/*
 * RPR-0521 ROHM Ambient Light and Proximity Sensor
 *
 * Copyright (c) 2015, Intel Corporation.
 *
 * This file is subject to the terms and conditions of version 2 of
 * the GNU General Public License.  See the file COPYING in the main
 * directory of this archive for more details.
 *
 * IIO driver for RPR-0521RS (7-bit I2C slave address 0x38).
 *
 * TODO: illuminance channel
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/i2c.h>
#include <linux/regmap.h>
#include <linux/delay.h>
#include <linux/acpi.h>

#include <linux/iio/iio.h>
#include <linux/iio/buffer.h>
#include <linux/iio/trigger.h>
#include <linux/iio/trigger_consumer.h>
#include <linux/iio/triggered_buffer.h>
#include <linux/iio/sysfs.h>
#include <linux/pm_runtime.h>

#define RPR0521_REG_SYSTEM_CTRL         0x40
#define RPR0521_REG_MODE_CTRL           0x41
#define RPR0521_REG_ALS_CTRL            0x42
#define RPR0521_REG_PXS_CTRL            0x43
#define RPR0521_REG_PXS_DATA            0x44 /* 16-bit, little endian */
#define RPR0521_REG_ALS_DATA0           0x46 /* 16-bit, little endian */
#define RPR0521_REG_ALS_DATA1           0x48 /* 16-bit, little endian */
#define RPR0521_REG_INTERRUPT           0x4A
#define RPR0521_REG_PS_OFFSET_LSB       0x53
#define RPR0521_REG_ID                  0x92

#define RPR0521_MODE_ALS_MASK           BIT(7)
#define RPR0521_MODE_PXS_MASK           BIT(6)
#define RPR0521_MODE_MEAS_TIME_MASK     GENMASK(3, 0)
#define RPR0521_ALS_DATA0_GAIN_MASK     GENMASK(5, 4)
#define RPR0521_ALS_DATA0_GAIN_SHIFT    4
#define RPR0521_ALS_DATA1_GAIN_MASK     GENMASK(3, 2)
#define RPR0521_ALS_DATA1_GAIN_SHIFT    2
#define RPR0521_PXS_GAIN_MASK           GENMASK(5, 4)
#define RPR0521_PXS_GAIN_SHIFT          4
#define RPR0521_PXS_PERSISTENCE_MASK    GENMASK(3, 0)
#define RPR0521_INTERRUPT_INT_TRIG_PS_MASK      BIT(0)
#define RPR0521_INTERRUPT_INT_TRIG_ALS_MASK     BIT(1)
#define RPR0521_INTERRUPT_INT_REASSERT_MASK     BIT(3)
#define RPR0521_INTERRUPT_ALS_INT_STATUS_MASK   BIT(6)
#define RPR0521_INTERRUPT_PS_INT_STATUS_MASK    BIT(7)

#define RPR0521_MODE_ALS_ENABLE         BIT(7)
#define RPR0521_MODE_ALS_DISABLE        0x00
#define RPR0521_MODE_PXS_ENABLE         BIT(6)
#define RPR0521_MODE_PXS_DISABLE        0x00
#define RPR0521_PXS_PERSISTENCE_DRDY    0x00

#define RPR0521_INTERRUPT_INT_TRIG_PS_ENABLE    BIT(0)
#define RPR0521_INTERRUPT_INT_TRIG_PS_DISABLE   0x00
#define RPR0521_INTERRUPT_INT_TRIG_ALS_ENABLE   BIT(1)
#define RPR0521_INTERRUPT_INT_TRIG_ALS_DISABLE  0x00
#define RPR0521_INTERRUPT_INT_REASSERT_ENABLE   BIT(3)
#define RPR0521_INTERRUPT_INT_REASSERT_DISABLE  0x00

#define RPR0521_MANUFACT_ID             0xE0
#define RPR0521_DEFAULT_MEAS_TIME       0x06 /* ALS - 100ms, PXS - 100ms */

#define RPR0521_DRV_NAME                "RPR0521"
#define RPR0521_IRQ_NAME                "rpr0521_event"
#define RPR0521_REGMAP_NAME             "rpr0521_regmap"

