/*
 * Provides I2C support for Philips PNX010x/PNX4008 boards.
 *
 * Authors: Dennis Kovalev <dkovalev@ru.mvista.com>
 *          Vitaly Wool <vwool@ru.mvista.com>
 *
 * 2004-2006 (c) MontaVista Software, Inc. This file is licensed under
 * the terms of the GNU General Public License version 2. This program
 * is licensed "as is" without any warranty of any kind, whether express
 * or implied.
 */

#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/ioport.h>
#include <linux/delay.h>
#include <linux/i2c.h>
#include <linux/timer.h>
#include <linux/completion.h>
#include <linux/platform_device.h>
#include <linux/i2c-pnx.h>
#include <linux/io.h>
#include <linux/err.h>
#include <linux/clk.h>
#include <linux/slab.h>

#define I2C_PNX_TIMEOUT_DEFAULT         10 /* msec */
#define I2C_PNX_SPEED_KHZ_DEFAULT       100
#define I2C_PNX_REGION_SIZE             0x100

enum {
        mstatus_tdi = 0x00000001,
        mstatus_afi = 0x00000002,
        mstatus_nai = 0x00000004,
        mstatus_drmi = 0x00000008,
        mstatus_active = 0x00000020,
        mstatus_scl = 0x00000040,
        mstatus_sda = 0x00000080,
        mstatus_rff = 0x00000100,
        mstatus_rfe = 0x00000200,
        mstatus_tff = 0x00000400,
        mstatus_tfe = 0x00000800,
};

enum {
        mcntrl_tdie = 0x00000001,
        mcntrl_afie = 0x00000002,
        mcntrl_naie = 0x00000004,
        mcntrl_drmie = 0x00000008,
        mcntrl_drsie = 0x00000010,
        mcntrl_rffie = 0x00000020,
        mcntrl_daie = 0x00000040,
        mcntrl_tffie = 0x00000080,
        mcntrl_reset = 0x00000100,
        mcntrl_cdbmode = 0x00000400,
};

enum {
        rw_bit = 1 << 0,
        start_bit = 1 << 8,
        stop_bit = 1 << 9,
};

#define I2C_REG_RX(a)   ((a)->ioaddr)           /* Rx FIFO reg (RO) */
#define I2C_REG_TX(a)   ((a)->ioaddr)           /* Tx FIFO reg (WO) */
#define I2C_REG_STS(a)  ((a)->ioaddr + 0x04)    /* Status reg (RO) */
#define I2C_REG_CTL(a)  ((a)->ioaddr + 0x08)    /* Ctl reg */
#define I2C_REG_CKL(a)  ((a)->ioaddr + 0x0c)    /* Clock divider low */
#define I2C_REG_CKH(a)  ((a)->ioaddr + 0x10)    /* Clock divider high */
#define I2C_REG_ADR(a)  ((a)->ioaddr + 0x14)    /* I2C address */
#define I2C_REG_RFL(a)  ((a)->ioaddr + 0x18)    /* Rx FIFO level (RO) */
#define I2C_REG_TFL(a)  ((a)->ioaddr + 0x1c)    /* Tx FIFO level (RO) */
#define I2C_REG_RXB(a)  ((a)->ioaddr + 0x20)    /* Num of bytes Rx-ed (RO) */
#define I2C_REG_TXB(a)  ((a)->ioaddr + 0x24)    /* Num of bytes Tx-ed (RO) */
#define I2C_REG_TXS(a)  ((a)->ioaddr + 0x28)    /* Tx slave FIFO (RO) */
#define I2C_REG_STFL(a) ((a)->ioaddr + 0x2c)    /* Tx slave FIFO level (RO) */

static inline int wait_timeout(struct i2c_pnx_algo_data *data)
{
        long timeout = data->timeout;
        while (timeout > 0 &&
                        (ioread32(I2C_REG_STS(data)) & mstatus_active)) {
                mdelay(1);
                timeout--;
        }
        return (timeout <= 0);
}

static inline int wait_reset(struct i2c_pnx_algo_data *data)
{
        long timeout = data->timeout;
        while (timeout > 0 &&
                        (ioread32(I2C_REG_CTL(data)) & mcntrl_reset)) {
                mdelay(1);
                timeout--;
        }
        return (timeout <= 0);
}

static inline void i2c_pnx_arm_timer(struct i2c_pnx_algo_data *alg_data)
{
        struct timer_list *timer = &alg_data->mif.timer;
        unsigned long expires = msecs_to_jiffies(alg_data->timeout);

