/*
 * Copyright (C) ST-Ericsson SA 2010
 *
 * License Terms: GNU General Public License v2
 * Author: Arun R Murthy <arun.murthy@stericsson.com>
 * Author: Daniel Willerud <daniel.willerud@stericsson.com>
 * Author: Johan Palsson <johan.palsson@stericsson.com>
 */
#include <linux/init.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/interrupt.h>
#include <linux/spinlock.h>
#include <linux/delay.h>
#include <linux/pm_runtime.h>
#include <linux/platform_device.h>
#include <linux/completion.h>
#include <linux/regulator/consumer.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/list.h>
#include <linux/mfd/abx500.h>
#include <linux/mfd/abx500/ab8500.h>
#include <linux/mfd/abx500/ab8500-gpadc.h>

/*
 * GPADC register offsets
 * Bank : 0x0A
 */
#define AB8500_GPADC_CTRL1_REG          0x00
#define AB8500_GPADC_CTRL2_REG          0x01
#define AB8500_GPADC_CTRL3_REG          0x02
#define AB8500_GPADC_AUTO_TIMER_REG     0x03
#define AB8500_GPADC_STAT_REG           0x04
#define AB8500_GPADC_MANDATAL_REG       0x05
#define AB8500_GPADC_MANDATAH_REG       0x06
#define AB8500_GPADC_AUTODATAL_REG      0x07
#define AB8500_GPADC_AUTODATAH_REG      0x08
#define AB8500_GPADC_MUX_CTRL_REG       0x09
#define AB8540_GPADC_MANDATA2L_REG      0x09
#define AB8540_GPADC_MANDATA2H_REG      0x0A
#define AB8540_GPADC_APEAAX_REG         0x10
#define AB8540_GPADC_APEAAT_REG         0x11
#define AB8540_GPADC_APEAAM_REG         0x12
#define AB8540_GPADC_APEAAH_REG         0x13
#define AB8540_GPADC_APEAAL_REG         0x14

/*
 * OTP register offsets
 * Bank : 0x15
 */
#define AB8500_GPADC_CAL_1              0x0F
#define AB8500_GPADC_CAL_2              0x10
#define AB8500_GPADC_CAL_3              0x11
#define AB8500_GPADC_CAL_4              0x12
#define AB8500_GPADC_CAL_5              0x13
#define AB8500_GPADC_CAL_6              0x14
#define AB8500_GPADC_CAL_7              0x15
/* New calibration for 8540 */
#define AB8540_GPADC_OTP4_REG_7 0x38
#define AB8540_GPADC_OTP4_REG_6 0x39
#define AB8540_GPADC_OTP4_REG_5 0x3A

/* gpadc constants */
#define EN_VINTCORE12                   0x04
#define EN_VTVOUT                       0x02
#define EN_GPADC                        0x01
#define DIS_GPADC                       0x00
#define AVG_1                           0x00
#define AVG_4                           0x20
#define AVG_8                           0x40
#define AVG_16                          0x60
#define ADC_SW_CONV                     0x04
#define EN_ICHAR                        0x80
#define BTEMP_PULL_UP                   0x08
#define EN_BUF                          0x40
#define DIS_ZERO                        0x00
#define GPADC_BUSY                      0x01
#define EN_FALLING                      0x10
#define EN_TRIG_EDGE                    0x02
#define EN_VBIAS_XTAL_TEMP              0x02

/* GPADC constants from AB8500 spec, UM0836 */
#define ADC_RESOLUTION                  1024
#define ADC_CH_BTEMP_MIN                0
#define ADC_CH_BTEMP_MAX                1350
#define ADC_CH_DIETEMP_MIN              0
#define ADC_CH_DIETEMP_MAX              1350
#define ADC_CH_CHG_V_MIN                0
#define ADC_CH_CHG_V_MAX                20030
#define ADC_CH_ACCDET2_MIN              0
#define ADC_CH_ACCDET2_MAX              2500
#define ADC_CH_VBAT_MIN                 2300
#define ADC_CH_VBAT_MAX                 4800
#define ADC_CH_CHG_I_MIN                0
#define ADC_CH_CHG_I_MAX                1500
#define ADC_CH_BKBAT_MIN                0
#define ADC_CH_BKBAT_MAX                3200

/* GPADC constants from AB8540 spec */
#define ADC_CH_IBAT_MIN                 (-6000) /* mA range measured by ADC for ibat*/
#define ADC_CH_IBAT_MAX                 6000
#define ADC_CH_IBAT_MIN_V               (-60)   /* mV range measured by ADC for ibat*/
#define ADC_CH_IBAT_MAX_V               60
#define IBAT_VDROP_L                    (-56)  /* mV */
#define IBAT_VDROP_H                    56

/* This is used to not lose precision when dividing to get gain and offset */
#define CALIB_SCALE             1000
/*
 * Number of bits shift used to not lose precision
 * when dividing to get ibat gain.
 */
#define CALIB_SHIFT_IBAT        20

/* Time in ms before disabling regulator */
#define GPADC_AUDOSUSPEND_DELAY         1

#define CONVERSION_TIME                 500 /* ms */

enum cal_channels {
        ADC_INPUT_VMAIN = 0,
        ADC_INPUT_BTEMP,
        ADC_INPUT_VBAT,
        ADC_INPUT_IBAT,
        NBR_CAL_INPUTS,
};

/**
 * struct adc_cal_data - Table for storing gain and offset for the calibrated
 * ADC channels
 * @gain:               Gain of the ADC channel
 * @offset:             Offset of the ADC channel
 */
struct adc_cal_data {
        s64 gain;
        s64 offset;
        u16 otp_calib_hi;
        u16 otp_calib_lo;
};

