/*
 * sca3000_core.c -- support VTI sca3000 series accelerometers via SPI
 *
 * 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.
 *
 * Copyright (c) 2009 Jonathan Cameron <jic23@kernel.org>
 *
 * See industrialio/accels/sca3000.h for comments.
 */

#include <linux/interrupt.h>
#include <linux/fs.h>
#include <linux/device.h>
#include <linux/slab.h>
#include <linux/kernel.h>
#include <linux/spi/spi.h>
#include <linux/sysfs.h>
#include <linux/module.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/iio/events.h>
#include <linux/iio/buffer.h>

#include "sca3000.h"

enum sca3000_variant {
        d01,
        e02,
        e04,
        e05,
};

/*
 * Note where option modes are not defined, the chip simply does not
 * support any.
 * Other chips in the sca3000 series use i2c and are not included here.
 *
 * Some of these devices are only listed in the family data sheet and
 * do not actually appear to be available.
 */
static const struct sca3000_chip_info sca3000_spi_chip_info_tbl[] = {
        [d01] = {
                .scale = 7357,
                .temp_output = true,
                .measurement_mode_freq = 250,
                .option_mode_1 = SCA3000_OP_MODE_BYPASS,
                .option_mode_1_freq = 250,
                .mot_det_mult_xz = {50, 100, 200, 350, 650, 1300},
                .mot_det_mult_y = {50, 100, 150, 250, 450, 850, 1750},
        },
        [e02] = {
                .scale = 9810,
                .measurement_mode_freq = 125,
                .option_mode_1 = SCA3000_OP_MODE_NARROW,
                .option_mode_1_freq = 63,
                .mot_det_mult_xz = {100, 150, 300, 550, 1050, 2050},
                .mot_det_mult_y = {50, 100, 200, 350, 700, 1350, 2700},
        },
        [e04] = {
                .scale = 19620,
                .measurement_mode_freq = 100,
                .option_mode_1 = SCA3000_OP_MODE_NARROW,
                .option_mode_1_freq = 50,
                .option_mode_2 = SCA3000_OP_MODE_WIDE,
                .option_mode_2_freq = 400,
                .mot_det_mult_xz = {200, 300, 600, 1100, 2100, 4100},
                .mot_det_mult_y = {100, 200, 400, 7000, 1400, 2700, 54000},
        },
        [e05] = {
                .scale = 61313,
                .measurement_mode_freq = 200,
                .option_mode_1 = SCA3000_OP_MODE_NARROW,
                .option_mode_1_freq = 50,
                .option_mode_2 = SCA3000_OP_MODE_WIDE,
                .option_mode_2_freq = 400,
                .mot_det_mult_xz = {600, 900, 1700, 3200, 6100, 11900},
                .mot_det_mult_y = {300, 600, 1200, 2000, 4100, 7800, 15600},
        },
};

int sca3000_write_reg(struct sca3000_state *st, u8 address, u8 val)
{
        st->tx[0] = SCA3000_WRITE_REG(address);
        st->tx[1] = val;
        return spi_write(st->us, st->tx, 2);
}

int sca3000_read_data_short(struct sca3000_state *st,
                            u8 reg_address_high,
                            int len)
{
        struct spi_transfer xfer[2] = {
                {
                        .len = 1,
                        .tx_buf = st->tx,
                }, {
                        .len = len,
                        .rx_buf = st->rx,
                }
        };
        st->tx[0] = SCA3000_READ_REG(reg_address_high);

        return spi_sync_transfer(st->us, xfer, ARRAY_SIZE(xfer));
}

/**
 * sca3000_reg_lock_on() test if the ctrl register lock is on
 *
 * Lock must be held.
 **/
static int sca3000_reg_lock_on(struct sca3000_state *st)
{
        int ret;

        ret = sca3000_read_data_short(st, SCA3000_REG_ADDR_STATUS, 1);
        if (ret < 0)
                return ret;

        return !(st->rx[0] & SCA3000_LOCKED);
}

/**
 * __sca3000_unlock_reg_lock() unlock the control registers
 *
 * Note the device does not appear to support doing this in a single transfer.
 * This should only ever be used as part of ctrl reg read.
 * Lock must be held before calling this
 **/
static int __sca3000_unlock_reg_lock(struct sca3000_state *st)
{
        struct spi_transfer xfer[3] = {
                {
                        .len = 2,
                        .cs_change = 1,
                        .tx_buf = st->tx,
                }, {
                        .len = 2,
                        .cs_change = 1,
                        .tx_buf = st->tx + 2,
                }, {
                        .len = 2,
                        .tx_buf = st->tx + 4,
                },
        };
        st->tx[0] = SCA3000_WRITE_REG(SCA3000_REG_ADDR_UNLOCK);
        st->tx[1] = 0x00;
        st->tx[2] = SCA3000_WRITE_REG(SCA3000_REG_ADDR_UNLOCK);
        st->tx[3] = 0x50;
        st->tx[4] = SCA3000_WRITE_REG(SCA3000_REG_ADDR_UNLOCK);
        st->tx[5] = 0xA0;

        return spi_sync_transfer(st->us, xfer, ARRAY_SIZE(xfer));
}

/**
 * sca3000_write_ctrl_reg() write to a lock protect ctrl register
 * @sel: selects which registers we wish to write to
 * @val: the value to be written
 *
 * Certain control registers are protected against overwriting by the lock
 * register and use a shared write address. This function allows writing of
 * these registers.
 * Lock must be held.
 **/
static int sca3000_write_ctrl_reg(struct sca3000_state *st,
                                  u8 sel,
                                  uint8_t val)
{
        int ret;

        ret = sca3000_reg_lock_on(st);
        if (ret < 0)
                goto error_ret;
        if (ret) {
                ret = __sca3000_unlock_reg_lock(st);
                if (ret)
                        goto error_ret;
        }

