drivers/iio/light/vl6180.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * vl6180.c - Support for STMicroelectronics VL6180 ALS, range and proximity
  * sensor
  *
  * Copyright 2017 Peter Meerwald-Stadler <pmeerw@pmeerw.net>
  * Copyright 2017 Manivannan Sadhasivam <manivannanece23@gmail.com>
  *
  * IIO driver for VL6180 (7-bit I2C slave address 0x29)
  *
  * Range: 0 to 100mm
  * ALS: < 1 Lux up to 100 kLux
  * IR: 850nm
  *
  * TODO: irq, threshold events, continuous mode, hardware buffer
  */

 #include <linux/module.h>
 #include <linux/mod_devicetable.h>
 #include <linux/i2c.h>
 #include <linux/mutex.h>
 #include <linux/err.h>
 #include <linux/delay.h>
 #include <linux/util_macros.h>

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

 #define VL6180_DRV_NAME "vl6180"

 /* Device identification register and value */
 #define VL6180_MODEL_ID	0x000
 #define VL6180_MODEL_ID_VAL 0xb4

 /* Configuration registers */
 #define VL6180_INTR_CONFIG 0x014
 #define VL6180_INTR_CLEAR 0x015
 #define VL6180_OUT_OF_RESET 0x016
 #define VL6180_HOLD 0x017
 #define VL6180_RANGE_START 0x018
 #define VL6180_ALS_START 0x038
 #define VL6180_ALS_GAIN 0x03f
 #define VL6180_ALS_IT 0x040

 /* Status registers */
 #define VL6180_RANGE_STATUS 0x04d
 #define VL6180_ALS_STATUS 0x04e
 #define VL6180_INTR_STATUS 0x04f

 /* Result value registers */
 #define VL6180_ALS_VALUE 0x050
 #define VL6180_RANGE_VALUE 0x062
 #define VL6180_RANGE_RATE 0x066

 /* bits of the RANGE_START and ALS_START register */
 #define VL6180_MODE_CONT BIT(1) /* continuous mode */
 #define VL6180_STARTSTOP BIT(0) /* start measurement, auto-reset */

 /* bits of the INTR_STATUS and INTR_CONFIG register */
 #define VL6180_ALS_READY BIT(5)
 #define VL6180_RANGE_READY BIT(2)

 /* bits of the INTR_CLEAR register */
 #define VL6180_CLEAR_ERROR BIT(2)
 #define VL6180_CLEAR_ALS BIT(1)
 #define VL6180_CLEAR_RANGE BIT(0)

 /* bits of the HOLD register */
 #define VL6180_HOLD_ON BIT(0)

 /* default value for the ALS_IT register */
 #define VL6180_ALS_IT_100 0x63 /* 100 ms */

 /* values for the ALS_GAIN register */
 #define VL6180_ALS_GAIN_1 0x46
 #define VL6180_ALS_GAIN_1_25 0x45
 #define VL6180_ALS_GAIN_1_67 0x44
 #define VL6180_ALS_GAIN_2_5 0x43
 #define VL6180_ALS_GAIN_5 0x42
 #define VL6180_ALS_GAIN_10 0x41
 #define VL6180_ALS_GAIN_20 0x40
 #define VL6180_ALS_GAIN_40 0x47

 struct vl6180_data {
 	struct i2c_client *client;
 	struct mutex lock;
 	unsigned int als_gain_milli;
 	unsigned int als_it_ms;
 };

 enum { VL6180_ALS, VL6180_RANGE, VL6180_PROX };

 /**
  * struct vl6180_chan_regs - Registers for accessing channels
  * @drdy_mask:			Data ready bit in status register
  * @start_reg:			Conversion start register
  * @value_reg:			Result value register
  * @word:			Register word length
  */
 struct vl6180_chan_regs {
 	u8 drdy_mask;
 	u16 start_reg, value_reg;
 	bool word;
 };

 static const struct vl6180_chan_regs vl6180_chan_regs_table[] = {
 	[VL6180_ALS] = {
 		.drdy_mask = VL6180_ALS_READY,
 		.start_reg = VL6180_ALS_START,
 		.value_reg = VL6180_ALS_VALUE,
 		.word = true,
 	},
 	[VL6180_RANGE] = {
 		.drdy_mask = VL6180_RANGE_READY,
 		.start_reg = VL6180_RANGE_START,
 		.value_reg = VL6180_RANGE_VALUE,
 		.word = false,
 	},
 	[VL6180_PROX] = {
 		.drdy_mask = VL6180_RANGE_READY,
 		.start_reg = VL6180_RANGE_START,
 		.value_reg = VL6180_RANGE_RATE,
 		.word = true,
 	},
 };

