// SPDX-License-Identifier: GPL-2.0-only
/*
 * mag3110.c - Support for Freescale MAG3110 magnetometer sensor
 *
 * Copyright (c) 2013 Peter Meerwald <pmeerw@pmeerw.net>
 *
 * (7-bit I2C slave address 0x0e)
 *
 * TODO: irq, user offset, oversampling, continuous mode
 */

#include <linux/cleanup.h>
#include <linux/module.h>
#include <linux/i2c.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 <linux/regulator/consumer.h>

#define MAG3110_STATUS 0x00
#define MAG3110_OUT_X 0x01 /* MSB first */
#define MAG3110_OUT_Y 0x03
#define MAG3110_OUT_Z 0x05
#define MAG3110_WHO_AM_I 0x07
#define MAG3110_SYSMOD 0x08
#define MAG3110_OFF_X 0x09 /* MSB first */
#define MAG3110_OFF_Y 0x0b
#define MAG3110_OFF_Z 0x0d
#define MAG3110_DIE_TEMP 0x0f
#define MAG3110_CTRL_REG1 0x10
#define MAG3110_CTRL_REG2 0x11

#define MAG3110_STATUS_DRDY (BIT(2) | BIT(1) | BIT(0))

#define MAG3110_CTRL_DR_MASK (BIT(7) | BIT(6) | BIT(5))
#define MAG3110_CTRL_DR_SHIFT 5
#define MAG3110_CTRL_DR_DEFAULT 0

#define MAG3110_SYSMOD_MODE_MASK GENMASK(1, 0)

#define MAG3110_CTRL_TM BIT(1) /* trigger single measurement */
#define MAG3110_CTRL_AC BIT(0) /* continuous measurements */

#define MAG3110_CTRL_AUTO_MRST_EN BIT(7) /* magnetic auto-reset */
#define MAG3110_CTRL_RAW BIT(5) /* measurements not user-offset corrected */

#define MAG3110_DEVICE_ID 0xc4

/* Each client has this additional data */
struct mag3110_data {
        struct i2c_client *client;
        struct mutex lock;
        u8 ctrl_reg1;
        int sleep_val;
        struct regulator *vdd_reg;
        struct regulator *vddio_reg;
        /* Ensure natural alignment of timestamp */
        struct {
                __be16 channels[3];
                u8 temperature;
                aligned_s64 ts;
        } scan;
};

static int mag3110_request(struct mag3110_data *data)
{
        int ret, tries = 150;

        if ((data->ctrl_reg1 & MAG3110_CTRL_AC) == 0) {
                /* trigger measurement */
                ret = i2c_smbus_write_byte_data(data->client, MAG3110_CTRL_REG1,
                        data->ctrl_reg1 | MAG3110_CTRL_TM);
                if (ret < 0)
                        return ret;
        }

        while (tries-- > 0) {
                ret = i2c_smbus_read_byte_data(data->client, MAG3110_STATUS);
                if (ret < 0)
                        return ret;
                /* wait for data ready */
                if ((ret & MAG3110_STATUS_DRDY) == MAG3110_STATUS_DRDY)
                        break;

                if (data->sleep_val <= 20)
                        usleep_range(data->sleep_val * 250, data->sleep_val * 500);
                else
                        msleep(20);
        }

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

        return 0;
}

static int mag3110_read(struct mag3110_data *data, __be16 buf[3])
{
        int ret;

        guard(mutex)(&data->lock);
        ret = mag3110_request(data);
        if (ret < 0)
                return ret;
        return i2c_smbus_read_i2c_block_data(data->client, MAG3110_OUT_X,
                                             3 * sizeof(__be16), (u8 *) buf);
}

static ssize_t mag3110_show_int_plus_micros(char *buf,
        const int (*vals)[2], int n)
{
        size_t len = 0;

        while (n-- > 0)
                len += scnprintf(buf + len, PAGE_SIZE - len,
                        "%d.%06d ", vals[n][0], vals[n][1]);