        /* Set the control select register */
        ret = sca3000_write_reg(st, SCA3000_REG_ADDR_CTRL_SEL, sel);
        if (ret)
                goto error_ret;

        /* Write the actual value into the register */
        ret = sca3000_write_reg(st, SCA3000_REG_ADDR_CTRL_DATA, val);

error_ret:
        return ret;
}

/**
 * sca3000_read_ctrl_reg() read from lock protected control register.
 *
 * Lock must be held.
 **/
static int sca3000_read_ctrl_reg(struct sca3000_state *st,
                                 u8 ctrl_reg)
{
        int ret;

        ret = sca3000_reg_lock_on(st);
        if (ret < 0)
                goto error_ret;
        if (ret) {
                ret = __sca3000_unlock_reg_lock(st);
                if (ret)
                        goto error_ret;
        }
        /* Set the control select register */
        ret = sca3000_write_reg(st, SCA3000_REG_ADDR_CTRL_SEL, ctrl_reg);
        if (ret)
                goto error_ret;
        ret = sca3000_read_data_short(st, SCA3000_REG_ADDR_CTRL_DATA, 1);
        if (ret)
                goto error_ret;
        return st->rx[0];
error_ret:
        return ret;
}

/**
 * sca3000_show_rev() - sysfs interface to read the chip revision number
 **/
static ssize_t sca3000_show_rev(struct device *dev,
                                struct device_attribute *attr,
                                char *buf)
{
        int len = 0, ret;
        struct iio_dev *indio_dev = dev_to_iio_dev(dev);
        struct sca3000_state *st = iio_priv(indio_dev);

        mutex_lock(&st->lock);
        ret = sca3000_read_data_short(st, SCA3000_REG_ADDR_REVID, 1);
        if (ret < 0)
                goto error_ret;
        len += sprintf(buf + len,
                       "major=%d, minor=%d\n",
                       st->rx[0] & SCA3000_REVID_MAJOR_MASK,
                       st->rx[0] & SCA3000_REVID_MINOR_MASK);
error_ret:
        mutex_unlock(&st->lock);

        return ret ? ret : len;
}

/**
 * sca3000_show_available_measurement_modes() display available modes
 *
 * This is all read from chip specific data in the driver. Not all
 * of the sca3000 series support modes other than normal.
 **/
static ssize_t
sca3000_show_available_measurement_modes(struct device *dev,
                                         struct device_attribute *attr,
                                         char *buf)
{
        struct iio_dev *indio_dev = dev_to_iio_dev(dev);
        struct sca3000_state *st = iio_priv(indio_dev);
        int len = 0;

        len += sprintf(buf + len, "0 - normal mode");
        switch (st->info->option_mode_1) {
        case SCA3000_OP_MODE_NARROW:
                len += sprintf(buf + len, ", 1 - narrow mode");
                break;
        case SCA3000_OP_MODE_BYPASS:
                len += sprintf(buf + len, ", 1 - bypass mode");
                break;
        }
        switch (st->info->option_mode_2) {
        case SCA3000_OP_MODE_WIDE:
                len += sprintf(buf + len, ", 2 - wide mode");
                break;
        }
        /* always supported */
        len += sprintf(buf + len, " 3 - motion detection\n");

        return len;
}

/**
 * sca3000_show_measurement_mode() sysfs read of current mode
 **/
static ssize_t
sca3000_show_measurement_mode(struct device *dev,
                              struct device_attribute *attr,
                              char *buf)
{
        struct iio_dev *indio_dev = dev_to_iio_dev(dev);
        struct sca3000_state *st = iio_priv(indio_dev);
        int len = 0, ret;

        mutex_lock(&st->lock);
        ret = sca3000_read_data_short(st, SCA3000_REG_ADDR_MODE, 1);
        if (ret)
                goto error_ret;
        /* mask bottom 2 bits - only ones that are relevant */
        st->rx[0] &= 0x03;
        switch (st->rx[0]) {
        case SCA3000_MEAS_MODE_NORMAL:
                len += sprintf(buf + len, "0 - normal mode\n");
                break;
        case SCA3000_MEAS_MODE_MOT_DET:
                len += sprintf(buf + len, "3 - motion detection\n");
                break;
        case SCA3000_MEAS_MODE_OP_1:
                switch (st->info->option_mode_1) {
                case SCA3000_OP_MODE_NARROW:
                        len += sprintf(buf + len, "1 - narrow mode\n");
                        break;
                case SCA3000_OP_MODE_BYPASS:
                        len += sprintf(buf + len, "1 - bypass mode\n");
                        break;
                }
                break;
        case SCA3000_MEAS_MODE_OP_2:
                switch (st->info->option_mode_2) {
                case SCA3000_OP_MODE_WIDE:
                        len += sprintf(buf + len, "2 - wide mode\n");
                        break;
                }
                break;
        }

