/*
 * Copyright (C) 2007-2010 ST-Ericsson
 * License terms: GNU General Public License (GPL) version 2
 * Low-level core for exclusive access to the AB3100 IC on the I2C bus
 * and some basic chip-configuration.
 * Author: Linus Walleij <linus.walleij@stericsson.com>
 */

#include <linux/i2c.h>
#include <linux/mutex.h>
#include <linux/list.h>
#include <linux/notifier.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/device.h>
#include <linux/interrupt.h>
#include <linux/random.h>
#include <linux/debugfs.h>
#include <linux/seq_file.h>
#include <linux/uaccess.h>
#include <linux/mfd/core.h>
#include <linux/mfd/ab3100.h>
#include <linux/mfd/abx500.h>

/* These are the only registers inside AB3100 used in this main file */

/* Interrupt event registers */
#define AB3100_EVENTA1          0x21
#define AB3100_EVENTA2          0x22
#define AB3100_EVENTA3          0x23

/* AB3100 DAC converter registers */
#define AB3100_DIS              0x00
#define AB3100_D0C              0x01
#define AB3100_D1C              0x02
#define AB3100_D2C              0x03
#define AB3100_D3C              0x04

/* Chip ID register */
#define AB3100_CID              0x20

/* AB3100 interrupt registers */
#define AB3100_IMRA1            0x24
#define AB3100_IMRA2            0x25
#define AB3100_IMRA3            0x26
#define AB3100_IMRB1            0x2B
#define AB3100_IMRB2            0x2C
#define AB3100_IMRB3            0x2D

/* System Power Monitoring and control registers */
#define AB3100_MCA              0x2E
#define AB3100_MCB              0x2F

/* SIM power up */
#define AB3100_SUP              0x50

/*
 * I2C communication
 *
 * The AB3100 is usually assigned address 0x48 (7-bit)
 * The chip is defined in the platform i2c_board_data section.
 */
static int ab3100_get_chip_id(struct device *dev)
{
        struct ab3100 *ab3100 = dev_get_drvdata(dev->parent);

        return (int)ab3100->chip_id;
}

static int ab3100_set_register_interruptible(struct ab3100 *ab3100,
        u8 reg, u8 regval)
{
        u8 regandval[2] = {reg, regval};
        int err;

        err = mutex_lock_interruptible(&ab3100->access_mutex);
        if (err)
                return err;

        /*
         * A two-byte write message with the first byte containing the register
         * number and the second byte containing the value to be written
         * effectively sets a register in the AB3100.
         */
        err = i2c_master_send(ab3100->i2c_client, regandval, 2);
        if (err < 0) {
                dev_err(ab3100->dev,
                        "write error (write register): %d\n",
                        err);
        } else if (err != 2) {
                dev_err(ab3100->dev,
                        "write error (write register)\n"
                        "  %d bytes transferred (expected 2)\n",
                        err);
                err = -EIO;
        } else {
                /* All is well */
                err = 0;
        }
        mutex_unlock(&ab3100->access_mutex);
        return err;
}

static int set_register_interruptible(struct device *dev,
        u8 bank, u8 reg, u8 value)
{
        struct ab3100 *ab3100 = dev_get_drvdata(dev->parent);

        return ab3100_set_register_interruptible(ab3100, reg, value);
}

/*
 * The test registers exist at an I2C bus address up one
 * from the ordinary base. They are not supposed to be used
 * in production code, but sometimes you have to do that
 * anyway. It's currently only used from this file so declare
 * it static and do not export.
 */
static int ab3100_set_test_register_interruptible(struct ab3100 *ab3100,
                                    u8 reg, u8 regval)
{
        u8 regandval[2] = {reg, regval};
        int err;

        err = mutex_lock_interruptible(&ab3100->access_mutex);
        if (err)
                return err;

