// SPDX-License-Identifier: GPL-2.0-only
/*
 * itg3200_core.c -- support InvenSense ITG3200
 *                   Digital 3-Axis Gyroscope driver
 *
 * Copyright (c) 2011 Christian Strobel <christian.strobel@iis.fraunhofer.de>
 * Copyright (c) 2011 Manuel Stahl <manuel.stahl@iis.fraunhofer.de>
 * Copyright (c) 2012 Thorsten Nowak <thorsten.nowak@iis.fraunhofer.de>
 *
 * TODO:
 * - Support digital low pass filter
 * - Support power management
 */

#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/i2c.h>
#include <linux/slab.h>
#include <linux/stat.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/delay.h>

#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/iio/events.h>
#include <linux/iio/buffer.h>

#include <linux/iio/gyro/itg3200.h>


int itg3200_write_reg_8(struct iio_dev *indio_dev,
                u8 reg_address, u8 val)
{
        struct itg3200 *st = iio_priv(indio_dev);

        return i2c_smbus_write_byte_data(st->i2c, 0x80 | reg_address, val);
}

int itg3200_read_reg_8(struct iio_dev *indio_dev,
                u8 reg_address, u8 *val)
{
        struct itg3200 *st = iio_priv(indio_dev);
        int ret;

        ret = i2c_smbus_read_byte_data(st->i2c, reg_address);
        if (ret < 0)
                return ret;
        *val = ret;
        return 0;
}

static int itg3200_read_reg_s16(struct iio_dev *indio_dev, u8 lower_reg_address,
                int *val)
{
        struct itg3200 *st = iio_priv(indio_dev);
        struct i2c_client *client = st->i2c;
        int ret;
        s16 out;

        struct i2c_msg msg[2] = {
                {
                        .addr = client->addr,
                        .flags = client->flags,
                        .len = 1,
                        .buf = (char *)&lower_reg_address,
                },
                {
                        .addr = client->addr,
                        .flags = client->flags | I2C_M_RD,
                        .len = 2,
                        .buf = (char *)&out,
                },
        };

        lower_reg_address |= 0x80;
        ret = i2c_transfer(client->adapter, msg, 2);
        be16_to_cpus(&out);
        *val = out;

        return (ret == 2) ? 0 : ret;
}

static int itg3200_read_raw(struct iio_dev *indio_dev,
                const struct iio_chan_spec *chan,
                int *val, int *val2, long info)
{
        int ret = 0;
        u8 reg;
        u8 regval;

        switch (info) {
        case IIO_CHAN_INFO_RAW:
                reg = (u8)chan->address;
                ret = itg3200_read_reg_s16(indio_dev, reg, val);
                if (ret)
                        return ret;
                return IIO_VAL_INT;
        case IIO_CHAN_INFO_SCALE:
                *val = 0;
                if (chan->type == IIO_TEMP)
                        *val2 = 1000000000/280;
                else
                        *val2 = 1214142; /* (1 / 14,375) * (PI / 180) */
                return IIO_VAL_INT_PLUS_NANO;
        case IIO_CHAN_INFO_OFFSET:
                /* Only the temperature channel has an offset */
                *val = 23000;
                return IIO_VAL_INT;
        case IIO_CHAN_INFO_SAMP_FREQ:
                ret = itg3200_read_reg_8(indio_dev, ITG3200_REG_DLPF, &regval);
                if (ret)
                        return ret;

                *val = (regval & ITG3200_DLPF_CFG_MASK) ? 1000 : 8000;

                ret = itg3200_read_reg_8(indio_dev,
                                         ITG3200_REG_SAMPLE_RATE_DIV,
                                         &regval);
                if (ret)
                        return ret;

