/*
 * Copyright (C) 2007-2010 ST-Ericsson
 * License terms: GNU General Public License (GPL) version 2
 * Low-level core for exclusive access to the AB3550 IC on the I2C bus
 * and some basic chip-configuration.
 * Author: Bengt Jonsson <bengt.g.jonsson@stericsson.com>
 * Author: Mattias Nilsson <mattias.i.nilsson@stericsson.com>
 * Author: Mattias Wallin <mattias.wallin@stericsson.com>
 * Author: Rickard Andersson <rickard.andersson@stericsson.com>
 */

#include <linux/i2c.h>
#include <linux/mutex.h>
#include <linux/err.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/device.h>
#include <linux/irq.h>
#include <linux/interrupt.h>
#include <linux/random.h>
#include <linux/workqueue.h>
#include <linux/debugfs.h>
#include <linux/seq_file.h>
#include <linux/uaccess.h>
#include <linux/mfd/abx500.h>
#include <linux/list.h>
#include <linux/bitops.h>
#include <linux/spinlock.h>
#include <linux/mfd/core.h>

#define AB3550_NAME_STRING "ab3550"
#define AB3550_ID_FORMAT_STRING "AB3550 %s"
#define AB3550_NUM_BANKS 2
#define AB3550_NUM_EVENT_REG 5

/* These are the only registers inside AB3550 used in this main file */

/* Chip ID register */
#define AB3550_CID_REG           0x20

/* Interrupt event registers */
#define AB3550_EVENT_BANK        0
#define AB3550_EVENT_REG         0x22

/* Read/write operation values. */
#define AB3550_PERM_RD (0x01)
#define AB3550_PERM_WR (0x02)

/* Read/write permissions. */
#define AB3550_PERM_RO (AB3550_PERM_RD)
#define AB3550_PERM_RW (AB3550_PERM_RD | AB3550_PERM_WR)

/**
 * struct ab3550
 * @access_mutex: lock out concurrent accesses to the AB registers
 * @i2c_client: I2C client for this chip
 * @chip_name: name of this chip variant
 * @chip_id: 8 bit chip ID for this chip variant
 * @mask_work: a worker for writing to mask registers
 * @event_lock: a lock to protect the event_mask
 * @event_mask: a local copy of the mask event registers
 * @startup_events: a copy of the first reading of the event registers
 * @startup_events_read: whether the first events have been read
 */
struct ab3550 {
        struct mutex access_mutex;
        struct i2c_client *i2c_client[AB3550_NUM_BANKS];
        char chip_name[32];
        u8 chip_id;
        struct work_struct mask_work;
        spinlock_t event_lock;
        u8 event_mask[AB3550_NUM_EVENT_REG];
        u8 startup_events[AB3550_NUM_EVENT_REG];
        bool startup_events_read;
#ifdef CONFIG_DEBUG_FS
        unsigned int debug_bank;
        unsigned int debug_address;
#endif
};

/**
 * struct ab3550_reg_range
 * @first: the first address of the range
 * @last: the last address of the range
 * @perm: access permissions for the range
 */
struct ab3550_reg_range {
        u8 first;
        u8 last;
        u8 perm;
};

/**
 * struct ab3550_reg_ranges
 * @count: the number of ranges in the list
 * @range: the list of register ranges
 */
struct ab3550_reg_ranges {
        u8 count;
        const struct ab3550_reg_range *range;
};

/*
 * Permissible register ranges for reading and writing per device and bank.
 *
 * The ranges must be listed in increasing address order, and no overlaps are
 * allowed. It is assumed that write permission implies read permission
 * (i.e. only RO and RW permissions should be used).  Ranges with write
 * permission must not be split up.
 */

#define NO_RANGE {.count = 0, .range = NULL,}

static struct
ab3550_reg_ranges ab3550_reg_ranges[AB3550_NUM_DEVICES][AB3550_NUM_BANKS] = {
        [AB3550_DEVID_DAC] = {
                NO_RANGE,
                {
                        .count = 2,
                        .range = (struct ab3550_reg_range[]) {
                                {
                                        .first = 0xb0,
                                        .last = 0xba,
                                        .perm = AB3550_PERM_RW,
                                },
                                {
                                        .first = 0xbc,
                                        .last = 0xc3,
                                        .perm = AB3550_PERM_RW,
                                },
                        },
                },
        },
        [AB3550_DEVID_LEDS] = {
                NO_RANGE,
                {
                        .count = 2,
                        .range = (struct ab3550_reg_range[]) {
                                {
                                        .first = 0x5a,
                                        .last = 0x88,
                                        .perm = AB3550_PERM_RW,
                                },
                                {
                                        .first = 0x8a,
                                        .last = 0xad,
                                        .perm = AB3550_PERM_RW,
                                },
                        }
                },
        },
        [AB3550_DEVID_POWER] = {
                {
                        .count = 1,
                        .range = (struct ab3550_reg_range[]) {
                                {
                                        .first = 0x21,
                                        .last = 0x21,
                                        .perm = AB3550_PERM_RO,
                                },
                        }
                },
                NO_RANGE,
        },
        [AB3550_DEVID_REGULATORS] = {
                {
                        .count = 1,
                        .range = (struct ab3550_reg_range[]) {
                                {
                                        .first = 0x69,
                                        .last = 0xa3,
                                        .perm = AB3550_PERM_RW,
                                },
                        }
                },
                {
                        .count = 1,
                        .range = (struct ab3550_reg_range[]) {
                                {
                                        .first = 0x14,
                                        .last = 0x16,
                                        .perm = AB3550_PERM_RW,
                                },
                        }
                },
        },
        [AB3550_DEVID_SIM] = {
                {
                        .count = 1,
                        .range = (struct ab3550_reg_range[]) {
                                {
                                        .first = 0x21,
                                        .last = 0x21,
                                        .perm = AB3550_PERM_RO,
                                },
                        }
                },
                {
                        .count = 1,
                        .range = (struct ab3550_reg_range[]) {
                                {
                                        .first = 0x14,
                                        .last = 0x17,
                                        .perm = AB3550_PERM_RW,
                                },
                        }