        err = i2c_master_send(ab3100->testreg_client, regandval, 2);
        if (err < 0) {
                dev_err(ab3100->dev,
                        "write error (write test register): %d\n",
                        err);
        } else if (err != 2) {
                dev_err(ab3100->dev,
                        "write error (write test register)\n"
                        "  %d bytes transferred (expected 2)\n",
                        err);
                err = -EIO;
        } else {
                /* All is well */
                err = 0;
        }
        mutex_unlock(&ab3100->access_mutex);

        return err;
}

static int ab3100_get_register_interruptible(struct ab3100 *ab3100,
                                             u8 reg, u8 *regval)
{
        int err;

        err = mutex_lock_interruptible(&ab3100->access_mutex);
        if (err)
                return err;

        /*
         * AB3100 require an I2C "stop" command between each message, else
         * it will not work. The only way of achieveing this with the
         * message transport layer is to send the read and write messages
         * separately.
         */
        err = i2c_master_send(ab3100->i2c_client, &reg, 1);
        if (err < 0) {
                dev_err(ab3100->dev,
                        "write error (send register address): %d\n",
                        err);
                goto get_reg_out_unlock;
        } else if (err != 1) {
                dev_err(ab3100->dev,
                        "write error (send register address)\n"
                        "  %d bytes transferred (expected 1)\n",
                        err);
                err = -EIO;
                goto get_reg_out_unlock;
        } else {
                /* All is well */
                err = 0;
        }

        err = i2c_master_recv(ab3100->i2c_client, regval, 1);
        if (err < 0) {
                dev_err(ab3100->dev,
                        "write error (read register): %d\n",
                        err);
                goto get_reg_out_unlock;
        } else if (err != 1) {
                dev_err(ab3100->dev,
                        "write error (read register)\n"
                        "  %d bytes transferred (expected 1)\n",
                        err);
                err = -EIO;
                goto get_reg_out_unlock;
        } else {
                /* All is well */
                err = 0;
        }

 get_reg_out_unlock:
        mutex_unlock(&ab3100->access_mutex);
        return err;
}

static int get_register_interruptible(struct device *dev, u8 bank, u8 reg,
                                      u8 *value)
{
        struct ab3100 *ab3100 = dev_get_drvdata(dev->parent);

        return ab3100_get_register_interruptible(ab3100, reg, value);
}

static int ab3100_get_register_page_interruptible(struct ab3100 *ab3100,
                             u8 first_reg, u8 *regvals, u8 numregs)
{
        int err;

        if (ab3100->chip_id == 0xa0 ||
            ab3100->chip_id == 0xa1)
                /* These don't support paged reads */
                return -EIO;

        err = mutex_lock_interruptible(&ab3100->access_mutex);
        if (err)
                return err;

        /*
         * Paged read also require an I2C "stop" command.
         */
        err = i2c_master_send(ab3100->i2c_client, &first_reg, 1);
        if (err < 0) {
                dev_err(ab3100->dev,
                        "write error (send first register address): %d\n",
                        err);
                goto get_reg_page_out_unlock;
        } else if (err != 1) {
                dev_err(ab3100->dev,
                        "write error (send first register address)\n"
                        "  %d bytes transferred (expected 1)\n",
                        err);
                err = -EIO;
                goto get_reg_page_out_unlock;
        }

        err = i2c_master_recv(ab3100->i2c_client, regvals, numregs);
        if (err < 0) {
                dev_err(ab3100->dev,
                        "write error (read register page): %d\n",
                        err);
                goto get_reg_page_out_unlock;
        } else if (err != numregs) {
                dev_err(ab3100->dev,
                        "write error (read register page)\n"
                        "  %d bytes transferred (expected %d)\n",
                        err, numregs);
                err = -EIO;
                goto get_reg_page_out_unlock;
        }

