// SPDX-License-Identifier: GPL-2.0-only
/*
 * Freescale MMA7660FC 3-Axis Accelerometer
 *
 * Copyright (c) 2016, Intel Corporation.
 *
 * IIO driver for Freescale MMA7660FC; 7-bit I2C address: 0x4c.
 */

#include <linux/i2c.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>

#define MMA7660_DRIVER_NAME     "mma7660"

#define MMA7660_REG_XOUT        0x00
#define MMA7660_REG_YOUT        0x01
#define MMA7660_REG_ZOUT        0x02
#define MMA7660_REG_OUT_BIT_ALERT       BIT(6)

#define MMA7660_REG_MODE        0x07
#define MMA7660_REG_MODE_BIT_MODE       BIT(0)
#define MMA7660_REG_MODE_BIT_TON        BIT(2)

#define MMA7660_I2C_READ_RETRIES        5

/*
 * The accelerometer has one measurement range:
 *
 * -1.5g - +1.5g (6-bit, signed)
 *
 * scale = (1.5 + 1.5) * 9.81 / (2^6 - 1)       = 0.467142857
 */

#define MMA7660_SCALE_AVAIL     "0.467142857"

static const int mma7660_nscale = 467142857;

enum mma7660_mode {
        MMA7660_MODE_STANDBY,
        MMA7660_MODE_ACTIVE
};

struct mma7660_data {
        struct i2c_client *client;
        struct mutex lock;
        enum mma7660_mode mode;
        struct iio_mount_matrix orientation;
};

static const struct iio_mount_matrix *
mma7660_get_mount_matrix(const struct iio_dev *indio_dev,
                        const struct iio_chan_spec *chan)
{
        struct mma7660_data *data = iio_priv(indio_dev);

        return &data->orientation;
}

static const struct iio_chan_spec_ext_info mma7660_ext_info[] = {
        IIO_MOUNT_MATRIX(IIO_SHARED_BY_DIR, mma7660_get_mount_matrix),
        { }
};

static IIO_CONST_ATTR(in_accel_scale_available, MMA7660_SCALE_AVAIL);

static struct attribute *mma7660_attributes[] = {
        &iio_const_attr_in_accel_scale_available.dev_attr.attr,
        NULL,
};

static const struct attribute_group mma7660_attribute_group = {
        .attrs = mma7660_attributes
};

#define MMA7660_CHANNEL(reg, axis) {    \
        .type = IIO_ACCEL,      \
        .address = reg, \
        .modified = 1,  \
        .channel2 = IIO_MOD_##axis,     \
        .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),   \
        .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),   \
        .ext_info = mma7660_ext_info,                           \
}

static const struct iio_chan_spec mma7660_channels[] = {
        MMA7660_CHANNEL(MMA7660_REG_XOUT, X),
        MMA7660_CHANNEL(MMA7660_REG_YOUT, Y),
        MMA7660_CHANNEL(MMA7660_REG_ZOUT, Z),
};

static int mma7660_set_mode(struct mma7660_data *data,
                                enum mma7660_mode mode)
{
        int ret;
        struct i2c_client *client = data->client;

        if (mode == data->mode)
                return 0;

        ret = i2c_smbus_read_byte_data(client, MMA7660_REG_MODE);
        if (ret < 0) {
                dev_err(&client->dev, "failed to read sensor mode\n");
                return ret;
        }

        if (mode == MMA7660_MODE_ACTIVE) {
                ret &= ~MMA7660_REG_MODE_BIT_TON;
                ret |= MMA7660_REG_MODE_BIT_MODE;
        } else {
                ret &= ~MMA7660_REG_MODE_BIT_TON;
                ret &= ~MMA7660_REG_MODE_BIT_MODE;
        }

        ret = i2c_smbus_write_byte_data(client, MMA7660_REG_MODE, ret);
        if (ret < 0) {
                dev_err(&client->dev, "failed to change sensor mode\n");
                return ret;
        }

        data->mode = mode;

        return ret;
}

static int mma7660_read_accel(struct mma7660_data *data, u8 address)
{
        int ret, retries = MMA7660_I2C_READ_RETRIES;
        struct i2c_client *client = data->client;