/**
 * struct ab8500_gpadc - AB8500 GPADC device information
 * @dev:                        pointer to the struct device
 * @node:                       a list of AB8500 GPADCs, hence prepared for
                                reentrance
 * @parent:                     pointer to the struct ab8500
 * @ab8500_gpadc_complete:      pointer to the struct completion, to indicate
 *                              the completion of gpadc conversion
 * @ab8500_gpadc_lock:          structure of type mutex
 * @regu:                       pointer to the struct regulator
 * @irq_sw:                     interrupt number that is used by gpadc for Sw
 *                              conversion
 * @irq_hw:                     interrupt number that is used by gpadc for Hw
 *                              conversion
 * @cal_data                    array of ADC calibration data structs
 */
struct ab8500_gpadc {
        struct device *dev;
        struct list_head node;
        struct ab8500 *parent;
        struct completion ab8500_gpadc_complete;
        struct mutex ab8500_gpadc_lock;
        struct regulator *regu;
        int irq_sw;
        int irq_hw;
        struct adc_cal_data cal_data[NBR_CAL_INPUTS];
};

static LIST_HEAD(ab8500_gpadc_list);

/**
 * ab8500_gpadc_get() - returns a reference to the primary AB8500 GPADC
 * (i.e. the first GPADC in the instance list)
 */
struct ab8500_gpadc *ab8500_gpadc_get(char *name)
{
        struct ab8500_gpadc *gpadc;

        list_for_each_entry(gpadc, &ab8500_gpadc_list, node) {
                if (!strcmp(name, dev_name(gpadc->dev)))
                    return gpadc;
        }

        return ERR_PTR(-ENOENT);
}
EXPORT_SYMBOL(ab8500_gpadc_get);

/**
 * ab8500_gpadc_ad_to_voltage() - Convert a raw ADC value to a voltage
 */
int ab8500_gpadc_ad_to_voltage(struct ab8500_gpadc *gpadc, u8 channel,
        int ad_value)
{
        int res;

        switch (channel) {
        case MAIN_CHARGER_V:
                /* For some reason we don't have calibrated data */
                if (!gpadc->cal_data[ADC_INPUT_VMAIN].gain) {
                        res = ADC_CH_CHG_V_MIN + (ADC_CH_CHG_V_MAX -
                                ADC_CH_CHG_V_MIN) * ad_value /
                                ADC_RESOLUTION;
                        break;
                }
                /* Here we can use the calibrated data */
                res = (int) (ad_value * gpadc->cal_data[ADC_INPUT_VMAIN].gain +
                        gpadc->cal_data[ADC_INPUT_VMAIN].offset) / CALIB_SCALE;
                break;

        case XTAL_TEMP:
        case BAT_CTRL:
        case BTEMP_BALL:
        case ACC_DETECT1:
        case ADC_AUX1:
        case ADC_AUX2:
                /* For some reason we don't have calibrated data */
                if (!gpadc->cal_data[ADC_INPUT_BTEMP].gain) {
                        res = ADC_CH_BTEMP_MIN + (ADC_CH_BTEMP_MAX -
                                ADC_CH_BTEMP_MIN) * ad_value /
                                ADC_RESOLUTION;
                        break;
                }
                /* Here we can use the calibrated data */
                res = (int) (ad_value * gpadc->cal_data[ADC_INPUT_BTEMP].gain +
                        gpadc->cal_data[ADC_INPUT_BTEMP].offset) / CALIB_SCALE;
                break;

        case MAIN_BAT_V:
        case VBAT_TRUE_MEAS:
                /* For some reason we don't have calibrated data */
                if (!gpadc->cal_data[ADC_INPUT_VBAT].gain) {
                        res = ADC_CH_VBAT_MIN + (ADC_CH_VBAT_MAX -
                                ADC_CH_VBAT_MIN) * ad_value /
                                ADC_RESOLUTION;
                        break;
                }
                /* Here we can use the calibrated data */
                res = (int) (ad_value * gpadc->cal_data[ADC_INPUT_VBAT].gain +
                        gpadc->cal_data[ADC_INPUT_VBAT].offset) / CALIB_SCALE;
                break;

        case DIE_TEMP:
                res = ADC_CH_DIETEMP_MIN +
                        (ADC_CH_DIETEMP_MAX - ADC_CH_DIETEMP_MIN) * ad_value /
                        ADC_RESOLUTION;
                break;

        case ACC_DETECT2:
                res = ADC_CH_ACCDET2_MIN +
                        (ADC_CH_ACCDET2_MAX - ADC_CH_ACCDET2_MIN) * ad_value /
                        ADC_RESOLUTION;
                break;

        case VBUS_V:
                res = ADC_CH_CHG_V_MIN +
                        (ADC_CH_CHG_V_MAX - ADC_CH_CHG_V_MIN) * ad_value /
                        ADC_RESOLUTION;
                break;

        case MAIN_CHARGER_C:
        case USB_CHARGER_C:
                res = ADC_CH_CHG_I_MIN +
                        (ADC_CH_CHG_I_MAX - ADC_CH_CHG_I_MIN) * ad_value /
                        ADC_RESOLUTION;
                break;

        case BK_BAT_V:
                res = ADC_CH_BKBAT_MIN +
                        (ADC_CH_BKBAT_MAX - ADC_CH_BKBAT_MIN) * ad_value /
                        ADC_RESOLUTION;
                break;

        case IBAT_VIRTUAL_CHANNEL:
                /* For some reason we don't have calibrated data */
                if (!gpadc->cal_data[ADC_INPUT_IBAT].gain) {
                        res = ADC_CH_IBAT_MIN + (ADC_CH_IBAT_MAX -
                                ADC_CH_IBAT_MIN) * ad_value /
                                ADC_RESOLUTION;
                        break;
                }
                /* Here we can use the calibrated data */
                res = (int) (ad_value * gpadc->cal_data[ADC_INPUT_IBAT].gain +
                                gpadc->cal_data[ADC_INPUT_IBAT].offset)
                                >> CALIB_SHIFT_IBAT;
                break;

        default:
                dev_err(gpadc->dev,
                        "unknown channel, not possible to convert\n");
                res = -EINVAL;
                break;