                },
        },
        [AB3550_DEVID_UART] = {
                NO_RANGE,
                NO_RANGE,
        },
        [AB3550_DEVID_RTC] = {
                {
                        .count = 1,
                        .range = (struct ab3550_reg_range[]) {
                                {
                                        .first = 0x00,
                                        .last = 0x0c,
                                        .perm = AB3550_PERM_RW,
                                },
                        }
                },
                NO_RANGE,
        },
        [AB3550_DEVID_CHARGER] = {
                {
                        .count = 2,
                        .range = (struct ab3550_reg_range[]) {
                                {
                                        .first = 0x10,
                                        .last = 0x1a,
                                        .perm = AB3550_PERM_RW,
                                },
                                {
                                        .first = 0x21,
                                        .last = 0x21,
                                        .perm = AB3550_PERM_RO,
                                },
                        }
                },
                NO_RANGE,
        },
        [AB3550_DEVID_ADC] = {
                NO_RANGE,
                {
                        .count = 1,
                        .range = (struct ab3550_reg_range[]) {
                                {
                                        .first = 0x20,
                                        .last = 0x56,
                                        .perm = AB3550_PERM_RW,
                                },

                        }
                },
        },
        [AB3550_DEVID_FUELGAUGE] = {
                {
                        .count = 1,
                        .range = (struct ab3550_reg_range[]) {
                                {
                                        .first = 0x21,
                                        .last = 0x21,
                                        .perm = AB3550_PERM_RO,
                                },
                        }
                },
                {
                        .count = 1,
                        .range = (struct ab3550_reg_range[]) {
                                {
                                        .first = 0x00,
                                        .last = 0x0e,
                                        .perm = AB3550_PERM_RW,
                                },
                        }
                },
        },
        [AB3550_DEVID_VIBRATOR] = {
                NO_RANGE,
                {
                        .count = 1,
                        .range = (struct ab3550_reg_range[]) {
                                {
                                        .first = 0x10,
                                        .last = 0x13,
                                        .perm = AB3550_PERM_RW,
                                },

                        }
                },
        },
        [AB3550_DEVID_CODEC] = {
                {
                        .count = 2,
                        .range = (struct ab3550_reg_range[]) {
                                {
                                        .first = 0x31,
                                        .last = 0x63,
                                        .perm = AB3550_PERM_RW,
                                },
                                {
                                        .first = 0x65,
                                        .last = 0x68,
                                        .perm = AB3550_PERM_RW,
                                },
                        }
                },
                NO_RANGE,
        },
};

