entry(trans->transfer_list.next,
                               struct spi_transfer, transfer_list);
                return RUNNING_STATE;
        }

        return DONE_STATE;
}

/*
 * caller already set message->status;
 * dma and pio irqs are blocked give finished message back
 */
static void
bfin_sport_spi_giveback(struct bfin_sport_spi_master_data *drv_data)
{
        struct bfin_sport_spi_slave_data *chip = drv_data->cur_chip;
        unsigned long flags;
        struct spi_message *msg;

        spin_lock_irqsave(&drv_data->lock, flags);
        msg = drv_data->cur_msg;
        drv_data->state = START_STATE;
        drv_data->cur_msg = NULL;
        drv_data->cur_transfer = NULL;
        drv_data->cur_chip = NULL;
        queue_work(drv_data->workqueue, &drv_data->pump_messages);
        spin_unlock_irqrestore(&drv_data->lock, flags);

        if (!drv_data->cs_change)
                bfin_sport_spi_cs_deactive(chip);

        if (msg->complete)
                msg->complete(msg->context);
}

static irqreturn_t
sport_err_handler(int irq, void *dev_id)
{
        struct bfin_sport_spi_master_data *drv_data = dev_id;
        u16 status;

        dev_dbg(drv_data->dev, "%s enter\n", __func__);
        status = bfin_read(&drv_data->regs->stat) & (TOVF | TUVF | ROVF | RUVF);

        if (status) {
                bfin_write(&drv_data->regs->stat, status);
                SSYNC();

                bfin_sport_spi_disable(drv_data);
                dev_err(drv_data->dev, "status error:%s%s%s%s\n",
                        status & TOVF ? " TOVF" : "",
                        status & TUVF ? " TUVF" : "",
                        status & ROVF ? " ROVF" : "",
                        status & RUVF ? " RUVF" : "");
        }

        return IRQ_HANDLED;
}

static void
bfin_sport_spi_pump_transfers(unsigned long data)
{
        struct bfin_sport_spi_master_data *drv_data = (void *)data;
        struct spi_message *message = NULL;
        struct spi_transfer *transfer = NULL;
        struct spi_transfer *previous = NULL;
        struct bfin_sport_spi_slave_data *chip = NULL;
        unsigned int bits_per_word;
        u32 tranf_success = 1;
        u32 transfer_speed;
        u8 full_duplex = 0;

        /* Get current state information */
        message = drv_data->cur_msg;
        transfer = drv_data->cur_transfer;
        chip = drv_data->cur_chip;

        if (transfer->speed_hz)
                transfer_speed = bfin_sport_hz_to_spi_baud(transfer->speed_hz);
        else
                transfer_speed = chip->baud;
        bfin_write(&drv_data->regs->tclkdiv, transfer_speed);
        SSYNC();

        /*
         * if msg is error or done, report it back using complete() callback
         */

         /* Handle for abort */
        if (drv_data->state == ERROR_STATE) {
                dev_dbg(drv_data->dev, "transfer: we've hit an error\n");
                message->status = -EIO;
                bfin_sport_spi_giveback(drv_data);
                return;
        }

        /* Handle end of message */
        if (drv_data->state == DONE_STATE) {
                dev_dbg(drv_data->dev, "transfer: all done!\n");
                message->status = 0;
                bfin_sport_spi_giveback(drv_data);
                return;
        }

        /* Delay if requested at end of transfer */
        if (drv_data->state == RUNNING_STATE) {
                dev_dbg(drv_data->dev, "transfer: still running ...\n");
                previous = list_entry(transfer->transfer_list.prev,
                                      struct spi_transfer, transfer_list);
                if (previous->delay_usecs)
                        udelay(previous->delay_usecs);
        }

        if (transfer->len == 0) {
                /* Move to next transfer of this msg */
                drv_data->state = bfin_sport_spi_next_transfer(drv_data);
                /* Schedule next transfer tasklet */
                tasklet_schedule(&drv_data->pump_transfers);
        }

        if (transfer->tx_buf != NULL) {
                drv_data->tx = (void *)transfer->tx_buf;
                drv_data->tx_end = drv_data->tx + transfer->len;
                dev_dbg(drv_data->dev, "tx_buf is %p, tx_end is %p\n",
                        transfer->tx_buf, drv_data->tx_end);
        } else
                drv_data->tx = NULL;

        if (transfer->rx_buf != NULL) {
                full_duplex = transfer->tx_buf != NULL;
                drv_data->rx = transfer->rx_buf;
                drv_data->rx_end = drv_data->rx + transfer->len;
                dev_dbg(drv_data->dev, "rx_buf is %p, rx_end is %p\n",
                        transfer->rx_buf, drv_data->rx_end);
        } else
                drv_data->rx = NULL;

        drv_data->cs_change = transfer->cs_change;

