// SPDX-License-Identifier: GPL-2.0+
/*
 * pulsedlight-lidar-lite-v2.c - Support for PulsedLight LIDAR sensor
 *
 * Copyright (C) 2015, 2017-2018
 * Author: Matt Ranostay <matt.ranostay@konsulko.com>
 *
 * TODO: interrupt mode, and signal strength reporting
 */

#include <linux/err.h>
#include <linux/init.h>
#include <linux/i2c.h>
#include <linux/delay.h>
#include <linux/module.h>
#include <linux/mod_devicetable.h>
#include <linux/pm_runtime.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/iio/buffer.h>
#include <linux/iio/trigger.h>
#include <linux/iio/triggered_buffer.h>
#include <linux/iio/trigger_consumer.h>

#define LIDAR_REG_CONTROL               0x00
#define LIDAR_REG_CONTROL_ACQUIRE       BIT(2)

#define LIDAR_REG_STATUS                0x01
#define LIDAR_REG_STATUS_INVALID        BIT(3)
#define LIDAR_REG_STATUS_READY          BIT(0)

#define LIDAR_REG_DATA_HBYTE            0x0f
#define LIDAR_REG_DATA_LBYTE            0x10
#define LIDAR_REG_DATA_WORD_READ        BIT(7)

#define LIDAR_REG_PWR_CONTROL   0x65

#define LIDAR_DRV_NAME "lidar"

struct lidar_data {
        struct iio_dev *indio_dev;
        struct i2c_client *client;

        int (*xfer)(struct lidar_data *data, u8 reg, u8 *val, int len);
        int i2c_enabled;
};

static const struct iio_chan_spec lidar_channels[] = {
        {
                .type = IIO_DISTANCE,
                .info_mask_separate =
                        BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),
                .scan_index = 0,
                .scan_type = {
                        .sign = 'u',
                        .realbits = 16,
                        .storagebits = 16,
                },
        },
        IIO_CHAN_SOFT_TIMESTAMP(1),
};

static int lidar_i2c_xfer(struct lidar_data *data, u8 reg, u8 *val, int len)
{
        struct i2c_client *client = data->client;
        struct i2c_msg msg[2];
        int ret;

        msg[0].addr = client->addr;
        msg[0].flags = client->flags | I2C_M_STOP;
        msg[0].len = 1;
        msg[0].buf  = (char *) &reg;

        msg[1].addr = client->addr;
        msg[1].flags = client->flags | I2C_M_RD;
        msg[1].len = len;
        msg[1].buf = (char *) val;

        ret = i2c_transfer(client->adapter, msg, 2);

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

static int lidar_smbus_xfer(struct lidar_data *data, u8 reg, u8 *val, int len)
{
        struct i2c_client *client = data->client;
        int ret;

        /*
         * Device needs a STOP condition between address write, and data read
         * so in turn i2c_smbus_read_byte_data cannot be used
         */

        while (len--) {
                ret = i2c_smbus_write_byte(client, reg++);
                if (ret < 0) {
                        dev_err(&client->dev, "cannot write addr value");
                        return ret;
                }

                ret = i2c_smbus_read_byte(client);
                if (ret < 0) {
                        dev_err(&client->dev, "cannot read data value");
                        return ret;
                }

                *(val++) = ret;
        }

        return 0;
}

static int lidar_read_byte(struct lidar_data *data, u8 reg)
{
        int ret;
        u8 val;

        ret = data->xfer(data, reg, &val, 1);
        if (ret < 0)
                return ret;

        return val;
}

static inline int lidar_write_control(struct lidar_data *data, int val)
{
        return i2c_smbus_write_byte_data(data->client, LIDAR_REG_CONTROL, val);
}

static inline int lidar_write_power(struct lidar_data *data, int val)
{
        return i2c_smbus_write_byte_data(data->client,
                                         LIDAR_REG_PWR_CONTROL, val);
}

static int lidar_read_measurement(struct lidar_data *data, u16 *reg)
{
        __be16 value;
        int ret = data->xfer(data, LIDAR_REG_DATA_HBYTE |
                        (data->i2c_enabled ? LIDAR_REG_DATA_WORD_READ : 0),
                        (u8 *) &value, 2);

        if (!ret)
                *reg = be16_to_cpu(value);

        return ret;
}

static int lidar_get_measurement(struct lidar_data *data, u16 *reg)
{
        struct i2c_client *client = data->client;
        int tries = 10;
        int ret;

        ret = pm_runtime_resume_and_get(&client->dev);
        if (ret < 0)
                return ret;

        /* start sample */
        ret = lidar_write_control(data, LIDAR_REG_CONTROL_ACQUIRE);
        if (ret < 0) {
                dev_err(&client->dev, "cannot send start measurement command");
                pm_runtime_put_noidle(&client->dev);
                return ret;
        }

        while (tries--) {
                usleep_range(1000, 2000);

                ret = lidar_read_byte(data, LIDAR_REG_STATUS);
                if (ret < 0)
                        break;

                /* return -EINVAL since laser is likely pointed out of range */
                if (ret & LIDAR_REG_STATUS_INVALID) {
                        *reg = 0;
                        ret = -EINVAL;
                        break;
                }