static struct mfd_cell ab3550_devs[AB3550_NUM_DEVICES] = {
        [AB3550_DEVID_DAC] = {
                .name = "ab3550-dac",
                .id = AB3550_DEVID_DAC,
                .num_resources = 0,
        },
        [AB3550_DEVID_LEDS] = {
                .name = "ab3550-leds",
                .id = AB3550_DEVID_LEDS,
        },
        [AB3550_DEVID_POWER] = {
                .name = "ab3550-power",
                .id = AB3550_DEVID_POWER,
        },
        [AB3550_DEVID_REGULATORS] = {
                .name = "ab3550-regulators",
                .id = AB3550_DEVID_REGULATORS,
        },
        [AB3550_DEVID_SIM] = {
                .name = "ab3550-sim",
                .id = AB3550_DEVID_SIM,
        },
        [AB3550_DEVID_UART] = {
                .name = "ab3550-uart",
                .id = AB3550_DEVID_UART,
        },
        [AB3550_DEVID_RTC] = {
                .name = "ab3550-rtc",
                .id = AB3550_DEVID_RTC,
        },
        [AB3550_DEVID_CHARGER] = {
                .name = "ab3550-charger",
                .id = AB3550_DEVID_CHARGER,
        },
        [AB3550_DEVID_ADC] = {
                .name = "ab3550-adc",
                .id = AB3550_DEVID_ADC,
                .num_resources = 10,
                .resources = (struct resource[]) {
                        {
                                .name = "TRIGGER-0",
                                .flags = IORESOURCE_IRQ,
                                .start = 16,
                                .end = 16,
                        },
                        {
                                .name = "TRIGGER-1",
                                .flags = IORESOURCE_IRQ,
                                .start = 17,
                                .end = 17,
                        },
                        {
                                .name = "TRIGGER-2",
                                .flags = IORESOURCE_IRQ,
                                .start = 18,
                                .end = 18,
                        },
                        {
                                .name = "TRIGGER-3",
                                .flags = IORESOURCE_IRQ,
                                .start = 19,
                                .end = 19,
                        },
                        {
                                .name = "TRIGGER-4",
                                .flags = IORESOURCE_IRQ,
                                .start = 20,
                                .end = 20,
                        },
                        {
                                .name = "TRIGGER-5",
                                .flags = IORESOURCE_IRQ,
                                .start = 21,
                                .end = 21,
                        },
                        {
                                .name = "TRIGGER-6",
                                .flags = IORESOURCE_IRQ,
                                .start = 22,
                                .end = 22,
                        },
                        {
                                .name = "TRIGGER-7",
                                .flags = IORESOURCE_IRQ,
                                .start = 23,
                                .end = 23,
                        },
                        {
                                .name = "TRIGGER-VBAT-TXON",
                                .flags = IORESOURCE_IRQ,
                                .start = 13,
                                .end = 13,
                        },
                        {
                                .name = "TRIGGER-VBAT",
                                .flags = IORESOURCE_IRQ,
                                .start = 12,
                                .end = 12,
                        },
                },
        },
        [AB3550_DEVID_FUELGAUGE] = {
                .name = "ab3550-fuelgauge",
                .id = AB3550_DEVID_FUELGAUGE,
        },
        [AB3550_DEVID_VIBRATOR] = {
                .name = "ab3550-vibrator",
                .id = AB3550_DEVID_VIBRATOR,
        },
        [AB3550_DEVID_CODEC] = {
                .name = "ab3550-codec",
                .id = AB3550_DEVID_CODEC,
        },
};

/*
 * I2C transactions with error messages.
 */
static int ab3550_i2c_master_send(struct ab3550 *ab, u8 bank, u8 *data,
        u8 count)
{
        int err;

        err = i2c_master_send(ab->i2c_client[bank], data, count);
        if (err < 0) {
                dev_err(&ab->i2c_client[0]->dev, "send error: %d\n", err);
                return err;
        }
        return 0;
}

static int ab3550_i2c_master_recv(struct ab3550 *ab, u8 bank, u8 *data,
        u8 count)
{
        int err;

        err = i2c_master_recv(ab->i2c_client[bank], data, count);
        if (err < 0) {
                dev_err(&ab->i2c_client[0]->dev, "receive error: %d\n", err);
                return err;
        }
        return 0;
}

/*
 * Functionality for getting/setting register values.
 */
static int get_register_interruptible(struct ab3550 *ab, u8 bank, u8 reg,
        u8 *value)
{
        int err;

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

        err = ab3550_i2c_master_send(ab, bank, &reg, 1);
        if (!err)
                err = ab3550_i2c_master_recv(ab, bank, value, 1);

        mutex_unlock(&ab->access_mutex);
        return err;
}

static int get_register_page_interruptible(struct ab3550 *ab, u8 bank,
        u8 first_reg, u8 *regvals, u8 numregs)
{
        int err;

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

        err = ab3550_i2c_master_send(ab, bank, &first_reg, 1);
        if (!err)
                err = ab3550_i2c_master_recv(ab, bank, regvals, numregs);

        mutex_unlock(&ab->access_mutex);
        return err;
}

static int mask_and_set_register_interruptible(struct ab3550 *ab, u8 bank,
        u8 reg, u8 bitmask, u8 bitvalues)
{
        int err = 0;

        if (likely(bitmask)) {
                u8 reg_bits[2] = {reg, 0};

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

                if (bitmask == 0xFF) /* No need to read in this case. */
                        reg_bits[1] = bitvalues;
                else { /* Read and modify the register value. */
                        u8 bits;

                        err = ab3550_i2c_master_send(ab, bank, &reg, 1);
                        if (err)
                                goto unlock_and_return;
                        err = ab3550_i2c_master_recv(ab, bank, &bits, 1);
                        if (err)
                                goto unlock_and_return;
                        reg_bits[1] = ((~bitmask & bits) |
                                (bitmask & bitvalues));
                }
                /* Write the new value. */
                err = ab3550_i2c_master_send(ab, bank, reg_bits, 2);
unlock_and_return:
                mutex_unlock(&ab->access_mutex);
        }
        return err;
}

