/*
 * This file is part of the APDS990x sensor driver.
 * Chip is combined proximity and ambient light sensor.
 *
 * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
 *
 * Contact: Samu Onkalo <samu.p.onkalo@nokia.com>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * version 2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA
 *
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/mutex.h>
#include <linux/regulator/consumer.h>
#include <linux/pm_runtime.h>
#include <linux/delay.h>
#include <linux/wait.h>
#include <linux/slab.h>
#include <linux/platform_data/apds990x.h>

/* Register map */
#define APDS990X_ENABLE  0x00 /* Enable of states and interrupts */
#define APDS990X_ATIME   0x01 /* ALS ADC time  */
#define APDS990X_PTIME   0x02 /* Proximity ADC time  */
#define APDS990X_WTIME   0x03 /* Wait time  */
#define APDS990X_AILTL   0x04 /* ALS interrupt low threshold low byte */
#define APDS990X_AILTH   0x05 /* ALS interrupt low threshold hi byte */
#define APDS990X_AIHTL   0x06 /* ALS interrupt hi threshold low byte */
#define APDS990X_AIHTH   0x07 /* ALS interrupt hi threshold hi byte */
#define APDS990X_PILTL   0x08 /* Proximity interrupt low threshold low byte */
#define APDS990X_PILTH   0x09 /* Proximity interrupt low threshold hi byte */
#define APDS990X_PIHTL   0x0a /* Proximity interrupt hi threshold low byte */
#define APDS990X_PIHTH   0x0b /* Proximity interrupt hi threshold hi byte */
#define APDS990X_PERS    0x0c /* Interrupt persistence filters */
#define APDS990X_CONFIG  0x0d /* Configuration */
#define APDS990X_PPCOUNT 0x0e /* Proximity pulse count */
#define APDS990X_CONTROL 0x0f /* Gain control register */
#define APDS990X_REV     0x11 /* Revision Number */
#define APDS990X_ID      0x12 /* Device ID */
#define APDS990X_STATUS  0x13 /* Device status */
#define APDS990X_CDATAL  0x14 /* Clear ADC low data register */
#define APDS990X_CDATAH  0x15 /* Clear ADC high data register */
#define APDS990X_IRDATAL 0x16 /* IR ADC low data register */
#define APDS990X_IRDATAH 0x17 /* IR ADC high data register */
#define APDS990X_PDATAL  0x18 /* Proximity ADC low data register */
#define APDS990X_PDATAH  0x19 /* Proximity ADC high data register */

/* Control */
#define APDS990X_MAX_AGAIN      3

/* Enable register */
#define APDS990X_EN_PIEN        (0x1 << 5)
#define APDS990X_EN_AIEN        (0x1 << 4)
#define APDS990X_EN_WEN         (0x1 << 3)
#define APDS990X_EN_PEN         (0x1 << 2)
#define APDS990X_EN_AEN         (0x1 << 1)
#define APDS990X_EN_PON         (0x1 << 0)
#define APDS990X_EN_DISABLE_ALL 0

/* Status register */
#define APDS990X_ST_PINT        (0x1 << 5)
#define APDS990X_ST_AINT        (0x1 << 4)

/* I2C access types */
#define APDS990x_CMD_TYPE_MASK  (0x03 << 5)
#define APDS990x_CMD_TYPE_RB    (0x00 << 5) /* Repeated byte */
#define APDS990x_CMD_TYPE_INC   (0x01 << 5) /* Auto increment */
#define APDS990x_CMD_TYPE_SPE   (0x03 << 5) /* Special function */

#define APDS990x_ADDR_SHIFT     0
#define APDS990x_CMD            0x80

/* Interrupt ack commands */
#define APDS990X_INT_ACK_ALS    0x6
#define APDS990X_INT_ACK_PS     0x5
#define APDS990X_INT_ACK_BOTH   0x7

/* ptime */
#define APDS990X_PTIME_DEFAULT  0xff /* Recommended conversion time 2.7ms*/

/* wtime */
#define APDS990X_WTIME_DEFAULT  0xee /* ~50ms wait time */

#define APDS990X_TIME_TO_ADC    1024 /* One timetick as ADC count value */

/* Persistence */
#define APDS990X_APERS_SHIFT    0
#define APDS990X_PPERS_SHIFT    4

/* Supported ID:s */
#define APDS990X_ID_0           0x0
#define APDS990X_ID_4           0x4
#define APDS990X_ID_29          0x29

/* pgain and pdiode settings */
#define APDS_PGAIN_1X          0x0
#define APDS_PDIODE_IR         0x2

#define APDS990X_LUX_OUTPUT_SCALE 10

/* Reverse chip factors for threshold calculation */
struct reverse_factors {
        u32 afactor;
        int cf1;
        int irf1;
        int cf2;
        int irf2;
};

struct apds990x_chip {
        struct apds990x_platform_data   *pdata;
        struct i2c_client               *client;
        struct mutex                    mutex; /* avoid parallel access */
        struct regulator_bulk_data      regs[2];
        wait_queue_head_t               wait;

        int     prox_en;
        bool    prox_continuous_mode;
        bool    lux_wait_fresh_res;

        /* Chip parameters */
        struct  apds990x_chip_factors   cf;
        struct  reverse_factors         rcf;
        u16     atime;          /* als integration time */
        u16     arate;          /* als reporting rate */
        u16     a_max_result;   /* Max possible ADC value with current atime */
        u8      again_meas;     /* Gain used in last measurement */
        u8      again_next;     /* Next calculated gain */
        u8      pgain;
        u8      pdiode;
        u8      pdrive;
        u8      lux_persistence;
        u8      prox_persistence;

        u32     lux_raw;
        u32     lux;
        u16     lux_clear;
        u16     lux_ir;
        u16     lux_calib;
        u32     lux_thres_hi;
        u32     lux_thres_lo;

        u32     prox_thres;
        u16     prox_data;
        u16     prox_calib;

        char    chipname[10];
        u8      revision;
};

