// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Device driver for the HMC5843 multi-chip module designed
 * for low field magnetic sensing.
 *
 * Copyright (C) 2010 Texas Instruments
 *
 * Author: Shubhrajyoti Datta <shubhrajyoti@ti.com>
 * Acknowledgment: Jonathan Cameron <jic23@kernel.org> for valuable inputs.
 * Support for HMC5883 and HMC5883L by Peter Meerwald <pmeerw@pmeerw.net>.
 * Split to multiple files by Josef Gajdusek <atx@atx.name> - 2014
 */

#include <linux/module.h>
#include <linux/regmap.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/iio/trigger_consumer.h>
#include <linux/iio/buffer.h>
#include <linux/iio/triggered_buffer.h>
#include <linux/delay.h>

#include "hmc5843.h"

/*
 * Range gain settings in (+-)Ga
 * Beware: HMC5843 and HMC5883 have different recommended sensor field
 * ranges; default corresponds to +-1.0 Ga and +-1.3 Ga, respectively
 */
#define HMC5843_RANGE_GAIN_OFFSET               0x05
#define HMC5843_RANGE_GAIN_DEFAULT              0x01
#define HMC5843_RANGE_GAIN_MASK         0xe0

/* Device status */
#define HMC5843_DATA_READY                      0x01
#define HMC5843_DATA_OUTPUT_LOCK                0x02

/* Mode register configuration */
#define HMC5843_MODE_CONVERSION_CONTINUOUS      0x00
#define HMC5843_MODE_CONVERSION_SINGLE          0x01
#define HMC5843_MODE_IDLE                       0x02
#define HMC5843_MODE_SLEEP                      0x03
#define HMC5843_MODE_MASK                       0x03

/*
 * HMC5843: Minimum data output rate
 * HMC5883: Typical data output rate
 */
#define HMC5843_RATE_OFFSET                     0x02
#define HMC5843_RATE_DEFAULT                    0x04
#define HMC5843_RATE_MASK               0x1c

/* Device measurement configuration */
#define HMC5843_MEAS_CONF_NORMAL                0x00
#define HMC5843_MEAS_CONF_POSITIVE_BIAS         0x01
#define HMC5843_MEAS_CONF_NEGATIVE_BIAS         0x02
#define HMC5843_MEAS_CONF_MASK                  0x03

/*
 * API for setting the measurement configuration to
 * Normal, Positive bias and Negative bias
 *
 * From the datasheet:
 * 0 - Normal measurement configuration (default): In normal measurement
 *     configuration the device follows normal measurement flow. Pins BP
 *     and BN are left floating and high impedance.
 *
 * 1 - Positive bias configuration: In positive bias configuration, a
 *     positive current is forced across the resistive load on pins BP
 *     and BN.
 *
 * 2 - Negative bias configuration. In negative bias configuration, a
 *     negative current is forced across the resistive load on pins BP
 *     and BN.
 *
 * 3 - Only available on HMC5983. Magnetic sensor is disabled.
 *     Temperature sensor is enabled.
 */

static const char *const hmc5843_meas_conf_modes[] = {"normal", "positivebias",
                                                      "negativebias"};

static const char *const hmc5983_meas_conf_modes[] = {"normal", "positivebias",
                                                      "negativebias",
                                                      "disabled"};
/* Scaling factors: 10000000/Gain */
static const int hmc5843_regval_to_nanoscale[] = {
        6173, 7692, 10309, 12821, 18868, 21739, 25641, 35714
};

static const int hmc5883_regval_to_nanoscale[] = {
        7812, 9766, 13021, 16287, 24096, 27701, 32573, 45662
};

static const int hmc5883l_regval_to_nanoscale[] = {
        7299, 9174, 12195, 15152, 22727, 25641, 30303, 43478
};