        if (expires <= 1)
                expires = 2;

        del_timer_sync(timer);

        dev_dbg(&alg_data->adapter.dev, "Timer armed at %lu plus %lu jiffies.\n",
                jiffies, expires);

        timer->expires = jiffies + expires;
        timer->data = (unsigned long)alg_data;

        add_timer(timer);
}

/**
 * i2c_pnx_start - start a device
 * @slave_addr:         slave address
 * @adap:               pointer to adapter structure
 *
 * Generate a START signal in the desired mode.
 */
static int i2c_pnx_start(unsigned char slave_addr,
        struct i2c_pnx_algo_data *alg_data)
{
        dev_dbg(&alg_data->adapter.dev, "%s(): addr 0x%x mode %d\n", __func__,
                slave_addr, alg_data->mif.mode);

        /* Check for 7 bit slave addresses only */
        if (slave_addr & ~0x7f) {
                dev_err(&alg_data->adapter.dev,
                        "%s: Invalid slave address %x. Only 7-bit addresses are supported\n",
                        alg_data->adapter.name, slave_addr);
                return -EINVAL;
        }

        /* First, make sure bus is idle */
        if (wait_timeout(alg_data)) {
                /* Somebody else is monopolizing the bus */
                dev_err(&alg_data->adapter.dev,
                        "%s: Bus busy. Slave addr = %02x, cntrl = %x, stat = %x\n",
                        alg_data->adapter.name, slave_addr,
                        ioread32(I2C_REG_CTL(alg_data)),
                        ioread32(I2C_REG_STS(alg_data)));
                return -EBUSY;
        } else if (ioread32(I2C_REG_STS(alg_data)) & mstatus_afi) {
                /* Sorry, we lost the bus */
                dev_err(&alg_data->adapter.dev,
                        "%s: Arbitration failure. Slave addr = %02x\n",
                        alg_data->adapter.name, slave_addr);
                return -EIO;
        }

        /*
         * OK, I2C is enabled and we have the bus.
         * Clear the current TDI and AFI status flags.
         */
        iowrite32(ioread32(I2C_REG_STS(alg_data)) | mstatus_tdi | mstatus_afi,
                  I2C_REG_STS(alg_data));

        dev_dbg(&alg_data->adapter.dev, "%s(): sending %#x\n", __func__,
                (slave_addr << 1) | start_bit | alg_data->mif.mode);

        /* Write the slave address, START bit and R/W bit */
        iowrite32((slave_addr << 1) | start_bit | alg_data->mif.mode,
                  I2C_REG_TX(alg_data));

        dev_dbg(&alg_data->adapter.dev, "%s(): exit\n", __func__);

        return 0;
}

/**
 * i2c_pnx_stop - stop a device
 * @adap:               pointer to I2C adapter structure
 *
 * Generate a STOP signal to terminate the master transaction.
 */
static void i2c_pnx_stop(struct i2c_pnx_algo_data *alg_data)
{
        /* Only 1 msec max timeout due to interrupt context */
        long timeout = 1000;

        dev_dbg(&alg_data->adapter.dev, "%s(): entering: stat = %04x.\n",
                __func__, ioread32(I2C_REG_STS(alg_data)));

        /* Write a STOP bit to TX FIFO */
        iowrite32(0xff | stop_bit, I2C_REG_TX(alg_data));

        /* Wait until the STOP is seen. */
        while (timeout > 0 &&
               (ioread32(I2C_REG_STS(alg_data)) & mstatus_active)) {
                /* may be called from interrupt context */
                udelay(1);
                timeout--;
        }

        dev_dbg(&alg_data->adapter.dev, "%s(): exiting: stat = %04x.\n",
                __func__, ioread32(I2C_REG_STS(alg_data)));
}