                /* sample ready to read */
                if (!(ret & LIDAR_REG_STATUS_READY)) {
                        ret = lidar_read_measurement(data, reg);
                        break;
                }
                ret = -EIO;
        }
        pm_runtime_put_autosuspend(&client->dev);

        return ret;
}

static int lidar_read_raw(struct iio_dev *indio_dev,
                          struct iio_chan_spec const *chan,
                          int *val, int *val2, long mask)
{
        struct lidar_data *data = iio_priv(indio_dev);
        int ret = -EINVAL;

        switch (mask) {
        case IIO_CHAN_INFO_RAW: {
                u16 reg;

                if (!iio_device_claim_direct(indio_dev))
                        return -EBUSY;

                ret = lidar_get_measurement(data, &reg);
                if (!ret) {
                        *val = reg;
                        ret = IIO_VAL_INT;
                }
                iio_device_release_direct(indio_dev);
                break;
        }
        case IIO_CHAN_INFO_SCALE:
                *val = 0;
                *val2 = 10000;
                ret = IIO_VAL_INT_PLUS_MICRO;
                break;
        }

        return ret;
}

static irqreturn_t lidar_trigger_handler(int irq, void *private)
{
        struct iio_poll_func *pf = private;
        struct iio_dev *indio_dev = pf->indio_dev;
        struct lidar_data *data = iio_priv(indio_dev);
        int ret;
        struct {
                u16 chan;
                aligned_s64 timestamp;
        } scan = { };

        ret = lidar_get_measurement(data, &scan.chan);
        if (!ret) {
                iio_push_to_buffers_with_ts(indio_dev, &scan, sizeof(scan),
                                            iio_get_time_ns(indio_dev));
        } else if (ret != -EINVAL) {
                dev_err(&data->client->dev, "cannot read LIDAR measurement");
        }

        iio_trigger_notify_done(indio_dev->trig);

        return IRQ_HANDLED;
}

static const struct iio_info lidar_info = {
        .read_raw = lidar_read_raw,
};

static int lidar_probe(struct i2c_client *client)
{
        struct lidar_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);

        if (i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
                data->xfer = lidar_i2c_xfer;
                data->i2c_enabled = 1;
        } else if (i2c_check_functionality(client->adapter,
                                I2C_FUNC_SMBUS_WORD_DATA | I2C_FUNC_SMBUS_BYTE))
                data->xfer = lidar_smbus_xfer;
        else
                return -EOPNOTSUPP;

        indio_dev->info = &lidar_info;
        indio_dev->name = LIDAR_DRV_NAME;
        indio_dev->channels = lidar_channels;
        indio_dev->num_channels = ARRAY_SIZE(lidar_channels);
        indio_dev->modes = INDIO_DIRECT_MODE;

        i2c_set_clientdata(client, indio_dev);

        data->client = client;
        data->indio_dev = indio_dev;

        ret = iio_triggered_buffer_setup(indio_dev, NULL,
                                         lidar_trigger_handler, NULL);
        if (ret)
                return ret;

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

        pm_runtime_set_autosuspend_delay(&client->dev, 1000);
        pm_runtime_use_autosuspend(&client->dev);

        ret = pm_runtime_set_active(&client->dev);
        if (ret)
                goto error_unreg_buffer;
        pm_runtime_enable(&client->dev);
        pm_runtime_idle(&client->dev);

        return 0;

error_unreg_buffer:
        iio_triggered_buffer_cleanup(indio_dev);

        return ret;
}

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

        iio_device_unregister(indio_dev);
        iio_triggered_buffer_cleanup(indio_dev);

        pm_runtime_disable(&client->dev);
        pm_runtime_set_suspended(&client->dev);
}

static const struct i2c_device_id lidar_id[] = {
        { "lidar-lite-v2" },
        { "lidar-lite-v3" },
        { }
};
MODULE_DEVICE_TABLE(i2c, lidar_id);

static const struct of_device_id lidar_dt_ids[] = {
        { .compatible = "pulsedlight,lidar-lite-v2" },
        { .compatible = "grmn,lidar-lite-v3" },
        { }
};
MODULE_DEVICE_TABLE(of, lidar_dt_ids);

static int lidar_pm_runtime_suspend(struct device *dev)
{
        struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
        struct lidar_data *data = iio_priv(indio_dev);

        return lidar_write_power(data, 0x0f);
}

static int lidar_pm_runtime_resume(struct device *dev)
{
        struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
        struct lidar_data *data = iio_priv(indio_dev);
        int ret = lidar_write_power(data, 0);

        /* regulator and FPGA needs settling time */
        usleep_range(15000, 20000);

        return ret;
}

static const struct dev_pm_ops lidar_pm_ops = {
        RUNTIME_PM_OPS(lidar_pm_runtime_suspend, lidar_pm_runtime_resume, NULL)
};

static struct i2c_driver lidar_driver = {
        .driver = {
                .name   = LIDAR_DRV_NAME,
                .of_match_table = lidar_dt_ids,
                .pm     = pm_ptr(&lidar_pm_ops),
        },
        .probe          = lidar_probe,
        .remove         = lidar_remove,
        .id_table       = lidar_id,
};
module_i2c_driver(lidar_driver);

MODULE_AUTHOR("Matt Ranostay <matt.ranostay@konsulko.com>");
MODULE_DESCRIPTION("PulsedLight LIDAR sensor");
MODULE_LICENSE("GPL");