/*
 * From the datasheet:
 * Value        | HMC5843               | HMC5883/HMC5883L
 *              | Data output rate (Hz) | Data output rate (Hz)
 * 0            | 0.5                   | 0.75
 * 1            | 1                     | 1.5
 * 2            | 2                     | 3
 * 3            | 5                     | 7.5
 * 4            | 10 (default)          | 15
 * 5            | 20                    | 30
 * 6            | 50                    | 75
 * 7            | Not used              | Not used
 */
static const int hmc5843_regval_to_samp_freq[][2] = {
        {0, 500000}, {1, 0}, {2, 0}, {5, 0}, {10, 0}, {20, 0}, {50, 0}
};

static const int hmc5883_regval_to_samp_freq[][2] = {
        {0, 750000}, {1, 500000}, {3, 0}, {7, 500000}, {15, 0}, {30, 0},
        {75, 0}
};

static const int hmc5983_regval_to_samp_freq[][2] = {
        {0, 750000}, {1, 500000}, {3, 0}, {7, 500000}, {15, 0}, {30, 0},
        {75, 0}, {220, 0}
};

/* Describe chip variants */
struct hmc5843_chip_info {
        const struct iio_chan_spec *channels;
        const int (*regval_to_samp_freq)[2];
        const int n_regval_to_samp_freq;
        const int *regval_to_nanoscale;
        const int n_regval_to_nanoscale;
};

/* The lower two bits contain the current conversion mode */
static s32 hmc5843_set_mode(struct hmc5843_data *data, u8 operating_mode)
{
        int ret;

        mutex_lock(&data->lock);
        ret = regmap_update_bits(data->regmap, HMC5843_MODE_REG,
                                 HMC5843_MODE_MASK, operating_mode);
        mutex_unlock(&data->lock);

        return ret;
}

static int hmc5843_wait_measurement(struct hmc5843_data *data)
{
        int tries = 150;
        unsigned int val;
        int ret;

        while (tries-- > 0) {
                ret = regmap_read(data->regmap, HMC5843_STATUS_REG, &val);
                if (ret < 0)
                        return ret;
                if (val & HMC5843_DATA_READY)
                        break;
                msleep(20);
        }

        if (tries < 0) {
                dev_err(data->dev, "data not ready\n");
                return -EIO;
        }

        return 0;
}

/* Return the measurement value from the specified channel */
static int hmc5843_read_measurement(struct hmc5843_data *data,
                                    int idx, int *val)
{
        __be16 values[3];
        int ret;

        mutex_lock(&data->lock);
        ret = hmc5843_wait_measurement(data);
        if (ret < 0) {
                mutex_unlock(&data->lock);
                return ret;
        }
        ret = regmap_bulk_read(data->regmap, HMC5843_DATA_OUT_MSB_REGS,
                               values, sizeof(values));
        mutex_unlock(&data->lock);
        if (ret < 0)
                return ret;

        *val = sign_extend32(be16_to_cpu(values[idx]), 15);
        return IIO_VAL_INT;
}

static int hmc5843_set_meas_conf(struct hmc5843_data *data, u8 meas_conf)
{
        int ret;

        mutex_lock(&data->lock);
        ret = regmap_update_bits(data->regmap, HMC5843_CONFIG_REG_A,
                                 HMC5843_MEAS_CONF_MASK, meas_conf);
        mutex_unlock(&data->lock);

        return ret;
}

static
int hmc5843_show_measurement_configuration(struct iio_dev *indio_dev,
                                           const struct iio_chan_spec *chan)
{
        struct hmc5843_data *data = iio_priv(indio_dev);
        unsigned int val;
        int ret;

        ret = regmap_read(data->regmap, HMC5843_CONFIG_REG_A, &val);
        if (ret)
                return ret;

        return val & HMC5843_MEAS_CONF_MASK;
}

static
int hmc5843_set_measurement_configuration(struct iio_dev *indio_dev,
                                          const struct iio_chan_spec *chan,
                                          unsigned int meas_conf)
{
        struct hmc5843_data *data = iio_priv(indio_dev);

        return hmc5843_set_meas_conf(data, meas_conf);
}

static const struct iio_mount_matrix *
hmc5843_get_mount_matrix(const struct iio_dev *indio_dev,
                          const struct iio_chan_spec *chan)
{
        struct hmc5843_data *data = iio_priv(indio_dev);

        return &data->orientation;
}

static const struct iio_enum hmc5843_meas_conf_enum = {
        .items = hmc5843_meas_conf_modes,
        .num_items = ARRAY_SIZE(hmc5843_meas_conf_modes),
        .get = hmc5843_show_measurement_configuration,
        .set = hmc5843_set_measurement_configuration,
};