#define RPR0521_SLEEP_DELAY_MS  2000

#define RPR0521_ALS_SCALE_AVAIL "0.007812 0.015625 0.5 1"
#define RPR0521_PXS_SCALE_AVAIL "0.125 0.5 1"

struct rpr0521_gain {
        int scale;
        int uscale;
};

static const struct rpr0521_gain rpr0521_als_gain[4] = {
        {1, 0},         /* x1 */
        {0, 500000},    /* x2 */
        {0, 15625},     /* x64 */
        {0, 7812},      /* x128 */
};

static const struct rpr0521_gain rpr0521_pxs_gain[3] = {
        {1, 0},         /* x1 */
        {0, 500000},    /* x2 */
        {0, 125000},    /* x4 */
};

enum rpr0521_channel {
        RPR0521_CHAN_PXS,
        RPR0521_CHAN_ALS_DATA0,
        RPR0521_CHAN_ALS_DATA1,
};

struct rpr0521_reg_desc {
        u8 address;
        u8 device_mask;
};

static const struct rpr0521_reg_desc rpr0521_data_reg[] = {
        [RPR0521_CHAN_PXS]      = {
                .address        = RPR0521_REG_PXS_DATA,
                .device_mask    = RPR0521_MODE_PXS_MASK,
        },
        [RPR0521_CHAN_ALS_DATA0] = {
                .address        = RPR0521_REG_ALS_DATA0,
                .device_mask    = RPR0521_MODE_ALS_MASK,
        },
        [RPR0521_CHAN_ALS_DATA1] = {
                .address        = RPR0521_REG_ALS_DATA1,
                .device_mask    = RPR0521_MODE_ALS_MASK,
        },
};

static const struct rpr0521_gain_info {
        u8 reg;
        u8 mask;
        u8 shift;
        const struct rpr0521_gain *gain;
        int size;
} rpr0521_gain[] = {
        [RPR0521_CHAN_PXS] = {
                .reg    = RPR0521_REG_PXS_CTRL,
                .mask   = RPR0521_PXS_GAIN_MASK,
                .shift  = RPR0521_PXS_GAIN_SHIFT,
                .gain   = rpr0521_pxs_gain,
                .size   = ARRAY_SIZE(rpr0521_pxs_gain),
        },
        [RPR0521_CHAN_ALS_DATA0] = {
                .reg    = RPR0521_REG_ALS_CTRL,
                .mask   = RPR0521_ALS_DATA0_GAIN_MASK,
                .shift  = RPR0521_ALS_DATA0_GAIN_SHIFT,
                .gain   = rpr0521_als_gain,
                .size   = ARRAY_SIZE(rpr0521_als_gain),
        },
        [RPR0521_CHAN_ALS_DATA1] = {
                .reg    = RPR0521_REG_ALS_CTRL,
                .mask   = RPR0521_ALS_DATA1_GAIN_MASK,
                .shift  = RPR0521_ALS_DATA1_GAIN_SHIFT,
                .gain   = rpr0521_als_gain,
                .size   = ARRAY_SIZE(rpr0521_als_gain),
        },
};

struct rpr0521_samp_freq {
        int     als_hz;
        int     als_uhz;
        int     pxs_hz;
        int     pxs_uhz;
};

static const struct rpr0521_samp_freq rpr0521_samp_freq_i[13] = {
/*      {ALS, PXS},                W==currently writable option */
        {0, 0, 0, 0},           /* W0000, 0=standby */
        {0, 0, 100, 0},         /*  0001 */
        {0, 0, 25, 0},          /*  0010 */
        {0, 0, 10, 0},          /*  0011 */
        {0, 0, 2, 500000},      /*  0100 */
        {10, 0, 20, 0},         /*  0101 */
        {10, 0, 10, 0},         /* W0110 */
        {10, 0, 2, 500000},     /*  0111 */
        {2, 500000, 20, 0},     /*  1000, measurement 100ms, sleep 300ms */
        {2, 500000, 10, 0},     /*  1001, measurement 100ms, sleep 300ms */
        {2, 500000, 0, 0},      /*  1010, high sensitivity mode */
        {2, 500000, 2, 500000}, /* W1011, high sensitivity mode */
        {20, 0, 20, 0}  /* 1100, ALS_data x 0.5, see specification P.18 */
};

struct rpr0521_data {
        struct i2c_client *client;

        /* protect device params updates (e.g state, gain) */
        struct mutex lock;

        /* device active status */
        bool als_dev_en;
        bool pxs_dev_en;

        struct iio_trigger *drdy_trigger0;
        s64 irq_timestamp;

        /* optimize runtime pm ops - enable/disable device only if needed */
        bool als_ps_need_en;
        bool pxs_ps_need_en;
        bool als_need_dis;
        bool pxs_need_dis;

        struct regmap *regmap;
};

static IIO_CONST_ATTR(in_intensity_scale_available, RPR0521_ALS_SCALE_AVAIL);
static IIO_CONST_ATTR(in_proximity_scale_available, RPR0521_PXS_SCALE_AVAIL);

/*
 * Start with easy freq first, whole table of freq combinations is more
 * complicated.
 */
static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("2.5 10");

static struct attribute *rpr0521_attributes[] = {
        &iio_const_attr_in_intensity_scale_available.dev_attr.attr,
        &iio_const_attr_in_proximity_scale_available.dev_attr.attr,
        &iio_const_attr_sampling_frequency_available.dev_attr.attr,
        NULL,
};

static const struct attribute_group rpr0521_attribute_group = {
        .attrs = rpr0521_attributes,
};