error_ret:
        mutex_unlock(&st->lock);

        return ret ? ret : len;
}

/**
 * sca3000_store_measurement_mode() set the current mode
 **/
static ssize_t
sca3000_store_measurement_mode(struct device *dev,
                               struct device_attribute *attr,
                               const char *buf,
                               size_t len)
{
        struct iio_dev *indio_dev = dev_to_iio_dev(dev);
        struct sca3000_state *st = iio_priv(indio_dev);
        int ret;
        u8 mask = 0x03;
        u8 val;

        mutex_lock(&st->lock);
        ret = kstrtou8(buf, 10, &val);
        if (ret)
                goto error_ret;
        if (val > 3) {
                ret = -EINVAL;
                goto error_ret;
        }
        ret = sca3000_read_data_short(st, SCA3000_REG_ADDR_MODE, 1);
        if (ret)
                goto error_ret;
        st->rx[0] &= ~mask;
        st->rx[0] |= (val & mask);
        ret = sca3000_write_reg(st, SCA3000_REG_ADDR_MODE, st->rx[0]);
        if (ret)
                goto error_ret;
        mutex_unlock(&st->lock);

        return len;

error_ret:
        mutex_unlock(&st->lock);

        return ret;
}

/*
 * Not even vaguely standard attributes so defined here rather than
 * in the relevant IIO core headers
 */
static IIO_DEVICE_ATTR(measurement_mode_available, S_IRUGO,
                       sca3000_show_available_measurement_modes,
                       NULL, 0);

static IIO_DEVICE_ATTR(measurement_mode, S_IRUGO | S_IWUSR,
                       sca3000_show_measurement_mode,
                       sca3000_store_measurement_mode,
                       0);

/* More standard attributes */

static IIO_DEVICE_ATTR(revision, S_IRUGO, sca3000_show_rev, NULL, 0);

static const struct iio_event_spec sca3000_event = {
        .type = IIO_EV_TYPE_MAG,
        .dir = IIO_EV_DIR_RISING,
        .mask_separate = BIT(IIO_EV_INFO_VALUE) | BIT(IIO_EV_INFO_ENABLE),
};

#define SCA3000_CHAN(index, mod)                                \
        {                                                       \
                .type = IIO_ACCEL,                              \
                .modified = 1,                                  \
                .channel2 = mod,                                \
                .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),   \
                .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),\
                .address = index,                               \
                .scan_index = index,                            \
                .scan_type = {                                  \
                        .sign = 's',                            \
                        .realbits = 11,                         \
                        .storagebits = 16,                      \
                        .shift = 5,                             \
                },                                              \
                .event_spec = &sca3000_event,                   \
                .num_event_specs = 1,                           \
         }

static const struct iio_chan_spec sca3000_channels[] = {
        SCA3000_CHAN(0, IIO_MOD_X),
        SCA3000_CHAN(1, IIO_MOD_Y),
        SCA3000_CHAN(2, IIO_MOD_Z),
};

static const struct iio_chan_spec sca3000_channels_with_temp[] = {
        SCA3000_CHAN(0, IIO_MOD_X),
        SCA3000_CHAN(1, IIO_MOD_Y),
        SCA3000_CHAN(2, IIO_MOD_Z),
        {
                .type = IIO_TEMP,
                .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
                .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) |
                        BIT(IIO_CHAN_INFO_OFFSET),
                /* No buffer support */
                .scan_index = -1,
        },
};

static u8 sca3000_addresses[3][3] = {
        [0] = {SCA3000_REG_ADDR_X_MSB, SCA3000_REG_CTRL_SEL_MD_X_TH,
               SCA3000_MD_CTRL_OR_X},
        [1] = {SCA3000_REG_ADDR_Y_MSB, SCA3000_REG_CTRL_SEL_MD_Y_TH,
               SCA3000_MD_CTRL_OR_Y},
        [2] = {SCA3000_REG_ADDR_Z_MSB, SCA3000_REG_CTRL_SEL_MD_Z_TH,
               SCA3000_MD_CTRL_OR_Z},
};

static int sca3000_read_raw(struct iio_dev *indio_dev,
                            struct iio_chan_spec const *chan,
                            int *val,
                            int *val2,
                            long mask)
{
        struct sca3000_state *st = iio_priv(indio_dev);
        int ret;
        u8 address;