                *val /= regval + 1;
                return IIO_VAL_INT;

        default:
                return -EINVAL;
        }
}

static int itg3200_write_raw(struct iio_dev *indio_dev,
                             struct iio_chan_spec const *chan,
                             int val,
                             int val2,
                             long mask)
{
        struct itg3200 *st = iio_priv(indio_dev);
        int ret;
        u8 t;

        switch (mask) {
        case IIO_CHAN_INFO_SAMP_FREQ:
                if (val == 0 || val2 != 0)
                        return -EINVAL;

                mutex_lock(&st->lock);

                ret = itg3200_read_reg_8(indio_dev, ITG3200_REG_DLPF, &t);
                if (ret) {
                        mutex_unlock(&st->lock);
                        return ret;
                }
                t = ((t & ITG3200_DLPF_CFG_MASK) ? 1000u : 8000u) / val - 1;

                ret = itg3200_write_reg_8(indio_dev,
                                          ITG3200_REG_SAMPLE_RATE_DIV,
                                          t);

                mutex_unlock(&st->lock);
                return ret;

        default:
                return -EINVAL;
        }
}

/*
 * Reset device and internal registers to the power-up-default settings
 * Use the gyro clock as reference, as suggested by the datasheet
 */
static int itg3200_reset(struct iio_dev *indio_dev)
{
        struct itg3200 *st = iio_priv(indio_dev);
        int ret;

        dev_dbg(&st->i2c->dev, "reset device");

        ret = itg3200_write_reg_8(indio_dev,
                        ITG3200_REG_POWER_MANAGEMENT,
                        ITG3200_RESET);
        if (ret) {
                dev_err(&st->i2c->dev, "error resetting device");
                goto error_ret;
        }

        /* Wait for PLL (1ms according to datasheet) */
        udelay(1500);

        ret = itg3200_write_reg_8(indio_dev,
                        ITG3200_REG_IRQ_CONFIG,
                        ITG3200_IRQ_ACTIVE_HIGH |
                        ITG3200_IRQ_PUSH_PULL |
                        ITG3200_IRQ_LATCH_50US_PULSE |
                        ITG3200_IRQ_LATCH_CLEAR_ANY);

        if (ret)
                dev_err(&st->i2c->dev, "error init device");

error_ret:
        return ret;
}

/* itg3200_enable_full_scale() - Disables the digital low pass filter */
static int itg3200_enable_full_scale(struct iio_dev *indio_dev)
{
        u8 val;
        int ret;

        ret = itg3200_read_reg_8(indio_dev, ITG3200_REG_DLPF, &val);
        if (ret)
                goto err_ret;

        val |= ITG3200_DLPF_FS_SEL_2000;
        return itg3200_write_reg_8(indio_dev, ITG3200_REG_DLPF, val);

err_ret:
        return ret;
}

static int itg3200_initial_setup(struct iio_dev *indio_dev)
{
        struct itg3200 *st = iio_priv(indio_dev);
        int ret;
        u8 val;

        ret = itg3200_reset(indio_dev);
        if (ret)
                goto err_ret;

        ret = itg3200_read_reg_8(indio_dev, ITG3200_REG_ADDRESS, &val);
        if (ret)
                goto err_ret;

        if (((val >> 1) & 0x3f) != 0x34) {
                dev_err(&st->i2c->dev, "invalid reg value 0x%02x", val);
                ret = -ENXIO;
                goto err_ret;
        }

        ret = itg3200_enable_full_scale(indio_dev);
err_ret:
        return ret;
}

static const struct iio_mount_matrix *
itg3200_get_mount_matrix(const struct iio_dev *indio_dev,
                          const struct iio_chan_spec *chan)
{
        struct itg3200 *data = iio_priv(indio_dev);

        return &data->orientation;
}

static const struct iio_chan_spec_ext_info itg3200_ext_info[] = {
        IIO_MOUNT_MATRIX(IIO_SHARED_BY_DIR, itg3200_get_mount_matrix),
        { }
};

#define ITG3200_ST                                              \
        { .sign = 's', .realbits = 16, .storagebits = 16, .endianness = IIO_BE }

#define ITG3200_GYRO_CHAN(_mod) { \
        .type = IIO_ANGL_VEL, \
        .modified = 1, \
        .channel2 = IIO_MOD_ ## _mod, \
        .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
        .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
        .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ), \
        .address = ITG3200_REG_GYRO_ ## _mod ## OUT_H, \
        .scan_index = ITG3200_SCAN_GYRO_ ## _mod, \
        .scan_type = ITG3200_ST, \
        .ext_info = itg3200_ext_info, \
}