/**
 * i2c_pnx_master_xmit - transmit data to slave
 * @adap:               pointer to I2C adapter structure
 *
 * Sends one byte of data to the slave
 */
static int i2c_pnx_master_xmit(struct i2c_pnx_algo_data *alg_data)
{
        u32 val;

        dev_dbg(&alg_data->adapter.dev, "%s(): entering: stat = %04x.\n",
                __func__, ioread32(I2C_REG_STS(alg_data)));

        if (alg_data->mif.len > 0) {
                /* We still have something to talk about... */
                val = *alg_data->mif.buf++;

                if (alg_data->mif.len == 1)
                        val |= stop_bit;

                alg_data->mif.len--;
                iowrite32(val, I2C_REG_TX(alg_data));

                dev_dbg(&alg_data->adapter.dev, "%s(): xmit %#x [%d]\n",
                        __func__, val, alg_data->mif.len + 1);

                if (alg_data->mif.len == 0) {
                        if (alg_data->last) {
                                /* Wait until the STOP is seen. */
                                if (wait_timeout(alg_data))
                                        dev_err(&alg_data->adapter.dev,
                                                "The bus is still active after timeout\n");
                        }
                        /* Disable master interrupts */
                        iowrite32(ioread32(I2C_REG_CTL(alg_data)) &
                                ~(mcntrl_afie | mcntrl_naie | mcntrl_drmie),
                                  I2C_REG_CTL(alg_data));

                        del_timer_sync(&alg_data->mif.timer);

                        dev_dbg(&alg_data->adapter.dev,
                                "%s(): Waking up xfer routine.\n",
                                __func__);

                        complete(&alg_data->mif.complete);
                }
        } else if (alg_data->mif.len == 0) {
                /* zero-sized transfer */
                i2c_pnx_stop(alg_data);

                /* Disable master interrupts. */
                iowrite32(ioread32(I2C_REG_CTL(alg_data)) &
                        ~(mcntrl_afie | mcntrl_naie | mcntrl_drmie),
                          I2C_REG_CTL(alg_data));

                /* Stop timer. */
                del_timer_sync(&alg_data->mif.timer);
                dev_dbg(&alg_data->adapter.dev,
                        "%s(): Waking up xfer routine after zero-xfer.\n",
                        __func__);

                complete(&alg_data->mif.complete);
        }

        dev_dbg(&alg_data->adapter.dev, "%s(): exiting: stat = %04x.\n",
                __func__, ioread32(I2C_REG_STS(alg_data)));

        return 0;
}

/**
 * i2c_pnx_master_rcv - receive data from slave
 * @adap:               pointer to I2C adapter structure
 *
 * Reads one byte data from the slave
 */
static int i2c_pnx_master_rcv(struct i2c_pnx_algo_data *alg_data)
{
        unsigned int val = 0;
        u32 ctl = 0;

        dev_dbg(&alg_data->adapter.dev, "%s(): entering: stat = %04x.\n",
                __func__, ioread32(I2C_REG_STS(alg_data)));

        /* Check, whether there is already data,
         * or we didn't 'ask' for it yet.
         */
        if (ioread32(I2C_REG_STS(alg_data)) & mstatus_rfe) {
                /* 'Asking' is done asynchronously, e.g. dummy TX of several
                 * bytes is done before the first actual RX arrives in FIFO.
                 * Therefore, ordered bytes (via TX) are counted separately.
                 */
                if (alg_data->mif.order) {
                        dev_dbg(&alg_data->adapter.dev,
                                "%s(): Write dummy data to fill Rx-fifo...\n",
                                __func__);

                        if (alg_data->mif.order == 1) {
                                /* Last byte, do not acknowledge next rcv. */
                                val |= stop_bit;

                                /*
                                 * Enable interrupt RFDAIE (data in Rx fifo),
                                 * and disable DRMIE (need data for Tx)
                                 */
                                ctl = ioread32(I2C_REG_CTL(alg_data));
                                ctl |= mcntrl_rffie | mcntrl_daie;
                                ctl &= ~mcntrl_drmie;
                                iowrite32(ctl, I2C_REG_CTL(alg_data));
                        }

                        /*
                         * Now we'll 'ask' for data:
                         * For each byte we want to receive, we must
                         * write a (dummy) byte to the Tx-FIFO.
                         */
                        iowrite32(val, I2C_REG_TX(alg_data));
                        alg_data->mif.order--;
                }
                return 0;
        }

        /* Handle data. */
        if (alg_data->mif.len > 0) {
                val = ioread32(I2C_REG_RX(alg_data));
                *alg_data->mif.buf++ = (u8) (val & 0xff);
                dev_dbg(&alg_data->adapter.dev, "%s(): rcv 0x%x [%d]\n",
                        __func__, val, alg_data->mif.len);

                alg_data->mif.len--;
                if (alg_data->mif.len == 0) {
                        if (alg_data->last)
                                /* Wait until the STOP is seen. */
                                if (wait_timeout(alg_data))
                                        dev_err(&alg_data->adapter.dev,
                                                "The bus is still active after timeout\n");