        /* All is well */
        err = 0;

 get_reg_page_out_unlock:
        mutex_unlock(&ab3100->access_mutex);
        return err;
}

static int get_register_page_interruptible(struct device *dev, u8 bank,
        u8 first_reg, u8 *regvals, u8 numregs)
{
        struct ab3100 *ab3100 = dev_get_drvdata(dev->parent);

        return ab3100_get_register_page_interruptible(ab3100,
                        first_reg, regvals, numregs);
}

static int ab3100_mask_and_set_register_interruptible(struct ab3100 *ab3100,
                                 u8 reg, u8 andmask, u8 ormask)
{
        u8 regandval[2] = {reg, 0};
        int err;

        err = mutex_lock_interruptible(&ab3100->access_mutex);
        if (err)
                return err;

        /* First read out the target register */
        err = i2c_master_send(ab3100->i2c_client, &reg, 1);
        if (err < 0) {
                dev_err(ab3100->dev,
                        "write error (maskset send address): %d\n",
                        err);
                goto get_maskset_unlock;
        } else if (err != 1) {
                dev_err(ab3100->dev,
                        "write error (maskset send address)\n"
                        "  %d bytes transferred (expected 1)\n",
                        err);
                err = -EIO;
                goto get_maskset_unlock;
        }

        err = i2c_master_recv(ab3100->i2c_client, &regandval[1], 1);
        if (err < 0) {
                dev_err(ab3100->dev,
                        "write error (maskset read register): %d\n",
                        err);
                goto get_maskset_unlock;
        } else if (err != 1) {
                dev_err(ab3100->dev,
                        "write error (maskset read register)\n"
                        "  %d bytes transferred (expected 1)\n",
                        err);
                err = -EIO;
                goto get_maskset_unlock;
        }

        /* Modify the register */
        regandval[1] &= andmask;
        regandval[1] |= ormask;

        /* Write the register */
        err = i2c_master_send(ab3100->i2c_client, regandval, 2);
        if (err < 0) {
                dev_err(ab3100->dev,
                        "write error (write register): %d\n",
                        err);
                goto get_maskset_unlock;
        } else if (err != 2) {
                dev_err(ab3100->dev,
                        "write error (write register)\n"
                        "  %d bytes transferred (expected 2)\n",
                        err);
                err = -EIO;
                goto get_maskset_unlock;
        }

        /* All is well */
        err = 0;

 get_maskset_unlock:
        mutex_unlock(&ab3100->access_mutex);
        return err;
}

static int mask_and_set_register_interruptible(struct device *dev, u8 bank,
        u8 reg, u8 bitmask, u8 bitvalues)
{
        struct ab3100 *ab3100 = dev_get_drvdata(dev->parent);

        return ab3100_mask_and_set_register_interruptible(ab3100,
                        reg, bitmask, (bitmask & bitvalues));
}

/*
 * Register a simple callback for handling any AB3100 events.
 */
int ab3100_event_register(struct ab3100 *ab3100,
                          struct notifier_block *nb)
{
        return blocking_notifier_chain_register(&ab3100->event_subscribers,
                                               nb);
}
EXPORT_SYMBOL(ab3100_event_register);

/*
 * Remove a previously registered callback.
 */
int ab3100_event_unregister(struct ab3100 *ab3100,
                            struct notifier_block *nb)
{
        return blocking_notifier_chain_unregister(&ab3100->event_subscribers,
                                            nb);
}
EXPORT_SYMBOL(ab3100_event_unregister);


static int ab3100_event_registers_startup_state_get(struct device *dev,
                                             u8 *event)
{
        struct ab3100 *ab3100 = dev_get_drvdata(dev->parent);

        if (!ab3100->startup_events_read)
                return -EAGAIN; /* Try again later */
        memcpy(event, ab3100->startup_events, 3);

        return 0;
}

static struct abx500_ops ab3100_ops = {
        .get_chip_id = ab3100_get_chip_id,
        .set_register = set_register_interruptible,
        .get_register = get_register_interruptible,
        .get_register_page = get_register_page_interruptible,
        .set_register_page = NULL,
        .mask_and_set_register = mask_and_set_register_interruptible,
        .event_registers_startup_state_get =
                ab3100_event_registers_startup_state_get,
        .startup_irq_enabled = NULL,
};

