root/drivers/iio/accel/mxc4005.c
// SPDX-License-Identifier: GPL-2.0-only
/*
 * 3-axis accelerometer driver for MXC4005XC Memsic sensor
 *
 * Copyright (c) 2014, Intel Corporation.
 */

#include <linux/delay.h>
#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/iio/iio.h>
#include <linux/mod_devicetable.h>
#include <linux/regmap.h>
#include <linux/types.h>
#include <linux/iio/sysfs.h>
#include <linux/iio/trigger.h>
#include <linux/iio/buffer.h>
#include <linux/iio/triggered_buffer.h>
#include <linux/iio/trigger_consumer.h>

#define MXC4005_DRV_NAME                "mxc4005"

#define MXC4005_REG_XOUT_UPPER          0x03
#define MXC4005_REG_XOUT_LOWER          0x04
#define MXC4005_REG_YOUT_UPPER          0x05
#define MXC4005_REG_YOUT_LOWER          0x06
#define MXC4005_REG_ZOUT_UPPER          0x07
#define MXC4005_REG_ZOUT_LOWER          0x08

#define MXC4005_REG_INT_MASK0           0x0A

#define MXC4005_REG_INT_MASK1           0x0B
#define MXC4005_REG_INT_MASK1_BIT_DRDYE 0x01

#define MXC4005_REG_INT_CLR0            0x00

#define MXC4005_REG_INT_CLR1            0x01
#define MXC4005_REG_INT_CLR1_BIT_DRDYC  0x01
#define MXC4005_REG_INT_CLR1_SW_RST     0x10

#define MXC4005_REG_CONTROL             0x0D
#define MXC4005_REG_CONTROL_MASK_FSR    GENMASK(6, 5)
#define MXC4005_CONTROL_FSR_SHIFT       5

#define MXC4005_REG_DEVICE_ID           0x0E

/* Datasheet does not specify a reset time, this is a conservative guess */
#define MXC4005_RESET_TIME_US           2000

enum mxc4005_axis {
        AXIS_X,
        AXIS_Y,
        AXIS_Z,
};

enum mxc4005_range {
        MXC4005_RANGE_2G,
        MXC4005_RANGE_4G,
        MXC4005_RANGE_8G,
};

struct mxc4005_data {
        struct device *dev;
        struct mutex mutex;
        struct regmap *regmap;
        struct iio_trigger *dready_trig;
        struct iio_mount_matrix orientation;
        /* Ensure timestamp is naturally aligned */
        struct {
                __be16 chans[3];
                aligned_s64 timestamp;
        } scan;
        bool trigger_enabled;
        unsigned int control;
        unsigned int int_mask1;
};

/*
 * MXC4005 can operate in the following ranges:
 * +/- 2G, 4G, 8G (the default +/-2G)
 *
 * (2 + 2) * 9.81 / (2^12 - 1) = 0.009582
 * (4 + 4) * 9.81 / (2^12 - 1) = 0.019164
 * (8 + 8) * 9.81 / (2^12 - 1) = 0.038329
 */
static const struct {
        u8 range;
        int scale;
} mxc4005_scale_table[] = {
        {MXC4005_RANGE_2G, 9582},
        {MXC4005_RANGE_4G, 19164},
        {MXC4005_RANGE_8G, 38329},
};


static IIO_CONST_ATTR(in_accel_scale_available, "0.009582 0.019164 0.038329");

static struct attribute *mxc4005_attributes[] = {
        &iio_const_attr_in_accel_scale_available.dev_attr.attr,
        NULL,
};

static const struct attribute_group mxc4005_attrs_group = {
        .attrs = mxc4005_attributes,
};