        }
        return res;
}
EXPORT_SYMBOL(ab8500_gpadc_ad_to_voltage);

/**
 * ab8500_gpadc_sw_hw_convert() - gpadc conversion
 * @channel:    analog channel to be converted to digital data
 * @avg_sample:  number of ADC sample to average
 * @trig_egde:  selected ADC trig edge
 * @trig_timer: selected ADC trigger delay timer
 * @conv_type: selected conversion type (HW or SW conversion)
 *
 * This function converts the selected analog i/p to digital
 * data.
 */
int ab8500_gpadc_sw_hw_convert(struct ab8500_gpadc *gpadc, u8 channel,
                u8 avg_sample, u8 trig_edge, u8 trig_timer, u8 conv_type)
{
        int ad_value;
        int voltage;

        ad_value = ab8500_gpadc_read_raw(gpadc, channel, avg_sample,
                        trig_edge, trig_timer, conv_type);
/* On failure retry a second time */
        if (ad_value < 0)
                ad_value = ab8500_gpadc_read_raw(gpadc, channel, avg_sample,
                        trig_edge, trig_timer, conv_type);
if (ad_value < 0) {
                dev_err(gpadc->dev, "GPADC raw value failed ch: %d\n",
                                channel);
                return ad_value;
        }

        voltage = ab8500_gpadc_ad_to_voltage(gpadc, channel, ad_value);
        if (voltage < 0)
                dev_err(gpadc->dev, "GPADC to voltage conversion failed ch:"
                        " %d AD: 0x%x\n", channel, ad_value);

        return voltage;
}
EXPORT_SYMBOL(ab8500_gpadc_sw_hw_convert);

/**
 * ab8500_gpadc_read_raw() - gpadc read
 * @channel:    analog channel to be read
 * @avg_sample:  number of ADC sample to average
 * @trig_edge:  selected trig edge
 * @trig_timer: selected ADC trigger delay timer
 * @conv_type: selected conversion type (HW or SW conversion)
 *
 * This function obtains the raw ADC value for an hardware conversion,
 * this then needs to be converted by calling ab8500_gpadc_ad_to_voltage()
 */
int ab8500_gpadc_read_raw(struct ab8500_gpadc *gpadc, u8 channel,
                u8 avg_sample, u8 trig_edge, u8 trig_timer, u8 conv_type)
{
        int raw_data;
        raw_data = ab8500_gpadc_double_read_raw(gpadc, channel,
                        avg_sample, trig_edge, trig_timer, conv_type, NULL);
        return raw_data;
}

int ab8500_gpadc_double_read_raw(struct ab8500_gpadc *gpadc, u8 channel,
                u8 avg_sample, u8 trig_edge, u8 trig_timer, u8 conv_type,
                int *ibat)
{
        int ret;
        int looplimit = 0;
        unsigned long completion_timeout;
        u8 val, low_data, high_data, low_data2, high_data2;
        u8 val_reg1 = 0;
        unsigned int delay_min = 0;
        unsigned int delay_max = 0;
        u8 data_low_addr, data_high_addr;

        if (!gpadc)
                return -ENODEV;

        /* check if convertion is supported */
        if ((gpadc->irq_sw < 0) && (conv_type == ADC_SW))
                return -ENOTSUPP;
        if ((gpadc->irq_hw < 0) && (conv_type == ADC_HW))
                return -ENOTSUPP;

        mutex_lock(&gpadc->ab8500_gpadc_lock);
        /* Enable VTVout LDO this is required for GPADC */
        pm_runtime_get_sync(gpadc->dev);

        /* Check if ADC is not busy, lock and proceed */
        do {
                ret = abx500_get_register_interruptible(gpadc->dev,
                        AB8500_GPADC, AB8500_GPADC_STAT_REG, &val);
                if (ret < 0)
                        goto out;
                if (!(val & GPADC_BUSY))
                        break;
                msleep(10);
        } while (++looplimit < 10);
        if (looplimit >= 10 && (val & GPADC_BUSY)) {
                dev_err(gpadc->dev, "gpadc_conversion: GPADC busy");
                ret = -EINVAL;
                goto out;
        }

        /* Enable GPADC */
        val_reg1 |= EN_GPADC;

        /* Select the channel source and set average samples */
        switch (avg_sample) {
        case SAMPLE_1:
                val = channel | AVG_1;
                break;
        case SAMPLE_4:
                val = channel | AVG_4;
                break;
        case SAMPLE_8:
                val = channel | AVG_8;
                break;
        default:
                val = channel | AVG_16;
                break;
        }

        if (conv_type == ADC_HW) {
                ret = abx500_set_register_interruptible(gpadc->dev,
                                AB8500_GPADC, AB8500_GPADC_CTRL3_REG, val);
                val_reg1 |= EN_TRIG_EDGE;
                if (trig_edge)
                        val_reg1 |= EN_FALLING;
        }
        else
                ret = abx500_set_register_interruptible(gpadc->dev,
                                AB8500_GPADC, AB8500_GPADC_CTRL2_REG, val);
        if (ret < 0) {
                dev_err(gpadc->dev,
                        "gpadc_conversion: set avg samples failed\n");
                goto out;
        }

        /*
         * Enable ADC, buffering, select rising edge and enable ADC path
         * charging current sense if it needed, ABB 3.0 needs some special
         * treatment too.
         */
        switch (channel) {
        case MAIN_CHARGER_C:
        case USB_CHARGER_C:
                val_reg1 |= EN_BUF | EN_ICHAR;
                break;
        case BTEMP_BALL:
                if (!is_ab8500_2p0_or_earlier(gpadc->parent)) {
                        val_reg1 |= EN_BUF | BTEMP_PULL_UP;
                        /*
                        * Delay might be needed for ABB8500 cut 3.0, if not,
                        * remove when hardware will be availible
                        */
                        delay_min = 1000; /* Delay in micro seconds */
                        delay_max = 10000; /* large range to optimise sleep mode */
                        break;
                }
                /* Intentional fallthrough */
        default:
                val_reg1 |= EN_BUF;
                break;
        }