        /*
         * Read data. If the Alert bit is set, the register was read at
         * the same time as the device was attempting to update the content.
         * The solution is to read the register again. Do this only
         * MMA7660_I2C_READ_RETRIES times to avoid spending too much time
         * in the kernel.
         */
        do {
                ret = i2c_smbus_read_byte_data(client, address);
                if (ret < 0) {
                        dev_err(&client->dev, "register read failed\n");
                        return ret;
                }
        } while (retries-- > 0 && ret & MMA7660_REG_OUT_BIT_ALERT);

        if (ret & MMA7660_REG_OUT_BIT_ALERT) {
                dev_err(&client->dev, "all register read retries failed\n");
                return -ETIMEDOUT;
        }

        return ret;
}

static int mma7660_read_raw(struct iio_dev *indio_dev,
                                struct iio_chan_spec const *chan,
                                int *val, int *val2, long mask)
{
        struct mma7660_data *data = iio_priv(indio_dev);
        int ret;

        switch (mask) {
        case IIO_CHAN_INFO_RAW:
                mutex_lock(&data->lock);
                ret = mma7660_read_accel(data, chan->address);
                mutex_unlock(&data->lock);
                if (ret < 0)
                        return ret;
                *val = sign_extend32(ret, 5);
                return IIO_VAL_INT;
        case IIO_CHAN_INFO_SCALE:
                *val = 0;
                *val2 = mma7660_nscale;
                return IIO_VAL_INT_PLUS_NANO;
        default:
                return -EINVAL;
        }

        return -EINVAL;
}

static const struct iio_info mma7660_info = {
        .read_raw               = mma7660_read_raw,
        .attrs                  = &mma7660_attribute_group,
};

static int mma7660_probe(struct i2c_client *client)
{
        int ret;
        struct iio_dev *indio_dev;
        struct mma7660_data *data;

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

        data = iio_priv(indio_dev);
        data->client = client;
        i2c_set_clientdata(client, indio_dev);
        mutex_init(&data->lock);
        data->mode = MMA7660_MODE_STANDBY;

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

        indio_dev->info = &mma7660_info;
        indio_dev->name = MMA7660_DRIVER_NAME;
        indio_dev->modes = INDIO_DIRECT_MODE;
        indio_dev->channels = mma7660_channels;
        indio_dev->num_channels = ARRAY_SIZE(mma7660_channels);

        ret = mma7660_set_mode(data, MMA7660_MODE_ACTIVE);
        if (ret < 0)
                return ret;

        ret = iio_device_register(indio_dev);
        if (ret < 0) {
                dev_err(&client->dev, "device_register failed\n");
                mma7660_set_mode(data, MMA7660_MODE_STANDBY);
        }

        return ret;
}

static void mma7660_remove(struct i2c_client *client)
{
        struct iio_dev *indio_dev = i2c_get_clientdata(client);
        int ret;

        iio_device_unregister(indio_dev);

        ret = mma7660_set_mode(iio_priv(indio_dev), MMA7660_MODE_STANDBY);
        if (ret)
                dev_warn(&client->dev, "Failed to put device in stand-by mode (%pe), ignoring\n",
                         ERR_PTR(ret));
}

static int mma7660_suspend(struct device *dev)
{
        struct mma7660_data *data;

        data = iio_priv(i2c_get_clientdata(to_i2c_client(dev)));

        return mma7660_set_mode(data, MMA7660_MODE_STANDBY);
}

static int mma7660_resume(struct device *dev)
{
        struct mma7660_data *data;

        data = iio_priv(i2c_get_clientdata(to_i2c_client(dev)));

        return mma7660_set_mode(data, MMA7660_MODE_ACTIVE);
}

static DEFINE_SIMPLE_DEV_PM_OPS(mma7660_pm_ops, mma7660_suspend,
                                mma7660_resume);

static const struct i2c_device_id mma7660_i2c_id[] = {
        { "mma7660" },
        { }
};
MODULE_DEVICE_TABLE(i2c, mma7660_i2c_id);

static const struct of_device_id mma7660_of_match[] = {
        { .compatible = "fsl,mma7660" },
        { }
};
MODULE_DEVICE_TABLE(of, mma7660_of_match);

static const struct acpi_device_id mma7660_acpi_id[] = {
        {"MMA7660", 0},
        { }
};

MODULE_DEVICE_TABLE(acpi, mma7660_acpi_id);

static struct i2c_driver mma7660_driver = {
        .driver = {
                .name = "mma7660",
                .pm = pm_sleep_ptr(&mma7660_pm_ops),
                .of_match_table = mma7660_of_match,
                .acpi_match_table = mma7660_acpi_id,
        },
        .probe          = mma7660_probe,
        .remove         = mma7660_remove,
        .id_table       = mma7660_i2c_id,
};

module_i2c_driver(mma7660_driver);

MODULE_AUTHOR("Constantin Musca <constantin.musca@intel.com>");
MODULE_DESCRIPTION("Freescale MMA7660FC 3-Axis Accelerometer driver");
MODULE_LICENSE("GPL v2");