                        /* Disable master interrupts */
                        ctl = ioread32(I2C_REG_CTL(alg_data));
                        ctl &= ~(mcntrl_afie | mcntrl_naie | mcntrl_rffie |
                                 mcntrl_drmie | mcntrl_daie);
                        iowrite32(ctl, I2C_REG_CTL(alg_data));

                        /* Kill timer. */
                        del_timer_sync(&alg_data->mif.timer);
                        complete(&alg_data->mif.complete);
                }
        }

        dev_dbg(&alg_data->adapter.dev, "%s(): exiting: stat = %04x.\n",
                __func__, ioread32(I2C_REG_STS(alg_data)));

        return 0;
}

static irqreturn_t i2c_pnx_interrupt(int irq, void *dev_id)
{
        struct i2c_pnx_algo_data *alg_data = dev_id;
        u32 stat, ctl;

        dev_dbg(&alg_data->adapter.dev,
                "%s(): mstat = %x mctrl = %x, mode = %d\n",
                __func__,
                ioread32(I2C_REG_STS(alg_data)),
                ioread32(I2C_REG_CTL(alg_data)),
                alg_data->mif.mode);
        stat = ioread32(I2C_REG_STS(alg_data));

        /* let's see what kind of event this is */
        if (stat & mstatus_afi) {
                /* We lost arbitration in the midst of a transfer */
                alg_data->mif.ret = -EIO;

                /* Disable master interrupts. */
                ctl = ioread32(I2C_REG_CTL(alg_data));
                ctl &= ~(mcntrl_afie | mcntrl_naie | mcntrl_rffie |
                         mcntrl_drmie);
                iowrite32(ctl, I2C_REG_CTL(alg_data));

                /* Stop timer, to prevent timeout. */
                del_timer_sync(&alg_data->mif.timer);
                complete(&alg_data->mif.complete);
        } else if (stat & mstatus_nai) {
                /* Slave did not acknowledge, generate a STOP */
                dev_dbg(&alg_data->adapter.dev,
                        "%s(): Slave did not acknowledge, generating a STOP.\n",
                        __func__);
                i2c_pnx_stop(alg_data);

                /* Disable master interrupts. */
                ctl = ioread32(I2C_REG_CTL(alg_data));
                ctl &= ~(mcntrl_afie | mcntrl_naie | mcntrl_rffie |
                         mcntrl_drmie);
                iowrite32(ctl, I2C_REG_CTL(alg_data));

                /* Our return value. */
                alg_data->mif.ret = -EIO;

                /* Stop timer, to prevent timeout. */
                del_timer_sync(&alg_data->mif.timer);
                complete(&alg_data->mif.complete);
        } else {
                /*
                 * Two options:
                 * - Master Tx needs data.
                 * - There is data in the Rx-fifo
                 * The latter is only the case if we have requested for data,
                 * via a dummy write. (See 'i2c_pnx_master_rcv'.)
                 * We therefore check, as a sanity check, whether that interrupt
                 * has been enabled.
                 */
                if ((stat & mstatus_drmi) || !(stat & mstatus_rfe)) {
                        if (alg_data->mif.mode == I2C_SMBUS_WRITE) {
                                i2c_pnx_master_xmit(alg_data);
                        } else if (alg_data->mif.mode == I2C_SMBUS_READ) {
                                i2c_pnx_master_rcv(alg_data);
                        }
                }
        }

        /* Clear TDI and AFI bits */
        stat = ioread32(I2C_REG_STS(alg_data));
        iowrite32(stat | mstatus_tdi | mstatus_afi, I2C_REG_STS(alg_data));

        dev_dbg(&alg_data->adapter.dev,
                "%s(): exiting, stat = %x ctrl = %x.\n",
                 __func__, ioread32(I2C_REG_STS(alg_data)),
                 ioread32(I2C_REG_CTL(alg_data)));

        return IRQ_HANDLED;
}

static void i2c_pnx_timeout(unsigned long data)
{
        struct i2c_pnx_algo_data *alg_data = (struct i2c_pnx_algo_data *)data;
        u32 ctl;

        dev_err(&alg_data->adapter.dev,
                "Master timed out. stat = %04x, cntrl = %04x. Resetting master...\n",
                ioread32(I2C_REG_STS(alg_data)),
                ioread32(I2C_REG_CTL(alg_data)));