#define APDS_CALIB_SCALER               8192
#define APDS_LUX_NEUTRAL_CALIB_VALUE    (1 * APDS_CALIB_SCALER)
#define APDS_PROX_NEUTRAL_CALIB_VALUE   (1 * APDS_CALIB_SCALER)

#define APDS_PROX_DEF_THRES             600
#define APDS_PROX_HYSTERESIS            50
#define APDS_LUX_DEF_THRES_HI           101
#define APDS_LUX_DEF_THRES_LO           100
#define APDS_DEFAULT_PROX_PERS          1

#define APDS_TIMEOUT                    2000
#define APDS_STARTUP_DELAY              25000 /* us */
#define APDS_RANGE                      65535
#define APDS_PROX_RANGE                 1023
#define APDS_LUX_GAIN_LO_LIMIT          100
#define APDS_LUX_GAIN_LO_LIMIT_STRICT   25

#define TIMESTEP                        87 /* 2.7ms is about 87 / 32 */
#define TIME_STEP_SCALER                32

#define APDS_LUX_AVERAGING_TIME         50 /* tolerates 50/60Hz ripple */
#define APDS_LUX_DEFAULT_RATE           200

static const u8 again[] = {1, 8, 16, 120}; /* ALS gain steps */

/* Following two tables must match i.e 10Hz rate means 1 as persistence value */
static const u16 arates_hz[] = {10, 5, 2, 1};
static const u8 apersis[] = {1, 2, 4, 5};

/* Regulators */
static const char reg_vcc[] = "Vdd";
static const char reg_vled[] = "Vled";

static int apds990x_read_byte(struct apds990x_chip *chip, u8 reg, u8 *data)
{
        struct i2c_client *client = chip->client;
        s32 ret;

        reg &= ~APDS990x_CMD_TYPE_MASK;
        reg |= APDS990x_CMD | APDS990x_CMD_TYPE_RB;

        ret = i2c_smbus_read_byte_data(client, reg);
        *data = ret;
        return (int)ret;
}

static int apds990x_read_word(struct apds990x_chip *chip, u8 reg, u16 *data)
{
        struct i2c_client *client = chip->client;
        s32 ret;

        reg &= ~APDS990x_CMD_TYPE_MASK;
        reg |= APDS990x_CMD | APDS990x_CMD_TYPE_INC;

        ret = i2c_smbus_read_word_data(client, reg);
        *data = ret;
        return (int)ret;
}

static int apds990x_write_byte(struct apds990x_chip *chip, u8 reg, u8 data)
{
        struct i2c_client *client = chip->client;
        s32 ret;

        reg &= ~APDS990x_CMD_TYPE_MASK;
        reg |= APDS990x_CMD | APDS990x_CMD_TYPE_RB;

        ret = i2c_smbus_write_byte_data(client, reg, data);
        return (int)ret;
}

static int apds990x_write_word(struct apds990x_chip *chip, u8 reg, u16 data)
{
        struct i2c_client *client = chip->client;
        s32 ret;

        reg &= ~APDS990x_CMD_TYPE_MASK;
        reg |= APDS990x_CMD | APDS990x_CMD_TYPE_INC;

        ret = i2c_smbus_write_word_data(client, reg, data);
        return (int)ret;
}

static int apds990x_mode_on(struct apds990x_chip *chip)
{
        /* ALS is mandatory, proximity optional */
        u8 reg = APDS990X_EN_AIEN | APDS990X_EN_PON | APDS990X_EN_AEN |
                APDS990X_EN_WEN;

        if (chip->prox_en)
                reg |= APDS990X_EN_PIEN | APDS990X_EN_PEN;

        return apds990x_write_byte(chip, APDS990X_ENABLE, reg);
}

static u16 apds990x_lux_to_threshold(struct apds990x_chip *chip, u32 lux)
{
        u32 thres;
        u32 cpl;
        u32 ir;

        if (lux == 0)
                return 0;
        else if (lux == APDS_RANGE)
                return APDS_RANGE;

        /*
         * Reported LUX value is a combination of the IR and CLEAR channel
         * values. However, interrupt threshold is only for clear channel.
         * This function approximates needed HW threshold value for a given
         * LUX value in the current lightning type.
         * IR level compared to visible light varies heavily depending on the
         * source of the light
         *
         * Calculate threshold value for the next measurement period.
         * Math: threshold = lux * cpl where
         * cpl = atime * again / (glass_attenuation * device_factor)
         * (count-per-lux)
         *
         * First remove calibration. Division by four is to avoid overflow
         */
        lux = lux * (APDS_CALIB_SCALER / 4) / (chip->lux_calib / 4);

        /* Multiplication by 64 is to increase accuracy */
        cpl = ((u32)chip->atime * (u32)again[chip->again_next] *
                APDS_PARAM_SCALE * 64) / (chip->cf.ga * chip->cf.df);

        thres = lux * cpl / 64;
        /*
         * Convert IR light from the latest result to match with
         * new gain step. This helps to adapt with the current
         * source of light.
         */
        ir = (u32)chip->lux_ir * (u32)again[chip->again_next] /
                (u32)again[chip->again_meas];

