// SPDX-License-Identifier: GPL-2.0-only
/*
 * Digital temperature sensor with integrated Non-volatile memory
 * Copyright (c) 2021 Puranjay Mohan <puranjay12@gmail.com>
 *
 * Driver for the Texas Instruments TMP117 Temperature Sensor
 * (7-bit I2C slave address (0x48 - 0x4B), changeable via ADD pins)
 *
 * Note: This driver assumes that the sensor has been calibrated beforehand.
 */

#include <linux/delay.h>
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/module.h>
#include <linux/bitops.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/limits.h>
#include <linux/property.h>
#include <linux/regulator/consumer.h>

#include <linux/iio/iio.h>

#define TMP117_REG_TEMP                 0x0
#define TMP117_REG_CFGR                 0x1
#define TMP117_REG_HIGH_LIM             0x2
#define TMP117_REG_LOW_LIM              0x3
#define TMP117_REG_EEPROM_UL            0x4
#define TMP117_REG_EEPROM1              0x5
#define TMP117_REG_EEPROM2              0x6
#define TMP117_REG_TEMP_OFFSET          0x7
#define TMP117_REG_EEPROM3              0x8
#define TMP117_REG_DEVICE_ID            0xF

#define TMP117_RESOLUTION_10UC          78125
#define MICRODEGREE_PER_10MILLIDEGREE   10000

#define TMP116_DEVICE_ID                0x1116
#define TMP117_DEVICE_ID                0x0117

struct tmp117_data {
        struct i2c_client *client;
        s16 calibbias;
};

struct tmp11x_info {
        const char *name;
        struct iio_chan_spec const *channels;
        int num_channels;
};

static int tmp117_read_raw(struct iio_dev *indio_dev,
                           struct iio_chan_spec const *channel, int *val,
                           int *val2, long mask)
{
        struct tmp117_data *data = iio_priv(indio_dev);
        s32 ret;

        switch (mask) {
        case IIO_CHAN_INFO_RAW:
                ret = i2c_smbus_read_word_swapped(data->client,
                                                  TMP117_REG_TEMP);
                if (ret < 0)
                        return ret;
                *val = sign_extend32(ret, 15);
                return IIO_VAL_INT;

        case IIO_CHAN_INFO_CALIBBIAS:
                ret = i2c_smbus_read_word_swapped(data->client,
                                                  TMP117_REG_TEMP_OFFSET);
                if (ret < 0)
                        return ret;
                *val = sign_extend32(ret, 15);
                return IIO_VAL_INT;

        case IIO_CHAN_INFO_SCALE:
                /*
                 * Conversion from 10s of uC to mC
                 * as IIO reports temperature in mC
                 */
                *val = TMP117_RESOLUTION_10UC / MICRODEGREE_PER_10MILLIDEGREE;
                *val2 = (TMP117_RESOLUTION_10UC %
                                        MICRODEGREE_PER_10MILLIDEGREE) * 100;

                return IIO_VAL_INT_PLUS_MICRO;

        default:
                return -EINVAL;
        }
}

static int tmp117_write_raw(struct iio_dev *indio_dev, struct iio_chan_spec
                            const *channel, int val, int val2, long mask)
{
        struct tmp117_data *data = iio_priv(indio_dev);
        s16 off;

        switch (mask) {
        case IIO_CHAN_INFO_CALIBBIAS:
                off = clamp_t(int, val, S16_MIN, S16_MAX);
                if (off == data->calibbias)
                        return 0;
                data->calibbias = off;
                return i2c_smbus_write_word_swapped(data->client,
                                                TMP117_REG_TEMP_OFFSET, off);

        default:
                return -EINVAL;
        }
}

static const struct iio_chan_spec tmp117_channels[] = {
        {
                .type = IIO_TEMP,
                .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
                                      BIT(IIO_CHAN_INFO_CALIBBIAS) |
                                      BIT(IIO_CHAN_INFO_SCALE),
        },
};

static const struct iio_chan_spec tmp116_channels[] = {
        {
                .type = IIO_TEMP,
                .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
                                      BIT(IIO_CHAN_INFO_SCALE),
        },
};

static const struct tmp11x_info tmp116_channels_info = {
        .name = "tmp116",
        .channels = tmp116_channels,
        .num_channels = ARRAY_SIZE(tmp116_channels)
};

static const struct tmp11x_info tmp117_channels_info = {
        .name = "tmp117",
        .channels = tmp117_channels,
        .num_channels = ARRAY_SIZE(tmp117_channels)
};

static const struct iio_info tmp117_info = {
        .read_raw = tmp117_read_raw,
        .write_raw = tmp117_write_raw,
};

static int tmp117_probe(struct i2c_client *client)
{
        const struct tmp11x_info *match_data;
        struct tmp117_data *data;
        struct iio_dev *indio_dev;
        int dev_id;
        int ret;

        if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA))
                return -EOPNOTSUPP;

        ret = devm_regulator_get_enable(&client->dev, "vcc");
        if (ret)
                return ret;

        fsleep(1500);

        dev_id = i2c_smbus_read_word_swapped(client, TMP117_REG_DEVICE_ID);
        if (dev_id < 0)
                return dev_id;

        switch (dev_id) {
        case TMP116_DEVICE_ID:
                match_data = &tmp116_channels_info;
                break;
        case TMP117_DEVICE_ID:
                match_data = &tmp117_channels_info;
                break;
        default:
                dev_info(&client->dev,
                         "Unknown device id (0x%x), use fallback compatible\n",
                         dev_id);
                match_data = i2c_get_match_data(client);
        }

        if (!match_data)
                return dev_err_probe(&client->dev, -ENODEV,
                                     "Failed to identify unsupported device\n");

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

        data = iio_priv(indio_dev);
        data->client = client;
        data->calibbias = 0;

        indio_dev->modes = INDIO_DIRECT_MODE;
        indio_dev->info = &tmp117_info;
        indio_dev->channels = match_data->channels;
        indio_dev->num_channels = match_data->num_channels;
        indio_dev->name = match_data->name;


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

static const struct of_device_id tmp117_of_match[] = {
        { .compatible = "ti,tmp116", .data = &tmp116_channels_info },
        { .compatible = "ti,tmp117", .data = &tmp117_channels_info },
        { }
};
MODULE_DEVICE_TABLE(of, tmp117_of_match);

static const struct i2c_device_id tmp117_id[] = {
        { .name = "tmp116", .driver_data = (kernel_ulong_t)&tmp116_channels_info },
        { .name = "tmp117", .driver_data = (kernel_ulong_t)&tmp117_channels_info },
        { }
};
MODULE_DEVICE_TABLE(i2c, tmp117_id);

static struct i2c_driver tmp117_driver = {
        .driver = {
                .name   = "tmp117",
                .of_match_table = tmp117_of_match,
        },
        .probe          = tmp117_probe,
        .id_table       = tmp117_id,
};
module_i2c_driver(tmp117_driver);

MODULE_AUTHOR("Puranjay Mohan <puranjay12@gmail.com>");
MODULE_DESCRIPTION("TI TMP117 Temperature sensor driver");
MODULE_LICENSE("GPL");