        /* Reset master and disable interrupts */
        ctl = ioread32(I2C_REG_CTL(alg_data));
        ctl &= ~(mcntrl_afie | mcntrl_naie | mcntrl_rffie | mcntrl_drmie);
        iowrite32(ctl, I2C_REG_CTL(alg_data));

        ctl |= mcntrl_reset;
        iowrite32(ctl, I2C_REG_CTL(alg_data));
        wait_reset(alg_data);
        alg_data->mif.ret = -EIO;
        complete(&alg_data->mif.complete);
}

static inline void bus_reset_if_active(struct i2c_pnx_algo_data *alg_data)
{
        u32 stat;

        if ((stat = ioread32(I2C_REG_STS(alg_data))) & mstatus_active) {
                dev_err(&alg_data->adapter.dev,
                        "%s: Bus is still active after xfer. Reset it...\n",
                        alg_data->adapter.name);
                iowrite32(ioread32(I2C_REG_CTL(alg_data)) | mcntrl_reset,
                          I2C_REG_CTL(alg_data));
                wait_reset(alg_data);
        } else if (!(stat & mstatus_rfe) || !(stat & mstatus_tfe)) {
                /* If there is data in the fifo's after transfer,
                 * flush fifo's by reset.
                 */
                iowrite32(ioread32(I2C_REG_CTL(alg_data)) | mcntrl_reset,
                          I2C_REG_CTL(alg_data));
                wait_reset(alg_data);
        } else if (stat & mstatus_nai) {
                iowrite32(ioread32(I2C_REG_CTL(alg_data)) | mcntrl_reset,
                          I2C_REG_CTL(alg_data));
                wait_reset(alg_data);
        }
}

/**
 * i2c_pnx_xfer - generic transfer entry point
 * @adap:               pointer to I2C adapter structure
 * @msgs:               array of messages
 * @num:                number of messages
 *
 * Initiates the transfer
 */
static int
i2c_pnx_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
{
        struct i2c_msg *pmsg;
        int rc = 0, completed = 0, i;
        struct i2c_pnx_algo_data *alg_data = adap->algo_data;
        u32 stat = ioread32(I2C_REG_STS(alg_data));

        dev_dbg(&alg_data->adapter.dev,
                "%s(): entering: %d messages, stat = %04x.\n",
                __func__, num, ioread32(I2C_REG_STS(alg_data)));

        bus_reset_if_active(alg_data);

        /* Process transactions in a loop. */
        for (i = 0; rc >= 0 && i < num; i++) {
                u8 addr;

                pmsg = &msgs[i];
                addr = pmsg->addr;

                if (pmsg->flags & I2C_M_TEN) {
                        dev_err(&alg_data->adapter.dev,
                                "%s: 10 bits addr not supported!\n",
                                alg_data->adapter.name);
                        rc = -EINVAL;
                        break;
                }

                alg_data->mif.buf = pmsg->buf;
                alg_data->mif.len = pmsg->len;
                alg_data->mif.order = pmsg->len;
                alg_data->mif.mode = (pmsg->flags & I2C_M_RD) ?
                        I2C_SMBUS_READ : I2C_SMBUS_WRITE;
                alg_data->mif.ret = 0;
                alg_data->last = (i == num - 1);

                dev_dbg(&alg_data->adapter.dev, "%s(): mode %d, %d bytes\n",
                        __func__, alg_data->mif.mode, alg_data->mif.len);

                i2c_pnx_arm_timer(alg_data);

                /* initialize the completion var */
                init_completion(&alg_data->mif.complete);

                /* Enable master interrupt */
                iowrite32(ioread32(I2C_REG_CTL(alg_data)) | mcntrl_afie |
                                mcntrl_naie | mcntrl_drmie,
                          I2C_REG_CTL(alg_data));

                /* Put start-code and slave-address on the bus. */
                rc = i2c_pnx_start(addr, alg_data);
                if (rc < 0)
                        break;

                /* Wait for completion */
                wait_for_completion(&alg_data->mif.complete);

                if (!(rc = alg_data->mif.ret))
                        completed++;
                dev_dbg(&alg_data->adapter.dev,
                        "%s(): Complete, return code = %d.\n",
                        __func__, rc);