        /*
         * Compensate count with IR light impact
         * IAC1 > IAC2 (see apds990x_get_lux for formulas)
         */
        if (chip->lux_clear * APDS_PARAM_SCALE >=
                chip->rcf.afactor * chip->lux_ir)
                thres = (chip->rcf.cf1 * thres + chip->rcf.irf1 * ir) /
                        APDS_PARAM_SCALE;
        else
                thres = (chip->rcf.cf2 * thres + chip->rcf.irf2 * ir) /
                        APDS_PARAM_SCALE;

        if (thres >= chip->a_max_result)
                thres = chip->a_max_result - 1;
        return thres;
}

static inline int apds990x_set_atime(struct apds990x_chip *chip, u32 time_ms)
{
        u8 reg_value;

        chip->atime = time_ms;
        /* Formula is specified in the data sheet */
        reg_value = 256 - ((time_ms * TIME_STEP_SCALER) / TIMESTEP);
        /* Calculate max ADC value for given integration time */
        chip->a_max_result = (u16)(256 - reg_value) * APDS990X_TIME_TO_ADC;
        return apds990x_write_byte(chip, APDS990X_ATIME, reg_value);
}

/* Called always with mutex locked */
static int apds990x_refresh_pthres(struct apds990x_chip *chip, int data)
{
        int ret, lo, hi;

        /* If the chip is not in use, don't try to access it */
        if (pm_runtime_suspended(&chip->client->dev))
                return 0;

        if (data < chip->prox_thres) {
                lo = 0;
                hi = chip->prox_thres;
        } else {
                lo = chip->prox_thres - APDS_PROX_HYSTERESIS;
                if (chip->prox_continuous_mode)
                        hi = chip->prox_thres;
                else
                        hi = APDS_RANGE;
        }

        ret = apds990x_write_word(chip, APDS990X_PILTL, lo);
        ret |= apds990x_write_word(chip, APDS990X_PIHTL, hi);
        return ret;
}

/* Called always with mutex locked */
static int apds990x_refresh_athres(struct apds990x_chip *chip)
{
        int ret;
        /* If the chip is not in use, don't try to access it */
        if (pm_runtime_suspended(&chip->client->dev))
                return 0;

        ret = apds990x_write_word(chip, APDS990X_AILTL,
                        apds990x_lux_to_threshold(chip, chip->lux_thres_lo));
        ret |= apds990x_write_word(chip, APDS990X_AIHTL,
                        apds990x_lux_to_threshold(chip, chip->lux_thres_hi));

        return ret;
}

/* Called always with mutex locked */
static void apds990x_force_a_refresh(struct apds990x_chip *chip)
{
        /* This will force ALS interrupt after the next measurement. */
        apds990x_write_word(chip, APDS990X_AILTL, APDS_LUX_DEF_THRES_LO);
        apds990x_write_word(chip, APDS990X_AIHTL, APDS_LUX_DEF_THRES_HI);
}

/* Called always with mutex locked */
static void apds990x_force_p_refresh(struct apds990x_chip *chip)
{
        /* This will force proximity interrupt after the next measurement. */
        apds990x_write_word(chip, APDS990X_PILTL, APDS_PROX_DEF_THRES - 1);
        apds990x_write_word(chip, APDS990X_PIHTL, APDS_PROX_DEF_THRES);
}

/* Called always with mutex locked */
static int apds990x_calc_again(struct apds990x_chip *chip)
{
        int curr_again = chip->again_meas;
        int next_again = chip->again_meas;
        int ret = 0;

        /* Calculate suitable als gain */
        if (chip->lux_clear == chip->a_max_result)
                next_again -= 2; /* ALS saturated. Decrease gain by 2 steps */
        else if (chip->lux_clear > chip->a_max_result / 2)
                next_again--;
        else if (chip->lux_clear < APDS_LUX_GAIN_LO_LIMIT_STRICT)
                next_again += 2; /* Too dark. Increase gain by 2 steps */
        else if (chip->lux_clear < APDS_LUX_GAIN_LO_LIMIT)
                next_again++;

        /* Limit gain to available range */
        if (next_again < 0)
                next_again = 0;
        else if (next_again > APDS990X_MAX_AGAIN)
                next_again = APDS990X_MAX_AGAIN;

        /* Let's check can we trust the measured result */
        if (chip->lux_clear == chip->a_max_result)
                /* Result can be totally garbage due to saturation */
                ret = -ERANGE;
        else if (next_again != curr_again &&
                chip->lux_clear < APDS_LUX_GAIN_LO_LIMIT_STRICT)
                /*
                 * Gain is changed and measurement result is very small.
                 * Result can be totally garbage due to underflow
                 */
                ret = -ERANGE;

        chip->again_next = next_again;
        apds990x_write_byte(chip, APDS990X_CONTROL,
                        (chip->pdrive << 6) |
                        (chip->pdiode << 4) |
                        (chip->pgain << 2) |
                        (chip->again_next << 0));

        /*
         * Error means bad result -> re-measurement is needed. The forced
         * refresh uses fastest possible persistence setting to get result
         * as soon as possible.
         */
        if (ret < 0)
                apds990x_force_a_refresh(chip);
        else
                apds990x_refresh_athres(chip);

        return ret;
}

/* Called always with mutex locked */
static int apds990x_get_lux(struct apds990x_chip *chip, int clear, int ir)
{
        int iac, iac1, iac2; /* IR adjusted counts */
        u32 lpc; /* Lux per count */