static bool mxc4005_is_readable_reg(struct device *dev, unsigned int reg)
{
        switch (reg) {
        case MXC4005_REG_XOUT_UPPER:
        case MXC4005_REG_XOUT_LOWER:
        case MXC4005_REG_YOUT_UPPER:
        case MXC4005_REG_YOUT_LOWER:
        case MXC4005_REG_ZOUT_UPPER:
        case MXC4005_REG_ZOUT_LOWER:
        case MXC4005_REG_DEVICE_ID:
        case MXC4005_REG_CONTROL:
                return true;
        default:
                return false;
        }
}

static bool mxc4005_is_writeable_reg(struct device *dev, unsigned int reg)
{
        switch (reg) {
        case MXC4005_REG_INT_CLR0:
        case MXC4005_REG_INT_CLR1:
        case MXC4005_REG_INT_MASK0:
        case MXC4005_REG_INT_MASK1:
        case MXC4005_REG_CONTROL:
                return true;
        default:
                return false;
        }
}

static const struct regmap_config mxc4005_regmap_config = {
        .name = "mxc4005_regmap",

        .reg_bits = 8,
        .val_bits = 8,

        .max_register = MXC4005_REG_DEVICE_ID,

        .readable_reg = mxc4005_is_readable_reg,
        .writeable_reg = mxc4005_is_writeable_reg,
};

static int mxc4005_read_xyz(struct mxc4005_data *data)
{
        int ret;

        ret = regmap_bulk_read(data->regmap, MXC4005_REG_XOUT_UPPER,
                               data->scan.chans, sizeof(data->scan.chans));
        if (ret < 0) {
                dev_err(data->dev, "failed to read axes\n");
                return ret;
        }

        return 0;
}

static int mxc4005_read_axis(struct mxc4005_data *data,
                             unsigned int addr)
{
        __be16 reg;
        int ret;

        ret = regmap_bulk_read(data->regmap, addr, &reg, sizeof(reg));
        if (ret < 0) {
                dev_err(data->dev, "failed to read reg %02x\n", addr);
                return ret;
        }

        return be16_to_cpu(reg);
}

static int mxc4005_read_scale(struct mxc4005_data *data)
{
        unsigned int reg;
        int ret;
        int i;

        ret = regmap_read(data->regmap, MXC4005_REG_CONTROL, &reg);
        if (ret < 0) {
                dev_err(data->dev, "failed to read reg_control\n");
                return ret;
        }

        i = reg >> MXC4005_CONTROL_FSR_SHIFT;

        if (i < 0 || i >= ARRAY_SIZE(mxc4005_scale_table))
                return -EINVAL;

        return mxc4005_scale_table[i].scale;
}

static int mxc4005_set_scale(struct mxc4005_data *data, int val)
{
        unsigned int reg;
        int i;
        int ret;

        for (i = 0; i < ARRAY_SIZE(mxc4005_scale_table); i++) {
                if (mxc4005_scale_table[i].scale == val) {
                        reg = i << MXC4005_CONTROL_FSR_SHIFT;
                        ret = regmap_update_bits(data->regmap,
                                                 MXC4005_REG_CONTROL,
                                                 MXC4005_REG_CONTROL_MASK_FSR,
                                                 reg);
                        if (ret < 0)
                                dev_err(data->dev,
                                        "failed to write reg_control\n");
                        return ret;
                }
        }

        return -EINVAL;
}

static int mxc4005_read_raw(struct iio_dev *indio_dev,
                            struct iio_chan_spec const *chan,
                            int *val, int *val2, long mask)
{
        struct mxc4005_data *data = iio_priv(indio_dev);
        int ret;

        switch (mask) {
        case IIO_CHAN_INFO_RAW:
                switch (chan->type) {
                case IIO_ACCEL:
                        if (iio_buffer_enabled(indio_dev))
                                return -EBUSY;

                        ret = mxc4005_read_axis(data, chan->address);
                        if (ret < 0)
                                return ret;
                        *val = sign_extend32(ret >> chan->scan_type.shift,
                                             chan->scan_type.realbits - 1);
                        return IIO_VAL_INT;
                default:
                        return -EINVAL;
                }
        case IIO_CHAN_INFO_SCALE:
                ret = mxc4005_read_scale(data);
                if (ret < 0)
                        return ret;