/*
 * This is a threaded interrupt handler so we can make some
 * I2C calls etc.
 */
static irqreturn_t ab3100_irq_handler(int irq, void *data)
{
        struct ab3100 *ab3100 = data;
        u8 event_regs[3];
        u32 fatevent;
        int err;

        err = ab3100_get_register_page_interruptible(ab3100, AB3100_EVENTA1,
                                       event_regs, 3);
        if (err)
                goto err_event;

        fatevent = (event_regs[0] << 16) |
                (event_regs[1] << 8) |
                event_regs[2];

        if (!ab3100->startup_events_read) {
                ab3100->startup_events[0] = event_regs[0];
                ab3100->startup_events[1] = event_regs[1];
                ab3100->startup_events[2] = event_regs[2];
                ab3100->startup_events_read = true;
        }
        /*
         * The notified parties will have to mask out the events
         * they're interested in and react to them. They will be
         * notified on all events, then they use the fatevent value
         * to determine if they're interested.
         */
        blocking_notifier_call_chain(&ab3100->event_subscribers,
                                     fatevent, NULL);

        dev_dbg(ab3100->dev,
                "IRQ Event: 0x%08x\n", fatevent);

        return IRQ_HANDLED;

 err_event:
        dev_dbg(ab3100->dev,
                "error reading event status\n");
        return IRQ_HANDLED;
}

#ifdef CONFIG_DEBUG_FS
/*
 * Some debugfs entries only exposed if we're using debug
 */
static int ab3100_registers_print(struct seq_file *s, void *p)
{
        struct ab3100 *ab3100 = s->private;
        u8 value;
        u8 reg;

        seq_puts(s, "AB3100 registers:\n");

        for (reg = 0; reg < 0xff; reg++) {
                ab3100_get_register_interruptible(ab3100, reg, &value);
                seq_printf(s, "[0x%x]:  0x%x\n", reg, value);
        }
        return 0;
}

static int ab3100_registers_open(struct inode *inode, struct file *file)
{
        return single_open(file, ab3100_registers_print, inode->i_private);
}

static const struct file_operations ab3100_registers_fops = {
        .open = ab3100_registers_open,
        .read = seq_read,
        .llseek = seq_lseek,
        .release = single_release,
        .owner = THIS_MODULE,
};

struct ab3100_get_set_reg_priv {
        struct ab3100 *ab3100;
        bool mode;
};

static ssize_t ab3100_get_set_reg(struct file *file,
                                  const char __user *user_buf,
                                  size_t count, loff_t *ppos)
{
        struct ab3100_get_set_reg_priv *priv = file->private_data;
        struct ab3100 *ab3100 = priv->ab3100;
        char buf[32];
        ssize_t buf_size;
        int regp;
        u8 user_reg;
        int err;
        int i = 0;

        /* Get userspace string and assure termination */
        buf_size = min(count, (sizeof(buf)-1));
        if (copy_from_user(buf, user_buf, buf_size))
                return -EFAULT;
        buf[buf_size] = 0;

        /*
         * The idea is here to parse a string which is either
         * "0xnn" for reading a register, or "0xaa 0xbb" for
         * writing 0xbb to the register 0xaa. First move past
         * whitespace and then begin to parse the register.
         */
        while ((i < buf_size) && (buf[i] == ' '))
                i++;
        regp = i;

        /*
         * Advance pointer to end of string then terminate
         * the register string. This is needed to satisfy
         * the kstrtou8() function.
         */
        while ((i < buf_size) && (buf[i] != ' '))
                i++;
        buf[i] = '\0';

        err = kstrtou8(&buf[regp], 16, &user_reg);
        if (err)
                return err;