static const struct iio_chan_spec itg3200_channels[] = {
        {
                .type = IIO_TEMP,
                .channel2 = IIO_NO_MOD,
                .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
                .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_OFFSET) |
                BIT(IIO_CHAN_INFO_SCALE),
                .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
                .address = ITG3200_REG_TEMP_OUT_H,
                .scan_index = ITG3200_SCAN_TEMP,
                .scan_type = ITG3200_ST,
        },
        ITG3200_GYRO_CHAN(X),
        ITG3200_GYRO_CHAN(Y),
        ITG3200_GYRO_CHAN(Z),
        IIO_CHAN_SOFT_TIMESTAMP(ITG3200_SCAN_ELEMENTS),
};

static const struct iio_info itg3200_info = {
        .read_raw = &itg3200_read_raw,
        .write_raw = &itg3200_write_raw,
};

static const unsigned long itg3200_available_scan_masks[] = { 0xffffffff, 0x0 };

static int itg3200_probe(struct i2c_client *client)
{
        int ret;
        struct itg3200 *st;
        struct iio_dev *indio_dev;

        dev_dbg(&client->dev, "probe I2C dev with IRQ %i", client->irq);

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

        st = iio_priv(indio_dev);

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

        i2c_set_clientdata(client, indio_dev);
        st->i2c = client;

        indio_dev->name = client->dev.driver->name;
        indio_dev->channels = itg3200_channels;
        indio_dev->num_channels = ARRAY_SIZE(itg3200_channels);
        indio_dev->available_scan_masks = itg3200_available_scan_masks;
        indio_dev->info = &itg3200_info;
        indio_dev->modes = INDIO_DIRECT_MODE;

        ret = itg3200_buffer_configure(indio_dev);
        if (ret)
                return ret;

        if (client->irq) {
                ret = itg3200_probe_trigger(indio_dev);
                if (ret)
                        goto error_unconfigure_buffer;
        }

        ret = itg3200_initial_setup(indio_dev);
        if (ret)
                goto error_remove_trigger;

        mutex_init(&st->lock);

        ret = iio_device_register(indio_dev);
        if (ret)
                goto error_remove_trigger;

        return 0;

error_remove_trigger:
        if (client->irq)
                itg3200_remove_trigger(indio_dev);
error_unconfigure_buffer:
        itg3200_buffer_unconfigure(indio_dev);
        return ret;
}

static void itg3200_remove(struct i2c_client *client)
{
        struct iio_dev *indio_dev = i2c_get_clientdata(client);

        iio_device_unregister(indio_dev);

        if (client->irq)
                itg3200_remove_trigger(indio_dev);

        itg3200_buffer_unconfigure(indio_dev);
}

static int itg3200_suspend(struct device *dev)
{
        struct iio_dev *indio_dev = dev_get_drvdata(dev);
        struct itg3200 *st = iio_priv(indio_dev);

        dev_dbg(&st->i2c->dev, "suspend device");

        return itg3200_write_reg_8(indio_dev, ITG3200_REG_POWER_MANAGEMENT,
                                   ITG3200_SLEEP);
}

static int itg3200_resume(struct device *dev)
{
        struct iio_dev *indio_dev = dev_get_drvdata(dev);

        return itg3200_initial_setup(indio_dev);
}

static DEFINE_SIMPLE_DEV_PM_OPS(itg3200_pm_ops, itg3200_suspend,
                                itg3200_resume);

static const struct i2c_device_id itg3200_id[] = {
        { "itg3200" },
        { }
};
MODULE_DEVICE_TABLE(i2c, itg3200_id);

static const struct of_device_id itg3200_of_match[] = {
        { .compatible = "invensense,itg3200" },
        { }
};
MODULE_DEVICE_TABLE(of, itg3200_of_match);

static struct i2c_driver itg3200_driver = {
        .driver = {
                .name   = "itg3200",
                .of_match_table = itg3200_of_match,
                .pm     = pm_sleep_ptr(&itg3200_pm_ops),
        },
        .id_table       = itg3200_id,
        .probe          = itg3200_probe,
        .remove         = itg3200_remove,
};

module_i2c_driver(itg3200_driver);

MODULE_AUTHOR("Christian Strobel <christian.strobel@iis.fraunhofer.de>");
MODULE_DESCRIPTION("ITG3200 Gyroscope I2C driver");
MODULE_LICENSE("GPL v2");