        /* Write configuration to register */
        ret = abx500_set_register_interruptible(gpadc->dev,
                AB8500_GPADC, AB8500_GPADC_CTRL1_REG, val_reg1);
        if (ret < 0) {
                dev_err(gpadc->dev,
                        "gpadc_conversion: set Control register failed\n");
                goto out;
        }

        if (delay_min != 0)
                usleep_range(delay_min, delay_max);

        if (conv_type == ADC_HW) {
                /* Set trigger delay timer */
                ret = abx500_set_register_interruptible(gpadc->dev,
                        AB8500_GPADC, AB8500_GPADC_AUTO_TIMER_REG, trig_timer);
                if (ret < 0) {
                        dev_err(gpadc->dev,
                                "gpadc_conversion: trig timer failed\n");
                        goto out;
                }
                completion_timeout = 2 * HZ;
                data_low_addr = AB8500_GPADC_AUTODATAL_REG;
                data_high_addr = AB8500_GPADC_AUTODATAH_REG;
        } else {
                /* Start SW conversion */
                ret = abx500_mask_and_set_register_interruptible(gpadc->dev,
                        AB8500_GPADC, AB8500_GPADC_CTRL1_REG,
                        ADC_SW_CONV, ADC_SW_CONV);
                if (ret < 0) {
                        dev_err(gpadc->dev,
                                "gpadc_conversion: start s/w conv failed\n");
                        goto out;
                }
                completion_timeout = msecs_to_jiffies(CONVERSION_TIME);
                data_low_addr = AB8500_GPADC_MANDATAL_REG;
                data_high_addr = AB8500_GPADC_MANDATAH_REG;
        }

        /* wait for completion of conversion */
        if (!wait_for_completion_timeout(&gpadc->ab8500_gpadc_complete,
                        completion_timeout)) {
                dev_err(gpadc->dev,
                        "timeout didn't receive GPADC conv interrupt\n");
                ret = -EINVAL;
                goto out;
        }

        /* Read the converted RAW data */
        ret = abx500_get_register_interruptible(gpadc->dev,
                        AB8500_GPADC, data_low_addr, &low_data);
        if (ret < 0) {
                dev_err(gpadc->dev, "gpadc_conversion: read low data failed\n");
                goto out;
        }

        ret = abx500_get_register_interruptible(gpadc->dev,
                AB8500_GPADC, data_high_addr, &high_data);
        if (ret < 0) {
                dev_err(gpadc->dev, "gpadc_conversion: read high data failed\n");
                goto out;
        }

        /* Check if double convertion is required */
        if ((channel == BAT_CTRL_AND_IBAT) ||
                        (channel == VBAT_MEAS_AND_IBAT) ||
                        (channel == VBAT_TRUE_MEAS_AND_IBAT) ||
                        (channel == BAT_TEMP_AND_IBAT)) {

                if (conv_type == ADC_HW) {
                        /* not supported */
                        ret = -ENOTSUPP;
                        dev_err(gpadc->dev,
                                "gpadc_conversion: only SW double conversion supported\n");
                        goto out;
                } else {
                        /* Read the converted RAW data 2 */
                        ret = abx500_get_register_interruptible(gpadc->dev,
                                AB8500_GPADC, AB8540_GPADC_MANDATA2L_REG,
                                &low_data2);
                        if (ret < 0) {
                                dev_err(gpadc->dev,
                                        "gpadc_conversion: read sw low data 2 failed\n");
                                goto out;
                        }

                        ret = abx500_get_register_interruptible(gpadc->dev,
                                AB8500_GPADC, AB8540_GPADC_MANDATA2H_REG,
                                &high_data2);
                        if (ret < 0) {
                                dev_err(gpadc->dev,
                                        "gpadc_conversion: read sw high data 2 failed\n");
                                goto out;
                        }
                        if (ibat != NULL) {
                                *ibat = (high_data2 << 8) | low_data2;
                        } else {
                                dev_warn(gpadc->dev,
                                        "gpadc_conversion: ibat not stored\n");
                        }

                }
        }

        /* Disable GPADC */
        ret = abx500_set_register_interruptible(gpadc->dev, AB8500_GPADC,
                AB8500_GPADC_CTRL1_REG, DIS_GPADC);
        if (ret < 0) {
                dev_err(gpadc->dev, "gpadc_conversion: disable gpadc failed\n");
                goto out;
        }

        /* Disable VTVout LDO this is required for GPADC */
        pm_runtime_mark_last_busy(gpadc->dev);
        pm_runtime_put_autosuspend(gpadc->dev);

        mutex_unlock(&gpadc->ab8500_gpadc_lock);

        return (high_data << 8) | low_data;

out:
        /*
         * It has shown to be needed to turn off the GPADC if an error occurs,
         * otherwise we might have problem when waiting for the busy bit in the
         * GPADC status register to go low. In V1.1 there wait_for_completion
         * seems to timeout when waiting for an interrupt.. Not seen in V2.0
         */
        (void) abx500_set_register_interruptible(gpadc->dev, AB8500_GPADC,
                AB8500_GPADC_CTRL1_REG, DIS_GPADC);
        pm_runtime_put(gpadc->dev);
        mutex_unlock(&gpadc->ab8500_gpadc_lock);
        dev_err(gpadc->dev,
                "gpadc_conversion: Failed to AD convert channel %d\n", channel);
        return ret;
}
EXPORT_SYMBOL(ab8500_gpadc_read_raw);