        /* Formulas:
         * iac1 = CF1 * CLEAR_CH - IRF1 * IR_CH
         * iac2 = CF2 * CLEAR_CH - IRF2 * IR_CH
         */
        iac1 = (chip->cf.cf1 * clear - chip->cf.irf1 * ir) / APDS_PARAM_SCALE;
        iac2 = (chip->cf.cf2 * clear - chip->cf.irf2 * ir) / APDS_PARAM_SCALE;

        iac = max(iac1, iac2);
        iac = max(iac, 0);

        lpc = APDS990X_LUX_OUTPUT_SCALE * (chip->cf.df * chip->cf.ga) /
                (u32)(again[chip->again_meas] * (u32)chip->atime);

        return (iac * lpc) / APDS_PARAM_SCALE;
}

static int apds990x_ack_int(struct apds990x_chip *chip, u8 mode)
{
        struct i2c_client *client = chip->client;
        s32 ret;
        u8 reg = APDS990x_CMD | APDS990x_CMD_TYPE_SPE;

        switch (mode & (APDS990X_ST_AINT | APDS990X_ST_PINT)) {
        case APDS990X_ST_AINT:
                reg |= APDS990X_INT_ACK_ALS;
                break;
        case APDS990X_ST_PINT:
                reg |= APDS990X_INT_ACK_PS;
                break;
        default:
                reg |= APDS990X_INT_ACK_BOTH;
                break;
        }

        ret = i2c_smbus_read_byte_data(client, reg);
        return (int)ret;
}

static irqreturn_t apds990x_irq(int irq, void *data)
{
        struct apds990x_chip *chip = data;
        u8 status;

        apds990x_read_byte(chip, APDS990X_STATUS, &status);
        apds990x_ack_int(chip, status);

        mutex_lock(&chip->mutex);
        if (!pm_runtime_suspended(&chip->client->dev)) {
                if (status & APDS990X_ST_AINT) {
                        apds990x_read_word(chip, APDS990X_CDATAL,
                                        &chip->lux_clear);
                        apds990x_read_word(chip, APDS990X_IRDATAL,
                                        &chip->lux_ir);
                        /* Store used gain for calculations */
                        chip->again_meas = chip->again_next;

                        chip->lux_raw = apds990x_get_lux(chip,
                                                        chip->lux_clear,
                                                        chip->lux_ir);

                        if (apds990x_calc_again(chip) == 0) {
                                /* Result is valid */
                                chip->lux = chip->lux_raw;
                                chip->lux_wait_fresh_res = false;
                                wake_up(&chip->wait);
                                sysfs_notify(&chip->client->dev.kobj,
                                        NULL, "lux0_input");
                        }
                }

                if ((status & APDS990X_ST_PINT) && chip->prox_en) {
                        u16 clr_ch;

                        apds990x_read_word(chip, APDS990X_CDATAL, &clr_ch);
                        /*
                         * If ALS channel is saturated at min gain,
                         * proximity gives false posivite values.
                         * Just ignore them.
                         */
                        if (chip->again_meas == 0 &&
                                clr_ch == chip->a_max_result)
                                chip->prox_data = 0;
                        else
                                apds990x_read_word(chip,
                                                APDS990X_PDATAL,
                                                &chip->prox_data);

                        apds990x_refresh_pthres(chip, chip->prox_data);
                        if (chip->prox_data < chip->prox_thres)
                                chip->prox_data = 0;
                        else if (!chip->prox_continuous_mode)
                                chip->prox_data = APDS_PROX_RANGE;
                        sysfs_notify(&chip->client->dev.kobj,
                                NULL, "prox0_raw");
                }
        }
        mutex_unlock(&chip->mutex);
        return IRQ_HANDLED;
}

static int apds990x_configure(struct apds990x_chip *chip)
{
        /* It is recommended to use disabled mode during these operations */
        apds990x_write_byte(chip, APDS990X_ENABLE, APDS990X_EN_DISABLE_ALL);

        /* conversion and wait times for different state machince states */
        apds990x_write_byte(chip, APDS990X_PTIME, APDS990X_PTIME_DEFAULT);
        apds990x_write_byte(chip, APDS990X_WTIME, APDS990X_WTIME_DEFAULT);
        apds990x_set_atime(chip, APDS_LUX_AVERAGING_TIME);

        apds990x_write_byte(chip, APDS990X_CONFIG, 0);

        /* Persistence levels */
        apds990x_write_byte(chip, APDS990X_PERS,
                        (chip->lux_persistence << APDS990X_APERS_SHIFT) |
                        (chip->prox_persistence << APDS990X_PPERS_SHIFT));

        apds990x_write_byte(chip, APDS990X_PPCOUNT, chip->pdata->ppcount);

        /* Start with relatively small gain */
        chip->again_meas = 1;
        chip->again_next = 1;
        apds990x_write_byte(chip, APDS990X_CONTROL,
                        (chip->pdrive << 6) |
                        (chip->pdiode << 4) |
                        (chip->pgain << 2) |
                        (chip->again_next << 0));
        return 0;
}

static int apds990x_detect(struct apds990x_chip *chip)
{
        struct i2c_client *client = chip->client;
        int ret;
        u8 id;

        ret = apds990x_read_byte(chip, APDS990X_ID, &id);
        if (ret < 0) {
                dev_err(&client->dev, "ID read failed\n");
                return ret;
        }

        ret = apds990x_read_byte(chip, APDS990X_REV, &chip->revision);
        if (ret < 0) {
                dev_err(&client->dev, "REV read failed\n");
                return ret;
        }

        switch (id) {
        case APDS990X_ID_0:
        case APDS990X_ID_4:
        case APDS990X_ID_29:
                snprintf(chip->chipname, sizeof(chip->chipname), "APDS-990x");
                break;
        default:
                ret = -ENODEV;
                break;
        }
        return ret;
}

#ifdef CONFIG_PM
static int apds990x_chip_on(struct apds990x_chip *chip)
{
        int err  = regulator_bulk_enable(ARRAY_SIZE(chip->regs),
                                        chip->regs);
        if (err < 0)
                return err;

        usleep_range(APDS_STARTUP_DELAY, 2 * APDS_STARTUP_DELAY);