                /* Clear TDI and AFI bits in case they are set. */
                if ((stat = ioread32(I2C_REG_STS(alg_data))) & mstatus_tdi) {
                        dev_dbg(&alg_data->adapter.dev,
                                "%s: TDI still set... clearing now.\n",
                                alg_data->adapter.name);
                        iowrite32(stat, I2C_REG_STS(alg_data));
                }
                if ((stat = ioread32(I2C_REG_STS(alg_data))) & mstatus_afi) {
                        dev_dbg(&alg_data->adapter.dev,
                                "%s: AFI still set... clearing now.\n",
                                alg_data->adapter.name);
                        iowrite32(stat, I2C_REG_STS(alg_data));
                }
        }

        bus_reset_if_active(alg_data);

        /* Cleanup to be sure... */
        alg_data->mif.buf = NULL;
        alg_data->mif.len = 0;
        alg_data->mif.order = 0;

        dev_dbg(&alg_data->adapter.dev, "%s(): exiting, stat = %x\n",
                __func__, ioread32(I2C_REG_STS(alg_data)));

        if (completed != num)
                return ((rc < 0) ? rc : -EREMOTEIO);

        return num;
}

static u32 i2c_pnx_func(struct i2c_adapter *adapter)
{
        return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
}

static struct i2c_algorithm pnx_algorithm = {
        .master_xfer = i2c_pnx_xfer,
        .functionality = i2c_pnx_func,
};

#ifdef CONFIG_PM
static int i2c_pnx_controller_suspend(struct device *dev)
{
        struct i2c_pnx_algo_data *alg_data = dev_get_drvdata(dev);

        clk_disable(alg_data->clk);

        return 0;
}

static int i2c_pnx_controller_resume(struct device *dev)
{
        struct i2c_pnx_algo_data *alg_data = dev_get_drvdata(dev);

        return clk_enable(alg_data->clk);
}

static SIMPLE_DEV_PM_OPS(i2c_pnx_pm,
                         i2c_pnx_controller_suspend, i2c_pnx_controller_resume);
#define PNX_I2C_PM      (&i2c_pnx_pm)
#else
#define PNX_I2C_PM      NULL
#endif

static int i2c_pnx_probe(struct platform_device *pdev)
{
        unsigned long tmp;
        int ret = 0;
        struct i2c_pnx_algo_data *alg_data;
        unsigned long freq;
        struct resource *res;
        u32 speed = I2C_PNX_SPEED_KHZ_DEFAULT * 1000;

        alg_data = kzalloc(sizeof(*alg_data), GFP_KERNEL);
        if (!alg_data) {
                ret = -ENOMEM;
                goto err_kzalloc;
        }

        platform_set_drvdata(pdev, alg_data);

        alg_data->adapter.dev.parent = &pdev->dev;
        alg_data->adapter.algo = &pnx_algorithm;
        alg_data->adapter.algo_data = alg_data;
        alg_data->adapter.nr = pdev->id;

        alg_data->timeout = I2C_PNX_TIMEOUT_DEFAULT;
#ifdef CONFIG_OF
        alg_data->adapter.dev.of_node = of_node_get(pdev->dev.of_node);
        if (pdev->dev.of_node) {
                of_property_read_u32(pdev->dev.of_node, "clock-frequency",
                                     &speed);
                /*
                 * At this point, it is planned to add an OF timeout property.
                 * As soon as there is a consensus about how to call and handle
                 * this, sth. like the following can be put here:
                 *
                 * of_property_read_u32(pdev->dev.of_node, "timeout",
                 *                      &alg_data->timeout);
                 */
        }
#endif
        alg_data->clk = clk_get(&pdev->dev, NULL);
        if (IS_ERR(alg_data->clk)) {
                ret = PTR_ERR(alg_data->clk);
                goto out_drvdata;
        }

        init_timer(&alg_data->mif.timer);
        alg_data->mif.timer.function = i2c_pnx_timeout;
        alg_data->mif.timer.data = (unsigned long)alg_data;

        snprintf(alg_data->adapter.name, sizeof(alg_data->adapter.name),
                 "%s", pdev->name);

        /* Register I/O resource */
        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        if (!res) {
                dev_err(&pdev->dev, "Unable to get mem resource.\n");
                ret = -EBUSY;
                goto out_clkget;
        }
        if (!request_mem_region(res->start, I2C_PNX_REGION_SIZE,
                                pdev->name)) {
                dev_err(&pdev->dev,
                       "I/O region 0x%08x for I2C already in use.\n",
                       res->start);
                ret = -ENOMEM;
                goto out_clkget;
        }

        alg_data->base = res->start;
        alg_data->ioaddr = ioremap(res->start, I2C_PNX_REGION_SIZE);
        if (!alg_data->ioaddr) {
                dev_err(&pdev->dev, "Couldn't ioremap I2C I/O region\n");
                ret = -ENOMEM;
                goto out_release;
        }

        ret = clk_enable(alg_data->clk);
        if (ret)
                goto out_unmap;

        freq = clk_get_rate(alg_data->clk);