        switch (mask) {
        case IIO_CHAN_INFO_RAW:
                mutex_lock(&st->lock);
                if (chan->type == IIO_ACCEL) {
                        if (st->mo_det_use_count) {
                                mutex_unlock(&st->lock);
                                return -EBUSY;
                        }
                        address = sca3000_addresses[chan->address][0];
                        ret = sca3000_read_data_short(st, address, 2);
                        if (ret < 0) {
                                mutex_unlock(&st->lock);
                                return ret;
                        }
                        *val = (be16_to_cpup((__be16 *)st->rx) >> 3) & 0x1FFF;
                        *val = ((*val) << (sizeof(*val) * 8 - 13)) >>
                                (sizeof(*val) * 8 - 13);
                } else {
                        /* get the temperature when available */
                        ret = sca3000_read_data_short(st,
                                                      SCA3000_REG_ADDR_TEMP_MSB,
                                                      2);
                        if (ret < 0) {
                                mutex_unlock(&st->lock);
                                return ret;
                        }
                        *val = ((st->rx[0] & 0x3F) << 3) |
                               ((st->rx[1] & 0xE0) >> 5);
                }
                mutex_unlock(&st->lock);
                return IIO_VAL_INT;
        case IIO_CHAN_INFO_SCALE:
                *val = 0;
                if (chan->type == IIO_ACCEL)
                        *val2 = st->info->scale;
                else /* temperature */
                        *val2 = 555556;
                return IIO_VAL_INT_PLUS_MICRO;
        case IIO_CHAN_INFO_OFFSET:
                *val = -214;
                *val2 = 600000;
                return IIO_VAL_INT_PLUS_MICRO;
        default:
                return -EINVAL;
        }
}

/**
 * sca3000_read_av_freq() sysfs function to get available frequencies
 *
 * The later modes are only relevant to the ring buffer - and depend on current
 * mode. Note that data sheet gives rather wide tolerances for these so integer
 * division will give good enough answer and not all chips have them specified
 * at all.
 **/
static ssize_t sca3000_read_av_freq(struct device *dev,
                                    struct device_attribute *attr,
                                    char *buf)
{
        struct iio_dev *indio_dev = dev_to_iio_dev(dev);
        struct sca3000_state *st = iio_priv(indio_dev);
        int len = 0, ret, val;

        mutex_lock(&st->lock);
        ret = sca3000_read_data_short(st, SCA3000_REG_ADDR_MODE, 1);
        val = st->rx[0];
        mutex_unlock(&st->lock);
        if (ret)
                goto error_ret;

        switch (val & 0x03) {
        case SCA3000_MEAS_MODE_NORMAL:
                len += sprintf(buf + len, "%d %d %d\n",
                               st->info->measurement_mode_freq,
                               st->info->measurement_mode_freq / 2,
                               st->info->measurement_mode_freq / 4);
                break;
        case SCA3000_MEAS_MODE_OP_1:
                len += sprintf(buf + len, "%d %d %d\n",
                               st->info->option_mode_1_freq,
                               st->info->option_mode_1_freq / 2,
                               st->info->option_mode_1_freq / 4);
                break;
        case SCA3000_MEAS_MODE_OP_2:
                len += sprintf(buf + len, "%d %d %d\n",
                               st->info->option_mode_2_freq,
                               st->info->option_mode_2_freq / 2,
                               st->info->option_mode_2_freq / 4);
                break;
        }
        return len;
error_ret:
        return ret;
}

/**
 * __sca3000_get_base_freq() obtain mode specific base frequency
 *
 * lock must be held
 **/
static inline int __sca3000_get_base_freq(struct sca3000_state *st,
                                          const struct sca3000_chip_info *info,
                                          int *base_freq)
{
        int ret;

        ret = sca3000_read_data_short(st, SCA3000_REG_ADDR_MODE, 1);
        if (ret)
                goto error_ret;
        switch (0x03 & st->rx[0]) {
        case SCA3000_MEAS_MODE_NORMAL:
                *base_freq = info->measurement_mode_freq;
                break;
        case SCA3000_MEAS_MODE_OP_1:
                *base_freq = info->option_mode_1_freq;
                break;
        case SCA3000_MEAS_MODE_OP_2:
                *base_freq = info->option_mode_2_freq;
                break;
        }
error_ret:
        return ret;
}

/**
 * sca3000_read_frequency() sysfs interface to get the current frequency
 **/
static ssize_t sca3000_read_frequency(struct device *dev,
                                      struct device_attribute *attr,
                                      char *buf)
{
        struct iio_dev *indio_dev = dev_to_iio_dev(dev);
        struct sca3000_state *st = iio_priv(indio_dev);
        int ret, len = 0, base_freq = 0, val;

        mutex_lock(&st->lock);
        ret = __sca3000_get_base_freq(st, st->info, &base_freq);
        if (ret)
                goto error_ret_mut;
        ret = sca3000_read_ctrl_reg(st, SCA3000_REG_CTRL_SEL_OUT_CTRL);
        mutex_unlock(&st->lock);
        if (ret)
                goto error_ret;
        val = ret;
        if (base_freq > 0)
                switch (val & 0x03) {
                case 0x00:
                case 0x03:
                        len = sprintf(buf, "%d\n", base_freq);
                        break;
                case 0x01:
                        len = sprintf(buf, "%d\n", base_freq / 2);
                        break;
                case 0x02:
                        len = sprintf(buf, "%d\n", base_freq / 4);
                        break;
        }

        return len;
error_ret_mut:
        mutex_unlock(&st->lock);
error_ret:
        return ret;
}