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

        return len;
}

static int mag3110_get_int_plus_micros_index(const int (*vals)[2], int n,
                                        int val, int val2)
{
        while (n-- > 0)
                if (val == vals[n][0] && val2 == vals[n][1])
                        return n;

        return -EINVAL;
}

static const int mag3110_samp_freq[8][2] = {
        {80, 0}, {40, 0}, {20, 0}, {10, 0}, {5, 0}, {2, 500000},
        {1, 250000}, {0, 625000}
};

static ssize_t mag3110_show_samp_freq_avail(struct device *dev,
                                struct device_attribute *attr, char *buf)
{
        return mag3110_show_int_plus_micros(buf, mag3110_samp_freq, 8);
}

static IIO_DEV_ATTR_SAMP_FREQ_AVAIL(mag3110_show_samp_freq_avail);

static int mag3110_get_samp_freq_index(struct mag3110_data *data,
        int val, int val2)
{
        return mag3110_get_int_plus_micros_index(mag3110_samp_freq, 8, val,
                val2);
}

static int mag3110_calculate_sleep(struct mag3110_data *data)
{
        int ret, i = data->ctrl_reg1 >> MAG3110_CTRL_DR_SHIFT;

        if (mag3110_samp_freq[i][0] > 0)
                ret = 1000 / mag3110_samp_freq[i][0];
        else
                ret = 1000;

        return ret == 0 ? 1 : ret;
}

static int mag3110_standby(struct mag3110_data *data)
{
        return i2c_smbus_write_byte_data(data->client, MAG3110_CTRL_REG1,
                data->ctrl_reg1 & ~MAG3110_CTRL_AC);
}

static int mag3110_wait_standby(struct mag3110_data *data)
{
        int ret, tries = 30;

        /*
         * Takes up to 1/ODR to come out of active mode into stby
         * Longest expected period is 12.5seconds.
         * We'll sleep for 500ms between checks
         */
        while (tries-- > 0) {
                ret = i2c_smbus_read_byte_data(data->client, MAG3110_SYSMOD);
                if (ret < 0) {
                        dev_err(&data->client->dev, "i2c error\n");
                        return ret;
                }
                /* wait for standby */
                if ((ret & MAG3110_SYSMOD_MODE_MASK) == 0)
                        break;

                msleep_interruptible(500);
        }

        if (tries < 0) {
                dev_err(&data->client->dev, "device not entering standby mode\n");
                return -EIO;
        }

        return 0;
}

static int mag3110_active(struct mag3110_data *data)
{
        return i2c_smbus_write_byte_data(data->client, MAG3110_CTRL_REG1,
                                         data->ctrl_reg1);
}

/* returns >0 if active, 0 if in standby and <0 on error */
static int mag3110_is_active(struct mag3110_data *data)
{
        int reg;

        reg = i2c_smbus_read_byte_data(data->client, MAG3110_CTRL_REG1);
        if (reg < 0)
                return reg;

        return reg & MAG3110_CTRL_AC;
}

static int mag3110_change_config(struct mag3110_data *data, u8 reg, u8 val)
{
        int ret;
        int is_active;

        guard(mutex)(&data->lock);

        is_active = mag3110_is_active(data);
        if (is_active < 0)
                return is_active;

        /* config can only be changed when in standby */
        if (is_active > 0) {
                ret = mag3110_standby(data);
                if (ret < 0)
                        return ret;
        }

        /*
         * After coming out of active we must wait for the part
         * to transition to STBY. This can take up to 1 /ODR to occur
         */
        ret = mag3110_wait_standby(data);
        if (ret < 0)
                return ret;

        ret = i2c_smbus_write_byte_data(data->client, reg, val);
        if (ret < 0)
                return ret;

        if (is_active > 0) {
                ret = mag3110_active(data);
                if (ret < 0)
                        return ret;
        }

        return 0;
}

static int __mag3110_read_info_raw(struct mag3110_data *data,
                                   struct iio_chan_spec const *chan,
                                   int *val)
{
        __be16 buffer[3];
        int ret;