 static int vl6180_read(struct i2c_client *client, u16 cmd, void *databuf,
 		       u8 len)
 {
 	__be16 cmdbuf = cpu_to_be16(cmd);
 	struct i2c_msg msgs[2] = {
 		{ .addr = client->addr, .len = sizeof(cmdbuf), .buf = (u8 *) &cmdbuf },
 		{ .addr = client->addr, .len = len, .buf = databuf,
 		  .flags = I2C_M_RD } };
 	int ret;

 	ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
 	if (ret < 0)
 		dev_err(&client->dev, "failed reading register 0x%04x\n", cmd);

 	return ret;
 }

 static int vl6180_read_byte(struct i2c_client *client, u16 cmd)
 {
 	u8 data;
 	int ret;

 	ret = vl6180_read(client, cmd, &data, sizeof(data));
 	if (ret < 0)
 		return ret;

 	return data;
 }

 static int vl6180_read_word(struct i2c_client *client, u16 cmd)
 {
 	__be16 data;
 	int ret;

 	ret = vl6180_read(client, cmd, &data, sizeof(data));
 	if (ret < 0)
 		return ret;

 	return be16_to_cpu(data);
 }

 static int vl6180_write_byte(struct i2c_client *client, u16 cmd, u8 val)
 {
 	u8 buf[3];
 	struct i2c_msg msgs[1] = {
 		{ .addr = client->addr, .len = sizeof(buf), .buf = (u8 *) &buf } };
 	int ret;

 	buf[0] = cmd >> 8;
 	buf[1] = cmd & 0xff;
 	buf[2] = val;

 	ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
 	if (ret < 0) {
 		dev_err(&client->dev, "failed writing register 0x%04x\n", cmd);
 		return ret;
 	}

 	return 0;
 }

 static int vl6180_write_word(struct i2c_client *client, u16 cmd, u16 val)
 {
 	__be16 buf[2];
 	struct i2c_msg msgs[1] = {
 		{ .addr = client->addr, .len = sizeof(buf), .buf = (u8 *) &buf } };
 	int ret;

 	buf[0] = cpu_to_be16(cmd);
 	buf[1] = cpu_to_be16(val);

 	ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
 	if (ret < 0) {
 		dev_err(&client->dev, "failed writing register 0x%04x\n", cmd);
 		return ret;
 	}

 	return 0;
 }

 static int vl6180_measure(struct vl6180_data *data, int addr)
 {
 	struct i2c_client *client = data->client;
 	int tries = 20, ret;
 	u16 value;

 	mutex_lock(&data->lock);
 	/* Start single shot measurement */
 	ret = vl6180_write_byte(client,
 		vl6180_chan_regs_table[addr].start_reg, VL6180_STARTSTOP);
 	if (ret < 0)
 		goto fail;

 	while (tries--) {
 		ret = vl6180_read_byte(client, VL6180_INTR_STATUS);
 		if (ret < 0)
 			goto fail;

 		if (ret & vl6180_chan_regs_table[addr].drdy_mask)
 			break;
 		msleep(20);
 	}

 	if (tries < 0) {
 		ret = -EIO;
 		goto fail;
 	}

 	/* Read result value from appropriate registers */
 	ret = vl6180_chan_regs_table[addr].word ?
 		vl6180_read_word(client, vl6180_chan_regs_table[addr].value_reg) :
 		vl6180_read_byte(client, vl6180_chan_regs_table[addr].value_reg);
 	if (ret < 0)
 		goto fail;
 	value = ret;

 	/* Clear the interrupt flag after data read */
 	ret = vl6180_write_byte(client, VL6180_INTR_CLEAR,
 		VL6180_CLEAR_ERROR | VL6180_CLEAR_ALS | VL6180_CLEAR_RANGE);
 	if (ret < 0)
 		goto fail;

 	ret = value;

 fail:
 	mutex_unlock(&data->lock);

 	return ret;
 }

 static const struct iio_chan_spec vl6180_channels[] = {
 	{
 		.type = IIO_LIGHT,
 		.address = VL6180_ALS,
 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
 			BIT(IIO_CHAN_INFO_INT_TIME) |
 			BIT(IIO_CHAN_INFO_SCALE) |
 			BIT(IIO_CHAN_INFO_HARDWAREGAIN),
 	}, {
 		.type = IIO_DISTANCE,
 		.address = VL6180_RANGE,
 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
 			BIT(IIO_CHAN_INFO_SCALE),
 	}, {
 		.type = IIO_PROXIMITY,
 		.address = VL6180_PROX,
 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
 	}
 };