/* Order of the channel data in buffer */
enum rpr0521_scan_index_order {
        RPR0521_CHAN_INDEX_PXS,
        RPR0521_CHAN_INDEX_BOTH,
        RPR0521_CHAN_INDEX_IR,
};

static const unsigned long rpr0521_available_scan_masks[] = {
        BIT(RPR0521_CHAN_INDEX_PXS) | BIT(RPR0521_CHAN_INDEX_BOTH) |
        BIT(RPR0521_CHAN_INDEX_IR),
        0
};

static const struct iio_chan_spec rpr0521_channels[] = {
        {
                .type = IIO_PROXIMITY,
                .address = RPR0521_CHAN_PXS,
                .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
                        BIT(IIO_CHAN_INFO_OFFSET) |
                        BIT(IIO_CHAN_INFO_SCALE),
                .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
                .scan_index = RPR0521_CHAN_INDEX_PXS,
                .scan_type = {
                        .sign = 'u',
                        .realbits = 16,
                        .storagebits = 16,
                        .endianness = IIO_LE,
                },
        },
        {
                .type = IIO_INTENSITY,
                .modified = 1,
                .address = RPR0521_CHAN_ALS_DATA0,
                .channel2 = IIO_MOD_LIGHT_BOTH,
                .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
                        BIT(IIO_CHAN_INFO_SCALE),
                .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
                .scan_index = RPR0521_CHAN_INDEX_BOTH,
                .scan_type = {
                        .sign = 'u',
                        .realbits = 16,
                        .storagebits = 16,
                        .endianness = IIO_LE,
                },
        },
        {
                .type = IIO_INTENSITY,
                .modified = 1,
                .address = RPR0521_CHAN_ALS_DATA1,
                .channel2 = IIO_MOD_LIGHT_IR,
                .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
                        BIT(IIO_CHAN_INFO_SCALE),
                .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
                .scan_index = RPR0521_CHAN_INDEX_IR,
                .scan_type = {
                        .sign = 'u',
                        .realbits = 16,
                        .storagebits = 16,
                        .endianness = IIO_LE,
                },
        },
};

static int rpr0521_als_enable(struct rpr0521_data *data, u8 status)
{
        int ret;

        ret = regmap_update_bits(data->regmap, RPR0521_REG_MODE_CTRL,
                                 RPR0521_MODE_ALS_MASK,
                                 status);
        if (ret < 0)
                return ret;

        if (status & RPR0521_MODE_ALS_MASK)
                data->als_dev_en = true;
        else
                data->als_dev_en = false;

        return 0;
}

static int rpr0521_pxs_enable(struct rpr0521_data *data, u8 status)
{
        int ret;

        ret = regmap_update_bits(data->regmap, RPR0521_REG_MODE_CTRL,
                                 RPR0521_MODE_PXS_MASK,
                                 status);
        if (ret < 0)
                return ret;

        if (status & RPR0521_MODE_PXS_MASK)
                data->pxs_dev_en = true;
        else
                data->pxs_dev_en = false;

        return 0;
}

/**
 * rpr0521_set_power_state - handles runtime PM state and sensors enabled status
 *
 * @data: rpr0521 device private data
 * @on: state to be set for devices in @device_mask
 * @device_mask: bitmask specifying for which device we need to update @on state
 *
 * Calls for this function must be balanced so that each ON should have matching
 * OFF. Otherwise pm usage_count gets out of sync.
 */
static int rpr0521_set_power_state(struct rpr0521_data *data, bool on,
                                   u8 device_mask)
{
#ifdef CONFIG_PM
        int ret;

        if (device_mask & RPR0521_MODE_ALS_MASK) {
                data->als_ps_need_en = on;
                data->als_need_dis = !on;
        }

        if (device_mask & RPR0521_MODE_PXS_MASK) {
                data->pxs_ps_need_en = on;
                data->pxs_need_dis = !on;
        }

        /*
         * On: _resume() is called only when we are suspended
         * Off: _suspend() is called after delay if _resume() is not
         * called before that.
         * Note: If either measurement is re-enabled before _suspend(),
         * both stay enabled until _suspend().
         */
        if (on) {
                ret = pm_runtime_get_sync(&data->client->dev);
        } else {
                pm_runtime_mark_last_busy(&data->client->dev);
                ret = pm_runtime_put_autosuspend(&data->client->dev);
        }
        if (ret < 0) {
                dev_err(&data->client->dev,
                        "Failed: rpr0521_set_power_state for %d, ret %d\n",
                        on, ret);
                if (on)
                        pm_runtime_put_noidle(&data->client->dev);

                return ret;
        }

        if (on) {
                /* If _resume() was not called, enable measurement now. */
                if (data->als_ps_need_en) {
                        ret = rpr0521_als_enable(data, RPR0521_MODE_ALS_ENABLE);
                        if (ret)
                                return ret;
                        data->als_ps_need_en = false;
                }

                if (data->pxs_ps_need_en) {
                        ret = rpr0521_pxs_enable(data, RPR0521_MODE_PXS_ENABLE);
                        if (ret)
                                return ret;
                        data->pxs_ps_need_en = false;
                }
        }
#endif
        return 0;
}