        /*
         * Clock Divisor High This value is the number of system clocks
         * the serial clock (SCL) will be high.
         * For example, if the system clock period is 50 ns and the maximum
         * desired serial period is 10000 ns (100 kHz), then CLKHI would be
         * set to 0.5*(f_sys/f_i2c)-2=0.5*(20e6/100e3)-2=98. The actual value
         * programmed into CLKHI will vary from this slightly due to
         * variations in the output pad's rise and fall times as well as
         * the deglitching filter length.
         */

        tmp = (freq / speed) / 2 - 2;
        if (tmp > 0x3FF)
                tmp = 0x3FF;
        iowrite32(tmp, I2C_REG_CKH(alg_data));
        iowrite32(tmp, I2C_REG_CKL(alg_data));

        iowrite32(mcntrl_reset, I2C_REG_CTL(alg_data));
        if (wait_reset(alg_data)) {
                ret = -ENODEV;
                goto out_clock;
        }
        init_completion(&alg_data->mif.complete);

        alg_data->irq = platform_get_irq(pdev, 0);
        if (alg_data->irq < 0) {
                dev_err(&pdev->dev, "Failed to get IRQ from platform resource\n");
                goto out_irq;
        }
        ret = request_irq(alg_data->irq, i2c_pnx_interrupt,
                        0, pdev->name, alg_data);
        if (ret)
                goto out_clock;

        /* Register this adapter with the I2C subsystem */
        ret = i2c_add_numbered_adapter(&alg_data->adapter);
        if (ret < 0) {
                dev_err(&pdev->dev, "I2C: Failed to add bus\n");
                goto out_irq;
        }

        dev_dbg(&pdev->dev, "%s: Master at %#8x, irq %d.\n",
                alg_data->adapter.name, res->start, alg_data->irq);

        return 0;

out_irq:
        free_irq(alg_data->irq, alg_data);
out_clock:
        clk_disable(alg_data->clk);
out_unmap:
        iounmap(alg_data->ioaddr);
out_release:
        release_mem_region(res->start, I2C_PNX_REGION_SIZE);
out_clkget:
        clk_put(alg_data->clk);
out_drvdata:
        kfree(alg_data);
err_kzalloc:
        return ret;
}

static int i2c_pnx_remove(struct platform_device *pdev)
{
        struct i2c_pnx_algo_data *alg_data = platform_get_drvdata(pdev);

        free_irq(alg_data->irq, alg_data);
        i2c_del_adapter(&alg_data->adapter);
        clk_disable(alg_data->clk);
        iounmap(alg_data->ioaddr);
        release_mem_region(alg_data->base, I2C_PNX_REGION_SIZE);
        clk_put(alg_data->clk);
        kfree(alg_data);

        return 0;
}

#ifdef CONFIG_OF
static const struct of_device_id i2c_pnx_of_match[] = {
        { .compatible = "nxp,pnx-i2c" },
        { },
};
MODULE_DEVICE_TABLE(of, i2c_pnx_of_match);
#endif

static struct platform_driver i2c_pnx_driver = {
        .driver = {
                .name = "pnx-i2c",
                .owner = THIS_MODULE,
                .of_match_table = of_match_ptr(i2c_pnx_of_match),
                .pm = PNX_I2C_PM,
        },
        .probe = i2c_pnx_probe,
        .remove = i2c_pnx_remove,
};

static int __init i2c_adap_pnx_init(void)
{
        return platform_driver_register(&i2c_pnx_driver);
}

static void __exit i2c_adap_pnx_exit(void)
{
        platform_driver_unregister(&i2c_pnx_driver);
}

MODULE_AUTHOR("Vitaly Wool, Dennis Kovalev <source@mvista.com>");
MODULE_DESCRIPTION("I2C driver for Philips IP3204-based I2C busses");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:pnx-i2c");

/* We need to make sure I2C is initialized before USB */
subsys_initcall(i2c_adap_pnx_init);
module_exit(i2c_adap_pnx_exit);