/*
 * Read/write permission checking functions.
 */
static bool page_write_allowed(const struct ab3550_reg_ranges *ranges,
        u8 first_reg, u8 last_reg)
{
        u8 i;

        if (last_reg < first_reg)
                return false;

        for (i = 0; i < ranges->count; i++) {
                if (first_reg < ranges->range[i].first)
                        break;
                if ((last_reg <= ranges->range[i].last) &&
                        (ranges->range[i].perm & AB3550_PERM_WR))
                        return true;
        }
        return false;
}

static bool reg_write_allowed(const struct ab3550_reg_ranges *ranges, u8 reg)
{
        return page_write_allowed(ranges, reg, reg);
}

static bool page_read_allowed(const struct ab3550_reg_ranges *ranges,
        u8 first_reg, u8 last_reg)
{
        u8 i;

        if (last_reg < first_reg)
                return false;
        /* Find the range (if it exists in the list) that includes first_reg. */
        for (i = 0; i < ranges->count; i++) {
                if (first_reg < ranges->range[i].first)
                        return false;
                if (first_reg <= ranges->range[i].last)
                        break;
        }
        /* Make sure that the entire range up to and including last_reg is
         * readable. This may span several of the ranges in the list.
         */
        while ((i < ranges->count) &&
                (ranges->range[i].perm & AB3550_PERM_RD)) {
                if (last_reg <= ranges->range[i].last)
                        return true;
                if ((++i >= ranges->count) ||
                        (ranges->range[i].first !=
                         (ranges->range[i - 1].last + 1))) {
                        break;
                }
        }
        return false;
}

static bool reg_read_allowed(const struct ab3550_reg_ranges *ranges, u8 reg)
{
        return page_read_allowed(ranges, reg, reg);
}

/*
 * The register access functionality.
 */
static int ab3550_get_chip_id(struct device *dev)
{
        struct ab3550 *ab = dev_get_drvdata(dev->parent);
        return (int)ab->chip_id;
}

static int ab3550_mask_and_set_register_interruptible(struct device *dev,
        u8 bank, u8 reg, u8 bitmask, u8 bitvalues)
{
        struct ab3550 *ab;
        struct platform_device *pdev = to_platform_device(dev);

        if ((AB3550_NUM_BANKS <= bank) ||
                !reg_write_allowed(&ab3550_reg_ranges[pdev->id][bank], reg))
                return -EINVAL;

        ab = dev_get_drvdata(dev->parent);
        return mask_and_set_register_interruptible(ab, bank, reg,
                bitmask, bitvalues);
}

static int ab3550_set_register_interruptible(struct device *dev, u8 bank,
        u8 reg, u8 value)
{
        return ab3550_mask_and_set_register_interruptible(dev, bank, reg, 0xFF,
                value);
}

static int ab3550_get_register_interruptible(struct device *dev, u8 bank,
        u8 reg, u8 *value)
{
        struct ab3550 *ab;
        struct platform_device *pdev = to_platform_device(dev);

        if ((AB3550_NUM_BANKS <= bank) ||
                !reg_read_allowed(&ab3550_reg_ranges[pdev->id][bank], reg))
                return -EINVAL;

        ab = dev_get_drvdata(dev->parent);
        return get_register_interruptible(ab, bank, reg, value);
}

static int ab3550_get_register_page_interruptible(struct device *dev, u8 bank,
        u8 first_reg, u8 *regvals, u8 numregs)
{
        struct ab3550 *ab;
        struct platform_device *pdev = to_platform_device(dev);

        if ((AB3550_NUM_BANKS <= bank) ||
                !page_read_allowed(&ab3550_reg_ranges[pdev->id][bank],
                        first_reg, (first_reg + numregs - 1)))
                return -EINVAL;

        ab = dev_get_drvdata(dev->parent);
        return get_register_page_interruptible(ab, bank, first_reg, regvals,
                numregs);
}

static int ab3550_event_registers_startup_state_get(struct device *dev,
        u8 *event)
{
        struct ab3550 *ab;

        ab = dev_get_drvdata(dev->parent);
        if (!ab->startup_events_read)
                return -EAGAIN; /* Try again later */

        memcpy(event, ab->startup_events, AB3550_NUM_EVENT_REG);
        return 0;
}

static int ab3550_startup_irq_enabled(struct device *dev, unsigned int irq)
{
        struct ab3550 *ab;
        struct ab3550_platform_data *plf_data;
        bool val;

        ab = irq_get_chip_data(irq);
        plf_data = ab->i2c_client[0]->dev.platform_data;
        irq -= plf_data->irq.base;
        val = ((ab->startup_events[irq / 8] & BIT(irq % 8)) != 0);

        return val;
}

static struct abx500_ops ab3550_ops = {
        .get_chip_id = ab3550_get_chip_id,
        .get_register = ab3550_get_register_interruptible,
        .set_register = ab3550_set_register_interruptible,
        .get_register_page = ab3550_get_register_page_interruptible,
        .set_register_page = NULL,
        .mask_and_set_register = ab3550_mask_and_set_register_interruptible,
        .event_registers_startup_state_get =
                ab3550_event_registers_startup_state_get,
        .startup_irq_enabled = ab3550_startup_irq_enabled,
};

static irqreturn_t ab3550_irq_handler(int irq, void *data)
{
        struct ab3550 *ab = data;
        int err;
        unsigned int i;
        u8 e[AB3550_NUM_EVENT_REG];
        u8 *events;
        unsigned long flags;

        events = (ab->startup_events_read ? e : ab->startup_events);

        err = get_register_page_interruptible(ab, AB3550_EVENT_BANK,
                AB3550_EVENT_REG, events, AB3550_NUM_EVENT_REG);
        if (err)
                goto err_event_rd;

        if (!ab->startup_events_read) {
                dev_info(&ab->i2c_client[0]->dev,
                        "startup events 0x%x,0x%x,0x%x,0x%x,0x%x\n",
                        ab->startup_events[0], ab->startup_events[1],
                        ab->startup_events[2], ab->startup_events[3],
                        ab->startup_events[4]);
                ab->startup_events_read = true;
                goto out;
        }