/**
 * ab8500_bm_gpadcconvend_handler() - isr for gpadc conversion completion
 * @irq:        irq number
 * @data:       pointer to the data passed during request irq
 *
 * This is a interrupt service routine for gpadc conversion completion.
 * Notifies the gpadc completion is completed and the converted raw value
 * can be read from the registers.
 * Returns IRQ status(IRQ_HANDLED)
 */
static irqreturn_t ab8500_bm_gpadcconvend_handler(int irq, void *_gpadc)
{
        struct ab8500_gpadc *gpadc = _gpadc;

        complete(&gpadc->ab8500_gpadc_complete);

        return IRQ_HANDLED;
}

static int otp_cal_regs[] = {
        AB8500_GPADC_CAL_1,
        AB8500_GPADC_CAL_2,
        AB8500_GPADC_CAL_3,
        AB8500_GPADC_CAL_4,
        AB8500_GPADC_CAL_5,
        AB8500_GPADC_CAL_6,
        AB8500_GPADC_CAL_7,
};

static int otp4_cal_regs[] = {
        AB8540_GPADC_OTP4_REG_7,
        AB8540_GPADC_OTP4_REG_6,
        AB8540_GPADC_OTP4_REG_5,
};

static void ab8500_gpadc_read_calibration_data(struct ab8500_gpadc *gpadc)
{
        int i;
        int ret[ARRAY_SIZE(otp_cal_regs)];
        u8 gpadc_cal[ARRAY_SIZE(otp_cal_regs)];
        int ret_otp4[ARRAY_SIZE(otp4_cal_regs)];
        u8 gpadc_otp4[ARRAY_SIZE(otp4_cal_regs)];
        int vmain_high, vmain_low;
        int btemp_high, btemp_low;
        int vbat_high, vbat_low;
        int ibat_high, ibat_low;
        s64 V_gain, V_offset, V2A_gain, V2A_offset;
        struct ab8500 *ab8500;

        ab8500 = gpadc->parent;

        /* First we read all OTP registers and store the error code */
        for (i = 0; i < ARRAY_SIZE(otp_cal_regs); i++) {
                ret[i] = abx500_get_register_interruptible(gpadc->dev,
                        AB8500_OTP_EMUL, otp_cal_regs[i],  &gpadc_cal[i]);
                if (ret[i] < 0)
                        dev_err(gpadc->dev, "%s: read otp reg 0x%02x failed\n",
                                __func__, otp_cal_regs[i]);
        }

        /*
         * The ADC calibration data is stored in OTP registers.
         * The layout of the calibration data is outlined below and a more
         * detailed description can be found in UM0836
         *
         * vm_h/l = vmain_high/low
         * bt_h/l = btemp_high/low
         * vb_h/l = vbat_high/low
         *
         * Data bits 8500/9540:
         * | 7     | 6     | 5     | 4     | 3     | 2     | 1     | 0
         * |.......|.......|.......|.......|.......|.......|.......|.......
         * |                                               | vm_h9 | vm_h8
         * |.......|.......|.......|.......|.......|.......|.......|.......
         * |               | vm_h7 | vm_h6 | vm_h5 | vm_h4 | vm_h3 | vm_h2
         * |.......|.......|.......|.......|.......|.......|.......|.......
         * | vm_h1 | vm_h0 | vm_l4 | vm_l3 | vm_l2 | vm_l1 | vm_l0 | bt_h9
         * |.......|.......|.......|.......|.......|.......|.......|.......
         * | bt_h8 | bt_h7 | bt_h6 | bt_h5 | bt_h4 | bt_h3 | bt_h2 | bt_h1
         * |.......|.......|.......|.......|.......|.......|.......|.......
         * | bt_h0 | bt_l4 | bt_l3 | bt_l2 | bt_l1 | bt_l0 | vb_h9 | vb_h8
         * |.......|.......|.......|.......|.......|.......|.......|.......
         * | vb_h7 | vb_h6 | vb_h5 | vb_h4 | vb_h3 | vb_h2 | vb_h1 | vb_h0
         * |.......|.......|.......|.......|.......|.......|.......|.......
         * | vb_l5 | vb_l4 | vb_l3 | vb_l2 | vb_l1 | vb_l0 |
         * |.......|.......|.......|.......|.......|.......|.......|.......
         *
         * Data bits 8540:
         * OTP2
         * | 7     | 6     | 5     | 4     | 3     | 2     | 1     | 0
         * |.......|.......|.......|.......|.......|.......|.......|.......
         * |
         * |.......|.......|.......|.......|.......|.......|.......|.......
         * | vm_h9 | vm_h8 | vm_h7 | vm_h6 | vm_h5 | vm_h4 | vm_h3 | vm_h2
         * |.......|.......|.......|.......|.......|.......|.......|.......
         * | vm_h1 | vm_h0 | vm_l4 | vm_l3 | vm_l2 | vm_l1 | vm_l0 | bt_h9
         * |.......|.......|.......|.......|.......|.......|.......|.......
         * | bt_h8 | bt_h7 | bt_h6 | bt_h5 | bt_h4 | bt_h3 | bt_h2 | bt_h1
         * |.......|.......|.......|.......|.......|.......|.......|.......
         * | bt_h0 | bt_l4 | bt_l3 | bt_l2 | bt_l1 | bt_l0 | vb_h9 | vb_h8
         * |.......|.......|.......|.......|.......|.......|.......|.......
         * | vb_h7 | vb_h6 | vb_h5 | vb_h4 | vb_h3 | vb_h2 | vb_h1 | vb_h0
         * |.......|.......|.......|.......|.......|.......|.......|.......
         * | vb_l5 | vb_l4 | vb_l3 | vb_l2 | vb_l1 | vb_l0 |
         * |.......|.......|.......|.......|.......|.......|.......|.......
         *
         * Data bits 8540:
         * OTP4
         * | 7     | 6     | 5     | 4     | 3     | 2     | 1     | 0
         * |.......|.......|.......|.......|.......|.......|.......|.......
         * |                                       | ib_h9 | ib_h8 | ib_h7
         * |.......|.......|.......|.......|.......|.......|.......|.......
         * | ib_h6 | ib_h5 | ib_h4 | ib_h3 | ib_h2 | ib_h1 | ib_h0 | ib_l5
         * |.......|.......|.......|.......|.......|.......|.......|.......
         * | ib_l4 | ib_l3 | ib_l2 | ib_l1 | ib_l0 |
         *
         *
         * Ideal output ADC codes corresponding to injected input voltages
         * during manufacturing is:
         *
         * vmain_high: Vin = 19500mV / ADC ideal code = 997
         * vmain_low:  Vin = 315mV   / ADC ideal code = 16
         * btemp_high: Vin = 1300mV  / ADC ideal code = 985
         * btemp_low:  Vin = 21mV    / ADC ideal code = 16
         * vbat_high:  Vin = 4700mV  / ADC ideal code = 982
         * vbat_low:   Vin = 2380mV  / ADC ideal code = 33
         */