        /* Refresh all configs in case of regulators were off */
        chip->prox_data = 0;
        apds990x_configure(chip);
        apds990x_mode_on(chip);
        return 0;
}
#endif

static int apds990x_chip_off(struct apds990x_chip *chip)
{
        apds990x_write_byte(chip, APDS990X_ENABLE, APDS990X_EN_DISABLE_ALL);
        regulator_bulk_disable(ARRAY_SIZE(chip->regs), chip->regs);
        return 0;
}

static ssize_t apds990x_lux_show(struct device *dev,
                                 struct device_attribute *attr, char *buf)
{
        struct apds990x_chip *chip = dev_get_drvdata(dev);
        ssize_t ret;
        u32 result;
        long timeout;

        if (pm_runtime_suspended(dev))
                return -EIO;

        timeout = wait_event_interruptible_timeout(chip->wait,
                                                !chip->lux_wait_fresh_res,
                                                msecs_to_jiffies(APDS_TIMEOUT));
        if (!timeout)
                return -EIO;

        mutex_lock(&chip->mutex);
        result = (chip->lux * chip->lux_calib) / APDS_CALIB_SCALER;
        if (result > (APDS_RANGE * APDS990X_LUX_OUTPUT_SCALE))
                result = APDS_RANGE * APDS990X_LUX_OUTPUT_SCALE;

        ret = sprintf(buf, "%d.%d\n",
                result / APDS990X_LUX_OUTPUT_SCALE,
                result % APDS990X_LUX_OUTPUT_SCALE);
        mutex_unlock(&chip->mutex);
        return ret;
}

static DEVICE_ATTR(lux0_input, S_IRUGO, apds990x_lux_show, NULL);

static ssize_t apds990x_lux_range_show(struct device *dev,
                                 struct device_attribute *attr, char *buf)
{
        return sprintf(buf, "%u\n", APDS_RANGE);
}

static DEVICE_ATTR(lux0_sensor_range, S_IRUGO, apds990x_lux_range_show, NULL);

static ssize_t apds990x_lux_calib_format_show(struct device *dev,
                                 struct device_attribute *attr, char *buf)
{
        return sprintf(buf, "%u\n", APDS_CALIB_SCALER);
}

static DEVICE_ATTR(lux0_calibscale_default, S_IRUGO,
                apds990x_lux_calib_format_show, NULL);

static ssize_t apds990x_lux_calib_show(struct device *dev,
                                 struct device_attribute *attr, char *buf)
{
        struct apds990x_chip *chip = dev_get_drvdata(dev);

        return sprintf(buf, "%u\n", chip->lux_calib);
}

static ssize_t apds990x_lux_calib_store(struct device *dev,
                                  struct device_attribute *attr,
                                  const char *buf, size_t len)
{
        struct apds990x_chip *chip = dev_get_drvdata(dev);
        unsigned long value;
        int ret;

        ret = kstrtoul(buf, 0, &value);
        if (ret)
                return ret;

        chip->lux_calib = value;

        return len;
}

static DEVICE_ATTR(lux0_calibscale, S_IRUGO | S_IWUSR, apds990x_lux_calib_show,
                apds990x_lux_calib_store);

static ssize_t apds990x_rate_avail(struct device *dev,
                                   struct device_attribute *attr, char *buf)
{
        int i;
        int pos = 0;

        for (i = 0; i < ARRAY_SIZE(arates_hz); i++)
                pos += sprintf(buf + pos, "%d ", arates_hz[i]);
        sprintf(buf + pos - 1, "\n");
        return pos;
}

static ssize_t apds990x_rate_show(struct device *dev,
                                   struct device_attribute *attr, char *buf)
{
        struct apds990x_chip *chip =  dev_get_drvdata(dev);

        return sprintf(buf, "%d\n", chip->arate);
}

static int apds990x_set_arate(struct apds990x_chip *chip, int rate)
{
        int i;

        for (i = 0; i < ARRAY_SIZE(arates_hz); i++)
                if (rate >= arates_hz[i])
                        break;

        if (i == ARRAY_SIZE(arates_hz))
                return -EINVAL;

        /* Pick up corresponding persistence value */
        chip->lux_persistence = apersis[i];
        chip->arate = arates_hz[i];

        /* If the chip is not in use, don't try to access it */
        if (pm_runtime_suspended(&chip->client->dev))
                return 0;

        /* Persistence levels */
        return apds990x_write_byte(chip, APDS990X_PERS,
                        (chip->lux_persistence << APDS990X_APERS_SHIFT) |
                        (chip->prox_persistence << APDS990X_PPERS_SHIFT));
}

static ssize_t apds990x_rate_store(struct device *dev,
                                  struct device_attribute *attr,
                                  const char *buf, size_t len)
{
        struct apds990x_chip *chip =  dev_get_drvdata(dev);
        unsigned long value;
        int ret;

        ret = kstrtoul(buf, 0, &value);
        if (ret)
                return ret;

        mutex_lock(&chip->mutex);
        ret = apds990x_set_arate(chip, value);
        mutex_unlock(&chip->mutex);

        if (ret < 0)
                return ret;
        return len;
}

static DEVICE_ATTR(lux0_rate_avail, S_IRUGO, apds990x_rate_avail, NULL);

static DEVICE_ATTR(lux0_rate, S_IRUGO | S_IWUSR, apds990x_rate_show,
                                                 apds990x_rate_store);

static ssize_t apds990x_prox_show(struct device *dev,
                                 struct device_attribute *attr, char *buf)
{
        ssize_t ret;
        struct apds990x_chip *chip =  dev_get_drvdata(dev);