/* Interrupt register tells if this sensor caused the interrupt or not. */
static inline bool rpr0521_is_triggered(struct rpr0521_data *data)
{
        int ret;
        int reg;

        ret = regmap_read(data->regmap, RPR0521_REG_INTERRUPT, &reg);
        if (ret < 0)
                return false;   /* Reg read failed. */
        if (reg &
            (RPR0521_INTERRUPT_ALS_INT_STATUS_MASK |
            RPR0521_INTERRUPT_PS_INT_STATUS_MASK))
                return true;
        else
                return false;   /* Int not from this sensor. */
}

/* IRQ to trigger handler */
static irqreturn_t rpr0521_drdy_irq_handler(int irq, void *private)
{
        struct iio_dev *indio_dev = private;
        struct rpr0521_data *data = iio_priv(indio_dev);

        data->irq_timestamp = iio_get_time_ns(indio_dev);
        /*
         * We need to wake the thread to read the interrupt reg. It
         * is not possible to do that here because regmap_read takes a
         * mutex.
         */

        return IRQ_WAKE_THREAD;
}

static irqreturn_t rpr0521_drdy_irq_thread(int irq, void *private)
{
        struct iio_dev *indio_dev = private;
        struct rpr0521_data *data = iio_priv(indio_dev);

        if (rpr0521_is_triggered(data)) {
                iio_trigger_poll_chained(data->drdy_trigger0);
                return IRQ_HANDLED;
        }

        return IRQ_NONE;
}

static irqreturn_t rpr0521_trigger_consumer_store_time(int irq, void *p)
{
        struct iio_poll_func *pf = p;
        struct iio_dev *indio_dev = pf->indio_dev;

        /* Other trigger polls store time here. */
        if (!iio_trigger_using_own(indio_dev))
                pf->timestamp = iio_get_time_ns(indio_dev);

        return IRQ_WAKE_THREAD;
}

static irqreturn_t rpr0521_trigger_consumer_handler(int irq, void *p)
{
        struct iio_poll_func *pf = p;
        struct iio_dev *indio_dev = pf->indio_dev;
        struct rpr0521_data *data = iio_priv(indio_dev);
        int err;

        u8 buffer[16]; /* 3 16-bit channels + padding + ts */

        /* Use irq timestamp when reasonable. */
        if (iio_trigger_using_own(indio_dev) && data->irq_timestamp) {
                pf->timestamp = data->irq_timestamp;
                data->irq_timestamp = 0;
        }
        /* Other chained trigger polls get timestamp only here. */
        if (!pf->timestamp)
                pf->timestamp = iio_get_time_ns(indio_dev);

        err = regmap_bulk_read(data->regmap, RPR0521_REG_PXS_DATA,
                &buffer,
                (3 * 2) + 1);   /* 3 * 16-bit + (discarded) int clear reg. */
        if (!err)
                iio_push_to_buffers_with_timestamp(indio_dev,
                                                   buffer, pf->timestamp);
        else
                dev_err(&data->client->dev,
                        "Trigger consumer can't read from sensor.\n");
        pf->timestamp = 0;

        iio_trigger_notify_done(indio_dev->trig);

        return IRQ_HANDLED;
}

static int rpr0521_write_int_enable(struct rpr0521_data *data)
{
        int err;

        /* Interrupt after each measurement */
        err = regmap_update_bits(data->regmap, RPR0521_REG_PXS_CTRL,
                RPR0521_PXS_PERSISTENCE_MASK,
                RPR0521_PXS_PERSISTENCE_DRDY);
        if (err) {
                dev_err(&data->client->dev, "PS control reg write fail.\n");
                return -EBUSY;
                }

        /* Ignore latch and mode because of drdy */
        err = regmap_write(data->regmap, RPR0521_REG_INTERRUPT,
                RPR0521_INTERRUPT_INT_REASSERT_DISABLE |
                RPR0521_INTERRUPT_INT_TRIG_ALS_DISABLE |
                RPR0521_INTERRUPT_INT_TRIG_PS_ENABLE
                );
        if (err) {
                dev_err(&data->client->dev, "Interrupt setup write fail.\n");
                return -EBUSY;
                }

        return 0;
}

static int rpr0521_write_int_disable(struct rpr0521_data *data)
{
        /* Don't care of clearing mode, assert and latch. */
        return regmap_write(data->regmap, RPR0521_REG_INTERRUPT,
                                RPR0521_INTERRUPT_INT_TRIG_ALS_DISABLE |
                                RPR0521_INTERRUPT_INT_TRIG_PS_DISABLE
                                );
}