        if (is_ab8540(ab8500)) {
                /* Calculate gain and offset for VMAIN if all reads succeeded*/
                if (!(ret[1] < 0 || ret[2] < 0)) {
                        vmain_high = (((gpadc_cal[1] & 0xFF) << 2) |
                                ((gpadc_cal[2] & 0xC0) >> 6));
                        vmain_low = ((gpadc_cal[2] & 0x3E) >> 1);

                        gpadc->cal_data[ADC_INPUT_VMAIN].otp_calib_hi =
                                (u16)vmain_high;
                        gpadc->cal_data[ADC_INPUT_VMAIN].otp_calib_lo =
                                (u16)vmain_low;

                        gpadc->cal_data[ADC_INPUT_VMAIN].gain = CALIB_SCALE *
                                (19500 - 315) / (vmain_high - vmain_low);
                        gpadc->cal_data[ADC_INPUT_VMAIN].offset = CALIB_SCALE *
                                19500 - (CALIB_SCALE * (19500 - 315) /
                                (vmain_high - vmain_low)) * vmain_high;
                } else {
                gpadc->cal_data[ADC_INPUT_VMAIN].gain = 0;
                }

                /* Read IBAT calibration Data */
                for (i = 0; i < ARRAY_SIZE(otp4_cal_regs); i++) {
                        ret_otp4[i] = abx500_get_register_interruptible(
                                        gpadc->dev, AB8500_OTP_EMUL,
                                        otp4_cal_regs[i],  &gpadc_otp4[i]);
                        if (ret_otp4[i] < 0)
                                dev_err(gpadc->dev,
                                        "%s: read otp4 reg 0x%02x failed\n",
                                        __func__, otp4_cal_regs[i]);
                }

                /* Calculate gain and offset for IBAT if all reads succeeded */
                if (!(ret_otp4[0] < 0 || ret_otp4[1] < 0 || ret_otp4[2] < 0)) {
                        ibat_high = (((gpadc_otp4[0] & 0x07) << 7) |
                                ((gpadc_otp4[1] & 0xFE) >> 1));
                        ibat_low = (((gpadc_otp4[1] & 0x01) << 5) |
                                ((gpadc_otp4[2] & 0xF8) >> 3));

                        gpadc->cal_data[ADC_INPUT_IBAT].otp_calib_hi =
                                (u16)ibat_high;
                        gpadc->cal_data[ADC_INPUT_IBAT].otp_calib_lo =
                                (u16)ibat_low;

                        V_gain = ((IBAT_VDROP_H - IBAT_VDROP_L)
                                << CALIB_SHIFT_IBAT) / (ibat_high - ibat_low);

                        V_offset = (IBAT_VDROP_H << CALIB_SHIFT_IBAT) -
                                (((IBAT_VDROP_H - IBAT_VDROP_L) <<
                                CALIB_SHIFT_IBAT) / (ibat_high - ibat_low))
                                * ibat_high;
                        /*
                         * Result obtained is in mV (at a scale factor),
                         * we need to calculate gain and offset to get mA
                         */
                        V2A_gain = (ADC_CH_IBAT_MAX - ADC_CH_IBAT_MIN)/
                                (ADC_CH_IBAT_MAX_V - ADC_CH_IBAT_MIN_V);
                        V2A_offset = ((ADC_CH_IBAT_MAX_V * ADC_CH_IBAT_MIN -
                                ADC_CH_IBAT_MAX * ADC_CH_IBAT_MIN_V)
                                << CALIB_SHIFT_IBAT)
                                / (ADC_CH_IBAT_MAX_V - ADC_CH_IBAT_MIN_V);

                        gpadc->cal_data[ADC_INPUT_IBAT].gain = V_gain * V2A_gain;
                        gpadc->cal_data[ADC_INPUT_IBAT].offset = V_offset *
                                V2A_gain + V2A_offset;
                } else {
                        gpadc->cal_data[ADC_INPUT_IBAT].gain = 0;
                }

                dev_dbg(gpadc->dev, "IBAT gain %llu offset %llu\n",
                        gpadc->cal_data[ADC_INPUT_IBAT].gain,
                        gpadc->cal_data[ADC_INPUT_IBAT].offset);
        } else {
                /* Calculate gain and offset for VMAIN if all reads succeeded */
                if (!(ret[0] < 0 || ret[1] < 0 || ret[2] < 0)) {
                        vmain_high = (((gpadc_cal[0] & 0x03) << 8) |
                                ((gpadc_cal[1] & 0x3F) << 2) |
                                ((gpadc_cal[2] & 0xC0) >> 6));
                        vmain_low = ((gpadc_cal[2] & 0x3E) >> 1);

                        gpadc->cal_data[ADC_INPUT_VMAIN].otp_calib_hi =
                                (u16)vmain_high;
                        gpadc->cal_data[ADC_INPUT_VMAIN].otp_calib_lo =
                                (u16)vmain_low;

                        gpadc->cal_data[ADC_INPUT_VMAIN].gain = CALIB_SCALE *
                                (19500 - 315) / (vmain_high - vmain_low);