        switch (chan->type) {
        case IIO_MAGN: /* in 0.1 uT / LSB */
                ret = mag3110_read(data, buffer);
                if (ret < 0)
                        return ret;
                *val = sign_extend32(be16_to_cpu(buffer[chan->scan_index]),
                                     chan->scan_type.realbits - 1);
                return IIO_VAL_INT;

        case IIO_TEMP: { /* in 1 C / LSB */
                guard(mutex)(&data->lock);
                ret = mag3110_request(data);
                if (ret < 0)
                        return ret;
                ret = i2c_smbus_read_byte_data(data->client,
                                               MAG3110_DIE_TEMP);
                if (ret < 0)
                        return ret;
                *val = sign_extend32(ret, chan->scan_type.realbits - 1);
                return IIO_VAL_INT;
        }
        default:
                return -EINVAL;
        }
}

static int mag3110_read_raw(struct iio_dev *indio_dev,
                            struct iio_chan_spec const *chan,
                            int *val, int *val2, long mask)
{
        struct mag3110_data *data = iio_priv(indio_dev);
        int i, ret;

        switch (mask) {
        case IIO_CHAN_INFO_RAW:
                if (!iio_device_claim_direct(indio_dev))
                        return -EBUSY;
                ret = __mag3110_read_info_raw(data, chan, val);
                iio_device_release_direct(indio_dev);
                return ret;

        case IIO_CHAN_INFO_SCALE:
                switch (chan->type) {
                case IIO_MAGN:
                        *val = 0;
                        *val2 = 1000;
                        return IIO_VAL_INT_PLUS_MICRO;
                case IIO_TEMP:
                        *val = 1000;
                        return IIO_VAL_INT;
                default:
                        return -EINVAL;
                }
        case IIO_CHAN_INFO_SAMP_FREQ:
                i = data->ctrl_reg1 >> MAG3110_CTRL_DR_SHIFT;
                *val = mag3110_samp_freq[i][0];
                *val2 = mag3110_samp_freq[i][1];
                return IIO_VAL_INT_PLUS_MICRO;
        case IIO_CHAN_INFO_CALIBBIAS:
                ret = i2c_smbus_read_word_swapped(data->client,
                        MAG3110_OFF_X + 2 * chan->scan_index);
                if (ret < 0)
                        return ret;
                *val = sign_extend32(ret >> 1, 14);
                return IIO_VAL_INT;
        }
        return -EINVAL;
}

static int __mag3110_write_raw(struct mag3110_data *data,
                              struct iio_chan_spec const *chan,
                              int val, int val2, long mask)
{
        int rate;

        switch (mask) {
        case IIO_CHAN_INFO_SAMP_FREQ:
                rate = mag3110_get_samp_freq_index(data, val, val2);
                if (rate < 0)
                        return -EINVAL;

                data->ctrl_reg1 &= 0xff & ~MAG3110_CTRL_DR_MASK
                                        & ~MAG3110_CTRL_AC;
                data->ctrl_reg1 |= rate << MAG3110_CTRL_DR_SHIFT;
                data->sleep_val = mag3110_calculate_sleep(data);
                if (data->sleep_val < 40)
                        data->ctrl_reg1 |= MAG3110_CTRL_AC;

                return mag3110_change_config(data, MAG3110_CTRL_REG1,
                                             data->ctrl_reg1);

        case IIO_CHAN_INFO_CALIBBIAS:
                if (val < -10000 || val > 10000)
                        return -EINVAL;

                return i2c_smbus_write_word_swapped(data->client,
                        MAG3110_OFF_X + 2 * chan->scan_index, val << 1);
        default:
                return -EINVAL;
        }
}

static int mag3110_write_raw(struct iio_dev *indio_dev,
                             struct iio_chan_spec const *chan,
                             int val, int val2, long mask)
{
        struct mag3110_data *data = iio_priv(indio_dev);
        int ret;

        if (!iio_device_claim_direct(indio_dev))
                return -EBUSY;
        ret = __mag3110_write_raw(data, chan, val, val2, mask);
        iio_device_release_direct(indio_dev);