        /* Either we read or we write a register here */
        if (!priv->mode) {
                /* Reading */
                u8 regvalue;

                ab3100_get_register_interruptible(ab3100, user_reg, &regvalue);

                dev_info(ab3100->dev,
                         "debug read AB3100 reg[0x%02x]: 0x%02x\n",
                         user_reg, regvalue);
        } else {
                int valp;
                u8 user_value;
                u8 regvalue;

                /*
                 * Writing, we need some value to write to
                 * the register so keep parsing the string
                 * from userspace.
                 */
                i++;
                while ((i < buf_size) && (buf[i] == ' '))
                        i++;
                valp = i;
                while ((i < buf_size) && (buf[i] != ' '))
                        i++;
                buf[i] = '\0';

                err = kstrtou8(&buf[valp], 16, &user_value);
                if (err)
                        return err;

                ab3100_set_register_interruptible(ab3100, user_reg, user_value);
                ab3100_get_register_interruptible(ab3100, user_reg, &regvalue);

                dev_info(ab3100->dev,
                         "debug write reg[0x%02x]\n"
                         "  with 0x%02x, after readback: 0x%02x\n",
                         user_reg, user_value, regvalue);
        }
        return buf_size;
}

static const struct file_operations ab3100_get_set_reg_fops = {
        .open = simple_open,
        .write = ab3100_get_set_reg,
        .llseek = noop_llseek,
};

static struct dentry *ab3100_dir;
static struct dentry *ab3100_reg_file;
static struct ab3100_get_set_reg_priv ab3100_get_priv;
static struct dentry *ab3100_get_reg_file;
static struct ab3100_get_set_reg_priv ab3100_set_priv;
static struct dentry *ab3100_set_reg_file;

static void ab3100_setup_debugfs(struct ab3100 *ab3100)
{
        int err;

        ab3100_dir = debugfs_create_dir("ab3100", NULL);
        if (!ab3100_dir)
                goto exit_no_debugfs;

        ab3100_reg_file = debugfs_create_file("registers",
                                S_IRUGO, ab3100_dir, ab3100,
                                &ab3100_registers_fops);
        if (!ab3100_reg_file) {
                err = -ENOMEM;
                goto exit_destroy_dir;
        }

        ab3100_get_priv.ab3100 = ab3100;
        ab3100_get_priv.mode = false;
        ab3100_get_reg_file = debugfs_create_file("get_reg",
                                S_IWUSR, ab3100_dir, &ab3100_get_priv,
                                &ab3100_get_set_reg_fops);
        if (!ab3100_get_reg_file) {
                err = -ENOMEM;
                goto exit_destroy_reg;
        }

        ab3100_set_priv.ab3100 = ab3100;
        ab3100_set_priv.mode = true;
        ab3100_set_reg_file = debugfs_create_file("set_reg",
                                S_IWUSR, ab3100_dir, &ab3100_set_priv,
                                &ab3100_get_set_reg_fops);
        if (!ab3100_set_reg_file) {
                err = -ENOMEM;
                goto exit_destroy_get_reg;
        }
        return;

 exit_destroy_get_reg:
        debugfs_remove(ab3100_get_reg_file);
 exit_destroy_reg:
        debugfs_remove(ab3100_reg_file);
 exit_destroy_dir:
        debugfs_remove(ab3100_dir);
 exit_no_debugfs:
        return;
}
#else
static inline void ab3100_setup_debugfs(struct ab3100 *ab3100)
{
}
#endif

/*
 * Basic set-up, datastructure creation/destruction and I2C interface.
 * This sets up a default config in the AB3100 chip so that it
 * will work as expected.
 */

struct ab3100_init_setting {
        u8 abreg;
        u8 setting;
};