                        gpadc->cal_data[ADC_INPUT_VMAIN].offset = CALIB_SCALE *
                                19500 - (CALIB_SCALE * (19500 - 315) /
                                (vmain_high - vmain_low)) * vmain_high;
                } else {
                        gpadc->cal_data[ADC_INPUT_VMAIN].gain = 0;
                }
        }

        /* Calculate gain and offset for BTEMP if all reads succeeded */
        if (!(ret[2] < 0 || ret[3] < 0 || ret[4] < 0)) {
                btemp_high = (((gpadc_cal[2] & 0x01) << 9) |
                        (gpadc_cal[3] << 1) | ((gpadc_cal[4] & 0x80) >> 7));
                btemp_low = ((gpadc_cal[4] & 0x7C) >> 2);

                gpadc->cal_data[ADC_INPUT_BTEMP].otp_calib_hi = (u16)btemp_high;
                gpadc->cal_data[ADC_INPUT_BTEMP].otp_calib_lo = (u16)btemp_low;

                gpadc->cal_data[ADC_INPUT_BTEMP].gain =
                        CALIB_SCALE * (1300 - 21) / (btemp_high - btemp_low);
                gpadc->cal_data[ADC_INPUT_BTEMP].offset = CALIB_SCALE * 1300 -
                        (CALIB_SCALE * (1300 - 21) / (btemp_high - btemp_low))
                        * btemp_high;
        } else {
                gpadc->cal_data[ADC_INPUT_BTEMP].gain = 0;
        }

        /* Calculate gain and offset for VBAT if all reads succeeded */
        if (!(ret[4] < 0 || ret[5] < 0 || ret[6] < 0)) {
                vbat_high = (((gpadc_cal[4] & 0x03) << 8) | gpadc_cal[5]);
                vbat_low = ((gpadc_cal[6] & 0xFC) >> 2);

                gpadc->cal_data[ADC_INPUT_VBAT].otp_calib_hi = (u16)vbat_high;
                gpadc->cal_data[ADC_INPUT_VBAT].otp_calib_lo = (u16)vbat_low;

                gpadc->cal_data[ADC_INPUT_VBAT].gain = CALIB_SCALE *
                        (4700 - 2380) / (vbat_high - vbat_low);
                gpadc->cal_data[ADC_INPUT_VBAT].offset = CALIB_SCALE * 4700 -
                        (CALIB_SCALE * (4700 - 2380) /
                        (vbat_high - vbat_low)) * vbat_high;
        } else {
                gpadc->cal_data[ADC_INPUT_VBAT].gain = 0;
        }

        dev_dbg(gpadc->dev, "VMAIN gain %llu offset %llu\n",
                gpadc->cal_data[ADC_INPUT_VMAIN].gain,
                gpadc->cal_data[ADC_INPUT_VMAIN].offset);

        dev_dbg(gpadc->dev, "BTEMP gain %llu offset %llu\n",
                gpadc->cal_data[ADC_INPUT_BTEMP].gain,
                gpadc->cal_data[ADC_INPUT_BTEMP].offset);

        dev_dbg(gpadc->dev, "VBAT gain %llu offset %llu\n",
                gpadc->cal_data[ADC_INPUT_VBAT].gain,
                gpadc->cal_data[ADC_INPUT_VBAT].offset);
}

static int ab8500_gpadc_runtime_suspend(struct device *dev)
{
        struct ab8500_gpadc *gpadc = dev_get_drvdata(dev);

        regulator_disable(gpadc->regu);
        return 0;
}

static int ab8500_gpadc_runtime_resume(struct device *dev)
{
        struct ab8500_gpadc *gpadc = dev_get_drvdata(dev);
        int ret;

        ret = regulator_enable(gpadc->regu);
        if (ret)
                dev_err(dev, "Failed to enable vtvout LDO: %d\n", ret);
        return ret;
}

static int ab8500_gpadc_runtime_idle(struct device *dev)
{
        pm_runtime_suspend(dev);
        return 0;
}

static int ab8500_gpadc_suspend(struct device *dev)
{
        struct ab8500_gpadc *gpadc = dev_get_drvdata(dev);

        mutex_lock(&gpadc->ab8500_gpadc_lock);

        pm_runtime_get_sync(dev);

        regulator_disable(gpadc->regu);
        return 0;
}

static int ab8500_gpadc_resume(struct device *dev)
{
        struct ab8500_gpadc *gpadc = dev_get_drvdata(dev);
        int ret;

        ret = regulator_enable(gpadc->regu);
        if (ret)
                dev_err(dev, "Failed to enable vtvout LDO: %d\n", ret);

        pm_runtime_mark_last_busy(gpadc->dev);
        pm_runtime_put_autosuspend(gpadc->dev);

        mutex_unlock(&gpadc->ab8500_gpadc_lock);
        return ret;
}

static int ab8500_gpadc_probe(struct platform_device *pdev)
{
        int ret = 0;
        struct ab8500_gpadc *gpadc;

        gpadc = kzalloc(sizeof(struct ab8500_gpadc), GFP_KERNEL);
        if (!gpadc) {
                dev_err(&pdev->dev, "Error: No memory\n");
                return -ENOMEM;
        }

        gpadc->irq_sw = platform_get_irq_byname(pdev, "SW_CONV_END");
        if (gpadc->irq_sw < 0)
                dev_err(gpadc->dev, "failed to get platform sw_conv_end irq\n");

        gpadc->irq_hw = platform_get_irq_byname(pdev, "HW_CONV_END");
        if (gpadc->irq_hw < 0)
                dev_err(gpadc->dev, "failed to get platform hw_conv_end irq\n");

        gpadc->dev = &pdev->dev;
        gpadc->parent = dev_get_drvdata(pdev->dev.parent);
        mutex_init(&gpadc->ab8500_gpadc_lock);