/*
 * Trigger producer enable / disable. Note that there will be trigs only when
 * measurement data is ready to be read.
 */
static int rpr0521_pxs_drdy_set_state(struct iio_trigger *trigger,
        bool enable_drdy)
{
        struct iio_dev *indio_dev = iio_trigger_get_drvdata(trigger);
        struct rpr0521_data *data = iio_priv(indio_dev);
        int err;

        if (enable_drdy)
                err = rpr0521_write_int_enable(data);
        else
                err = rpr0521_write_int_disable(data);
        if (err)
                dev_err(&data->client->dev, "rpr0521_pxs_drdy_set_state failed\n");

        return err;
}

static const struct iio_trigger_ops rpr0521_trigger_ops = {
        .set_trigger_state = rpr0521_pxs_drdy_set_state,
        };


static int rpr0521_buffer_preenable(struct iio_dev *indio_dev)
{
        int err;
        struct rpr0521_data *data = iio_priv(indio_dev);

        mutex_lock(&data->lock);
        err = rpr0521_set_power_state(data, true,
                (RPR0521_MODE_PXS_MASK | RPR0521_MODE_ALS_MASK));
        mutex_unlock(&data->lock);
        if (err)
                dev_err(&data->client->dev, "_buffer_preenable fail\n");

        return err;
}

static int rpr0521_buffer_postdisable(struct iio_dev *indio_dev)
{
        int err;
        struct rpr0521_data *data = iio_priv(indio_dev);

        mutex_lock(&data->lock);
        err = rpr0521_set_power_state(data, false,
                (RPR0521_MODE_PXS_MASK | RPR0521_MODE_ALS_MASK));
        mutex_unlock(&data->lock);
        if (err)
                dev_err(&data->client->dev, "_buffer_postdisable fail\n");

        return err;
}

static const struct iio_buffer_setup_ops rpr0521_buffer_setup_ops = {
        .preenable = rpr0521_buffer_preenable,
        .postenable = iio_triggered_buffer_postenable,
        .predisable = iio_triggered_buffer_predisable,
        .postdisable = rpr0521_buffer_postdisable,
};

static int rpr0521_get_gain(struct rpr0521_data *data, int chan,
                            int *val, int *val2)
{
        int ret, reg, idx;

        ret = regmap_read(data->regmap, rpr0521_gain[chan].reg, &reg);
        if (ret < 0)
                return ret;

        idx = (rpr0521_gain[chan].mask & reg) >> rpr0521_gain[chan].shift;
        *val = rpr0521_gain[chan].gain[idx].scale;
        *val2 = rpr0521_gain[chan].gain[idx].uscale;

        return 0;
}

static int rpr0521_set_gain(struct rpr0521_data *data, int chan,
                            int val, int val2)
{
        int i, idx = -EINVAL;

        /* get gain index */
        for (i = 0; i < rpr0521_gain[chan].size; i++)
                if (val == rpr0521_gain[chan].gain[i].scale &&
                    val2 == rpr0521_gain[chan].gain[i].uscale) {
                        idx = i;
                        break;
                }

        if (idx < 0)
                return idx;

        return regmap_update_bits(data->regmap, rpr0521_gain[chan].reg,
                                  rpr0521_gain[chan].mask,
                                  idx << rpr0521_gain[chan].shift);
}

static int rpr0521_read_samp_freq(struct rpr0521_data *data,
                                enum iio_chan_type chan_type,
                            int *val, int *val2)
{
        int reg, ret;

        ret = regmap_read(data->regmap, RPR0521_REG_MODE_CTRL, &reg);
        if (ret < 0)
                return ret;

        reg &= RPR0521_MODE_MEAS_TIME_MASK;
        if (reg >= ARRAY_SIZE(rpr0521_samp_freq_i))
                return -EINVAL;

        switch (chan_type) {
        case IIO_INTENSITY:
                *val = rpr0521_samp_freq_i[reg].als_hz;
                *val2 = rpr0521_samp_freq_i[reg].als_uhz;
                return 0;

        case IIO_PROXIMITY:
                *val = rpr0521_samp_freq_i[reg].pxs_hz;
                *val2 = rpr0521_samp_freq_i[reg].pxs_uhz;
                return 0;

        default:
                return -EINVAL;
        }
}

static int rpr0521_write_samp_freq_common(struct rpr0521_data *data,
                                enum iio_chan_type chan_type,
                                int val, int val2)
{
        int i;