        /* Bits per word setup */
        bits_per_word = transfer->bits_per_word;
        if (bits_per_word == 16)
                drv_data->ops = &bfin_sport_transfer_ops_u16;
        else
                drv_data->ops = &bfin_sport_transfer_ops_u8;
        bfin_write(&drv_data->regs->tcr2, bits_per_word - 1);
        bfin_write(&drv_data->regs->tfsdiv, bits_per_word - 1);
        bfin_write(&drv_data->regs->rcr2, bits_per_word - 1);

        drv_data->state = RUNNING_STATE;

        if (drv_data->cs_change)
                bfin_sport_spi_cs_active(chip);

        dev_dbg(drv_data->dev,
                "now pumping a transfer: width is %d, len is %d\n",
                bits_per_word, transfer->len);

        /* PIO mode write then read */
        dev_dbg(drv_data->dev, "doing IO transfer\n");

        bfin_sport_spi_enable(drv_data);
        if (full_duplex) {
                /* full duplex mode */
                BUG_ON((drv_data->tx_end - drv_data->tx) !=
                       (drv_data->rx_end - drv_data->rx));
                drv_data->ops->duplex(drv_data);

                if (drv_data->tx != drv_data->tx_end)
                        tranf_success = 0;
        } else if (drv_data->tx != NULL) {
                /* write only half duplex */

                drv_data->ops->write(drv_data);

                if (drv_data->tx != drv_data->tx_end)
                        tranf_success = 0;
        } else if (drv_data->rx != NULL) {
                /* read only half duplex */

                drv_data->ops->read(drv_data);
                if (drv_data->rx != drv_data->rx_end)
                        tranf_success = 0;
        }
        bfin_sport_spi_disable(drv_data);

        if (!tranf_success) {
                dev_dbg(drv_data->dev, "IO write error!\n");
                drv_data->state = ERROR_STATE;
        } else {
                /* Update total byte transferred */
                message->actual_length += transfer->len;
                /* Move to next transfer of this msg */
                drv_data->state = bfin_sport_spi_next_transfer(drv_data);
                if (drv_data->cs_change)
                        bfin_sport_spi_cs_deactive(chip);
        }

        /* Schedule next transfer tasklet */
        tasklet_schedule(&drv_data->pump_transfers);
}

/* pop a msg from queue and kick off real transfer */
static void
bfin_sport_spi_pump_messages(struct work_struct *work)
{
        struct bfin_sport_spi_master_data *drv_data;
        unsigned long flags;
        struct spi_message *next_msg;

        drv_data = container_of(work, struct bfin_sport_spi_master_data, pump_messages);

        /* Lock queue and check for queue work */
        spin_lock_irqsave(&drv_data->lock, flags);
        if (list_empty(&drv_data->queue) || !drv_data->run) {
                /* pumper kicked off but no work to do */
                drv_data->busy = 0;
                spin_unlock_irqrestore(&drv_data->lock, flags);
                return;
        }

        /* Make sure we are not already running a message */
        if (drv_data->cur_msg) {
                spin_unlock_irqrestore(&drv_data->lock, flags);
                return;
        }

        /* Extract head of queue */
        next_msg = list_entry(drv_data->queue.next,
                struct spi_message, queue);

        drv_data->cur_msg = next_msg;

        /* Setup the SSP using the per chip configuration */
        drv_data->cur_chip = spi_get_ctldata(drv_data->cur_msg->spi);

        list_del_init(&drv_data->cur_msg->queue);