static const struct iio_chan_spec_ext_info hmc5843_ext_info[] = {
        IIO_ENUM("meas_conf", IIO_SHARED_BY_TYPE, &hmc5843_meas_conf_enum),
        IIO_ENUM_AVAILABLE("meas_conf", IIO_SHARED_BY_TYPE, &hmc5843_meas_conf_enum),
        IIO_MOUNT_MATRIX(IIO_SHARED_BY_DIR, hmc5843_get_mount_matrix),
        { }
};

static const struct iio_enum hmc5983_meas_conf_enum = {
        .items = hmc5983_meas_conf_modes,
        .num_items = ARRAY_SIZE(hmc5983_meas_conf_modes),
        .get = hmc5843_show_measurement_configuration,
        .set = hmc5843_set_measurement_configuration,
};

static const struct iio_chan_spec_ext_info hmc5983_ext_info[] = {
        IIO_ENUM("meas_conf", IIO_SHARED_BY_TYPE, &hmc5983_meas_conf_enum),
        IIO_ENUM_AVAILABLE("meas_conf", IIO_SHARED_BY_TYPE, &hmc5983_meas_conf_enum),
        IIO_MOUNT_MATRIX(IIO_SHARED_BY_DIR, hmc5843_get_mount_matrix),
        { }
};

static
ssize_t hmc5843_show_samp_freq_avail(struct device *dev,
                                     struct device_attribute *attr, char *buf)
{
        struct hmc5843_data *data = iio_priv(dev_to_iio_dev(dev));
        size_t len = 0;
        int i;

        for (i = 0; i < data->variant->n_regval_to_samp_freq; i++)
                len += scnprintf(buf + len, PAGE_SIZE - len,
                        "%d.%d ", data->variant->regval_to_samp_freq[i][0],
                        data->variant->regval_to_samp_freq[i][1]);

        /* replace trailing space by newline */
        buf[len - 1] = '\n';

        return len;
}

static IIO_DEV_ATTR_SAMP_FREQ_AVAIL(hmc5843_show_samp_freq_avail);

static int hmc5843_set_samp_freq(struct hmc5843_data *data, u8 rate)
{
        int ret;

        mutex_lock(&data->lock);
        ret = regmap_update_bits(data->regmap, HMC5843_CONFIG_REG_A,
                                 HMC5843_RATE_MASK,
                                 rate << HMC5843_RATE_OFFSET);
        mutex_unlock(&data->lock);

        return ret;
}

static int hmc5843_get_samp_freq_index(struct hmc5843_data *data,
                                       int val, int val2)
{
        int i;

        for (i = 0; i < data->variant->n_regval_to_samp_freq; i++)
                if (val == data->variant->regval_to_samp_freq[i][0] &&
                    val2 == data->variant->regval_to_samp_freq[i][1])
                        return i;

        return -EINVAL;
}

static int hmc5843_set_range_gain(struct hmc5843_data *data, u8 range)
{
        int ret;

        mutex_lock(&data->lock);
        ret = regmap_update_bits(data->regmap, HMC5843_CONFIG_REG_B,
                                 HMC5843_RANGE_GAIN_MASK,
                                 range << HMC5843_RANGE_GAIN_OFFSET);
        mutex_unlock(&data->lock);

        return ret;
}

static ssize_t hmc5843_show_scale_avail(struct device *dev,
                                        struct device_attribute *attr,
                                        char *buf)
{
        struct hmc5843_data *data = iio_priv(dev_to_iio_dev(dev));

        size_t len = 0;
        int i;

        for (i = 0; i < data->variant->n_regval_to_nanoscale; i++)
                len += scnprintf(buf + len, PAGE_SIZE - len,
                        "0.%09d ", data->variant->regval_to_nanoscale[i]);