        /*
         * Ignore channel
         * both pxs and als are setup only to same freq because of simplicity
         */
        switch (val) {
        case 0:
                i = 0;
                break;

        case 2:
                if (val2 != 500000)
                        return -EINVAL;

                i = 11;
                break;

        case 10:
                i = 6;
                break;

        default:
                return -EINVAL;
        }

        return regmap_update_bits(data->regmap,
                RPR0521_REG_MODE_CTRL,
                RPR0521_MODE_MEAS_TIME_MASK,
                i);
}

static int rpr0521_read_ps_offset(struct rpr0521_data *data, int *offset)
{
        int ret;
        __le16 buffer;

        ret = regmap_bulk_read(data->regmap,
                RPR0521_REG_PS_OFFSET_LSB, &buffer, sizeof(buffer));

        if (ret < 0) {
                dev_err(&data->client->dev, "Failed to read PS OFFSET register\n");
                return ret;
        }
        *offset = le16_to_cpu(buffer);

        return ret;
}

static int rpr0521_write_ps_offset(struct rpr0521_data *data, int offset)
{
        int ret;
        __le16 buffer;

        buffer = cpu_to_le16(offset & 0x3ff);
        ret = regmap_raw_write(data->regmap,
                RPR0521_REG_PS_OFFSET_LSB, &buffer, sizeof(buffer));

        if (ret < 0) {
                dev_err(&data->client->dev, "Failed to write PS OFFSET register\n");
                return ret;
        }

        return ret;
}

static int rpr0521_read_raw(struct iio_dev *indio_dev,
                            struct iio_chan_spec const *chan, int *val,
                            int *val2, long mask)
{
        struct rpr0521_data *data = iio_priv(indio_dev);
        int ret;
        int busy;
        u8 device_mask;
        __le16 raw_data;

        switch (mask) {
        case IIO_CHAN_INFO_RAW:
                if (chan->type != IIO_INTENSITY && chan->type != IIO_PROXIMITY)
                        return -EINVAL;

                busy = iio_device_claim_direct_mode(indio_dev);
                if (busy)
                        return -EBUSY;

                device_mask = rpr0521_data_reg[chan->address].device_mask;

                mutex_lock(&data->lock);
                ret = rpr0521_set_power_state(data, true, device_mask);
                if (ret < 0)
                        goto rpr0521_read_raw_out;

                ret = regmap_bulk_read(data->regmap,
                                       rpr0521_data_reg[chan->address].address,
                                       &raw_data, sizeof(raw_data));
                if (ret < 0) {
                        rpr0521_set_power_state(data, false, device_mask);
                        goto rpr0521_read_raw_out;
                }

                ret = rpr0521_set_power_state(data, false, device_mask);

rpr0521_read_raw_out:
                mutex_unlock(&data->lock);
                iio_device_release_direct_mode(indio_dev);
                if (ret < 0)
                        return ret;

                *val = le16_to_cpu(raw_data);

                return IIO_VAL_INT;

        case IIO_CHAN_INFO_SCALE:
                mutex_lock(&data->lock);
                ret = rpr0521_get_gain(data, chan->address, val, val2);
                mutex_unlock(&data->lock);
                if (ret < 0)
                        return ret;

                return IIO_VAL_INT_PLUS_MICRO;

        case IIO_CHAN_INFO_SAMP_FREQ:
                mutex_lock(&data->lock);
                ret = rpr0521_read_samp_freq(data, chan->type, val, val2);
                mutex_unlock(&data->lock);
                if (ret < 0)
                        return ret;

                return IIO_VAL_INT_PLUS_MICRO;

        case IIO_CHAN_INFO_OFFSET:
                mutex_lock(&data->lock);
                ret = rpr0521_read_ps_offset(data, val);
                mutex_unlock(&data->lock);
                if (ret < 0)
                        return ret;

                return IIO_VAL_INT;

        default:
                return -EINVAL;
        }
}

static int rpr0521_write_raw(struct iio_dev *indio_dev,
                             struct iio_chan_spec const *chan, int val,
                             int val2, long mask)
{
        struct rpr0521_data *data = iio_priv(indio_dev);
        int ret;

        switch (mask) {
        case IIO_CHAN_INFO_SCALE:
                mutex_lock(&data->lock);
                ret = rpr0521_set_gain(data, chan->address, val, val2);
                mutex_unlock(&data->lock);

                return ret;

        case IIO_CHAN_INFO_SAMP_FREQ:
                mutex_lock(&data->lock);
                ret = rpr0521_write_samp_freq_common(data, chan->type,
                                                     val, val2);
                mutex_unlock(&data->lock);

                return ret;

        case IIO_CHAN_INFO_OFFSET:
                mutex_lock(&data->lock);
                ret = rpr0521_write_ps_offset(data, val);
                mutex_unlock(&data->lock);

                return ret;

        default:
                return -EINVAL;
        }
}

static const struct iio_info rpr0521_info = {
        .read_raw       = rpr0521_read_raw,
        .write_raw      = rpr0521_write_raw,
        .attrs          = &rpr0521_attribute_group,
};

static int rpr0521_init(struct rpr0521_data *data)
{
        int ret;
        int id;

        ret = regmap_read(data->regmap, RPR0521_REG_ID, &id);
        if (ret < 0) {
                dev_err(&data->client->dev, "Failed to read REG_ID register\n");
                return ret;
        }

        if (id != RPR0521_MANUFACT_ID) {
                dev_err(&data->client->dev, "Wrong id, got %x, expected %x\n",
                        id, RPR0521_MANUFACT_ID);
                return -ENODEV;
        }