        if (pm_runtime_suspended(dev) || !chip->prox_en)
                return -EIO;

        mutex_lock(&chip->mutex);
        ret = sprintf(buf, "%d\n", chip->prox_data);
        mutex_unlock(&chip->mutex);
        return ret;
}

static DEVICE_ATTR(prox0_raw, S_IRUGO, apds990x_prox_show, NULL);

static ssize_t apds990x_prox_range_show(struct device *dev,
                                 struct device_attribute *attr, char *buf)
{
        return sprintf(buf, "%u\n", APDS_PROX_RANGE);
}

static DEVICE_ATTR(prox0_sensor_range, S_IRUGO, apds990x_prox_range_show, NULL);

static ssize_t apds990x_prox_enable_show(struct device *dev,
                                   struct device_attribute *attr, char *buf)
{
        struct apds990x_chip *chip =  dev_get_drvdata(dev);

        return sprintf(buf, "%d\n", chip->prox_en);
}

static ssize_t apds990x_prox_enable_store(struct device *dev,
                                  struct device_attribute *attr,
                                  const char *buf, size_t len)
{
        struct apds990x_chip *chip =  dev_get_drvdata(dev);
        unsigned long value;
        int ret;

        ret = kstrtoul(buf, 0, &value);
        if (ret)
                return ret;

        mutex_lock(&chip->mutex);

        if (!chip->prox_en)
                chip->prox_data = 0;

        if (value)
                chip->prox_en++;
        else if (chip->prox_en > 0)
                chip->prox_en--;

        if (!pm_runtime_suspended(dev))
                apds990x_mode_on(chip);
        mutex_unlock(&chip->mutex);
        return len;
}

static DEVICE_ATTR(prox0_raw_en, S_IRUGO | S_IWUSR, apds990x_prox_enable_show,
                                                   apds990x_prox_enable_store);

static const char *reporting_modes[] = {"trigger", "periodic"};

static ssize_t apds990x_prox_reporting_mode_show(struct device *dev,
                                   struct device_attribute *attr, char *buf)
{
        struct apds990x_chip *chip =  dev_get_drvdata(dev);

        return sprintf(buf, "%s\n",
                reporting_modes[!!chip->prox_continuous_mode]);
}

static ssize_t apds990x_prox_reporting_mode_store(struct device *dev,
                                  struct device_attribute *attr,
                                  const char *buf, size_t len)
{
        struct apds990x_chip *chip =  dev_get_drvdata(dev);
        int ret;

        ret = sysfs_match_string(reporting_modes, buf);
        if (ret < 0)
                return ret;

        chip->prox_continuous_mode = ret;
        return len;
}

static DEVICE_ATTR(prox0_reporting_mode, S_IRUGO | S_IWUSR,
                apds990x_prox_reporting_mode_show,
                apds990x_prox_reporting_mode_store);

static ssize_t apds990x_prox_reporting_avail_show(struct device *dev,
                                   struct device_attribute *attr, char *buf)
{
        return sprintf(buf, "%s %s\n", reporting_modes[0], reporting_modes[1]);
}

static DEVICE_ATTR(prox0_reporting_mode_avail, S_IRUGO | S_IWUSR,
                apds990x_prox_reporting_avail_show, NULL);


static ssize_t apds990x_lux_thresh_above_show(struct device *dev,
                                   struct device_attribute *attr, char *buf)
{
        struct apds990x_chip *chip =  dev_get_drvdata(dev);

        return sprintf(buf, "%d\n", chip->lux_thres_hi);
}

static ssize_t apds990x_lux_thresh_below_show(struct device *dev,
                                   struct device_attribute *attr, char *buf)
{
        struct apds990x_chip *chip =  dev_get_drvdata(dev);

        return sprintf(buf, "%d\n", chip->lux_thres_lo);
}

static ssize_t apds990x_set_lux_thresh(struct apds990x_chip *chip, u32 *target,
                                const char *buf)
{
        unsigned long thresh;
        int ret;

        ret = kstrtoul(buf, 0, &thresh);
        if (ret)
                return ret;

        if (thresh > APDS_RANGE)
                return -EINVAL;

        mutex_lock(&chip->mutex);
        *target = thresh;
        /*
         * Don't update values in HW if we are still waiting for
         * first interrupt to come after device handle open call.
         */
        if (!chip->lux_wait_fresh_res)
                apds990x_refresh_athres(chip);
        mutex_unlock(&chip->mutex);
        return ret;

}

static ssize_t apds990x_lux_thresh_above_store(struct device *dev,
                                  struct device_attribute *attr,
                                  const char *buf, size_t len)
{
        struct apds990x_chip *chip =  dev_get_drvdata(dev);
        int ret = apds990x_set_lux_thresh(chip, &chip->lux_thres_hi, buf);

        if (ret < 0)
                return ret;
        return len;
}

static ssize_t apds990x_lux_thresh_below_store(struct device *dev,
                                  struct device_attribute *attr,
                                  const char *buf, size_t len)
{
        struct apds990x_chip *chip =  dev_get_drvdata(dev);
        int ret = apds990x_set_lux_thresh(chip, &chip->lux_thres_lo, buf);

        if (ret < 0)
                return ret;
        return len;
}

static DEVICE_ATTR(lux0_thresh_above_value, S_IRUGO | S_IWUSR,
                apds990x_lux_thresh_above_show,
                apds990x_lux_thresh_above_store);

static DEVICE_ATTR(lux0_thresh_below_value, S_IRUGO | S_IWUSR,
                apds990x_lux_thresh_below_show,
                apds990x_lux_thresh_below_store);

static ssize_t apds990x_prox_threshold_show(struct device *dev,
                                   struct device_attribute *attr, char *buf)
{
        struct apds990x_chip *chip =  dev_get_drvdata(dev);