        /* replace trailing space by newline */
        buf[len - 1] = '\n';

        return len;
}

static IIO_DEVICE_ATTR(scale_available, S_IRUGO,
        hmc5843_show_scale_avail, NULL, 0);

static int hmc5843_get_scale_index(struct hmc5843_data *data, int val, int val2)
{
        int i;

        if (val)
                return -EINVAL;

        for (i = 0; i < data->variant->n_regval_to_nanoscale; i++)
                if (val2 == data->variant->regval_to_nanoscale[i])
                        return i;

        return -EINVAL;
}

static int hmc5843_read_raw(struct iio_dev *indio_dev,
                            struct iio_chan_spec const *chan,
                            int *val, int *val2, long mask)
{
        struct hmc5843_data *data = iio_priv(indio_dev);
        unsigned int rval;
        int ret;

        switch (mask) {
        case IIO_CHAN_INFO_RAW:
                return hmc5843_read_measurement(data, chan->scan_index, val);
        case IIO_CHAN_INFO_SCALE:
                ret = regmap_read(data->regmap, HMC5843_CONFIG_REG_B, &rval);
                if (ret < 0)
                        return ret;
                rval >>= HMC5843_RANGE_GAIN_OFFSET;
                *val = 0;
                *val2 = data->variant->regval_to_nanoscale[rval];
                return IIO_VAL_INT_PLUS_NANO;
        case IIO_CHAN_INFO_SAMP_FREQ:
                ret = regmap_read(data->regmap, HMC5843_CONFIG_REG_A, &rval);
                if (ret < 0)
                        return ret;
                rval >>= HMC5843_RATE_OFFSET;
                *val = data->variant->regval_to_samp_freq[rval][0];
                *val2 = data->variant->regval_to_samp_freq[rval][1];
                return IIO_VAL_INT_PLUS_MICRO;
        }
        return -EINVAL;
}

static int hmc5843_write_raw(struct iio_dev *indio_dev,
                             struct iio_chan_spec const *chan,
                             int val, int val2, long mask)
{
        struct hmc5843_data *data = iio_priv(indio_dev);
        int rate, range;

        switch (mask) {
        case IIO_CHAN_INFO_SAMP_FREQ:
                rate = hmc5843_get_samp_freq_index(data, val, val2);
                if (rate < 0)
                        return -EINVAL;

                return hmc5843_set_samp_freq(data, rate);
        case IIO_CHAN_INFO_SCALE:
                range = hmc5843_get_scale_index(data, val, val2);
                if (range < 0)
                        return -EINVAL;

                return hmc5843_set_range_gain(data, range);
        default:
                return -EINVAL;
        }
}

static int hmc5843_write_raw_get_fmt(struct iio_dev *indio_dev,
                                     struct iio_chan_spec const *chan,
                                     long mask)
{
        switch (mask) {
        case IIO_CHAN_INFO_SAMP_FREQ:
                return IIO_VAL_INT_PLUS_MICRO;
        case IIO_CHAN_INFO_SCALE:
                return IIO_VAL_INT_PLUS_NANO;
        default:
                return -EINVAL;
        }
}

static irqreturn_t hmc5843_trigger_handler(int irq, void *p)
{
        struct iio_poll_func *pf = p;
        struct iio_dev *indio_dev = pf->indio_dev;
        struct hmc5843_data *data = iio_priv(indio_dev);
        int ret;

        mutex_lock(&data->lock);
        ret = hmc5843_wait_measurement(data);
        if (ret < 0) {
                mutex_unlock(&data->lock);
                goto done;
        }

        ret = regmap_bulk_read(data->regmap, HMC5843_DATA_OUT_MSB_REGS,
                               data->scan.chans, sizeof(data->scan.chans));

        mutex_unlock(&data->lock);
        if (ret < 0)
                goto done;

        iio_push_to_buffers_with_ts(indio_dev, &data->scan, sizeof(data->scan),
                                    iio_get_time_ns(indio_dev));

done:
        iio_trigger_notify_done(indio_dev->trig);

        return IRQ_HANDLED;
}

#define HMC5843_CHANNEL(axis, idx)                                      \
        {                                                               \
                .type = IIO_MAGN,                                       \
                .modified = 1,                                          \
                .channel2 = IIO_MOD_##axis,                             \
                .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),           \
                .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) |  \
                        BIT(IIO_CHAN_INFO_SAMP_FREQ),                   \
                .scan_index = idx,                                      \
                .scan_type = {                                          \
                        .sign = 's',                                    \
                        .realbits = 16,                                 \
                        .storagebits = 16,                              \
                        .endianness = IIO_BE,                           \
                },                                                      \
                .ext_info = hmc5843_ext_info,   \
        }