        /* Initialize message state */
        drv_data->cur_msg->state = START_STATE;
        drv_data->cur_transfer = list_entry(drv_data->cur_msg->transfers.next,
                                            struct spi_transfer, transfer_list);
        bfin_sport_spi_restore_state(drv_data);
        dev_dbg(drv_data->dev, "got a message to pump, "
                "state is set to: baud %d, cs_gpio %i, ctl 0x%x\n",
                drv_data->cur_chip->baud, drv_data->cur_chip->cs_gpio,
                drv_data->cur_chip->ctl_reg);

        dev_dbg(drv_data->dev,
                "the first transfer len is %d\n",
                drv_data->cur_transfer->len);

        /* Mark as busy and launch transfers */
        tasklet_schedule(&drv_data->pump_transfers);

        drv_data->busy = 1;
        spin_unlock_irqrestore(&drv_data->lock, flags);
}

/*
 * got a msg to transfer, queue it in drv_data->queue.
 * And kick off message pumper
 */
static int
bfin_sport_spi_transfer(struct spi_device *spi, struct spi_message *msg)
{
        struct bfin_sport_spi_master_data *drv_data = spi_master_get_devdata(spi->master);
        unsigned long flags;

        spin_lock_irqsave(&drv_data->lock, flags);

        if (!drv_data->run) {
                spin_unlock_irqrestore(&drv_data->lock, flags);
                return -ESHUTDOWN;
        }

        msg->actual_length = 0;
        msg->status = -EINPROGRESS;
        msg->state = START_STATE;

        dev_dbg(&spi->dev, "adding an msg in transfer()\n");
        list_add_tail(&msg->queue, &drv_data->queue);

        if (drv_data->run && !drv_data->busy)
                queue_work(drv_data->workqueue, &drv_data->pump_messages);

        spin_unlock_irqrestore(&drv_data->lock, flags);

        return 0;
}

/* Called every time common spi devices change state */
static int
bfin_sport_spi_setup(struct spi_device *spi)
{
        struct bfin_sport_spi_slave_data *chip, *first = NULL;
        int ret;

        /* Only alloc (or use chip_info) on first setup */
        chip = spi_get_ctldata(spi);
        if (chip == NULL) {
                struct bfin5xx_spi_chip *chip_info;

                chip = first = kzalloc(sizeof(*chip), GFP_KERNEL);
                if (!chip)
                        return -ENOMEM;

                /* platform chip_info isn't required */
                chip_info = spi->controller_data;
                if (chip_info) {
                        /*
                         * DITFS and TDTYPE are only thing we don't set, but
                         * they probably shouldn't be changed by people.
                         */
                        if (chip_info->ctl_reg || chip_info->enable_dma) {
                                ret = -EINVAL;
                                dev_err(&spi->dev, "don't set ctl_reg/enable_dma fields\n");
                                goto error;
                        }
                        chip->cs_chg_udelay = chip_info->cs_chg_udelay;
                        chip->idle_tx_val = chip_info->idle_tx_val;
                }
        }

        /* translate common spi framework into our register
         * following configure contents are same for tx and rx.
         */

        if (spi->mode & SPI_CPHA)
                chip->ctl_reg &= ~TCKFE;
        else
                chip->ctl_reg |= TCKFE;

        if (spi->mode & SPI_LSB_FIRST)
                chip->ctl_reg |= TLSBIT;
        else
                chip->ctl_reg &= ~TLSBIT;

        /* Sport in master mode */
        chip->ctl_reg |= ITCLK | ITFS | TFSR | LATFS | LTFS;

        chip->baud = bfin_sport_hz_to_spi_baud(spi->max_speed_hz);

        chip->cs_gpio = spi->chip_select;
        ret = gpio_request(chip->cs_gpio, spi->modalias);
        if (ret)
                goto error;

        dev_dbg(&spi->dev, "setup spi chip %s, width is %d\n",
                        spi->modalias, spi->bits_per_word);
        dev_dbg(&spi->dev, "ctl_reg is 0x%x, GPIO is %i\n",
                        chip->ctl_reg, spi->chip_select);

        spi_set_ctldata(spi, chip);

        bfin_sport_spi_cs_deactive(chip);

        return ret;

 error:
        kfree(first);
        return ret;
}

/*
 * callback for spi framework.
 * clean driver specific data
 */
static void
bfin_sport_spi_cleanup(struct spi_device *spi)
{
        struct bfin_sport_spi_slave_data *chip = spi_get_ctldata(spi);

        if (!chip)
                return;

        gpio_free(chip->cs_gpio);

        kfree(chip);
}

static int
bfin_sport_spi_init_queue(struct bfin_sport_spi_master_data *drv_data)
{
        INIT_LIST_HEAD(&drv_data->queue);
        spin_lock_init(&drv_data->lock);

        drv_data->run = false;
        drv_data->busy = 0;