 /*
  * Available Ambient Light Sensor gain settings, 1/1000th, and
  * corresponding setting for the VL6180_ALS_GAIN register
  */
 static const int vl6180_als_gain_tab[8] = {
 	1000, 1250, 1670, 2500, 5000, 10000, 20000, 40000
 };
 static const u8 vl6180_als_gain_tab_bits[8] = {
 	VL6180_ALS_GAIN_1,    VL6180_ALS_GAIN_1_25,
 	VL6180_ALS_GAIN_1_67, VL6180_ALS_GAIN_2_5,
 	VL6180_ALS_GAIN_5,    VL6180_ALS_GAIN_10,
 	VL6180_ALS_GAIN_20,   VL6180_ALS_GAIN_40
 };

 static int vl6180_read_raw(struct iio_dev *indio_dev,
 				struct iio_chan_spec const *chan,
 				int *val, int *val2, long mask)
 {
 	struct vl6180_data *data = iio_priv(indio_dev);
 	int ret;

 	switch (mask) {
 	case IIO_CHAN_INFO_RAW:
 		ret = vl6180_measure(data, chan->address);
 		if (ret < 0)
 			return ret;
 		*val = ret;

 		return IIO_VAL_INT;
 	case IIO_CHAN_INFO_INT_TIME:
 		*val = data->als_it_ms;
 		*val2 = 1000;

 		return IIO_VAL_FRACTIONAL;

 	case IIO_CHAN_INFO_SCALE:
 		switch (chan->type) {
 		case IIO_LIGHT:
 			/* one ALS count is 0.32 Lux @ gain 1, IT 100 ms */
 			*val = 32000; /* 0.32 * 1000 * 100 */
 			*val2 = data->als_gain_milli * data->als_it_ms;

 			return IIO_VAL_FRACTIONAL;

 		case IIO_DISTANCE:
 			*val = 0; /* sensor reports mm, scale to meter */
 			*val2 = 1000;
 			break;
 		default:
 			return -EINVAL;
 		}

 		return IIO_VAL_INT_PLUS_MICRO;
 	case IIO_CHAN_INFO_HARDWAREGAIN:
 		*val = data->als_gain_milli;
 		*val2 = 1000;

 		return IIO_VAL_FRACTIONAL;

 	default:
 		return -EINVAL;
 	}
 }

 static IIO_CONST_ATTR(als_gain_available, "1 1.25 1.67 2.5 5 10 20 40");

 static struct attribute *vl6180_attributes[] = {
 	&iio_const_attr_als_gain_available.dev_attr.attr,
 	NULL
 };

 static const struct attribute_group vl6180_attribute_group = {
 	.attrs = vl6180_attributes,
 };

 /* HOLD is needed before updating any config registers */
 static int vl6180_hold(struct vl6180_data *data, bool hold)
 {
 	return vl6180_write_byte(data->client, VL6180_HOLD,
 		hold ? VL6180_HOLD_ON : 0);
 }

 static int vl6180_set_als_gain(struct vl6180_data *data, int val, int val2)
 {
 	int i, ret, gain;

 	if (val < 1 || val > 40)
 		return -EINVAL;

 	gain = (val * 1000000 + val2) / 1000;
 	if (gain < 1 || gain > 40000)
 		return -EINVAL;

 	i = find_closest(gain, vl6180_als_gain_tab,
 			 ARRAY_SIZE(vl6180_als_gain_tab));

 	mutex_lock(&data->lock);
 	ret = vl6180_hold(data, true);
 	if (ret < 0)
 		goto fail;

 	ret = vl6180_write_byte(data->client, VL6180_ALS_GAIN,
 				vl6180_als_gain_tab_bits[i]);

 	if (ret >= 0)
 		data->als_gain_milli = vl6180_als_gain_tab[i];

 fail:
 	vl6180_hold(data, false);
 	mutex_unlock(&data->lock);
 	return ret;
 }

 static int vl6180_set_it(struct vl6180_data *data, int val, int val2)
 {
 	int ret, it_ms;

