root/drivers/iio/magnetometer/af8133j.c
// SPDX-License-Identifier: GPL-2.0-only
/*
 * af8133j.c - Voltafield AF8133J magnetometer driver
 *
 * Copyright 2021 Icenowy Zheng <icenowy@aosc.io>
 * Copyright 2024 Ondřej Jirman <megi@xff.cz>
 */

#include <linux/delay.h>
#include <linux/gpio/consumer.h>
#include <linux/i2c.h>
#include <linux/module.h>
#include <linux/pm_runtime.h>
#include <linux/regmap.h>
#include <linux/regulator/consumer.h>

#include <linux/iio/iio.h>
#include <linux/iio/trigger_consumer.h>
#include <linux/iio/triggered_buffer.h>

#define AF8133J_REG_OUT         0x03
#define AF8133J_REG_PCODE       0x00
#define AF8133J_REG_PCODE_VAL   0x5e
#define AF8133J_REG_STATUS      0x02
#define AF8133J_REG_STATUS_ACQ  BIT(0)
#define AF8133J_REG_STATE       0x0a
#define AF8133J_REG_STATE_STBY  0x00
#define AF8133J_REG_STATE_WORK  0x01
#define AF8133J_REG_RANGE       0x0b
#define AF8133J_REG_RANGE_22G   0x12
#define AF8133J_REG_RANGE_12G   0x34
#define AF8133J_REG_SWR         0x11
#define AF8133J_REG_SWR_PERFORM 0x81

static const char * const af8133j_supply_names[] = {
        "avdd",
        "dvdd",
};

struct af8133j_data {
        struct i2c_client *client;
        struct regmap *regmap;
        /*
         * Protect device internal state between starting a measurement
         * and reading the result.
         */
        struct mutex mutex;
        struct iio_mount_matrix orientation;

        struct gpio_desc *reset_gpiod;
        struct regulator_bulk_data supplies[ARRAY_SIZE(af8133j_supply_names)];

        u8 range;
};

enum af8133j_axis {
        AXIS_X = 0,
        AXIS_Y,
        AXIS_Z,
};

static struct iio_mount_matrix *
af8133j_get_mount_matrix(struct iio_dev *indio_dev,
                         const struct iio_chan_spec *chan)
{
        struct af8133j_data *data = iio_priv(indio_dev);

        return &data->orientation;
}

static const struct iio_chan_spec_ext_info af8133j_ext_info[] = {
        IIO_MOUNT_MATRIX(IIO_SHARED_BY_DIR, af8133j_get_mount_matrix),
        { }
};

#define AF8133J_CHANNEL(_si, _axis) { \
        .type = IIO_MAGN, \
        .modified = 1, \
        .channel2 = IIO_MOD_ ## _axis, \
        .address = AXIS_ ## _axis, \
        .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
        .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
        .info_mask_shared_by_type_available = BIT(IIO_CHAN_INFO_SCALE), \
        .ext_info = af8133j_ext_info, \
        .scan_index = _si, \
        .scan_type = { \
                .sign = 's', \
                .realbits = 16, \
                .storagebits = 16, \
                .endianness = IIO_LE, \
        }, \
}

static const struct iio_chan_spec af8133j_channels[] = {
        AF8133J_CHANNEL(0, X),
        AF8133J_CHANNEL(1, Y),
        AF8133J_CHANNEL(2, Z),
        IIO_CHAN_SOFT_TIMESTAMP(3),
};

static int af8133j_product_check(struct af8133j_data *data)
{
        struct device *dev = &data->client->dev;
        unsigned int val;
        int ret;

        ret = regmap_read(data->regmap, AF8133J_REG_PCODE, &val);
        if (ret) {
                dev_err(dev, "Error reading product code (%d)\n", ret);
                return ret;
        }

        if (val != AF8133J_REG_PCODE_VAL) {
                dev_warn(dev, "Invalid product code (0x%02x)\n", val);
                return 0; /* Allow unknown ID so fallback compatibles work */
        }

        return 0;
}

static int af8133j_reset(struct af8133j_data *data)
{
        struct device *dev = &data->client->dev;
        int ret;

        if (data->reset_gpiod) {
                /* If we have GPIO reset line, use it */
                gpiod_set_value_cansleep(data->reset_gpiod, 1);
                udelay(10);
                gpiod_set_value_cansleep(data->reset_gpiod, 0);
        } else {
                /* Otherwise use software reset */
                ret = regmap_write(data->regmap, AF8133J_REG_SWR,
                                   AF8133J_REG_SWR_PERFORM);
                if (ret) {
                        dev_err(dev, "Failed to reset the chip\n");
                        return ret;
                }
        }