static const struct ab3100_init_setting ab3100_init_settings[] = {
        {
                .abreg = AB3100_MCA,
                .setting = 0x01
        }, {
                .abreg = AB3100_MCB,
                .setting = 0x30
        }, {
                .abreg = AB3100_IMRA1,
                .setting = 0x00
        }, {
                .abreg = AB3100_IMRA2,
                .setting = 0xFF
        }, {
                .abreg = AB3100_IMRA3,
                .setting = 0x01
        }, {
                .abreg = AB3100_IMRB1,
                .setting = 0xBF
        }, {
                .abreg = AB3100_IMRB2,
                .setting = 0xFF
        }, {
                .abreg = AB3100_IMRB3,
                .setting = 0xFF
        }, {
                .abreg = AB3100_SUP,
                .setting = 0x00
        }, {
                .abreg = AB3100_DIS,
                .setting = 0xF0
        }, {
                .abreg = AB3100_D0C,
                .setting = 0x00
        }, {
                .abreg = AB3100_D1C,
                .setting = 0x00
        }, {
                .abreg = AB3100_D2C,
                .setting = 0x00
        }, {
                .abreg = AB3100_D3C,
                .setting = 0x00
        },
};

static int ab3100_setup(struct ab3100 *ab3100)
{
        int err = 0;
        int i;

        for (i = 0; i < ARRAY_SIZE(ab3100_init_settings); i++) {
                err = ab3100_set_register_interruptible(ab3100,
                                          ab3100_init_settings[i].abreg,
                                          ab3100_init_settings[i].setting);
                if (err)
                        goto exit_no_setup;
        }

        /*
         * Special trick to make the AB3100 use the 32kHz clock (RTC)
         * bit 3 in test register 0x02 is a special, undocumented test
         * register bit that only exist in AB3100 P1E
         */
        if (ab3100->chip_id == 0xc4) {
                dev_warn(ab3100->dev,
                         "AB3100 P1E variant detected forcing chip to 32KHz\n");
                err = ab3100_set_test_register_interruptible(ab3100,
                        0x02, 0x08);
        }

 exit_no_setup:
        return err;
}

/* The subdevices of the AB3100 */
static struct mfd_cell ab3100_devs[] = {
        {
                .name = "ab3100-dac",
                .id = -1,
        },
        {
                .name = "ab3100-leds",
                .id = -1,
        },
        {
                .name = "ab3100-power",
                .id = -1,
        },
        {
                .name = "ab3100-regulators",
                .of_compatible = "stericsson,ab3100-regulators",
                .id = -1,
        },
        {
                .name = "ab3100-sim",
                .id = -1,
        },
        {
                .name = "ab3100-uart",
                .id = -1,
        },
        {
                .name = "ab3100-rtc",
                .id = -1,
        },
        {
                .name = "ab3100-charger",
                .id = -1,
        },
        {
                .name = "ab3100-boost",
                .id = -1,
        },
        {
                .name = "ab3100-adc",
                .id = -1,
        },
        {
                .name = "ab3100-fuelgauge",
                .id = -1,
        },
        {
                .name = "ab3100-vibrator",
                .id = -1,
        },
        {
                .name = "ab3100-otp",
                .id = -1,
        },
        {
                .name = "ab3100-codec",
                .id = -1,
        },
};

struct ab_family_id {
        u8      id;
        char    *name;
};

static const struct ab_family_id ids[] = {
        /* AB3100 */
        {
                .id = 0xc0,
                .name = "P1A"
        }, {
                .id = 0xc1,
                .name = "P1B"
        }, {
                .id = 0xc2,
                .name = "P1C"
        }, {
                .id = 0xc3,
                .name = "P1D"
        }, {
                .id = 0xc4,
                .name = "P1E"
        }, {
                .id = 0xc5,
                .name = "P1F/R1A"
        }, {
                .id = 0xc6,
                .name = "P1G/R1A"
        }, {
                .id = 0xc7,
                .name = "P2A/R2A"
        }, {
                .id = 0xc8,
                .name = "P2B/R2B"
        },
        /* AB3000 variants, not supported */
        {
                .id = 0xa0
        }, {
                .id = 0xa1
        }, {
                .id = 0xa2
        }, {
                .id = 0xa3
        }, {
                .id = 0xa4
        }, {
                .id = 0xa5
        }, {
                .id = 0xa6
        }, {
                .id = 0xa7
        },
        /* Terminator */
        {
                .id = 0x00,
        },
};

static int ab3100_probe(struct i2c_client *client,
                                  const struct i2c_device_id *id)
{
        struct ab3100 *ab3100;
        struct ab3100_platform_data *ab3100_plf_data =
                dev_get_platdata(&client->dev);
        int err;
        int i;

        ab3100 = devm_kzalloc(&client->dev, sizeof(struct ab3100), GFP_KERNEL);
        if (!ab3100)
                return -ENOMEM;