 	it_ms = DIV_ROUND_CLOSEST(val2, 1000); /* round to ms */
 	if (val != 0 || it_ms < 1 || it_ms > 512)
 		return -EINVAL;

 	mutex_lock(&data->lock);
 	ret = vl6180_hold(data, true);
 	if (ret < 0)
 		goto fail;

 	ret = vl6180_write_word(data->client, VL6180_ALS_IT, it_ms - 1);

 	if (ret >= 0)
 		data->als_it_ms = it_ms;

 fail:
 	vl6180_hold(data, false);
 	mutex_unlock(&data->lock);

 	return ret;
 }

 static int vl6180_write_raw(struct iio_dev *indio_dev,
 			     struct iio_chan_spec const *chan,
 			     int val, int val2, long mask)
 {
 	struct vl6180_data *data = iio_priv(indio_dev);

 	switch (mask) {
 	case IIO_CHAN_INFO_INT_TIME:
 		return vl6180_set_it(data, val, val2);

 	case IIO_CHAN_INFO_HARDWAREGAIN:
 		if (chan->type != IIO_LIGHT)
 			return -EINVAL;

 		return vl6180_set_als_gain(data, val, val2);
 	default:
 		return -EINVAL;
 	}
 }

 static const struct iio_info vl6180_info = {
 	.read_raw = vl6180_read_raw,
 	.write_raw = vl6180_write_raw,
 	.attrs = &vl6180_attribute_group,
 };

 static int vl6180_init(struct vl6180_data *data)
 {
 	struct i2c_client *client = data->client;
 	int ret;

 	ret = vl6180_read_byte(client, VL6180_MODEL_ID);
 	if (ret < 0)
 		return ret;

 	if (ret != VL6180_MODEL_ID_VAL) {
 		dev_err(&client->dev, "invalid model ID %02x\n", ret);
 		return -ENODEV;
 	}

 	ret = vl6180_hold(data, true);
 	if (ret < 0)
 		return ret;

 	ret = vl6180_read_byte(client, VL6180_OUT_OF_RESET);
 	if (ret < 0)
 		return ret;

 	/*
 	 * Detect false reset condition here. This bit is always set when the
 	 * system comes out of reset.
 	 */
 	if (ret != 0x01)
 		dev_info(&client->dev, "device is not fresh out of reset\n");

 	/* Enable ALS and Range ready interrupts */
 	ret = vl6180_write_byte(client, VL6180_INTR_CONFIG,
 				VL6180_ALS_READY | VL6180_RANGE_READY);
 	if (ret < 0)
 		return ret;

 	/* ALS integration time: 100ms */
 	data->als_it_ms = 100;
 	ret = vl6180_write_word(client, VL6180_ALS_IT, VL6180_ALS_IT_100);
 	if (ret < 0)
 		return ret;

 	/* ALS gain: 1 */
 	data->als_gain_milli = 1000;
 	ret = vl6180_write_byte(client, VL6180_ALS_GAIN, VL6180_ALS_GAIN_1);
 	if (ret < 0)
 		return ret;

 	ret = vl6180_write_byte(client, VL6180_OUT_OF_RESET, 0x00);
 	if (ret < 0)
 		return ret;

 	return vl6180_hold(data, false);
 }

 static int vl6180_probe(struct i2c_client *client)
 {
 	struct vl6180_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);
 	i2c_set_clientdata(client, indio_dev);
 	data->client = client;
 	mutex_init(&data->lock);

 	indio_dev->info = &vl6180_info;
 	indio_dev->channels = vl6180_channels;
 	indio_dev->num_channels = ARRAY_SIZE(vl6180_channels);
 	indio_dev->name = VL6180_DRV_NAME;
 	indio_dev->modes = INDIO_DIRECT_MODE;

 	ret = vl6180_init(data);
 	if (ret < 0)
 		return ret;

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

 static const struct of_device_id vl6180_of_match[] = {
 	{ .compatible = "st,vl6180", },
 	{ },
 };
 MODULE_DEVICE_TABLE(of, vl6180_of_match);

 static const struct i2c_device_id vl6180_id[] = {
 	{ "vl6180" },
 	{ }
 };
 MODULE_DEVICE_TABLE(i2c, vl6180_id);

 static struct i2c_driver vl6180_driver = {
 	.driver = {
 		.name   = VL6180_DRV_NAME,
 		.of_match_table = vl6180_of_match,
 	},
 	.probe = vl6180_probe,
 	.id_table = vl6180_id,
 };

 module_i2c_driver(vl6180_driver);

