/*
 * tmp007.c - Support for TI TMP007 IR thermopile sensor with integrated math engine
 *
 * Copyright (c) 2017 Manivannan Sadhasivam <manivannanece23@gmail.com>
 *
 * This file is subject to the terms and conditions of version 2 of
 * the GNU General Public License.  See the file COPYING in the main
 * directory of this archive for more details.
 *
 * Driver for the Texas Instruments I2C 16-bit IR thermopile sensor
 *
 * (7-bit I2C slave address (0x40 - 0x47), changeable via ADR pins)
 *
 * Note: This driver assumes that the sensor has been calibrated beforehand
 *
 * TODO: ALERT irq, limit threshold events
 *
 */

#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/delay.h>
#include <linux/module.h>
#include <linux/pm.h>
#include <linux/bitops.h>
#include <linux/of.h>

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

#define TMP007_TDIE 0x01
#define TMP007_CONFIG 0x02
#define TMP007_TOBJECT 0x03
#define TMP007_STATUS 0x04
#define TMP007_STATUS_MASK 0x05
#define TMP007_MANUFACTURER_ID 0x1e
#define TMP007_DEVICE_ID 0x1f

#define TMP007_CONFIG_CONV_EN BIT(12)
#define TMP007_CONFIG_COMP_EN BIT(5)
#define TMP007_CONFIG_TC_EN BIT(6)
#define TMP007_CONFIG_CR_MASK GENMASK(11, 9)
#define TMP007_CONFIG_CR_SHIFT 9

#define TMP007_STATUS_CONV_READY BIT(14)
#define TMP007_STATUS_DATA_VALID BIT(9)

#define TMP007_MANUFACTURER_MAGIC 0x5449
#define TMP007_DEVICE_MAGIC 0x0078

#define TMP007_TEMP_SHIFT 2

struct tmp007_data {
	struct i2c_client *client;
	u16 config;
};

static const int tmp007_avgs[5][2] = { {4, 0}, {2, 0}, {1, 0},
					{0, 500000}, {0, 250000} };

static int tmp007_read_temperature(struct tmp007_data *data, u8 reg)
{
	s32 ret;
	int tries = 50;

	while (tries-- > 0) {
		ret = i2c_smbus_read_word_swapped(data->client,
			TMP007_STATUS);
		if (ret < 0)
			return ret;
		if ((ret & TMP007_STATUS_CONV_READY) &&
			!(ret & TMP007_STATUS_DATA_VALID))
				break;
		msleep(100);
	}

	if (tries < 0)
		return -EIO;

	return i2c_smbus_read_word_swapped(data->client, reg);
}

static int tmp007_powerdown(struct tmp007_data *data)
{
	return i2c_smbus_write_word_swapped(data->client, TMP007_CONFIG,
			data->config & ~TMP007_CONFIG_CONV_EN);
}

static int tmp007_read_raw(struct iio_dev *indio_dev,
		struct iio_chan_spec const *channel, int *val,
		int *val2, long mask)
{
	struct tmp007_data *data = iio_priv(indio_dev);
	s32 ret;
	int conv_rate;

	switch (mask) {
	case IIO_CHAN_INFO_RAW:
		switch (channel->channel2) {
		case IIO_MOD_TEMP_AMBIENT: /* LSB: 0.03125 degree Celsius */
			ret = i2c_smbus_read_word_swapped(data->client, TMP007_TDIE);
			if (ret < 0)
				return ret;
			break;
		case IIO_MOD_TEMP_OBJECT:
			ret = tmp007_read_temperature(data, TMP007_TOBJECT);
			if (ret < 0)
				return ret;
			break;
		default:
			return -EINVAL;
		}

		*val = sign_extend32(ret, 15) >> TMP007_TEMP_SHIFT;

		return IIO_VAL_INT;
	case IIO_CHAN_INFO_SCALE:
		*val = 31;
		*val2 = 250000;

		return IIO_VAL_INT_PLUS_MICRO;
	case IIO_CHAN_INFO_SAMP_FREQ:
		conv_rate = (data->config & TMP007_CONFIG_CR_MASK)
				>> TMP007_CONFIG_CR_SHIFT;
		*val = tmp007_avgs[conv_rate][0];
		*val2 = tmp007_avgs[conv_rate][1];

		return IIO_VAL_INT_PLUS_MICRO;
	default:
		return -EINVAL;
	}
}

static int tmp007_write_raw(struct iio_dev *indio_dev,
		struct iio_chan_spec const *channel, int val,
		int val2, long mask)
{
	struct tmp007_data *data = iio_priv(indio_dev);
	int i;
	u16 tmp;

	if (mask == IIO_CHAN_INFO_SAMP_FREQ) {
		for (i = 0; i < ARRAY_SIZE(tmp007_avgs); i++) {
			if ((val == tmp007_avgs[i][0]) &&
			(val2 == tmp007_avgs[i][1])) {
				tmp = data->config & ~TMP007_CONFIG_CR_MASK;
				tmp |= (i << TMP007_CONFIG_CR_SHIFT);

				return i2c_smbus_write_word_swapped(data->client,
								TMP007_CONFIG,
								data->config = tmp);
			}
		}
	}

	return -EINVAL;
}

static IIO_CONST_ATTR(sampling_frequency_available, "4 2 1 0.5 0.25");