                *val = 0;
                *val2 = ret;
                return IIO_VAL_INT_PLUS_MICRO;
        default:
                return -EINVAL;
        }
}

static int mxc4005_write_raw(struct iio_dev *indio_dev,
                             struct iio_chan_spec const *chan,
                             int val, int val2, long mask)
{
        struct mxc4005_data *data = iio_priv(indio_dev);

        switch (mask) {
        case IIO_CHAN_INFO_SCALE:
                if (val != 0)
                        return -EINVAL;

                return mxc4005_set_scale(data, val2);
        default:
                return -EINVAL;
        }
}

static const struct iio_mount_matrix *
mxc4005_get_mount_matrix(const struct iio_dev *indio_dev,
                           const struct iio_chan_spec *chan)
{
        struct mxc4005_data *data = iio_priv(indio_dev);

        return &data->orientation;
}

static const struct iio_chan_spec_ext_info mxc4005_ext_info[] = {
        IIO_MOUNT_MATRIX(IIO_SHARED_BY_TYPE, mxc4005_get_mount_matrix),
        { }
};

static const struct iio_info mxc4005_info = {
        .read_raw       = mxc4005_read_raw,
        .write_raw      = mxc4005_write_raw,
        .attrs          = &mxc4005_attrs_group,
};

static const unsigned long mxc4005_scan_masks[] = {
        BIT(AXIS_X) | BIT(AXIS_Y) | BIT(AXIS_Z),
        0
};

#define MXC4005_CHANNEL(_axis, _addr) {                         \
        .type = IIO_ACCEL,                                      \
        .modified = 1,                                          \
        .channel2 = IIO_MOD_##_axis,                            \
        .address = _addr,                                       \
        .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),           \
        .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),   \
        .scan_index = AXIS_##_axis,                             \
        .scan_type = {                                          \
                .sign = 's',                                    \
                .realbits = 12,                                 \
                .storagebits = 16,                              \
                .shift = 4,                                     \
                .endianness = IIO_BE,                           \
        },                                                      \
        .ext_info = mxc4005_ext_info,                           \
}

static const struct iio_chan_spec mxc4005_channels[] = {
        MXC4005_CHANNEL(X, MXC4005_REG_XOUT_UPPER),
        MXC4005_CHANNEL(Y, MXC4005_REG_YOUT_UPPER),
        MXC4005_CHANNEL(Z, MXC4005_REG_ZOUT_UPPER),
        IIO_CHAN_SOFT_TIMESTAMP(3),
};

static irqreturn_t mxc4005_trigger_handler(int irq, void *private)
{
        struct iio_poll_func *pf = private;
        struct iio_dev *indio_dev = pf->indio_dev;
        struct mxc4005_data *data = iio_priv(indio_dev);
        int ret;

        ret = mxc4005_read_xyz(data);
        if (ret < 0)
                goto err;

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

err:
        iio_trigger_notify_done(indio_dev->trig);

        return IRQ_HANDLED;
}

static void mxc4005_clr_intr(struct mxc4005_data *data)
{
        int ret;

        /* clear interrupt */
        ret = regmap_write(data->regmap, MXC4005_REG_INT_CLR1,
                           MXC4005_REG_INT_CLR1_BIT_DRDYC);
        if (ret < 0)
                dev_err(data->dev, "failed to write to reg_int_clr1\n");
}

static int mxc4005_set_trigger_state(struct iio_trigger *trig,
                                     bool state)
{
        struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
        struct mxc4005_data *data = iio_priv(indio_dev);
        unsigned int val;
        int ret;

        mutex_lock(&data->mutex);