/**
 * sca3000_set_frequency() sysfs interface to set the current frequency
 **/
static ssize_t sca3000_set_frequency(struct device *dev,
                                     struct device_attribute *attr,
                                     const char *buf,
                                     size_t len)
{
        struct iio_dev *indio_dev = dev_to_iio_dev(dev);
        struct sca3000_state *st = iio_priv(indio_dev);
        int ret, base_freq = 0;
        int ctrlval;
        int val;

        ret = kstrtoint(buf, 10, &val);
        if (ret)
                return ret;

        mutex_lock(&st->lock);
        /* What mode are we in? */
        ret = __sca3000_get_base_freq(st, st->info, &base_freq);
        if (ret)
                goto error_free_lock;

        ret = sca3000_read_ctrl_reg(st, SCA3000_REG_CTRL_SEL_OUT_CTRL);
        if (ret < 0)
                goto error_free_lock;
        ctrlval = ret;
        /* clear the bits */
        ctrlval &= ~0x03;

        if (val == base_freq / 2) {
                ctrlval |= SCA3000_OUT_CTRL_BUF_DIV_2;
        } else if (val == base_freq / 4) {
                ctrlval |= SCA3000_OUT_CTRL_BUF_DIV_4;
        } else if (val != base_freq) {
                ret = -EINVAL;
                goto error_free_lock;
        }
        ret = sca3000_write_ctrl_reg(st, SCA3000_REG_CTRL_SEL_OUT_CTRL,
                                     ctrlval);
error_free_lock:
        mutex_unlock(&st->lock);

        return ret ? ret : len;
}

/*
 * Should only really be registered if ring buffer support is compiled in.
 * Does no harm however and doing it right would add a fair bit of complexity
 */
static IIO_DEV_ATTR_SAMP_FREQ_AVAIL(sca3000_read_av_freq);

static IIO_DEV_ATTR_SAMP_FREQ(S_IWUSR | S_IRUGO,
                              sca3000_read_frequency,
                              sca3000_set_frequency);

/**
 * sca3000_read_thresh() - query of a threshold
 **/
static int sca3000_read_thresh(struct iio_dev *indio_dev,
                               const struct iio_chan_spec *chan,
                               enum iio_event_type type,
                               enum iio_event_direction dir,
                               enum iio_event_info info,
                               int *val, int *val2)
{
        int ret, i;
        struct sca3000_state *st = iio_priv(indio_dev);
        int num = chan->channel2;

        mutex_lock(&st->lock);
        ret = sca3000_read_ctrl_reg(st, sca3000_addresses[num][1]);
        mutex_unlock(&st->lock);
        if (ret < 0)
                return ret;
        *val = 0;
        if (num == 1)
                for_each_set_bit(i, (unsigned long *)&ret,
                                 ARRAY_SIZE(st->info->mot_det_mult_y))
                        *val += st->info->mot_det_mult_y[i];
        else
                for_each_set_bit(i, (unsigned long *)&ret,
                                 ARRAY_SIZE(st->info->mot_det_mult_xz))
                        *val += st->info->mot_det_mult_xz[i];

        return IIO_VAL_INT;
}

/**
 * sca3000_write_thresh() control of threshold
 **/
static int sca3000_write_thresh(struct iio_dev *indio_dev,
                                const struct iio_chan_spec *chan,
                                enum iio_event_type type,
                                enum iio_event_direction dir,
                                enum iio_event_info info,
                                int val, int val2)
{
        struct sca3000_state *st = iio_priv(indio_dev);
        int num = chan->channel2;
        int ret;
        int i;
        u8 nonlinear = 0;

        if (num == 1) {
                i = ARRAY_SIZE(st->info->mot_det_mult_y);
                while (i > 0)
                        if (val >= st->info->mot_det_mult_y[--i]) {
                                nonlinear |= (1 << i);
                                val -= st->info->mot_det_mult_y[i];
                        }
        } else {
                i = ARRAY_SIZE(st->info->mot_det_mult_xz);
                while (i > 0)
                        if (val >= st->info->mot_det_mult_xz[--i]) {
                                nonlinear |= (1 << i);
                                val -= st->info->mot_det_mult_xz[i];
                        }
        }

        mutex_lock(&st->lock);
        ret = sca3000_write_ctrl_reg(st, sca3000_addresses[num][1], nonlinear);
        mutex_unlock(&st->lock);

        return ret;
}

static struct attribute *sca3000_attributes[] = {
        &iio_dev_attr_revision.dev_attr.attr,
        &iio_dev_attr_measurement_mode_available.dev_attr.attr,
        &iio_dev_attr_measurement_mode.dev_attr.attr,
        &iio_dev_attr_sampling_frequency_available.dev_attr.attr,
        &iio_dev_attr_sampling_frequency.dev_attr.attr,
        NULL,
};

static const struct attribute_group sca3000_attribute_group = {
        .attrs = sca3000_attributes,
};

/**
 * sca3000_event_handler() - handling ring and non ring events
 *
 * Ring related interrupt handler. Depending on event, push to
 * the ring buffer event chrdev or the event one.
 *
 * This function is complicated by the fact that the devices can signify ring
 * and non ring events via the same interrupt line and they can only
 * be distinguished via a read of the relevant status register.
 **/
static irqreturn_t sca3000_event_handler(int irq, void *private)
{
        struct iio_dev *indio_dev = private;
        struct sca3000_state *st = iio_priv(indio_dev);
        int ret, val;
        s64 last_timestamp = iio_get_time_ns();