        /* Initialize completion used to notify completion of conversion */
        init_completion(&gpadc->ab8500_gpadc_complete);

        /* Register interrupts */
        if (gpadc->irq_sw >= 0) {
                ret = request_threaded_irq(gpadc->irq_sw, NULL,
                        ab8500_bm_gpadcconvend_handler,
                        IRQF_NO_SUSPEND | IRQF_SHARED, "ab8500-gpadc-sw",
                        gpadc);
                if (ret < 0) {
                        dev_err(gpadc->dev,
                                "Failed to register interrupt irq: %d\n",
                                gpadc->irq_sw);
                        goto fail;
                }
        }

        if (gpadc->irq_hw >= 0) {
                ret = request_threaded_irq(gpadc->irq_hw, NULL,
                        ab8500_bm_gpadcconvend_handler,
                        IRQF_NO_SUSPEND | IRQF_SHARED, "ab8500-gpadc-hw",
                        gpadc);
                if (ret < 0) {
                        dev_err(gpadc->dev,
                                "Failed to register interrupt irq: %d\n",
                                gpadc->irq_hw);
                        goto fail_irq;
                }
        }

        /* VTVout LDO used to power up ab8500-GPADC */
        gpadc->regu = devm_regulator_get(&pdev->dev, "vddadc");
        if (IS_ERR(gpadc->regu)) {
                ret = PTR_ERR(gpadc->regu);
                dev_err(gpadc->dev, "failed to get vtvout LDO\n");
                goto fail_irq;
        }

        platform_set_drvdata(pdev, gpadc);

        ret = regulator_enable(gpadc->regu);
        if (ret) {
                dev_err(gpadc->dev, "Failed to enable vtvout LDO: %d\n", ret);
                goto fail_enable;
        }

        pm_runtime_set_autosuspend_delay(gpadc->dev, GPADC_AUDOSUSPEND_DELAY);
        pm_runtime_use_autosuspend(gpadc->dev);
        pm_runtime_set_active(gpadc->dev);
        pm_runtime_enable(gpadc->dev);

        ab8500_gpadc_read_calibration_data(gpadc);
        list_add_tail(&gpadc->node, &ab8500_gpadc_list);
        dev_dbg(gpadc->dev, "probe success\n");

        return 0;

fail_enable:
fail_irq:
        free_irq(gpadc->irq_sw, gpadc);
        free_irq(gpadc->irq_hw, gpadc);
fail:
        kfree(gpadc);
        gpadc = NULL;
        return ret;
}

static int ab8500_gpadc_remove(struct platform_device *pdev)
{
        struct ab8500_gpadc *gpadc = platform_get_drvdata(pdev);

        /* remove this gpadc entry from the list */
        list_del(&gpadc->node);
        /* remove interrupt  - completion of Sw ADC conversion */
        if (gpadc->irq_sw >= 0)
                free_irq(gpadc->irq_sw, gpadc);
        if (gpadc->irq_hw >= 0)
                free_irq(gpadc->irq_hw, gpadc);

        pm_runtime_get_sync(gpadc->dev);
        pm_runtime_disable(gpadc->dev);

        regulator_disable(gpadc->regu);

        pm_runtime_set_suspended(gpadc->dev);

        pm_runtime_put_noidle(gpadc->dev);

        kfree(gpadc);
        gpadc = NULL;
        return 0;
}

static const struct dev_pm_ops ab8500_gpadc_pm_ops = {
        SET_RUNTIME_PM_OPS(ab8500_gpadc_runtime_suspend,
                           ab8500_gpadc_runtime_resume,
                           ab8500_gpadc_runtime_idle)
        SET_SYSTEM_SLEEP_PM_OPS(ab8500_gpadc_suspend,
                                ab8500_gpadc_resume)

};

static struct platform_driver ab8500_gpadc_driver = {
        .probe = ab8500_gpadc_probe,
        .remove = ab8500_gpadc_remove,
        .driver = {
                .name = "ab8500-gpadc",
                .owner = THIS_MODULE,
                .pm = &ab8500_gpadc_pm_ops,
        },
};

static int __init ab8500_gpadc_init(void)
{
        return platform_driver_register(&ab8500_gpadc_driver);
}

static void __exit ab8500_gpadc_exit(void)
{
        platform_driver_unregister(&ab8500_gpadc_driver);
}

/**
 * ab8540_gpadc_get_otp() - returns OTP values
 *
 */
void ab8540_gpadc_get_otp(struct ab8500_gpadc *gpadc,
                        u16 *vmain_l, u16 *vmain_h, u16 *btemp_l, u16 *btemp_h,
                        u16 *vbat_l, u16 *vbat_h, u16 *ibat_l, u16 *ibat_h)
{
        *vmain_l = gpadc->cal_data[ADC_INPUT_VMAIN].otp_calib_lo;
        *vmain_h = gpadc->cal_data[ADC_INPUT_VMAIN].otp_calib_hi;
        *btemp_l = gpadc->cal_data[ADC_INPUT_BTEMP].otp_calib_lo;
        *btemp_h = gpadc->cal_data[ADC_INPUT_BTEMP].otp_calib_hi;
        *vbat_l = gpadc->cal_data[ADC_INPUT_VBAT].otp_calib_lo;
        *vbat_h = gpadc->cal_data[ADC_INPUT_VBAT].otp_calib_hi;
        *ibat_l = gpadc->cal_data[ADC_INPUT_IBAT].otp_calib_lo;
        *ibat_h = gpadc->cal_data[ADC_INPUT_IBAT].otp_calib_hi;
        return ;
}

subsys_initcall_sync(ab8500_gpadc_init);
module_exit(ab8500_gpadc_exit);

MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Arun R Murthy, Daniel Willerud, Johan Palsson,"
                "M'boumba Cedric Madianga");
MODULE_ALIAS("platform:ab8500_gpadc");
MODULE_DESCRIPTION("AB8500 GPADC driver");