        return sprintf(buf, "%d\n", chip->prox_thres);
}

static ssize_t apds990x_prox_threshold_store(struct device *dev,
                                  struct device_attribute *attr,
                                  const char *buf, size_t len)
{
        struct apds990x_chip *chip =  dev_get_drvdata(dev);
        unsigned long value;
        int ret;

        ret = kstrtoul(buf, 0, &value);
        if (ret)
                return ret;

        if ((value > APDS_RANGE) || (value == 0) ||
                (value < APDS_PROX_HYSTERESIS))
                return -EINVAL;

        mutex_lock(&chip->mutex);
        chip->prox_thres = value;

        apds990x_force_p_refresh(chip);
        mutex_unlock(&chip->mutex);
        return len;
}

static DEVICE_ATTR(prox0_thresh_above_value, S_IRUGO | S_IWUSR,
                apds990x_prox_threshold_show,
                apds990x_prox_threshold_store);

static ssize_t apds990x_power_state_show(struct device *dev,
                                   struct device_attribute *attr, char *buf)
{
        return sprintf(buf, "%d\n", !pm_runtime_suspended(dev));

        return 0;
}

static ssize_t apds990x_power_state_store(struct device *dev,
                                  struct device_attribute *attr,
                                  const char *buf, size_t len)
{
        struct apds990x_chip *chip =  dev_get_drvdata(dev);
        unsigned long value;
        int ret;

        ret = kstrtoul(buf, 0, &value);
        if (ret)
                return ret;

        if (value) {
                pm_runtime_get_sync(dev);
                mutex_lock(&chip->mutex);
                chip->lux_wait_fresh_res = true;
                apds990x_force_a_refresh(chip);
                apds990x_force_p_refresh(chip);
                mutex_unlock(&chip->mutex);
        } else {
                if (!pm_runtime_suspended(dev))
                        pm_runtime_put(dev);
        }
        return len;
}

static DEVICE_ATTR(power_state, S_IRUGO | S_IWUSR,
                apds990x_power_state_show,
                apds990x_power_state_store);

static ssize_t apds990x_chip_id_show(struct device *dev,
                                   struct device_attribute *attr, char *buf)
{
        struct apds990x_chip *chip =  dev_get_drvdata(dev);

        return sprintf(buf, "%s %d\n", chip->chipname, chip->revision);
}

static DEVICE_ATTR(chip_id, S_IRUGO, apds990x_chip_id_show, NULL);

static struct attribute *sysfs_attrs_ctrl[] = {
        &dev_attr_lux0_calibscale.attr,
        &dev_attr_lux0_calibscale_default.attr,
        &dev_attr_lux0_input.attr,
        &dev_attr_lux0_sensor_range.attr,
        &dev_attr_lux0_rate.attr,
        &dev_attr_lux0_rate_avail.attr,
        &dev_attr_lux0_thresh_above_value.attr,
        &dev_attr_lux0_thresh_below_value.attr,
        &dev_attr_prox0_raw_en.attr,
        &dev_attr_prox0_raw.attr,
        &dev_attr_prox0_sensor_range.attr,
        &dev_attr_prox0_thresh_above_value.attr,
        &dev_attr_prox0_reporting_mode.attr,
        &dev_attr_prox0_reporting_mode_avail.attr,
        &dev_attr_chip_id.attr,
        &dev_attr_power_state.attr,
        NULL
};

static const struct attribute_group apds990x_attribute_group[] = {
        {.attrs = sysfs_attrs_ctrl },
};

static int apds990x_probe(struct i2c_client *client,
                                const struct i2c_device_id *id)
{
        struct apds990x_chip *chip;
        int err;

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

        i2c_set_clientdata(client, chip);
        chip->client  = client;

        init_waitqueue_head(&chip->wait);
        mutex_init(&chip->mutex);
        chip->pdata     = client->dev.platform_data;

        if (chip->pdata == NULL) {
                dev_err(&client->dev, "platform data is mandatory\n");
                err = -EINVAL;
                goto fail1;
        }

        if (chip->pdata->cf.ga == 0) {
                /* set uncovered sensor default parameters */
                chip->cf.ga = 1966; /* 0.48 * APDS_PARAM_SCALE */
                chip->cf.cf1 = 4096; /* 1.00 * APDS_PARAM_SCALE */
                chip->cf.irf1 = 9134; /* 2.23 * APDS_PARAM_SCALE */
                chip->cf.cf2 = 2867; /* 0.70 * APDS_PARAM_SCALE */
                chip->cf.irf2 = 5816; /* 1.42 * APDS_PARAM_SCALE */
                chip->cf.df = 52;
        } else {
                chip->cf = chip->pdata->cf;
        }

        /* precalculate inverse chip factors for threshold control */
        chip->rcf.afactor =
                (chip->cf.irf1 - chip->cf.irf2) * APDS_PARAM_SCALE /
                (chip->cf.cf1 - chip->cf.cf2);
        chip->rcf.cf1 = APDS_PARAM_SCALE * APDS_PARAM_SCALE /
                chip->cf.cf1;
        chip->rcf.irf1 = chip->cf.irf1 * APDS_PARAM_SCALE /
                chip->cf.cf1;
        chip->rcf.cf2 = APDS_PARAM_SCALE * APDS_PARAM_SCALE /
                chip->cf.cf2;
        chip->rcf.irf2 = chip->cf.irf2 * APDS_PARAM_SCALE /
                chip->cf.cf2;