        /* Initialize data structure */
        mutex_init(&ab3100->access_mutex);
        BLOCKING_INIT_NOTIFIER_HEAD(&ab3100->event_subscribers);

        ab3100->i2c_client = client;
        ab3100->dev = &ab3100->i2c_client->dev;

        i2c_set_clientdata(client, ab3100);

        /* Read chip ID register */
        err = ab3100_get_register_interruptible(ab3100, AB3100_CID,
                                                &ab3100->chip_id);
        if (err) {
                dev_err(&client->dev,
                        "failed to communicate with AB3100 chip\n");
                goto exit_no_detect;
        }

        for (i = 0; ids[i].id != 0x0; i++) {
                if (ids[i].id == ab3100->chip_id) {
                        if (ids[i].name)
                                break;

                        dev_err(&client->dev, "AB3000 is not supported\n");
                        goto exit_no_detect;
                }
        }

        snprintf(&ab3100->chip_name[0],
                 sizeof(ab3100->chip_name) - 1, "AB3100 %s", ids[i].name);

        if (ids[i].id == 0x0) {
                dev_err(&client->dev, "unknown analog baseband chip id: 0x%x\n",
                        ab3100->chip_id);
                dev_err(&client->dev,
                        "accepting it anyway. Please update the driver.\n");
                goto exit_no_detect;
        }

        dev_info(&client->dev, "Detected chip: %s\n",
                 &ab3100->chip_name[0]);

        /* Attach a second dummy i2c_client to the test register address */
        ab3100->testreg_client = i2c_new_dummy(client->adapter,
                                               client->addr + 1);
        if (!ab3100->testreg_client) {
                err = -ENOMEM;
                goto exit_no_testreg_client;
        }

        err = ab3100_setup(ab3100);
        if (err)
                goto exit_no_setup;

        err = devm_request_threaded_irq(&client->dev,
                                        client->irq, NULL, ab3100_irq_handler,
                                        IRQF_ONESHOT, "ab3100-core", ab3100);
        if (err)
                goto exit_no_irq;

        err = abx500_register_ops(&client->dev, &ab3100_ops);
        if (err)
                goto exit_no_ops;

        /* Set up and register the platform devices. */
        for (i = 0; i < ARRAY_SIZE(ab3100_devs); i++) {
                ab3100_devs[i].platform_data = ab3100_plf_data;
                ab3100_devs[i].pdata_size = sizeof(struct ab3100_platform_data);
        }

        err = mfd_add_devices(&client->dev, 0, ab3100_devs,
                              ARRAY_SIZE(ab3100_devs), NULL, 0, NULL);

        ab3100_setup_debugfs(ab3100);

        return 0;

 exit_no_ops:
 exit_no_irq:
 exit_no_setup:
        i2c_unregister_device(ab3100->testreg_client);
 exit_no_testreg_client:
 exit_no_detect:
        return err;
}

static const struct i2c_device_id ab3100_id[] = {
        { "ab3100", 0 },
        { }
};

static struct i2c_driver ab3100_driver = {
        .driver = {
                .name                   = "ab3100",
                .suppress_bind_attrs    = true,
        },
        .id_table       = ab3100_id,
        .probe          = ab3100_probe,
};

static int __init ab3100_i2c_init(void)
{
        return i2c_add_driver(&ab3100_driver);
}
subsys_initcall(ab3100_i2c_init);