        /* Wait for reset to finish */
        usleep_range(1000, 1100);

        /* Restore range setting */
        if (data->range == AF8133J_REG_RANGE_22G) {
                ret = regmap_write(data->regmap, AF8133J_REG_RANGE, data->range);
                if (ret)
                        return ret;
        }

        return 0;
}

static void af8133j_power_down(struct af8133j_data *data)
{
        gpiod_set_value_cansleep(data->reset_gpiod, 1);
        regulator_bulk_disable(ARRAY_SIZE(data->supplies), data->supplies);
}

static int af8133j_power_up(struct af8133j_data *data)
{
        struct device *dev = &data->client->dev;
        int ret;

        ret = regulator_bulk_enable(ARRAY_SIZE(data->supplies), data->supplies);
        if (ret) {
                dev_err(dev, "Could not enable regulators\n");
                return ret;
        }

        gpiod_set_value_cansleep(data->reset_gpiod, 0);

        /* Wait for power on reset */
        usleep_range(15000, 16000);

        ret = af8133j_reset(data);
        if (ret) {
                af8133j_power_down(data);
                return ret;
        }

        return 0;
}

static int af8133j_take_measurement(struct af8133j_data *data)
{
        unsigned int val;
        int ret;

        ret = regmap_write(data->regmap,
                           AF8133J_REG_STATE, AF8133J_REG_STATE_WORK);
        if (ret)
                return ret;

        /* The datasheet says "Mesaure Time <1.5ms" */
        ret = regmap_read_poll_timeout(data->regmap, AF8133J_REG_STATUS, val,
                                       val & AF8133J_REG_STATUS_ACQ,
                                       500, 1500);
        if (ret)
                return ret;

        ret = regmap_write(data->regmap,
                           AF8133J_REG_STATE, AF8133J_REG_STATE_STBY);
        if (ret)
                return ret;

        return 0;
}

static int af8133j_read_measurement(struct af8133j_data *data, __le16 buf[3])
{
        struct device *dev = &data->client->dev;
        int ret;

        ret = pm_runtime_resume_and_get(dev);
        if (ret) {
                /*
                 * Ignore EACCES because that happens when RPM is disabled
                 * during system sleep, while userspace leave eg. hrtimer
                 * trigger attached and IIO core keeps trying to do measurements.
                 */
                if (ret != -EACCES)
                        dev_err(dev, "Failed to power on (%d)\n", ret);
                return ret;
        }

        scoped_guard(mutex, &data->mutex) {
                ret = af8133j_take_measurement(data);
                if (ret)
                        goto out_rpm_put;

                ret = regmap_bulk_read(data->regmap, AF8133J_REG_OUT,
                                       buf, sizeof(__le16) * 3);
        }

out_rpm_put:
        pm_runtime_mark_last_busy(dev);
        pm_runtime_put_autosuspend(dev);

        return ret;
}

static const int af8133j_scales[][2] = {
        [0] = { 0, 366210 }, /* 12 gauss */
        [1] = { 0, 671386 }, /* 22 gauss */
};

static int af8133j_read_raw(struct iio_dev *indio_dev,
                            struct iio_chan_spec const *chan, int *val,
                            int *val2, long mask)
{
        struct af8133j_data *data = iio_priv(indio_dev);
        __le16 buf[3];
        int ret;

        switch (mask) {
        case IIO_CHAN_INFO_RAW:
                ret = af8133j_read_measurement(data, buf);
                if (ret)
                        return ret;