#define HMC5983_CHANNEL(axis, idx)                                      \
        {                                                               \
                .type = IIO_MAGN,                                       \
                .modified = 1,                                          \
                .channel2 = IIO_MOD_##axis,                             \
                .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),           \
                .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) |  \
                        BIT(IIO_CHAN_INFO_SAMP_FREQ),                   \
                .scan_index = idx,                                      \
                .scan_type = {                                          \
                        .sign = 's',                                    \
                        .realbits = 16,                                 \
                        .storagebits = 16,                              \
                        .endianness = IIO_BE,                           \
                },                                                      \
                .ext_info = hmc5983_ext_info,   \
        }

static const struct iio_chan_spec hmc5843_channels[] = {
        HMC5843_CHANNEL(X, 0),
        HMC5843_CHANNEL(Y, 1),
        HMC5843_CHANNEL(Z, 2),
        IIO_CHAN_SOFT_TIMESTAMP(3),
};

/* Beware: Y and Z are exchanged on HMC5883 and 5983 */
static const struct iio_chan_spec hmc5883_channels[] = {
        HMC5843_CHANNEL(X, 0),
        HMC5843_CHANNEL(Z, 1),
        HMC5843_CHANNEL(Y, 2),
        IIO_CHAN_SOFT_TIMESTAMP(3),
};

static const struct iio_chan_spec hmc5983_channels[] = {
        HMC5983_CHANNEL(X, 0),
        HMC5983_CHANNEL(Z, 1),
        HMC5983_CHANNEL(Y, 2),
        IIO_CHAN_SOFT_TIMESTAMP(3),
};

static struct attribute *hmc5843_attributes[] = {
        &iio_dev_attr_scale_available.dev_attr.attr,
        &iio_dev_attr_sampling_frequency_available.dev_attr.attr,
        NULL
};

static const struct attribute_group hmc5843_group = {
        .attrs = hmc5843_attributes,
};

static const struct hmc5843_chip_info hmc5843_chip_info_tbl[] = {
        [HMC5843_ID] = {
                .channels = hmc5843_channels,
                .regval_to_samp_freq = hmc5843_regval_to_samp_freq,
                .n_regval_to_samp_freq =
                                ARRAY_SIZE(hmc5843_regval_to_samp_freq),
                .regval_to_nanoscale = hmc5843_regval_to_nanoscale,
                .n_regval_to_nanoscale =
                                ARRAY_SIZE(hmc5843_regval_to_nanoscale),
        },
        [HMC5883_ID] = {
                .channels = hmc5883_channels,
                .regval_to_samp_freq = hmc5883_regval_to_samp_freq,
                .n_regval_to_samp_freq =
                                ARRAY_SIZE(hmc5883_regval_to_samp_freq),
                .regval_to_nanoscale = hmc5883_regval_to_nanoscale,
                .n_regval_to_nanoscale =
                                ARRAY_SIZE(hmc5883_regval_to_nanoscale),
        },
        [HMC5883L_ID] = {
                .channels = hmc5883_channels,
                .regval_to_samp_freq = hmc5883_regval_to_samp_freq,
                .n_regval_to_samp_freq =
                                ARRAY_SIZE(hmc5883_regval_to_samp_freq),
                .regval_to_nanoscale = hmc5883l_regval_to_nanoscale,
                .n_regval_to_nanoscale =
                                ARRAY_SIZE(hmc5883l_regval_to_nanoscale),
        },
        [HMC5983_ID] = {
                .channels = hmc5983_channels,
                .regval_to_samp_freq = hmc5983_regval_to_samp_freq,
                .n_regval_to_samp_freq =
                                ARRAY_SIZE(hmc5983_regval_to_samp_freq),
                .regval_to_nanoscale = hmc5883l_regval_to_nanoscale,
                .n_regval_to_nanoscale =
                                ARRAY_SIZE(hmc5883l_regval_to_nanoscale),
        }
};

static int hmc5843_init(struct hmc5843_data *data)
{
        int ret;
        u8 id[3];