        return ret;
}

static irqreturn_t mag3110_trigger_handler(int irq, void *p)
{
        struct iio_poll_func *pf = p;
        struct iio_dev *indio_dev = pf->indio_dev;
        struct mag3110_data *data = iio_priv(indio_dev);
        int ret;

        ret = mag3110_read(data, data->scan.channels);
        if (ret < 0)
                goto done;

        if (test_bit(3, indio_dev->active_scan_mask)) {
                ret = i2c_smbus_read_byte_data(data->client,
                        MAG3110_DIE_TEMP);
                if (ret < 0)
                        goto done;
                data->scan.temperature = ret;
        }

        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 MAG3110_CHANNEL(axis, idx) { \
        .type = IIO_MAGN, \
        .modified = 1, \
        .channel2 = IIO_MOD_##axis, \
        .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
                BIT(IIO_CHAN_INFO_CALIBBIAS), \
        .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ) | \
                BIT(IIO_CHAN_INFO_SCALE), \
        .scan_index = idx, \
        .scan_type = { \
                .sign = 's', \
                .realbits = 16, \
                .storagebits = 16, \
                .endianness = IIO_BE, \
        }, \
}

static const struct iio_chan_spec mag3110_channels[] = {
        MAG3110_CHANNEL(X, 0),
        MAG3110_CHANNEL(Y, 1),
        MAG3110_CHANNEL(Z, 2),
        {
                .type = IIO_TEMP,
                .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
                        BIT(IIO_CHAN_INFO_SCALE),
                .scan_index = 3,
                .scan_type = {
                        .sign = 's',
                        .realbits = 8,
                        .storagebits = 8,
                        },
        },
        IIO_CHAN_SOFT_TIMESTAMP(4),
};

static struct attribute *mag3110_attributes[] = {
        &iio_dev_attr_sampling_frequency_available.dev_attr.attr,
        NULL
};

static const struct attribute_group mag3110_group = {
        .attrs = mag3110_attributes,
};

static const struct iio_info mag3110_info = {
        .attrs = &mag3110_group,
        .read_raw = &mag3110_read_raw,
        .write_raw = &mag3110_write_raw,
};

static const unsigned long mag3110_scan_masks[] = {0x7, 0xf, 0};

static int mag3110_probe(struct i2c_client *client)
{
        const struct i2c_device_id *id = i2c_client_get_device_id(client);
        struct mag3110_data *data;
        struct iio_dev *indio_dev;
        int ret;

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

        data = iio_priv(indio_dev);

        data->vdd_reg = devm_regulator_get(&client->dev, "vdd");
        if (IS_ERR(data->vdd_reg))
                return dev_err_probe(&client->dev, PTR_ERR(data->vdd_reg),
                                     "failed to get VDD regulator!\n");

        data->vddio_reg = devm_regulator_get(&client->dev, "vddio");
        if (IS_ERR(data->vddio_reg))
                return dev_err_probe(&client->dev, PTR_ERR(data->vddio_reg),
                                     "failed to get VDDIO regulator!\n");

        ret = regulator_enable(data->vdd_reg);
        if (ret) {
                dev_err(&client->dev, "failed to enable VDD regulator!\n");
                return ret;
        }

        ret = regulator_enable(data->vddio_reg);
        if (ret) {
                dev_err(&client->dev, "failed to enable VDDIO regulator!\n");
                goto disable_regulator_vdd;
        }

        ret = i2c_smbus_read_byte_data(client, MAG3110_WHO_AM_I);
        if (ret < 0)
                goto disable_regulators;
        if (ret != MAG3110_DEVICE_ID) {
                ret = -ENODEV;
                goto disable_regulators;
        }

        data->client = client;
        mutex_init(&data->lock);

        i2c_set_clientdata(client, indio_dev);
        indio_dev->info = &mag3110_info;
        indio_dev->name = id->name;
        indio_dev->modes = INDIO_DIRECT_MODE;
        indio_dev->channels = mag3110_channels;
        indio_dev->num_channels = ARRAY_SIZE(mag3110_channels);
        indio_dev->available_scan_masks = mag3110_scan_masks;