        /*
         * Could lead if badly timed to an extra read of status reg,
         * but ensures no interrupt is missed.
         */
        mutex_lock(&st->lock);
        ret = sca3000_read_data_short(st, SCA3000_REG_ADDR_INT_STATUS, 1);
        val = st->rx[0];
        mutex_unlock(&st->lock);
        if (ret)
                goto done;

        sca3000_ring_int_process(val, indio_dev->buffer);

        if (val & SCA3000_INT_STATUS_FREE_FALL)
                iio_push_event(indio_dev,
                               IIO_MOD_EVENT_CODE(IIO_ACCEL,
                                                  0,
                                                  IIO_MOD_X_AND_Y_AND_Z,
                                                  IIO_EV_TYPE_MAG,
                                                  IIO_EV_DIR_FALLING),
                               last_timestamp);

        if (val & SCA3000_INT_STATUS_Y_TRIGGER)
                iio_push_event(indio_dev,
                               IIO_MOD_EVENT_CODE(IIO_ACCEL,
                                                  0,
                                                  IIO_MOD_Y,
                                                  IIO_EV_TYPE_MAG,
                                                  IIO_EV_DIR_RISING),
                               last_timestamp);

        if (val & SCA3000_INT_STATUS_X_TRIGGER)
                iio_push_event(indio_dev,
                               IIO_MOD_EVENT_CODE(IIO_ACCEL,
                                                  0,
                                                  IIO_MOD_X,
                                                  IIO_EV_TYPE_MAG,
                                                  IIO_EV_DIR_RISING),
                               last_timestamp);

        if (val & SCA3000_INT_STATUS_Z_TRIGGER)
                iio_push_event(indio_dev,
                               IIO_MOD_EVENT_CODE(IIO_ACCEL,
                                                  0,
                                                  IIO_MOD_Z,
                                                  IIO_EV_TYPE_MAG,
                                                  IIO_EV_DIR_RISING),
                               last_timestamp);

done:
        return IRQ_HANDLED;
}

/**
 * sca3000_read_event_config() what events are enabled
 **/
static int sca3000_read_event_config(struct iio_dev *indio_dev,
                                     const struct iio_chan_spec *chan,
                                     enum iio_event_type type,
                                     enum iio_event_direction dir)
{
        struct sca3000_state *st = iio_priv(indio_dev);
        int ret;
        u8 protect_mask = 0x03;
        int num = chan->channel2;

        /* read current value of mode register */
        mutex_lock(&st->lock);
        ret = sca3000_read_data_short(st, SCA3000_REG_ADDR_MODE, 1);
        if (ret)
                goto error_ret;

        if ((st->rx[0] & protect_mask) != SCA3000_MEAS_MODE_MOT_DET) {
                ret = 0;
        } else {
                ret = sca3000_read_ctrl_reg(st, SCA3000_REG_CTRL_SEL_MD_CTRL);
                if (ret < 0)
                        goto error_ret;
                /* only supporting logical or's for now */
                ret = !!(ret & sca3000_addresses[num][2]);
        }
error_ret:
        mutex_unlock(&st->lock);

        return ret;
}

/**
 * sca3000_query_free_fall_mode() is free fall mode enabled
 **/
static ssize_t sca3000_query_free_fall_mode(struct device *dev,
                                            struct device_attribute *attr,
                                            char *buf)
{
        int ret;
        struct iio_dev *indio_dev = dev_to_iio_dev(dev);
        struct sca3000_state *st = iio_priv(indio_dev);
        int val;

        mutex_lock(&st->lock);
        ret = sca3000_read_data_short(st, SCA3000_REG_ADDR_MODE, 1);
        val = st->rx[0];
        mutex_unlock(&st->lock);
        if (ret < 0)
                return ret;
        return sprintf(buf, "%d\n", !!(val & SCA3000_FREE_FALL_DETECT));
}

/**
 * sca3000_set_free_fall_mode() simple on off control for free fall int
 *
 * In these chips the free fall detector should send an interrupt if
 * the device falls more than 25cm.  This has not been tested due
 * to fragile wiring.
 **/
static ssize_t sca3000_set_free_fall_mode(struct device *dev,
                                          struct device_attribute *attr,
                                          const char *buf,
                                          size_t len)
{
        struct iio_dev *indio_dev = dev_to_iio_dev(dev);
        struct sca3000_state *st = iio_priv(indio_dev);
        u8 val;
        int ret;
        u8 protect_mask = SCA3000_FREE_FALL_DETECT;

        mutex_lock(&st->lock);
        ret = kstrtou8(buf, 10, &val);
        if (ret)
                goto error_ret;

        /* read current value of mode register */
        ret = sca3000_read_data_short(st, SCA3000_REG_ADDR_MODE, 1);
        if (ret)
                goto error_ret;