        val = state ? MXC4005_REG_INT_MASK1_BIT_DRDYE : 0;
        ret = regmap_write(data->regmap, MXC4005_REG_INT_MASK1, val);
        if (ret < 0) {
                mutex_unlock(&data->mutex);
                dev_err(data->dev, "failed to update reg_int_mask1");
                return ret;
        }

        data->int_mask1 = val;
        data->trigger_enabled = state;
        mutex_unlock(&data->mutex);

        return 0;
}

static void mxc4005_trigger_reen(struct iio_trigger *trig)
{
        struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
        struct mxc4005_data *data = iio_priv(indio_dev);

        if (!data->dready_trig)
                return;

        mxc4005_clr_intr(data);
}

static const struct iio_trigger_ops mxc4005_trigger_ops = {
        .set_trigger_state = mxc4005_set_trigger_state,
        .reenable = mxc4005_trigger_reen,
};

static int mxc4005_chip_init(struct mxc4005_data *data)
{
        int ret;
        unsigned int reg;

        ret = regmap_read(data->regmap, MXC4005_REG_DEVICE_ID, &reg);
        if (ret < 0) {
                dev_err(data->dev, "failed to read chip id\n");
                return ret;
        }

        dev_dbg(data->dev, "MXC4005 chip id %02x\n", reg);

        ret = regmap_write(data->regmap, MXC4005_REG_INT_CLR1,
                           MXC4005_REG_INT_CLR1_SW_RST);
        if (ret < 0)
                return dev_err_probe(data->dev, ret, "resetting chip\n");

        fsleep(MXC4005_RESET_TIME_US);

        ret = regmap_write(data->regmap, MXC4005_REG_INT_MASK0, 0);
        if (ret < 0)
                return dev_err_probe(data->dev, ret, "writing INT_MASK0\n");

        ret = regmap_write(data->regmap, MXC4005_REG_INT_MASK1, 0);
        if (ret < 0)
                return dev_err_probe(data->dev, ret, "writing INT_MASK1\n");

        return 0;
}

static int mxc4005_probe(struct i2c_client *client)
{
        struct mxc4005_data *data;
        struct iio_dev *indio_dev;
        struct regmap *regmap;
        int ret;

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

        regmap = devm_regmap_init_i2c(client, &mxc4005_regmap_config);
        if (IS_ERR(regmap)) {
                dev_err(&client->dev, "failed to initialize regmap\n");
                return PTR_ERR(regmap);
        }

        data = iio_priv(indio_dev);
        i2c_set_clientdata(client, indio_dev);
        data->dev = &client->dev;
        data->regmap = regmap;

        ret = mxc4005_chip_init(data);
        if (ret < 0) {
                dev_err(&client->dev, "failed to initialize chip\n");
                return ret;
        }

        mutex_init(&data->mutex);

        if (!iio_read_acpi_mount_matrix(&client->dev, &data->orientation, "ROTM")) {
                ret = iio_read_mount_matrix(&client->dev, &data->orientation);
                if (ret)
                        return ret;
        }

        indio_dev->channels = mxc4005_channels;
        indio_dev->num_channels = ARRAY_SIZE(mxc4005_channels);
        indio_dev->available_scan_masks = mxc4005_scan_masks;
        indio_dev->name = MXC4005_DRV_NAME;
        indio_dev->modes = INDIO_DIRECT_MODE;
        indio_dev->info = &mxc4005_info;

        ret = devm_iio_triggered_buffer_setup(&client->dev, indio_dev,
                                         iio_pollfunc_store_time,
                                         mxc4005_trigger_handler,
                                         NULL);
        if (ret < 0) {
                dev_err(&client->dev,
                        "failed to setup iio triggered buffer\n");
                return ret;
        }

        if (client->irq > 0) {
                data->dready_trig = devm_iio_trigger_alloc(&client->dev,
                                                           "%s-dev%d",
                                                           indio_dev->name,
                                                           iio_device_id(indio_dev));
                if (!data->dready_trig)
                        return -ENOMEM;