                *val = sign_extend32(le16_to_cpu(buf[chan->address]),
                                     chan->scan_type.realbits - 1);
                return IIO_VAL_INT;
        case IIO_CHAN_INFO_SCALE:
                *val = 0;

                if (data->range == AF8133J_REG_RANGE_12G)
                        *val2 = af8133j_scales[0][1];
                else
                        *val2 = af8133j_scales[1][1];

                return IIO_VAL_INT_PLUS_NANO;
        default:
                return -EINVAL;
        }
}

static int af8133j_read_avail(struct iio_dev *indio_dev,
                              struct iio_chan_spec const *chan,
                              const int **vals, int *type, int *length,
                              long mask)
{
        switch (mask) {
        case IIO_CHAN_INFO_SCALE:
                *vals = (const int *)af8133j_scales;
                *length = ARRAY_SIZE(af8133j_scales) * 2;
                *type = IIO_VAL_INT_PLUS_NANO;
                return IIO_AVAIL_LIST;
        default:
                return -EINVAL;
        }
}

static int af8133j_set_scale(struct af8133j_data *data,
                             unsigned int val, unsigned int val2)
{
        struct device *dev = &data->client->dev;
        u8 range;
        int ret = 0;

        if (af8133j_scales[0][0] == val && af8133j_scales[0][1] == val2)
                range = AF8133J_REG_RANGE_12G;
        else if (af8133j_scales[1][0] == val && af8133j_scales[1][1] == val2)
                range = AF8133J_REG_RANGE_22G;
        else
                return -EINVAL;

        pm_runtime_disable(dev);

        /*
         * When suspended, just store the new range to data->range to be
         * applied later during power up.
         */
        if (!pm_runtime_status_suspended(dev)) {
                scoped_guard(mutex, &data->mutex)
                        ret = regmap_write(data->regmap,
                                           AF8133J_REG_RANGE, range);
        }

        pm_runtime_enable(dev);

        data->range = range;
        return ret;
}

static int af8133j_write_raw(struct iio_dev *indio_dev,
                             struct iio_chan_spec const *chan,
                             int val, int val2, long mask)
{
        struct af8133j_data *data = iio_priv(indio_dev);

        switch (mask) {
        case IIO_CHAN_INFO_SCALE:
                return af8133j_set_scale(data, val, val2);
        default:
                return -EINVAL;
        }
}

static int af8133j_write_raw_get_fmt(struct iio_dev *indio_dev,
                                     struct iio_chan_spec const *chan,
                                     long mask)
{
        return IIO_VAL_INT_PLUS_NANO;
}

static const struct iio_info af8133j_info = {
        .read_raw = af8133j_read_raw,
        .read_avail = af8133j_read_avail,
        .write_raw = af8133j_write_raw,
        .write_raw_get_fmt = af8133j_write_raw_get_fmt,
};

static irqreturn_t af8133j_trigger_handler(int irq, void *p)
{
        struct iio_poll_func *pf = p;
        struct iio_dev *indio_dev = pf->indio_dev;
        struct af8133j_data *data = iio_priv(indio_dev);
        s64 timestamp = iio_get_time_ns(indio_dev);
        struct {
                __le16 values[3];
                aligned_s64 timestamp;
        } sample = { };
        int ret;

        ret = af8133j_read_measurement(data, sample.values);
        if (ret)
                goto out_done;

        iio_push_to_buffers_with_ts(indio_dev, &sample, sizeof(sample),
                                    timestamp);

out_done:
        iio_trigger_notify_done(indio_dev->trig);

        return IRQ_HANDLED;
}

static const struct regmap_config af8133j_regmap_config = {
        .name = "af8133j_regmap",
        .reg_bits = 8,
        .val_bits = 8,
        .max_register = AF8133J_REG_SWR,
};

static void af8133j_power_down_action(void *ptr)
{
        struct af8133j_data *data = ptr;

        if (!pm_runtime_status_suspended(&data->client->dev))
                af8133j_power_down(data);
}

static int af8133j_probe(struct i2c_client *client)
{
        struct device *dev = &client->dev;
        struct af8133j_data *data;
        struct iio_dev *indio_dev;
        struct regmap *regmap;
        int ret, i;