 MODULE_AUTHOR("Peter Meerwald-Stadler <pmeerw@pmeerw.net>");
 MODULE_AUTHOR("Manivannan Sadhasivam <manivannanece23@gmail.com>");
 MODULE_DESCRIPTION("STMicro VL6180 ALS, range and proximity sensor driver");
 MODULE_LICENSE("GPL");
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* vl6180.c - Support for STMicroelectronics VL6180 ALS, range and proximity
	* sensor
	*
	* Copyright 2017 Peter Meerwald-Stadler <pmeerw@pmeerw.net>
	* Copyright 2017 Manivannan Sadhasivam <manivannanece23@gmail.com>
	*
	* IIO driver for VL6180 (7-bit I2C slave address 0x29)
	*
	* Range: 0 to 100mm
	* ALS: < 1 Lux up to 100 kLux
	* IR: 850nm
	*
	* TODO: irq, threshold events, continuous mode, hardware buffer
	*/

	#include <linux/module.h>
	#include <linux/mod_devicetable.h>
	#include <linux/i2c.h>
	#include <linux/mutex.h>
	#include <linux/err.h>
	#include <linux/delay.h>
	#include <linux/util_macros.h>

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

	#define VL6180_DRV_NAME "vl6180"

	/* Device identification register and value */
	#define VL6180_MODEL_ID 0x000
	#define VL6180_MODEL_ID_VAL 0xb4

	/* Configuration registers */
	#define VL6180_INTR_CONFIG 0x014
	#define VL6180_INTR_CLEAR 0x015
	#define VL6180_OUT_OF_RESET 0x016
	#define VL6180_HOLD 0x017
	#define VL6180_RANGE_START 0x018
	#define VL6180_ALS_START 0x038
	#define VL6180_ALS_GAIN 0x03f
	#define VL6180_ALS_IT 0x040

	/* Status registers */
	#define VL6180_RANGE_STATUS 0x04d
	#define VL6180_ALS_STATUS 0x04e
	#define VL6180_INTR_STATUS 0x04f

	/* Result value registers */
	#define VL6180_ALS_VALUE 0x050
	#define VL6180_RANGE_VALUE 0x062
	#define VL6180_RANGE_RATE 0x066

	/* bits of the RANGE_START and ALS_START register */
	#define VL6180_MODE_CONT BIT(1) /* continuous mode */
	#define VL6180_STARTSTOP BIT(0) /* start measurement, auto-reset */

	/* bits of the INTR_STATUS and INTR_CONFIG register */
	#define VL6180_ALS_READY BIT(5)
	#define VL6180_RANGE_READY BIT(2)

	/* bits of the INTR_CLEAR register */
	#define VL6180_CLEAR_ERROR BIT(2)
	#define VL6180_CLEAR_ALS BIT(1)
	#define VL6180_CLEAR_RANGE BIT(0)

	/* bits of the HOLD register */
	#define VL6180_HOLD_ON BIT(0)

	/* default value for the ALS_IT register */
	#define VL6180_ALS_IT_100 0x63 /* 100 ms */

	/* values for the ALS_GAIN register */
	#define VL6180_ALS_GAIN_1 0x46
	#define VL6180_ALS_GAIN_1_25 0x45
	#define VL6180_ALS_GAIN_1_67 0x44
	#define VL6180_ALS_GAIN_2_5 0x43
	#define VL6180_ALS_GAIN_5 0x42
	#define VL6180_ALS_GAIN_10 0x41
	#define VL6180_ALS_GAIN_20 0x40
	#define VL6180_ALS_GAIN_40 0x47

	struct vl6180_data {
	struct i2c_client *client;
	struct mutex lock;
	unsigned int als_gain_milli;
	unsigned int als_it_ms;
	};

	enum { VL6180_ALS, VL6180_RANGE, VL6180_PROX };