                ret = devm_request_irq(&client->dev, client->irq,
                                       iio_trigger_generic_data_rdy_poll,
                                       IRQF_TRIGGER_FALLING | IRQF_NO_THREAD,
                                       "mxc4005_event", data->dready_trig);
                if (ret) {
                        dev_err(&client->dev,
                                "failed to init threaded irq\n");
                        return ret;
                }

                data->dready_trig->ops = &mxc4005_trigger_ops;
                iio_trigger_set_drvdata(data->dready_trig, indio_dev);
                ret = devm_iio_trigger_register(&client->dev,
                                                data->dready_trig);
                if (ret) {
                        dev_err(&client->dev,
                                "failed to register trigger\n");
                        return ret;
                }

                indio_dev->trig = iio_trigger_get(data->dready_trig);
        }

        return devm_iio_device_register(&client->dev, indio_dev);
}

static int mxc4005_suspend(struct device *dev)
{
        struct iio_dev *indio_dev = dev_get_drvdata(dev);
        struct mxc4005_data *data = iio_priv(indio_dev);
        int ret;

        /* Save control to restore it on resume */
        ret = regmap_read(data->regmap, MXC4005_REG_CONTROL, &data->control);
        if (ret < 0)
                dev_err(data->dev, "failed to read reg_control\n");

        return ret;
}

static int mxc4005_resume(struct device *dev)
{
        struct iio_dev *indio_dev = dev_get_drvdata(dev);
        struct mxc4005_data *data = iio_priv(indio_dev);
        int ret;

        ret = regmap_write(data->regmap, MXC4005_REG_INT_CLR1,
                           MXC4005_REG_INT_CLR1_SW_RST);
        if (ret) {
                dev_err(data->dev, "failed to reset chip: %d\n", ret);
                return ret;
        }

        fsleep(MXC4005_RESET_TIME_US);

        ret = regmap_write(data->regmap, MXC4005_REG_CONTROL, data->control);
        if (ret) {
                dev_err(data->dev, "failed to restore control register\n");
                return ret;
        }

        ret = regmap_write(data->regmap, MXC4005_REG_INT_MASK0, 0);
        if (ret) {
                dev_err(data->dev, "failed to restore interrupt 0 mask\n");
                return ret;
        }

        ret = regmap_write(data->regmap, MXC4005_REG_INT_MASK1, data->int_mask1);
        if (ret) {
                dev_err(data->dev, "failed to restore interrupt 1 mask\n");
                return ret;
        }

        return 0;
}

static DEFINE_SIMPLE_DEV_PM_OPS(mxc4005_pm_ops, mxc4005_suspend, mxc4005_resume);

static const struct acpi_device_id mxc4005_acpi_match[] = {
        {"MXC4005",     0},
        {"MXC6655",     0},
        {"MDA6655",     0},
        { }
};
MODULE_DEVICE_TABLE(acpi, mxc4005_acpi_match);

static const struct of_device_id mxc4005_of_match[] = {
        { .compatible = "memsic,mxc4005", },
        { .compatible = "memsic,mxc6655", },
        { }
};
MODULE_DEVICE_TABLE(of, mxc4005_of_match);

static const struct i2c_device_id mxc4005_id[] = {
        { "mxc4005" },
        { "mxc6655" },
        { }
};
MODULE_DEVICE_TABLE(i2c, mxc4005_id);

static struct i2c_driver mxc4005_driver = {
        .driver = {
                .name = MXC4005_DRV_NAME,
                .acpi_match_table = mxc4005_acpi_match,
                .of_match_table = mxc4005_of_match,
                .pm = pm_sleep_ptr(&mxc4005_pm_ops),
        },
        .probe          = mxc4005_probe,
        .id_table       = mxc4005_id,
};

module_i2c_driver(mxc4005_driver);

MODULE_AUTHOR("Teodora Baluta <teodora.baluta@intel.com>");
MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("MXC4005 3-axis accelerometer driver");