        /* The two highest bits in event[4] are not used. */
        events[4] &= 0x3f;

        spin_lock_irqsave(&ab->event_lock, flags);
        for (i = 0; i < AB3550_NUM_EVENT_REG; i++)
                events[i] &= ~ab->event_mask[i];
        spin_unlock_irqrestore(&ab->event_lock, flags);

        for (i = 0; i < AB3550_NUM_EVENT_REG; i++) {
                u8 bit;
                u8 event_reg;

                dev_dbg(&ab->i2c_client[0]->dev, "IRQ Event[%d]: 0x%2x\n",
                        i, events[i]);

                event_reg = events[i];
                for (bit = 0; event_reg; bit++, event_reg /= 2) {
                        if (event_reg % 2) {
                                unsigned int irq;
                                struct ab3550_platform_data *plf_data;

                                plf_data = ab->i2c_client[0]->dev.platform_data;
                                irq = plf_data->irq.base + (i * 8) + bit;
                                handle_nested_irq(irq);
                        }
                }
        }
out:
        return IRQ_HANDLED;

err_event_rd:
        dev_dbg(&ab->i2c_client[0]->dev, "error reading event registers\n");
        return IRQ_HANDLED;
}

#ifdef CONFIG_DEBUG_FS
static struct ab3550_reg_ranges debug_ranges[AB3550_NUM_BANKS] = {
        {
                .count = 6,
                .range = (struct ab3550_reg_range[]) {
                        {
                                .first = 0x00,
                                .last = 0x0e,
                        },
                        {
                                .first = 0x10,
                                .last = 0x1a,
                        },
                        {
                                .first = 0x1e,
                                .last = 0x4f,
                        },
                        {
                                .first = 0x51,
                                .last = 0x63,
                        },
                        {
                                .first = 0x65,
                                .last = 0xa3,
                        },
                        {
                                .first = 0xa5,
                                .last = 0xa8,
                        },
                }
        },
        {
                .count = 8,
                .range = (struct ab3550_reg_range[]) {
                        {
                                .first = 0x00,
                                .last = 0x0e,
                        },
                        {
                                .first = 0x10,
                                .last = 0x17,
                        },
                        {
                                .first = 0x1a,
                                .last = 0x1c,
                        },
                        {
                                .first = 0x20,
                                .last = 0x56,
                        },
                        {
                                .first = 0x5a,
                                .last = 0x88,
                        },
                        {
                                .first = 0x8a,
                                .last = 0xad,
                        },
                        {
                                .first = 0xb0,
                                .last = 0xba,
                        },
                        {
                                .first = 0xbc,
                                .last = 0xc3,
                        },
                }
        },
};

static int ab3550_registers_print(struct seq_file *s, void *p)
{
        struct ab3550 *ab = s->private;
        int bank;

        seq_printf(s, AB3550_NAME_STRING " register values:\n");

        for (bank = 0; bank < AB3550_NUM_BANKS; bank++) {
                unsigned int i;

                seq_printf(s, " bank %d:\n", bank);
                for (i = 0; i < debug_ranges[bank].count; i++) {
                        u8 reg;

                        for (reg = debug_ranges[bank].range[i].first;
                                reg <= debug_ranges[bank].range[i].last;
                                reg++) {
                                u8 value;

                                get_register_interruptible(ab, bank, reg,
                                        &value);
                                seq_printf(s, "  [%d/0x%02X]: 0x%02X\n", bank,
                                        reg, value);
                        }
                }
        }
        return 0;
}

static int ab3550_registers_open(struct inode *inode, struct file *file)
{
        return single_open(file, ab3550_registers_print, inode->i_private);
}

static const struct file_operations ab3550_registers_fops = {
        .open = ab3550_registers_open,
        .read = seq_read,
        .llseek = seq_lseek,
        .release = single_release,
        .owner = THIS_MODULE,
};

static int ab3550_bank_print(struct seq_file *s, void *p)
{
        struct ab3550 *ab = s->private;

        seq_printf(s, "%d\n", ab->debug_bank);
        return 0;
}

static int ab3550_bank_open(struct inode *inode, struct file *file)
{
        return single_open(file, ab3550_bank_print, inode->i_private);
}

static ssize_t ab3550_bank_write(struct file *file,
        const char __user *user_buf,
        size_t count, loff_t *ppos)
{
        struct ab3550 *ab = ((struct seq_file *)(file->private_data))->private;
        unsigned long user_bank;
        int err;