	/**
	* struct vl6180_chan_regs - Registers for accessing channels
	* @drdy_mask: Data ready bit in status register
	* @start_reg: Conversion start register
	* @value_reg: Result value register
	* @word: Register word length
	*/
	struct vl6180_chan_regs {
	u8 drdy_mask;
	u16 start_reg, value_reg;
	bool word;
	};

	static const struct vl6180_chan_regs vl6180_chan_regs_table[] = {
	[VL6180_ALS] = {
	.drdy_mask = VL6180_ALS_READY,
	.start_reg = VL6180_ALS_START,
	.value_reg = VL6180_ALS_VALUE,
	.word = true,
	},
	[VL6180_RANGE] = {
	.drdy_mask = VL6180_RANGE_READY,
	.start_reg = VL6180_RANGE_START,
	.value_reg = VL6180_RANGE_VALUE,
	.word = false,
	},
	[VL6180_PROX] = {
	.drdy_mask = VL6180_RANGE_READY,
	.start_reg = VL6180_RANGE_START,
	.value_reg = VL6180_RANGE_RATE,
	.word = true,
	},
	};

	static int vl6180_read(struct i2c_client client, u16 cmd, void databuf,
	u8 len)
	{
	__be16 cmdbuf = cpu_to_be16(cmd);
	struct i2c_msg msgs[2] = {
	{ .addr = client->addr, .len = sizeof(cmdbuf), .buf = (u8 *) &cmdbuf },
	{ .addr = client->addr, .len = len, .buf = databuf,
	.flags = I2C_M_RD } };
	int ret;

	ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
	if (ret < 0)
	dev_err(&client->dev, "failed reading register 0x%04x\n", cmd);

	return ret;
	}

	static int vl6180_read_byte(struct i2c_client *client, u16 cmd)
	{
	u8 data;
	int ret;

	ret = vl6180_read(client, cmd, &data, sizeof(data));
	if (ret < 0)
	return ret;

	return data;
	}

	static int vl6180_read_word(struct i2c_client *client, u16 cmd)
	{
	__be16 data;
	int ret;

	ret = vl6180_read(client, cmd, &data, sizeof(data));
	if (ret < 0)
	return ret;

	return be16_to_cpu(data);
	}

	static int vl6180_write_byte(struct i2c_client *client, u16 cmd, u8 val)
	{
	u8 buf[3];
	struct i2c_msg msgs[1] = {
	{ .addr = client->addr, .len = sizeof(buf), .buf = (u8 *) &buf } };
	int ret;

	buf[0] = cmd >> 8;
	buf[1] = cmd & 0xff;
	buf[2] = val;

	ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
	if (ret < 0) {
	dev_err(&client->dev, "failed writing register 0x%04x\n", cmd);
	return ret;
	}

	return 0;
	}

	static int vl6180_write_word(struct i2c_client *client, u16 cmd, u16 val)
	{
	__be16 buf[2];
	struct i2c_msg msgs[1] = {
	{ .addr = client->addr, .len = sizeof(buf), .buf = (u8 *) &buf } };
	int ret;

	buf[0] = cpu_to_be16(cmd);
	buf[1] = cpu_to_be16(val);

	ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
	if (ret < 0) {
	dev_err(&client->dev, "failed writing register 0x%04x\n", cmd);
	return ret;
	}

	return 0;
	}

	static int vl6180_measure(struct vl6180_data *data, int addr)
	{
	struct i2c_client *client = data->client;
	int tries = 20, ret;
	u16 value;

	mutex_lock(&data->lock);
	/* Start single shot measurement */
	ret = vl6180_write_byte(client,
	vl6180_chan_regs_table[addr].start_reg, VL6180_STARTSTOP);
	if (ret < 0)
	goto fail;

	while (tries--) {
	ret = vl6180_read_byte(client, VL6180_INTR_STATUS);
	if (ret < 0)
	goto fail;

	if (ret & vl6180_chan_regs_table[addr].drdy_mask)
	break;
	msleep(20);
	}

	if (tries < 0) {
	ret = -EIO;
	goto fail;
	}

	/* Read result value from appropriate registers */
	ret = vl6180_chan_regs_table[addr].word ?
	vl6180_read_word(client, vl6180_chan_regs_table[addr].value_reg) :
	vl6180_read_byte(client, vl6180_chan_regs_table[addr].value_reg);
	if (ret < 0)
	goto fail;
	value = ret;

	/* Clear the interrupt flag after data read */
	ret = vl6180_write_byte(client, VL6180_INTR_CLEAR,
	VL6180_CLEAR_ERROR \| VL6180_CLEAR_ALS \| VL6180_CLEAR_RANGE);
	if (ret < 0)
	goto fail;

	ret = value;

	fail:
	mutex_unlock(&data->lock);

	return ret;
	}

	static const struct iio_chan_spec vl6180_channels[] = {
	{
	.type = IIO_LIGHT,
	.address = VL6180_ALS,
	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) \|
	BIT(IIO_CHAN_INFO_INT_TIME) \|
	BIT(IIO_CHAN_INFO_SCALE) \|
	BIT(IIO_CHAN_INFO_HARDWAREGAIN),
	}, {
	.type = IIO_DISTANCE,
	.address = VL6180_RANGE,
	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) \|
	BIT(IIO_CHAN_INFO_SCALE),
	}, {
	.type = IIO_PROXIMITY,
	.address = VL6180_PROX,
	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
	}
	};