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

        regmap = devm_regmap_init_i2c(client, &af8133j_regmap_config);
        if (IS_ERR(regmap))
                return dev_err_probe(dev, PTR_ERR(regmap),
                                     "regmap initialization failed\n");

        data = iio_priv(indio_dev);
        i2c_set_clientdata(client, indio_dev);
        data->client = client;
        data->regmap = regmap;
        data->range = AF8133J_REG_RANGE_12G;
        mutex_init(&data->mutex);

        data->reset_gpiod = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
        if (IS_ERR(data->reset_gpiod))
                return dev_err_probe(dev, PTR_ERR(data->reset_gpiod),
                                     "Failed to get reset gpio\n");

        for (i = 0; i < ARRAY_SIZE(af8133j_supply_names); i++)
                data->supplies[i].supply = af8133j_supply_names[i];
        ret = devm_regulator_bulk_get(dev, ARRAY_SIZE(data->supplies),
                                      data->supplies);
        if (ret)
                return ret;

        ret = iio_read_mount_matrix(dev, &data->orientation);
        if (ret)
                return dev_err_probe(dev, ret, "Failed to read mount matrix\n");

        ret = af8133j_power_up(data);
        if (ret)
                return ret;

        pm_runtime_set_active(dev);

        ret = devm_add_action_or_reset(dev, af8133j_power_down_action, data);
        if (ret)
                return ret;

        ret = af8133j_product_check(data);
        if (ret)
                return ret;

        pm_runtime_get_noresume(dev);
        pm_runtime_use_autosuspend(dev);
        pm_runtime_set_autosuspend_delay(dev, 500);
        ret = devm_pm_runtime_enable(dev);
        if (ret)
                return ret;

        pm_runtime_put_autosuspend(dev);

        indio_dev->info = &af8133j_info;
        indio_dev->name = "af8133j";
        indio_dev->channels = af8133j_channels;
        indio_dev->num_channels = ARRAY_SIZE(af8133j_channels);
        indio_dev->modes = INDIO_DIRECT_MODE;

        ret = devm_iio_triggered_buffer_setup(dev, indio_dev, NULL,
                                              &af8133j_trigger_handler, NULL);
        if (ret)
                return dev_err_probe(&client->dev, ret,
                                     "Failed to setup iio triggered buffer\n");

        ret = devm_iio_device_register(dev, indio_dev);
        if (ret)
                return dev_err_probe(dev, ret, "Failed to register iio device");

        return 0;
}

static int af8133j_runtime_suspend(struct device *dev)
{
        struct iio_dev *indio_dev = dev_get_drvdata(dev);
        struct af8133j_data *data = iio_priv(indio_dev);

        af8133j_power_down(data);

        return 0;
}

static int af8133j_runtime_resume(struct device *dev)
{
        struct iio_dev *indio_dev = dev_get_drvdata(dev);
        struct af8133j_data *data = iio_priv(indio_dev);

        return af8133j_power_up(data);
}

static const struct dev_pm_ops af8133j_pm_ops = {
        SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend, pm_runtime_force_resume)
        RUNTIME_PM_OPS(af8133j_runtime_suspend, af8133j_runtime_resume, NULL)
};

static const struct of_device_id af8133j_of_match[] = {
        { .compatible = "voltafield,af8133j", },
        { }
};
MODULE_DEVICE_TABLE(of, af8133j_of_match);

static const struct i2c_device_id af8133j_id[] = {
        { "af8133j" },
        { }
};
MODULE_DEVICE_TABLE(i2c, af8133j_id);

static struct i2c_driver af8133j_driver = {
        .driver = {
                .name = "af8133j",
                .of_match_table = af8133j_of_match,
                .pm = pm_ptr(&af8133j_pm_ops),
        },
        .probe = af8133j_probe,
        .id_table = af8133j_id,
};

module_i2c_driver(af8133j_driver);

MODULE_AUTHOR("Icenowy Zheng <icenowy@aosc.io>");
MODULE_AUTHOR("Ondřej Jirman <megi@xff.cz>");
MODULE_DESCRIPTION("Voltafield AF8133J magnetic sensor driver");
MODULE_LICENSE("GPL");