        /* init transfer tasklet */
        tasklet_init(&drv_data->pump_transfers,
                     bfin_sport_spi_pump_transfers, (unsigned long)drv_data);

        /* init messages workqueue */
        INIT_WORK(&drv_data->pump_messages, bfin_sport_spi_pump_messages);
        drv_data->workqueue =
            create_singlethread_workqueue(dev_name(drv_data->master->dev.parent));
        if (drv_data->workqueue == NULL)
                return -EBUSY;

        return 0;
}

static int
bfin_sport_spi_start_queue(struct bfin_sport_spi_master_data *drv_data)
{
        unsigned long flags;

        spin_lock_irqsave(&drv_data->lock, flags);

        if (drv_data->run || drv_data->busy) {
                spin_unlock_irqrestore(&drv_data->lock, flags);
                return -EBUSY;
        }

        drv_data->run = true;
        drv_data->cur_msg = NULL;
        drv_data->cur_transfer = NULL;
        drv_data->cur_chip = NULL;
        spin_unlock_irqrestore(&drv_data->lock, flags);

        queue_work(drv_data->workqueue, &drv_data->pump_messages);

        return 0;
}

static inline int
bfin_sport_spi_stop_queue(struct bfin_sport_spi_master_data *drv_data)
{
        unsigned long flags;
        unsigned limit = 500;
        int status = 0;

        spin_lock_irqsave(&drv_data->lock, flags);

        /*
         * This is a bit lame, but is optimized for the common execution path.
         * A wait_queue on the drv_data->busy could be used, but then the common
         * execution path (pump_messages) would be required to call wake_up or
         * friends on every SPI message. Do this instead
         */
        drv_data->run = false;
        while (!list_empty(&drv_data->queue) && drv_data->busy && limit--) {
                spin_unlock_irqrestore(&drv_data->lock, flags);
                msleep(10);
                spin_lock_irqsave(&drv_data->lock, flags);
        }

        if (!list_empty(&drv_data->queue) || drv_data->busy)
                status = -EBUSY;

        spin_unlock_irqrestore(&drv_data->lock, flags);

        return status;
}

static inline int
bfin_sport_spi_destroy_queue(struct bfin_sport_spi_master_data *drv_data)
{
        int status;

        status = bfin_sport_spi_stop_queue(drv_data);
        if (status)
                return status;

        destroy_workqueue(drv_data->workqueue);

        return 0;
}

static int bfin_sport_spi_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct bfin5xx_spi_master *platform_info;
        struct spi_master *master;
        struct resource *res, *ires;
        struct bfin_sport_spi_master_data *drv_data;
        int status;

        platform_info = dev_get_platdata(dev);

        /* Allocate master with space for drv_data */
        master = spi_alloc_master(dev, sizeof(*master) + 16);
        if (!master) {
                dev_err(dev, "cannot alloc spi_master\n");
                return -ENOMEM;
        }

        drv_data = spi_master_get_devdata(master);
        drv_data->master = master;
        drv_data->dev = dev;
        drv_data->pin_req = platform_info->pin_req;

        master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_LSB_FIRST;
        master->bits_per_word_mask = SPI_BPW_MASK(8) | SPI_BPW_MASK(16);
        master->bus_num = pdev->id;
        master->num_chipselect = platform_info->num_chipselect;
        master->cleanup = bfin_sport_spi_cleanup;
        master->setup = bfin_sport_spi_setup;
        master->transfer = bfin_sport_spi_transfer;