	/*
	* Available Ambient Light Sensor gain settings, 1/1000th, and
	* corresponding setting for the VL6180_ALS_GAIN register
	*/
	static const int vl6180_als_gain_tab[8] = {
	1000, 1250, 1670, 2500, 5000, 10000, 20000, 40000
	};
	static const u8 vl6180_als_gain_tab_bits[8] = {
	VL6180_ALS_GAIN_1, VL6180_ALS_GAIN_1_25,
	VL6180_ALS_GAIN_1_67, VL6180_ALS_GAIN_2_5,
	VL6180_ALS_GAIN_5, VL6180_ALS_GAIN_10,
	VL6180_ALS_GAIN_20, VL6180_ALS_GAIN_40
	};

	static int vl6180_read_raw(struct iio_dev *indio_dev,
	struct iio_chan_spec const *chan,
	int val, int val2, long mask)
	{
	struct vl6180_data *data = iio_priv(indio_dev);
	int ret;

	switch (mask) {
	case IIO_CHAN_INFO_RAW:
	ret = vl6180_measure(data, chan->address);
	if (ret < 0)
	return ret;
	*val = ret;

	return IIO_VAL_INT;
	case IIO_CHAN_INFO_INT_TIME:
	*val = data->als_it_ms;
	*val2 = 1000;

	return IIO_VAL_FRACTIONAL;

	case IIO_CHAN_INFO_SCALE:
	switch (chan->type) {
	case IIO_LIGHT:
	/* one ALS count is 0.32 Lux @ gain 1, IT 100 ms */
	val = 32000; / 0.32 * 1000 * 100 */
	val2 = data->als_gain_milli data->als_it_ms;

	return IIO_VAL_FRACTIONAL;

	case IIO_DISTANCE:
	val = 0; / sensor reports mm, scale to meter */
	*val2 = 1000;
	break;
	default:
	return -EINVAL;
	}

	return IIO_VAL_INT_PLUS_MICRO;
	case IIO_CHAN_INFO_HARDWAREGAIN:
	*val = data->als_gain_milli;
	*val2 = 1000;

	return IIO_VAL_FRACTIONAL;

	default:
	return -EINVAL;
	}
	}

	static IIO_CONST_ATTR(als_gain_available, "1 1.25 1.67 2.5 5 10 20 40");

	static struct attribute *vl6180_attributes[] = {
	&iio_const_attr_als_gain_available.dev_attr.attr,
	NULL
	};

	static const struct attribute_group vl6180_attribute_group = {
	.attrs = vl6180_attributes,
	};

	/* HOLD is needed before updating any config registers */
	static int vl6180_hold(struct vl6180_data *data, bool hold)
	{
	return vl6180_write_byte(data->client, VL6180_HOLD,
	hold ? VL6180_HOLD_ON : 0);
	}

	static int vl6180_set_als_gain(struct vl6180_data *data, int val, int val2)
	{
	int i, ret, gain;

	if (val < 1 \|\| val > 40)
	return -EINVAL;

	gain = (val * 1000000 + val2) / 1000;
	if (gain < 1 \|\| gain > 40000)
	return -EINVAL;

	i = find_closest(gain, vl6180_als_gain_tab,
	ARRAY_SIZE(vl6180_als_gain_tab));

	mutex_lock(&data->lock);
	ret = vl6180_hold(data, true);
	if (ret < 0)
	goto fail;

	ret = vl6180_write_byte(data->client, VL6180_ALS_GAIN,
	vl6180_als_gain_tab_bits[i]);

	if (ret >= 0)
	data->als_gain_milli = vl6180_als_gain_tab[i];

	fail:
	vl6180_hold(data, false);
	mutex_unlock(&data->lock);
	return ret;
	}

	static int vl6180_set_it(struct vl6180_data *data, int val, int val2)
	{
	int ret, it_ms;

	it_ms = DIV_ROUND_CLOSEST(val2, 1000); /* round to ms */
	if (val != 0 \|\| it_ms < 1 \|\| it_ms > 512)
	return -EINVAL;