        data->ctrl_reg1 = MAG3110_CTRL_DR_DEFAULT << MAG3110_CTRL_DR_SHIFT;
        data->sleep_val = mag3110_calculate_sleep(data);
        if (data->sleep_val < 40)
                data->ctrl_reg1 |= MAG3110_CTRL_AC;

        ret = mag3110_change_config(data, MAG3110_CTRL_REG1, data->ctrl_reg1);
        if (ret < 0)
                goto disable_regulators;

        ret = i2c_smbus_write_byte_data(client, MAG3110_CTRL_REG2,
                MAG3110_CTRL_AUTO_MRST_EN);
        if (ret < 0)
                goto standby_on_error;

        ret = iio_triggered_buffer_setup(indio_dev, NULL,
                mag3110_trigger_handler, NULL);
        if (ret < 0)
                goto standby_on_error;

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

buffer_cleanup:
        iio_triggered_buffer_cleanup(indio_dev);
standby_on_error:
        mag3110_standby(iio_priv(indio_dev));
disable_regulators:
        regulator_disable(data->vddio_reg);
disable_regulator_vdd:
        regulator_disable(data->vdd_reg);

        return ret;
}

static void mag3110_remove(struct i2c_client *client)
{
        struct iio_dev *indio_dev = i2c_get_clientdata(client);
        struct mag3110_data *data = iio_priv(indio_dev);

        iio_device_unregister(indio_dev);
        iio_triggered_buffer_cleanup(indio_dev);
        mag3110_standby(iio_priv(indio_dev));
        regulator_disable(data->vddio_reg);
        regulator_disable(data->vdd_reg);
}

static int mag3110_suspend(struct device *dev)
{
        struct mag3110_data *data = iio_priv(i2c_get_clientdata(
                to_i2c_client(dev)));
        int ret;

        ret = mag3110_standby(iio_priv(i2c_get_clientdata(
                to_i2c_client(dev))));
        if (ret)
                return ret;

        ret = regulator_disable(data->vddio_reg);
        if (ret) {
                dev_err(dev, "failed to disable VDDIO regulator\n");
                return ret;
        }

        ret = regulator_disable(data->vdd_reg);
        if (ret) {
                dev_err(dev, "failed to disable VDD regulator\n");
                return ret;
        }

        return 0;
}

static int mag3110_resume(struct device *dev)
{
        struct mag3110_data *data = iio_priv(i2c_get_clientdata(
                to_i2c_client(dev)));
        int ret;

        ret = regulator_enable(data->vdd_reg);
        if (ret) {
                dev_err(dev, "failed to enable VDD regulator\n");
                return ret;
        }

        ret = regulator_enable(data->vddio_reg);
        if (ret) {
                dev_err(dev, "failed to enable VDDIO regulator\n");
                regulator_disable(data->vdd_reg);
                return ret;
        }

        return i2c_smbus_write_byte_data(data->client, MAG3110_CTRL_REG1,
                data->ctrl_reg1);
}

static DEFINE_SIMPLE_DEV_PM_OPS(mag3110_pm_ops, mag3110_suspend,
                                mag3110_resume);

static const struct i2c_device_id mag3110_id[] = {
        { "mag3110" },
        { }
};
MODULE_DEVICE_TABLE(i2c, mag3110_id);

static const struct of_device_id mag3110_of_match[] = {
        { .compatible = "fsl,mag3110" },
        { }
};
MODULE_DEVICE_TABLE(of, mag3110_of_match);

static struct i2c_driver mag3110_driver = {
        .driver = {
                .name   = "mag3110",
                .of_match_table = mag3110_of_match,
                .pm     = pm_sleep_ptr(&mag3110_pm_ops),
        },
        .probe = mag3110_probe,
        .remove = mag3110_remove,
        .id_table = mag3110_id,
};
module_i2c_driver(mag3110_driver);

MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
MODULE_DESCRIPTION("Freescale MAG3110 magnetometer driver");
MODULE_LICENSE("GPL");