        /* Set something to start with */
        chip->lux_thres_hi = APDS_LUX_DEF_THRES_HI;
        chip->lux_thres_lo = APDS_LUX_DEF_THRES_LO;
        chip->lux_calib = APDS_LUX_NEUTRAL_CALIB_VALUE;

        chip->prox_thres = APDS_PROX_DEF_THRES;
        chip->pdrive = chip->pdata->pdrive;
        chip->pdiode = APDS_PDIODE_IR;
        chip->pgain = APDS_PGAIN_1X;
        chip->prox_calib = APDS_PROX_NEUTRAL_CALIB_VALUE;
        chip->prox_persistence = APDS_DEFAULT_PROX_PERS;
        chip->prox_continuous_mode = false;

        chip->regs[0].supply = reg_vcc;
        chip->regs[1].supply = reg_vled;

        err = regulator_bulk_get(&client->dev,
                                 ARRAY_SIZE(chip->regs), chip->regs);
        if (err < 0) {
                dev_err(&client->dev, "Cannot get regulators\n");
                goto fail1;
        }

        err = regulator_bulk_enable(ARRAY_SIZE(chip->regs), chip->regs);
        if (err < 0) {
                dev_err(&client->dev, "Cannot enable regulators\n");
                goto fail2;
        }

        usleep_range(APDS_STARTUP_DELAY, 2 * APDS_STARTUP_DELAY);

        err = apds990x_detect(chip);
        if (err < 0) {
                dev_err(&client->dev, "APDS990X not found\n");
                goto fail3;
        }

        pm_runtime_set_active(&client->dev);

        apds990x_configure(chip);
        apds990x_set_arate(chip, APDS_LUX_DEFAULT_RATE);
        apds990x_mode_on(chip);

        pm_runtime_enable(&client->dev);

        if (chip->pdata->setup_resources) {
                err = chip->pdata->setup_resources();
                if (err) {
                        err = -EINVAL;
                        goto fail3;
                }
        }

        err = sysfs_create_group(&chip->client->dev.kobj,
                                apds990x_attribute_group);
        if (err < 0) {
                dev_err(&chip->client->dev, "Sysfs registration failed\n");
                goto fail4;
        }

        err = request_threaded_irq(client->irq, NULL,
                                apds990x_irq,
                                IRQF_TRIGGER_FALLING | IRQF_TRIGGER_LOW |
                                IRQF_ONESHOT,
                                "apds990x", chip);
        if (err) {
                dev_err(&client->dev, "could not get IRQ %d\n",
                        client->irq);
                goto fail5;
        }
        return err;
fail5:
        sysfs_remove_group(&chip->client->dev.kobj,
                        &apds990x_attribute_group[0]);
fail4:
        if (chip->pdata && chip->pdata->release_resources)
                chip->pdata->release_resources();
fail3:
        regulator_bulk_disable(ARRAY_SIZE(chip->regs), chip->regs);
fail2:
        regulator_bulk_free(ARRAY_SIZE(chip->regs), chip->regs);
fail1:
        kfree(chip);
        return err;
}

static int apds990x_remove(struct i2c_client *client)
{
        struct apds990x_chip *chip = i2c_get_clientdata(client);

        free_irq(client->irq, chip);
        sysfs_remove_group(&chip->client->dev.kobj,
                        apds990x_attribute_group);

        if (chip->pdata && chip->pdata->release_resources)
                chip->pdata->release_resources();

        if (!pm_runtime_suspended(&client->dev))
                apds990x_chip_off(chip);

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

        regulator_bulk_free(ARRAY_SIZE(chip->regs), chip->regs);

        kfree(chip);
        return 0;
}

#ifdef CONFIG_PM_SLEEP
static int apds990x_suspend(struct device *dev)
{
        struct i2c_client *client = to_i2c_client(dev);
        struct apds990x_chip *chip = i2c_get_clientdata(client);

        apds990x_chip_off(chip);
        return 0;
}

static int apds990x_resume(struct device *dev)
{
        struct i2c_client *client = to_i2c_client(dev);
        struct apds990x_chip *chip = i2c_get_clientdata(client);

        /*
         * If we were enabled at suspend time, it is expected
         * everything works nice and smoothly. Chip_on is enough
         */
        apds990x_chip_on(chip);

        return 0;
}
#endif

#ifdef CONFIG_PM
static int apds990x_runtime_suspend(struct device *dev)
{
        struct i2c_client *client = to_i2c_client(dev);
        struct apds990x_chip *chip = i2c_get_clientdata(client);

        apds990x_chip_off(chip);
        return 0;
}

static int apds990x_runtime_resume(struct device *dev)
{
        struct i2c_client *client = to_i2c_client(dev);
        struct apds990x_chip *chip = i2c_get_clientdata(client);

        apds990x_chip_on(chip);
        return 0;
}

#endif

static const struct i2c_device_id apds990x_id[] = {
        {"apds990x", 0 },
        {}
};

MODULE_DEVICE_TABLE(i2c, apds990x_id);

static const struct dev_pm_ops apds990x_pm_ops = {
        SET_SYSTEM_SLEEP_PM_OPS(apds990x_suspend, apds990x_resume)
        SET_RUNTIME_PM_OPS(apds990x_runtime_suspend,
                        apds990x_runtime_resume,
                        NULL)
};

static struct i2c_driver apds990x_driver = {
        .driver  = {
                .name   = "apds990x",
                .pm     = &apds990x_pm_ops,
        },
        .probe    = apds990x_probe,
        .remove   = apds990x_remove,
        .id_table = apds990x_id,
};

module_i2c_driver(apds990x_driver);

MODULE_DESCRIPTION("APDS990X combined ALS and proximity sensor");
MODULE_AUTHOR("Samu Onkalo, Nokia Corporation");
MODULE_LICENSE("GPL v2");