	mutex_lock(&data->lock);
	ret = vl6180_hold(data, true);
	if (ret < 0)
	goto fail;

	ret = vl6180_write_word(data->client, VL6180_ALS_IT, it_ms - 1);

	if (ret >= 0)
	data->als_it_ms = it_ms;

	fail:
	vl6180_hold(data, false);
	mutex_unlock(&data->lock);

	return ret;
	}

	static int vl6180_write_raw(struct iio_dev *indio_dev,
	struct iio_chan_spec const *chan,
	int val, int val2, long mask)
	{
	struct vl6180_data *data = iio_priv(indio_dev);

	switch (mask) {
	case IIO_CHAN_INFO_INT_TIME:
	return vl6180_set_it(data, val, val2);

	case IIO_CHAN_INFO_HARDWAREGAIN:
	if (chan->type != IIO_LIGHT)
	return -EINVAL;

	return vl6180_set_als_gain(data, val, val2);
	default:
	return -EINVAL;
	}
	}

	static const struct iio_info vl6180_info = {
	.read_raw = vl6180_read_raw,
	.write_raw = vl6180_write_raw,
	.attrs = &vl6180_attribute_group,
	};

	static int vl6180_init(struct vl6180_data *data)
	{
	struct i2c_client *client = data->client;
	int ret;

	ret = vl6180_read_byte(client, VL6180_MODEL_ID);
	if (ret < 0)
	return ret;

	if (ret != VL6180_MODEL_ID_VAL) {
	dev_err(&client->dev, "invalid model ID %02x\n", ret);
	return -ENODEV;
	}

	ret = vl6180_hold(data, true);
	if (ret < 0)
	return ret;

	ret = vl6180_read_byte(client, VL6180_OUT_OF_RESET);
	if (ret < 0)
	return ret;

	/*
	* Detect false reset condition here. This bit is always set when the
	* system comes out of reset.
	*/
	if (ret != 0x01)
	dev_info(&client->dev, "device is not fresh out of reset\n");

	/* Enable ALS and Range ready interrupts */
	ret = vl6180_write_byte(client, VL6180_INTR_CONFIG,
	VL6180_ALS_READY \| VL6180_RANGE_READY);
	if (ret < 0)
	return ret;

	/* ALS integration time: 100ms */
	data->als_it_ms = 100;
	ret = vl6180_write_word(client, VL6180_ALS_IT, VL6180_ALS_IT_100);
	if (ret < 0)
	return ret;

	/* ALS gain: 1 */
	data->als_gain_milli = 1000;
	ret = vl6180_write_byte(client, VL6180_ALS_GAIN, VL6180_ALS_GAIN_1);
	if (ret < 0)
	return ret;

	ret = vl6180_write_byte(client, VL6180_OUT_OF_RESET, 0x00);
	if (ret < 0)
	return ret;

	return vl6180_hold(data, false);
	}

	static int vl6180_probe(struct i2c_client *client)
	{
	struct vl6180_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);
	i2c_set_clientdata(client, indio_dev);
	data->client = client;
	mutex_init(&data->lock);

	indio_dev->info = &vl6180_info;
	indio_dev->channels = vl6180_channels;
	indio_dev->num_channels = ARRAY_SIZE(vl6180_channels);
	indio_dev->name = VL6180_DRV_NAME;
	indio_dev->modes = INDIO_DIRECT_MODE;

	ret = vl6180_init(data);
	if (ret < 0)
	return ret;

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

	static const struct of_device_id vl6180_of_match[] = {
	{ .compatible = "st,vl6180", },
	{ },
	};
	MODULE_DEVICE_TABLE(of, vl6180_of_match);

	static const struct i2c_device_id vl6180_id[] = {
	{ "vl6180" },
	{ }
	};
	MODULE_DEVICE_TABLE(i2c, vl6180_id);

	static struct i2c_driver vl6180_driver = {
	.driver = {
	.name = VL6180_DRV_NAME,
	.of_match_table = vl6180_of_match,
	},
	.probe = vl6180_probe,
	.id_table = vl6180_id,
	};

	module_i2c_driver(vl6180_driver);

	MODULE_AUTHOR("Peter Meerwald-Stadler <pmeerw@pmeerw.net>");
	MODULE_AUTHOR("Manivannan Sadhasivam <manivannanece23@gmail.com>");
	MODULE_DESCRIPTION("STMicro VL6180 ALS, range and proximity sensor driver");
	MODULE_LICENSE("GPL");