        /* if off and should be on */
        if (val && !(st->rx[0] & protect_mask))
                ret = sca3000_write_reg(st, SCA3000_REG_ADDR_MODE,
                                        (st->rx[0] | SCA3000_FREE_FALL_DETECT));
        /* if on and should be off */
        else if (!val && (st->rx[0] & protect_mask))
                ret = sca3000_write_reg(st, SCA3000_REG_ADDR_MODE,
                                        (st->rx[0] & ~protect_mask));
error_ret:
        mutex_unlock(&st->lock);

        return ret ? ret : len;
}

/**
 * sca3000_write_event_config() simple on off control for motion detector
 *
 * This is a per axis control, but enabling any will result in the
 * motion detector unit being enabled.
 * N.B. enabling motion detector stops normal data acquisition.
 * There is a complexity in knowing which mode to return to when
 * this mode is disabled.  Currently normal mode is assumed.
 **/
static int sca3000_write_event_config(struct iio_dev *indio_dev,
                                      const struct iio_chan_spec *chan,
                                      enum iio_event_type type,
                                      enum iio_event_direction dir,
                                      int state)
{
        struct sca3000_state *st = iio_priv(indio_dev);
        int ret, ctrlval;
        u8 protect_mask = 0x03;
        int num = chan->channel2;

        mutex_lock(&st->lock);
        /*
         * First read the motion detector config to find out if
         * this axis is on
         */
        ret = sca3000_read_ctrl_reg(st, SCA3000_REG_CTRL_SEL_MD_CTRL);
        if (ret < 0)
                goto exit_point;
        ctrlval = ret;
        /* if off and should be on */
        if (state && !(ctrlval & sca3000_addresses[num][2])) {
                ret = sca3000_write_ctrl_reg(st,
                                             SCA3000_REG_CTRL_SEL_MD_CTRL,
                                             ctrlval |
                                             sca3000_addresses[num][2]);
                if (ret)
                        goto exit_point;
                st->mo_det_use_count++;
        } else if (!state && (ctrlval & sca3000_addresses[num][2])) {
                ret = sca3000_write_ctrl_reg(st,
                                             SCA3000_REG_CTRL_SEL_MD_CTRL,
                                             ctrlval &
                                             ~(sca3000_addresses[num][2]));
                if (ret)
                        goto exit_point;
                st->mo_det_use_count--;
        }

        /* read current value of mode register */
        ret = sca3000_read_data_short(st, SCA3000_REG_ADDR_MODE, 1);
        if (ret)
                goto exit_point;
        /* if off and should be on */
        if ((st->mo_det_use_count) &&
            ((st->rx[0] & protect_mask) != SCA3000_MEAS_MODE_MOT_DET))
                ret = sca3000_write_reg(st, SCA3000_REG_ADDR_MODE,
                                        (st->rx[0] & ~protect_mask)
                                        | SCA3000_MEAS_MODE_MOT_DET);
        /* if on and should be off */
        else if (!(st->mo_det_use_count) &&
                 ((st->rx[0] & protect_mask) == SCA3000_MEAS_MODE_MOT_DET))
                ret = sca3000_write_reg(st, SCA3000_REG_ADDR_MODE,
                                        (st->rx[0] & ~protect_mask));
exit_point:
        mutex_unlock(&st->lock);

        return ret;
}

/* Free fall detector related event attribute */
static IIO_DEVICE_ATTR_NAMED(accel_xayaz_mag_falling_en,
                             in_accel_x & y & z_mag_falling_en,

                             S_IRUGO | S_IWUSR,
                             sca3000_query_free_fall_mode,
                             sca3000_set_free_fall_mode,
                             0);

static IIO_CONST_ATTR_NAMED(accel_xayaz_mag_falling_period,
                            in_accel_x & y & z_mag_falling_period,
                            "0.226");

static struct attribute *sca3000_event_attributes[] = {
        &iio_dev_attr_accel_xayaz_mag_falling_en.dev_attr.attr,
        &iio_const_attr_accel_xayaz_mag_falling_period.dev_attr.attr,
        NULL,
};

static struct attribute_group sca3000_event_attribute_group = {
        .attrs = sca3000_event_attributes,
        .name = "events",
};

/**
 * sca3000_clean_setup() get the device into a predictable state
 *
 * Devices use flash memory to store many of the register values
 * and hence can come up in somewhat unpredictable states.
 * Hence reset everything on driver load.
 **/
static int sca3000_clean_setup(struct sca3000_state *st)
{
        int ret;

        mutex_lock(&st->lock);
        /* Ensure all interrupts have been acknowledged */
        ret = sca3000_read_data_short(st, SCA3000_REG_ADDR_INT_STATUS, 1);
        if (ret)
                goto error_ret;

        /* Turn off all motion detection channels */
        ret = sca3000_read_ctrl_reg(st, SCA3000_REG_CTRL_SEL_MD_CTRL);
        if (ret < 0)
                goto error_ret;
        ret = sca3000_write_ctrl_reg(st, SCA3000_REG_CTRL_SEL_MD_CTRL,
                                     ret & SCA3000_MD_CTRL_PROT_MASK);
        if (ret)
                goto error_ret;