        /* Get userspace string and assure termination */
        err = kstrtoul_from_user(user_buf, count, 0, &user_bank);
        if (err)
                return err;

        if (user_bank >= AB3550_NUM_BANKS) {
                dev_err(&ab->i2c_client[0]->dev,
                        "debugfs error input > number of banks\n");
                return -EINVAL;
        }

        ab->debug_bank = user_bank;

        return count;
}

static int ab3550_address_print(struct seq_file *s, void *p)
{
        struct ab3550 *ab = s->private;

        seq_printf(s, "0x%02X\n", ab->debug_address);
        return 0;
}

static int ab3550_address_open(struct inode *inode, struct file *file)
{
        return single_open(file, ab3550_address_print, inode->i_private);
}

static ssize_t ab3550_address_write(struct file *file,
        const char __user *user_buf,
        size_t count, loff_t *ppos)
{
        struct ab3550 *ab = ((struct seq_file *)(file->private_data))->private;
        unsigned long user_address;
        int err;

        /* Get userspace string and assure termination */
        err = kstrtoul_from_user(user_buf, count, 0, &user_address);
        if (err)
                return err;

        if (user_address > 0xff) {
                dev_err(&ab->i2c_client[0]->dev,
                        "debugfs error input > 0xff\n");
                return -EINVAL;
        }
        ab->debug_address = user_address;
        return count;
}

static int ab3550_val_print(struct seq_file *s, void *p)
{
        struct ab3550 *ab = s->private;
        int err;
        u8 regvalue;

        err = get_register_interruptible(ab, (u8)ab->debug_bank,
                (u8)ab->debug_address, &regvalue);
        if (err)
                return -EINVAL;
        seq_printf(s, "0x%02X\n", regvalue);

        return 0;
}

static int ab3550_val_open(struct inode *inode, struct file *file)
{
        return single_open(file, ab3550_val_print, inode->i_private);
}

static ssize_t ab3550_val_write(struct file *file,
        const char __user *user_buf,
        size_t count, loff_t *ppos)
{
        struct ab3550 *ab = ((struct seq_file *)(file->private_data))->private;
        unsigned long user_val;
        int err;
        u8 regvalue;

        /* Get userspace string and assure termination */
        err = kstrtoul_from_user(user_buf, count, 0, &user_val);
        if (err)
                return err;

        if (user_val > 0xff) {
                dev_err(&ab->i2c_client[0]->dev,
                        "debugfs error input > 0xff\n");
                return -EINVAL;
        }
        err = mask_and_set_register_interruptible(
                ab, (u8)ab->debug_bank,
                (u8)ab->debug_address, 0xFF, (u8)user_val);
        if (err)
                return -EINVAL;

        get_register_interruptible(ab, (u8)ab->debug_bank,
                (u8)ab->debug_address, &regvalue);
        if (err)
                return -EINVAL;

        return count;
}

static const struct file_operations ab3550_bank_fops = {
        .open = ab3550_bank_open,
        .write = ab3550_bank_write,
        .read = seq_read,
        .llseek = seq_lseek,
        .release = single_release,
        .owner = THIS_MODULE,
};

static const struct file_operations ab3550_address_fops = {
        .open = ab3550_address_open,
        .write = ab3550_address_write,

        .read = seq_read,
        .llseek = seq_lseek,
        .release = single_release,
        .owner = THIS_MODULE,
};

static const struct file_operations ab3550_val_fops = {
        .open = ab3550_val_open,
        .write = ab3550_val_write,
        .read = seq_read,
        .llseek = seq_lseek,
        .release = single_release,
        .owner = THIS_MODULE,
};

static struct dentry *ab3550_dir;
static struct dentry *ab3550_reg_file;
static struct dentry *ab3550_bank_file;
static struct dentry *ab3550_address_file;
static struct dentry *ab3550_val_file;

static inline void ab3550_setup_debugfs(struct ab3550 *ab)
{
        ab->debug_bank = 0;
        ab->debug_address = 0x00;

        ab3550_dir = debugfs_create_dir(AB3550_NAME_STRING, NULL);
        if (!ab3550_dir)
                goto exit_no_debugfs;

        ab3550_reg_file = debugfs_create_file("all-registers",
                S_IRUGO, ab3550_dir, ab, &ab3550_registers_fops);
        if (!ab3550_reg_file)
                goto exit_destroy_dir;

        ab3550_bank_file = debugfs_create_file("register-bank",
                (S_IRUGO | S_IWUSR), ab3550_dir, ab, &ab3550_bank_fops);
        if (!ab3550_bank_file)
                goto exit_destroy_reg;

        ab3550_address_file = debugfs_create_file("register-address",
                (S_IRUGO | S_IWUSR), ab3550_dir, ab, &ab3550_address_fops);
        if (!ab3550_address_file)
                goto exit_destroy_bank;

        ab3550_val_file = debugfs_create_file("register-value",
                (S_IRUGO | S_IWUSR), ab3550_dir, ab, &ab3550_val_fops);
        if (!ab3550_val_file)
                goto exit_destroy_address;

        return;

exit_destroy_address:
        debugfs_remove(ab3550_address_file);
exit_destroy_bank:
        debugfs_remove(ab3550_bank_file);
exit_destroy_reg:
        debugfs_remove(ab3550_reg_file);
exit_destroy_dir:
        debugfs_remove(ab3550_dir);
exit_no_debugfs:
        dev_err(&ab->i2c_client[0]->dev, "failed to create debugfs entries.\n");
        return;
}

static inline void ab3550_remove_debugfs(void)
{
        debugfs_remove(ab3550_val_file);
        debugfs_remove(ab3550_address_file);
        debugfs_remove(ab3550_bank_file);
        debugfs_remove(ab3550_reg_file);
        debugfs_remove(ab3550_dir);
}