        /* set default measurement time - 100 ms for both ALS and PS */
        ret = regmap_update_bits(data->regmap, RPR0521_REG_MODE_CTRL,
                                 RPR0521_MODE_MEAS_TIME_MASK,
                                 RPR0521_DEFAULT_MEAS_TIME);
        if (ret) {
                pr_err("regmap_update_bits returned %d\n", ret);
                return ret;
        }

#ifndef CONFIG_PM
        ret = rpr0521_als_enable(data, RPR0521_MODE_ALS_ENABLE);
        if (ret < 0)
                return ret;
        ret = rpr0521_pxs_enable(data, RPR0521_MODE_PXS_ENABLE);
        if (ret < 0)
                return ret;
#endif

        data->irq_timestamp = 0;

        return 0;
}

static int rpr0521_poweroff(struct rpr0521_data *data)
{
        int ret;
        int tmp;

        ret = regmap_update_bits(data->regmap, RPR0521_REG_MODE_CTRL,
                                 RPR0521_MODE_ALS_MASK |
                                 RPR0521_MODE_PXS_MASK,
                                 RPR0521_MODE_ALS_DISABLE |
                                 RPR0521_MODE_PXS_DISABLE);
        if (ret < 0)
                return ret;

        data->als_dev_en = false;
        data->pxs_dev_en = false;

        /*
         * Int pin keeps state after power off. Set pin to high impedance
         * mode to prevent power drain.
         */
        ret = regmap_read(data->regmap, RPR0521_REG_INTERRUPT, &tmp);
        if (ret) {
                dev_err(&data->client->dev, "Failed to reset int pin.\n");
                return ret;
        }

        return 0;
}

static bool rpr0521_is_volatile_reg(struct device *dev, unsigned int reg)
{
        switch (reg) {
        case RPR0521_REG_MODE_CTRL:
        case RPR0521_REG_ALS_CTRL:
        case RPR0521_REG_PXS_CTRL:
                return false;
        default:
                return true;
        }
}

static const struct regmap_config rpr0521_regmap_config = {
        .name           = RPR0521_REGMAP_NAME,

        .reg_bits       = 8,
        .val_bits       = 8,

        .max_register   = RPR0521_REG_ID,
        .cache_type     = REGCACHE_RBTREE,
        .volatile_reg   = rpr0521_is_volatile_reg,
};

static int rpr0521_probe(struct i2c_client *client,
                         const struct i2c_device_id *id)
{
        struct rpr0521_data *data;
        struct iio_dev *indio_dev;
        struct regmap *regmap;
        int ret;

        indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
        if (!indio_dev)
                return -ENOMEM;

        regmap = devm_regmap_init_i2c(client, &rpr0521_regmap_config);
        if (IS_ERR(regmap)) {
                dev_err(&client->dev, "regmap_init failed!\n");
                return PTR_ERR(regmap);
        }

        data = iio_priv(indio_dev);
        i2c_set_clientdata(client, indio_dev);
        data->client = client;
        data->regmap = regmap;

        mutex_init(&data->lock);

        indio_dev->dev.parent = &client->dev;
        indio_dev->info = &rpr0521_info;
        indio_dev->name = RPR0521_DRV_NAME;
        indio_dev->channels = rpr0521_channels;
        indio_dev->num_channels = ARRAY_SIZE(rpr0521_channels);
        indio_dev->modes = INDIO_DIRECT_MODE;

        ret = rpr0521_init(data);
        if (ret < 0) {
                dev_err(&client->dev, "rpr0521 chip init failed\n");
                return ret;
        }

        ret = pm_runtime_set_active(&client->dev);
        if (ret < 0)
                goto err_poweroff;

        pm_runtime_enable(&client->dev);
        pm_runtime_set_autosuspend_delay(&client->dev, RPR0521_SLEEP_DELAY_MS);
        pm_runtime_use_autosuspend(&client->dev);

        /*
         * If sensor write/read is needed in _probe after _use_autosuspend,
         * sensor needs to be _resumed first using rpr0521_set_power_state().
         */

        /* IRQ to trigger setup */
        if (client->irq) {
                /* Trigger0 producer setup */
                data->drdy_trigger0 = devm_iio_trigger_alloc(
                        indio_dev->dev.parent,
                        "%s-dev%d", indio_dev->name, indio_dev->id);
                if (!data->drdy_trigger0) {
                        ret = -ENOMEM;
                        goto err_pm_disable;
                }
                data->drdy_trigger0->dev.parent = indio_dev->dev.parent;
                data->drdy_trigger0->ops = &rpr0521_trigger_ops;
                indio_dev->available_scan_masks = rpr0521_available_scan_masks;
                iio_trigger_set_drvdata(data->drdy_trigger0, indio_dev);