        ret = regmap_bulk_read(data->regmap, HMC5843_ID_REG,
                               id, ARRAY_SIZE(id));
        if (ret < 0)
                return ret;
        if (id[0] != 'H' || id[1] != '4' || id[2] != '3') {
                dev_err(data->dev, "no HMC5843/5883/5883L/5983 sensor\n");
                return -ENODEV;
        }

        ret = hmc5843_set_meas_conf(data, HMC5843_MEAS_CONF_NORMAL);
        if (ret < 0)
                return ret;
        ret = hmc5843_set_samp_freq(data, HMC5843_RATE_DEFAULT);
        if (ret < 0)
                return ret;
        ret = hmc5843_set_range_gain(data, HMC5843_RANGE_GAIN_DEFAULT);
        if (ret < 0)
                return ret;
        return hmc5843_set_mode(data, HMC5843_MODE_CONVERSION_CONTINUOUS);
}

static const struct iio_info hmc5843_info = {
        .attrs = &hmc5843_group,
        .read_raw = &hmc5843_read_raw,
        .write_raw = &hmc5843_write_raw,
        .write_raw_get_fmt = &hmc5843_write_raw_get_fmt,
};

static const unsigned long hmc5843_scan_masks[] = {0x7, 0};

static int hmc5843_common_suspend(struct device *dev)
{
        return hmc5843_set_mode(iio_priv(dev_get_drvdata(dev)),
                                HMC5843_MODE_SLEEP);
}

static int hmc5843_common_resume(struct device *dev)
{
        return hmc5843_set_mode(iio_priv(dev_get_drvdata(dev)),
                HMC5843_MODE_CONVERSION_CONTINUOUS);
}
EXPORT_NS_SIMPLE_DEV_PM_OPS(hmc5843_pm_ops, hmc5843_common_suspend,
                            hmc5843_common_resume, IIO_HMC5843);

int hmc5843_common_probe(struct device *dev, struct regmap *regmap,
                         enum hmc5843_ids id, const char *name)
{
        struct hmc5843_data *data;
        struct iio_dev *indio_dev;
        int ret;

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

        dev_set_drvdata(dev, indio_dev);

        /* default settings at probe */
        data = iio_priv(indio_dev);
        data->dev = dev;
        data->regmap = regmap;
        data->variant = &hmc5843_chip_info_tbl[id];
        mutex_init(&data->lock);

        ret = iio_read_mount_matrix(dev, &data->orientation);
        if (ret)
                return ret;

        indio_dev->name = name;
        indio_dev->info = &hmc5843_info;
        indio_dev->modes = INDIO_DIRECT_MODE;
        indio_dev->channels = data->variant->channels;
        indio_dev->num_channels = 4;
        indio_dev->available_scan_masks = hmc5843_scan_masks;

        ret = hmc5843_init(data);
        if (ret < 0)
                return ret;

        ret = iio_triggered_buffer_setup(indio_dev, NULL,
                                         hmc5843_trigger_handler, NULL);
        if (ret < 0)
                goto buffer_setup_err;

        ret = iio_device_register(indio_dev);
        if (ret < 0)
                goto buffer_cleanup;

        return 0;

buffer_cleanup:
        iio_triggered_buffer_cleanup(indio_dev);
buffer_setup_err:
        hmc5843_set_mode(iio_priv(indio_dev), HMC5843_MODE_SLEEP);
        return ret;
}
EXPORT_SYMBOL_NS(hmc5843_common_probe, "IIO_HMC5843");

void hmc5843_common_remove(struct device *dev)
{
        struct iio_dev *indio_dev = dev_get_drvdata(dev);

        iio_device_unregister(indio_dev);
        iio_triggered_buffer_cleanup(indio_dev);

        /*  sleep mode to save power */
        hmc5843_set_mode(iio_priv(indio_dev), HMC5843_MODE_SLEEP);
}
EXPORT_SYMBOL_NS(hmc5843_common_remove, "IIO_HMC5843");

MODULE_AUTHOR("Shubhrajyoti Datta <shubhrajyoti@ti.com>");
MODULE_DESCRIPTION("HMC5843/5883/5883L/5983 core driver");
MODULE_LICENSE("GPL");