#else /* !CONFIG_DEBUG_FS */
static inline void ab3550_setup_debugfs(struct ab3550 *ab)
{
}
static inline void ab3550_remove_debugfs(void)
{
}
#endif

/*
 * Basic set-up, datastructure creation/destruction and I2C interface.
 * This sets up a default config in the AB3550 chip so that it
 * will work as expected.
 */
static int __init ab3550_setup(struct ab3550 *ab)
{
        int err = 0;
        int i;
        struct ab3550_platform_data *plf_data;
        struct abx500_init_settings *settings;

        plf_data = ab->i2c_client[0]->dev.platform_data;
        settings = plf_data->init_settings;

        for (i = 0; i < plf_data->init_settings_sz; i++) {
                err = mask_and_set_register_interruptible(ab,
                        settings[i].bank,
                        settings[i].reg,
                        0xFF, settings[i].setting);
                if (err)
                        goto exit_no_setup;

                /* If event mask register update the event mask in ab3550 */
                if ((settings[i].bank == 0) &&
                        (AB3550_IMR1 <= settings[i].reg) &&
                        (settings[i].reg <= AB3550_IMR5)) {
                        ab->event_mask[settings[i].reg - AB3550_IMR1] =
                                settings[i].setting;
                }
        }
exit_no_setup:
        return err;
}

static void ab3550_mask_work(struct work_struct *work)
{
        struct ab3550 *ab = container_of(work, struct ab3550, mask_work);
        int i;
        unsigned long flags;
        u8 mask[AB3550_NUM_EVENT_REG];

        spin_lock_irqsave(&ab->event_lock, flags);
        for (i = 0; i < AB3550_NUM_EVENT_REG; i++)
                mask[i] = ab->event_mask[i];
        spin_unlock_irqrestore(&ab->event_lock, flags);

        for (i = 0; i < AB3550_NUM_EVENT_REG; i++) {
                int err;

                err = mask_and_set_register_interruptible(ab, 0,
                        (AB3550_IMR1 + i), ~0, mask[i]);
                if (err)
                        dev_err(&ab->i2c_client[0]->dev,
                                "ab3550_mask_work failed 0x%x,0x%x\n",
                                (AB3550_IMR1 + i), mask[i]);
        }
}

static void ab3550_mask(struct irq_data *data)
{
        unsigned long flags;
        struct ab3550 *ab;
        struct ab3550_platform_data *plf_data;
        int irq;

        ab = irq_data_get_irq_chip_data(data);
        plf_data = ab->i2c_client[0]->dev.platform_data;
        irq = data->irq - plf_data->irq.base;

        spin_lock_irqsave(&ab->event_lock, flags);
        ab->event_mask[irq / 8] |= BIT(irq % 8);
        spin_unlock_irqrestore(&ab->event_lock, flags);

        schedule_work(&ab->mask_work);
}

static void ab3550_unmask(struct irq_data *data)
{
        unsigned long flags;
        struct ab3550 *ab;
        struct ab3550_platform_data *plf_data;
        int irq;

        ab = irq_data_get_irq_chip_data(data);
        plf_data = ab->i2c_client[0]->dev.platform_data;
        irq = data->irq - plf_data->irq.base;

        spin_lock_irqsave(&ab->event_lock, flags);
        ab->event_mask[irq / 8] &= ~BIT(irq % 8);
        spin_unlock_irqrestore(&ab->event_lock, flags);

        schedule_work(&ab->mask_work);
}

static void noop(struct irq_data *data)
{
}

static struct irq_chip ab3550_irq_chip = {
        .name           = "ab3550-core", /* Keep the same name as the request */
        .irq_disable    = ab3550_mask, /* No default to mask in chip.c */
        .irq_ack        = noop,
        .irq_mask       = ab3550_mask,
        .irq_unmask     = ab3550_unmask,
};

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

static const struct ab_family_id ids[] __initdata = {
        /* AB3550 */
        {
                .id = AB3550_P1A,
                .name = "P1A"
        },
        /* Terminator */
        {
                .id = 0x00,
        }
};

static int __init ab3550_probe(struct i2c_client *client,
        const struct i2c_device_id *id)
{
        struct ab3550 *ab;
        struct ab3550_platform_data *ab3550_plf_data =
                client->dev.platform_data;
        int err;
        int i;
        int num_i2c_clients = 0;

        ab = kzalloc(sizeof(struct ab3550), GFP_KERNEL);
        if (!ab) {
                dev_err(&client->dev,
                        "could not allocate " AB3550_NAME_STRING " device\n");
                return -ENOMEM;
        }