                /* Ties irq to trigger producer handler. */
                ret = devm_request_threaded_irq(&client->dev, client->irq,
                        rpr0521_drdy_irq_handler, rpr0521_drdy_irq_thread,
                        IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
                        RPR0521_IRQ_NAME, indio_dev);
                if (ret < 0) {

                        dev_err(&client->dev, "request irq %d for trigger0 failed\n",
                                client->irq);
                        goto err_pm_disable;
                        }

                ret = devm_iio_trigger_register(indio_dev->dev.parent,
                                                data->drdy_trigger0);
                if (ret) {
                        dev_err(&client->dev, "iio trigger register failed\n");
                        goto err_pm_disable;
                }

                /*
                 * Now whole pipe from physical interrupt (irq defined by
                 * devicetree to device) to trigger0 output is set up.
                 */

                /* Trigger consumer setup */
                ret = devm_iio_triggered_buffer_setup(indio_dev->dev.parent,
                        indio_dev,
                        rpr0521_trigger_consumer_store_time,
                        rpr0521_trigger_consumer_handler,
                        &rpr0521_buffer_setup_ops);
                if (ret < 0) {
                        dev_err(&client->dev, "iio triggered buffer setup failed\n");
                        goto err_pm_disable;
                }
        }

        ret = iio_device_register(indio_dev);
        if (ret)
                goto err_pm_disable;

        return 0;

err_pm_disable:
        pm_runtime_disable(&client->dev);
        pm_runtime_set_suspended(&client->dev);
        pm_runtime_put_noidle(&client->dev);
err_poweroff:
        rpr0521_poweroff(data);

        return ret;
}

static int rpr0521_remove(struct i2c_client *client)
{
        struct iio_dev *indio_dev = i2c_get_clientdata(client);

        iio_device_unregister(indio_dev);

        pm_runtime_disable(&client->dev);
        pm_runtime_set_suspended(&client->dev);
        pm_runtime_put_noidle(&client->dev);

        rpr0521_poweroff(iio_priv(indio_dev));

        return 0;
}

#ifdef CONFIG_PM
static int rpr0521_runtime_suspend(struct device *dev)
{
        struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
        struct rpr0521_data *data = iio_priv(indio_dev);
        int ret;

        mutex_lock(&data->lock);
        /* If measurements are enabled, enable them on resume */
        if (!data->als_need_dis)
                data->als_ps_need_en = data->als_dev_en;
        if (!data->pxs_need_dis)
                data->pxs_ps_need_en = data->pxs_dev_en;

        /* disable channels and sets {als,pxs}_dev_en to false */
        ret = rpr0521_poweroff(data);
        regcache_mark_dirty(data->regmap);
        mutex_unlock(&data->lock);

        return ret;
}

static int rpr0521_runtime_resume(struct device *dev)
{
        struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
        struct rpr0521_data *data = iio_priv(indio_dev);
        int ret;

        regcache_sync(data->regmap);
        if (data->als_ps_need_en) {
                ret = rpr0521_als_enable(data, RPR0521_MODE_ALS_ENABLE);
                if (ret < 0)
                        return ret;
                data->als_ps_need_en = false;
        }

        if (data->pxs_ps_need_en) {
                ret = rpr0521_pxs_enable(data, RPR0521_MODE_PXS_ENABLE);
                if (ret < 0)
                        return ret;
                data->pxs_ps_need_en = false;
        }
        msleep(100);    //wait for first measurement result

        return 0;
}
#endif

static const struct dev_pm_ops rpr0521_pm_ops = {
        SET_RUNTIME_PM_OPS(rpr0521_runtime_suspend,
                           rpr0521_runtime_resume, NULL)
};

static const struct acpi_device_id rpr0521_acpi_match[] = {
        {"RPR0521", 0},
        { }
};
MODULE_DEVICE_TABLE(acpi, rpr0521_acpi_match);

static const struct i2c_device_id rpr0521_id[] = {
        {"rpr0521", 0},
        { }
};

MODULE_DEVICE_TABLE(i2c, rpr0521_id);

static struct i2c_driver rpr0521_driver = {
        .driver = {
                .name   = RPR0521_DRV_NAME,
                .pm     = &rpr0521_pm_ops,
                .acpi_match_table = ACPI_PTR(rpr0521_acpi_match),
        },
        .probe          = rpr0521_probe,
        .remove         = rpr0521_remove,
        .id_table       = rpr0521_id,
};

module_i2c_driver(rpr0521_driver);

MODULE_AUTHOR("Daniel Baluta <daniel.baluta@intel.com>");
MODULE_DESCRIPTION("RPR0521 ROHM Ambient Light and Proximity Sensor driver");
MODULE_LICENSE("GPL v2");