static struct attribute *tmp007_attributes[] = {
	&iio_const_attr_sampling_frequency_available.dev_attr.attr,
	NULL
};

static const struct attribute_group tmp007_attribute_group = {
	.attrs = tmp007_attributes,
};

static const struct iio_chan_spec tmp007_channels[] = {
	{
		.type = IIO_TEMP,
		.modified = 1,
		.channel2 = IIO_MOD_TEMP_AMBIENT,
		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
				BIT(IIO_CHAN_INFO_SCALE),
		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
	},
	{
		.type = IIO_TEMP,
		.modified = 1,
		.channel2 = IIO_MOD_TEMP_OBJECT,
		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
				BIT(IIO_CHAN_INFO_SCALE),
		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
	}
};

static const struct iio_info tmp007_info = {
	.read_raw = tmp007_read_raw,
	.write_raw = tmp007_write_raw,
	.attrs = &tmp007_attribute_group,
	.driver_module = THIS_MODULE,
};

static bool tmp007_identify(struct i2c_client *client)
{
	int manf_id, dev_id;

	manf_id = i2c_smbus_read_word_swapped(client, TMP007_MANUFACTURER_ID);
	if (manf_id < 0)
		return false;

	dev_id = i2c_smbus_read_word_swapped(client, TMP007_DEVICE_ID);
	if (dev_id < 0)
		return false;

	return (manf_id == TMP007_MANUFACTURER_MAGIC && dev_id == TMP007_DEVICE_MAGIC);
}

static int tmp007_probe(struct i2c_client *client,
			const struct i2c_device_id *tmp007_id)
{
	struct tmp007_data *data;
	struct iio_dev *indio_dev;
	int ret;
	u16  status;

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

	if (!tmp007_identify(client)) {
		dev_err(&client->dev, "TMP007 not found\n");
		return -ENODEV;
	}

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

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

	indio_dev->dev.parent = &client->dev;
	indio_dev->name = "tmp007";
	indio_dev->modes = INDIO_DIRECT_MODE;
	indio_dev->info = &tmp007_info;

	indio_dev->channels = tmp007_channels;
	indio_dev->num_channels = ARRAY_SIZE(tmp007_channels);

	/*
	 * Set Configuration register:
	 * 1. Conversion ON
	 * 2. Comparator mode
	 * 3. Transient correction enable
	 */

	ret = i2c_smbus_read_word_swapped(data->client, TMP007_CONFIG);
	if (ret < 0)
		return ret;

	data->config = ret;
	data->config |= (TMP007_CONFIG_CONV_EN | TMP007_CONFIG_COMP_EN | TMP007_CONFIG_TC_EN);

	ret = i2c_smbus_write_word_swapped(data->client, TMP007_CONFIG,
					data->config);
	if (ret < 0)
		return ret;

	/*
	 * Set Status Mask register:
	 * 1. Conversion ready enable
	 * 2. Data valid enable
	 */

	ret = i2c_smbus_read_word_swapped(data->client, TMP007_STATUS_MASK);
	if (ret < 0)
		goto error_powerdown;

	status = ret;
	status |= (TMP007_STATUS_CONV_READY | TMP007_STATUS_DATA_VALID);

	ret = i2c_smbus_write_word_swapped(data->client, TMP007_STATUS_MASK, status);
	if (ret < 0)
		goto error_powerdown;

	return iio_device_register(indio_dev);

error_powerdown:
	tmp007_powerdown(data);

	return ret;
}

static int tmp007_remove(struct i2c_client *client)
{
	struct iio_dev *indio_dev = i2c_get_clientdata(client);
	struct tmp007_data *data = iio_priv(indio_dev);

	iio_device_unregister(indio_dev);
	tmp007_powerdown(data);

	return 0;
}

#ifdef CONFIG_PM_SLEEP
static int tmp007_suspend(struct device *dev)
{
	struct tmp007_data *data = iio_priv(i2c_get_clientdata(
			to_i2c_client(dev)));

	return tmp007_powerdown(data);
}

static int tmp007_resume(struct device *dev)
{
	struct tmp007_data *data = iio_priv(i2c_get_clientdata(
			to_i2c_client(dev)));

	return i2c_smbus_write_word_swapped(data->client, TMP007_CONFIG,
			data->config | TMP007_CONFIG_CONV_EN);
}
#endif

static SIMPLE_DEV_PM_OPS(tmp007_pm_ops, tmp007_suspend, tmp007_resume);

static const struct of_device_id tmp007_of_match[] = {
	{ .compatible = "ti,tmp007", },
	{ },
};
MODULE_DEVICE_TABLE(of, tmp007_of_match);

static const struct i2c_device_id tmp007_id[] = {
	{ "tmp007", 0 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, tmp007_id);

static struct i2c_driver tmp007_driver = {
	.driver = {
		.name	= "tmp007",
		.of_match_table = of_match_ptr(tmp007_of_match),
		.pm	= &tmp007_pm_ops,
	},
	.probe		= tmp007_probe,
	.remove		= tmp007_remove,
	.id_table	= tmp007_id,
};
module_i2c_driver(tmp007_driver);

MODULE_AUTHOR("Manivannan Sadhasivam <manivannanece23@gmail.com>");
MODULE_DESCRIPTION("TI TMP007 IR thermopile sensor driver");
MODULE_LICENSE("GPL");