        /* Find and map our resources */
        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        if (res == NULL) {
                dev_err(dev, "cannot get IORESOURCE_MEM\n");
                status = -ENOENT;
                goto out_error_get_res;
        }

        drv_data->regs = ioremap(res->start, resource_size(res));
        if (drv_data->regs == NULL) {
                dev_err(dev, "cannot map registers\n");
                status = -ENXIO;
                goto out_error_ioremap;
        }

        ires = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
        if (!ires) {
                dev_err(dev, "cannot get IORESOURCE_IRQ\n");
                status = -ENODEV;
                goto out_error_get_ires;
        }
        drv_data->err_irq = ires->start;

        /* Initial and start queue */
        status = bfin_sport_spi_init_queue(drv_data);
        if (status) {
                dev_err(dev, "problem initializing queue\n");
                goto out_error_queue_alloc;
        }

        status = bfin_sport_spi_start_queue(drv_data);
        if (status) {
                dev_err(dev, "problem starting queue\n");
                goto out_error_queue_alloc;
        }

        status = request_irq(drv_data->err_irq, sport_err_handler,
                0, "sport_spi_err", drv_data);
        if (status) {
                dev_err(dev, "unable to request sport err irq\n");
                goto out_error_irq;
        }

        status = peripheral_request_list(drv_data->pin_req, DRV_NAME);
        if (status) {
                dev_err(dev, "requesting peripherals failed\n");
                goto out_error_peripheral;
        }

        /* Register with the SPI framework */
        platform_set_drvdata(pdev, drv_data);
        status = spi_register_master(master);
        if (status) {
                dev_err(dev, "problem registering spi master\n");
                goto out_error_master;
        }

        dev_info(dev, "%s, regs_base@%p\n", DRV_DESC, drv_data->regs);
        return 0;

 out_error_master:
        peripheral_free_list(drv_data->pin_req);
 out_error_peripheral:
        free_irq(drv_data->err_irq, drv_data);
 out_error_irq:
 out_error_queue_alloc:
        bfin_sport_spi_destroy_queue(drv_data);
 out_error_get_ires:
        iounmap(drv_data->regs);
 out_error_ioremap:
 out_error_get_res:
        spi_master_put(master);

        return status;
}

/* stop hardware and remove the driver */
static int bfin_sport_spi_remove(struct platform_device *pdev)
{
        struct bfin_sport_spi_master_data *drv_data = platform_get_drvdata(pdev);
        int status = 0;

        if (!drv_data)
                return 0;

        /* Remove the queue */
        status = bfin_sport_spi_destroy_queue(drv_data);
        if (status)
                return status;

        /* Disable the SSP at the peripheral and SOC level */
        bfin_sport_spi_disable(drv_data);

        /* Disconnect from the SPI framework */
        spi_unregister_master(drv_data->master);

        peripheral_free_list(drv_data->pin_req);

        return 0;
}

#ifdef CONFIG_PM_SLEEP
static int bfin_sport_spi_suspend(struct device *dev)
{
        struct bfin_sport_spi_master_data *drv_data = dev_get_drvdata(dev);
        int status;

        status = bfin_sport_spi_stop_queue(drv_data);
        if (status)
                return status;

        /* stop hardware */
        bfin_sport_spi_disable(drv_data);

        return status;
}

static int bfin_sport_spi_resume(struct device *dev)
{
        struct bfin_sport_spi_master_data *drv_data = dev_get_drvdata(dev);
        int status;

        /* Enable the SPI interface */
        bfin_sport_spi_enable(drv_data);

        /* Start the queue running */
        status = bfin_sport_spi_start_queue(drv_data);
        if (status)
                dev_err(drv_data->dev, "problem resuming queue\n");

        return status;
}

static SIMPLE_DEV_PM_OPS(bfin_sport_spi_pm_ops, bfin_sport_spi_suspend,
                        bfin_sport_spi_resume);

#define BFIN_SPORT_SPI_PM_OPS           (&bfin_sport_spi_pm_ops)
#else
#define BFIN_SPORT_SPI_PM_OPS           NULL
#endif

static struct platform_driver bfin_sport_spi_driver = {
        .driver = {
                .name   = DRV_NAME,
                .pm     = BFIN_SPORT_SPI_PM_OPS,
        },
        .probe   = bfin_sport_spi_probe,
        .remove  = bfin_sport_spi_remove,
};
module_platform_driver(bfin_sport_spi_driver);