        /* Disable ring buffer */
        ret = sca3000_read_ctrl_reg(st, SCA3000_REG_CTRL_SEL_OUT_CTRL);
        ret = sca3000_write_ctrl_reg(st, SCA3000_REG_CTRL_SEL_OUT_CTRL,
                                     (ret & SCA3000_OUT_CTRL_PROT_MASK)
                                     | SCA3000_OUT_CTRL_BUF_X_EN
                                     | SCA3000_OUT_CTRL_BUF_Y_EN
                                     | SCA3000_OUT_CTRL_BUF_Z_EN
                                     | SCA3000_OUT_CTRL_BUF_DIV_4);
        if (ret)
                goto error_ret;
        /* Enable interrupts, relevant to mode and set up as active low */
        ret = sca3000_read_data_short(st, SCA3000_REG_ADDR_INT_MASK, 1);
        if (ret)
                goto error_ret;
        ret = sca3000_write_reg(st,
                                SCA3000_REG_ADDR_INT_MASK,
                                (ret & SCA3000_INT_MASK_PROT_MASK)
                                | SCA3000_INT_MASK_ACTIVE_LOW);
        if (ret)
                goto error_ret;
        /*
         * Select normal measurement mode, free fall off, ring off
         * Ring in 12 bit mode - it is fine to overwrite reserved bits 3,5
         * as that occurs in one of the example on the datasheet
         */
        ret = sca3000_read_data_short(st, SCA3000_REG_ADDR_MODE, 1);
        if (ret)
                goto error_ret;
        ret = sca3000_write_reg(st, SCA3000_REG_ADDR_MODE,
                                (st->rx[0] & SCA3000_MODE_PROT_MASK));
        st->bpse = 11;

error_ret:
        mutex_unlock(&st->lock);
        return ret;
}

static const struct iio_info sca3000_info = {
        .attrs = &sca3000_attribute_group,
        .read_raw = &sca3000_read_raw,
        .event_attrs = &sca3000_event_attribute_group,
        .read_event_value = &sca3000_read_thresh,
        .write_event_value = &sca3000_write_thresh,
        .read_event_config = &sca3000_read_event_config,
        .write_event_config = &sca3000_write_event_config,
        .driver_module = THIS_MODULE,
};

static int sca3000_probe(struct spi_device *spi)
{
        int ret;
        struct sca3000_state *st;
        struct iio_dev *indio_dev;

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

        st = iio_priv(indio_dev);
        spi_set_drvdata(spi, indio_dev);
        st->us = spi;
        mutex_init(&st->lock);
        st->info = &sca3000_spi_chip_info_tbl[spi_get_device_id(spi)
                                              ->driver_data];

        indio_dev->dev.parent = &spi->dev;
        indio_dev->name = spi_get_device_id(spi)->name;
        indio_dev->info = &sca3000_info;
        if (st->info->temp_output) {
                indio_dev->channels = sca3000_channels_with_temp;
                indio_dev->num_channels =
                        ARRAY_SIZE(sca3000_channels_with_temp);
        } else {
                indio_dev->channels = sca3000_channels;
                indio_dev->num_channels = ARRAY_SIZE(sca3000_channels);
        }
        indio_dev->modes = INDIO_DIRECT_MODE;

        sca3000_configure_ring(indio_dev);
        ret = iio_device_register(indio_dev);
        if (ret < 0)
                return ret;

        if (spi->irq) {
                ret = request_threaded_irq(spi->irq,
                                           NULL,
                                           &sca3000_event_handler,
                                           IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
                                           "sca3000",
                                           indio_dev);
                if (ret)
                        goto error_unregister_dev;
        }
        sca3000_register_ring_funcs(indio_dev);
        ret = sca3000_clean_setup(st);
        if (ret)
                goto error_free_irq;
        return 0;

error_free_irq:
        if (spi->irq)
                free_irq(spi->irq, indio_dev);
error_unregister_dev:
        iio_device_unregister(indio_dev);
        return ret;
}

static int sca3000_stop_all_interrupts(struct sca3000_state *st)
{
        int ret;

        mutex_lock(&st->lock);
        ret = sca3000_read_data_short(st, SCA3000_REG_ADDR_INT_MASK, 1);
        if (ret)
                goto error_ret;
        ret = sca3000_write_reg(st, SCA3000_REG_ADDR_INT_MASK,
                                (st->rx[0] &
                                 ~(SCA3000_INT_MASK_RING_THREE_QUARTER |
                                   SCA3000_INT_MASK_RING_HALF |
                                   SCA3000_INT_MASK_ALL_INTS)));
error_ret:
        mutex_unlock(&st->lock);
        return ret;
}

static int sca3000_remove(struct spi_device *spi)
{
        struct iio_dev *indio_dev = spi_get_drvdata(spi);
        struct sca3000_state *st = iio_priv(indio_dev);

        /* Must ensure no interrupts can be generated after this! */
        sca3000_stop_all_interrupts(st);
        if (spi->irq)
                free_irq(spi->irq, indio_dev);
        iio_device_unregister(indio_dev);
        sca3000_unconfigure_ring(indio_dev);

        return 0;
}

static const struct spi_device_id sca3000_id[] = {
        {"sca3000_d01", d01},
        {"sca3000_e02", e02},
        {"sca3000_e04", e04},
        {"sca3000_e05", e05},
        {}
};
MODULE_DEVICE_TABLE(spi, sca3000_id);

static struct spi_driver sca3000_driver = {
        .driver = {
                .name = "sca3000",
        },
        .probe = sca3000_probe,
        .remove = sca3000_remove,
        .id_table = sca3000_id,
};
module_spi_driver(sca3000_driver);

MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>");
MODULE_DESCRIPTION("VTI SCA3000 Series Accelerometers SPI driver");
MODULE_LICENSE("GPL v2");