        /* Initialize data structure */
        mutex_init(&ab->access_mutex);
        spin_lock_init(&ab->event_lock);
        ab->i2c_client[0] = client;

        i2c_set_clientdata(client, ab);

        /* Read chip ID register */
        err = get_register_interruptible(ab, 0, AB3550_CID_REG, &ab->chip_id);
        if (err) {
                dev_err(&client->dev, "could not communicate with the analog "
                        "baseband chip\n");
                goto exit_no_detect;
        }

        for (i = 0; ids[i].id != 0x0; i++) {
                if (ids[i].id == ab->chip_id) {
                        snprintf(&ab->chip_name[0], sizeof(ab->chip_name) - 1,
                                AB3550_ID_FORMAT_STRING, ids[i].name);
                        break;
                }
        }

        if (ids[i].id == 0x0) {
                dev_err(&client->dev, "unknown analog baseband chip id: 0x%x\n",
                        ab->chip_id);
                dev_err(&client->dev, "driver not started!\n");
                goto exit_no_detect;
        }

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

        /* Attach other dummy I2C clients. */
        while (++num_i2c_clients < AB3550_NUM_BANKS) {
                ab->i2c_client[num_i2c_clients] =
                        i2c_new_dummy(client->adapter,
                                (client->addr + num_i2c_clients));
                if (!ab->i2c_client[num_i2c_clients]) {
                        err = -ENOMEM;
                        goto exit_no_dummy_client;
                }
                strlcpy(ab->i2c_client[num_i2c_clients]->name, id->name,
                        sizeof(ab->i2c_client[num_i2c_clients]->name));
        }

        err = ab3550_setup(ab);
        if (err)
                goto exit_no_setup;

        INIT_WORK(&ab->mask_work, ab3550_mask_work);

        for (i = 0; i < ab3550_plf_data->irq.count; i++) {
                unsigned int irq;

                irq = ab3550_plf_data->irq.base + i;
                irq_set_chip_data(irq, ab);
                irq_set_chip_and_handler(irq, &ab3550_irq_chip,
                                         handle_simple_irq);
                irq_set_nested_thread(irq, 1);
#ifdef CONFIG_ARM
                set_irq_flags(irq, IRQF_VALID);
#else
                irq_set_noprobe(irq);
#endif
        }

        err = request_threaded_irq(client->irq, NULL, ab3550_irq_handler,
                IRQF_ONESHOT, "ab3550-core", ab);
        /* This real unpredictable IRQ is of course sampled for entropy */
        rand_initialize_irq(client->irq);

        if (err)
                goto exit_no_irq;

        err = abx500_register_ops(&client->dev, &ab3550_ops);
        if (err)
                goto exit_no_ops;

        /* Set up and register the platform devices. */
        for (i = 0; i < AB3550_NUM_DEVICES; i++) {
                ab3550_devs[i].platform_data = ab3550_plf_data->dev_data[i];
                ab3550_devs[i].pdata_size = ab3550_plf_data->dev_data_sz[i];
        }

        err = mfd_add_devices(&client->dev, 0, ab3550_devs,
                ARRAY_SIZE(ab3550_devs), NULL,
                ab3550_plf_data->irq.base);

        ab3550_setup_debugfs(ab);

        return 0;

exit_no_ops:
exit_no_irq:
exit_no_setup:
exit_no_dummy_client:
        /* Unregister the dummy i2c clients. */
        while (--num_i2c_clients)
                i2c_unregister_device(ab->i2c_client[num_i2c_clients]);
exit_no_detect:
        kfree(ab);
        return err;
}

static int __exit ab3550_remove(struct i2c_client *client)
{
        struct ab3550 *ab = i2c_get_clientdata(client);
        int num_i2c_clients = AB3550_NUM_BANKS;

        mfd_remove_devices(&client->dev);
        ab3550_remove_debugfs();

        while (--num_i2c_clients)
                i2c_unregister_device(ab->i2c_client[num_i2c_clients]);

        /*
         * At this point, all subscribers should have unregistered
         * their notifiers so deactivate IRQ
         */
        free_irq(client->irq, ab);
        kfree(ab);
        return 0;
}

static const struct i2c_device_id ab3550_id[] = {
        {AB3550_NAME_STRING, 0},
        {}
};
MODULE_DEVICE_TABLE(i2c, ab3550_id);

static struct i2c_driver ab3550_driver = {
        .driver = {
                .name   = AB3550_NAME_STRING,
                .owner  = THIS_MODULE,
        },
        .id_table       = ab3550_id,
        .probe          = ab3550_probe,
        .remove         = __exit_p(ab3550_remove),
};

static int __init ab3550_i2c_init(void)
{
        return i2c_add_driver(&ab3550_driver);
}

static void __exit ab3550_i2c_exit(void)
{
        i2c_del_driver(&ab3550_driver);
}

subsys_initcall(ab3550_i2c_init);
module_exit(ab3550_i2c_exit);

MODULE_AUTHOR("Mattias Wallin <mattias.wallin@stericsson.com>");
MODULE_DESCRIPTION("AB3550 core driver");
MODULE_LICENSE("GPL");