drivers/iio/health/max30100.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0+
 /*
  * max30100.c - Support for MAX30100 heart rate and pulse oximeter sensor
  *
  * Copyright (C) 2015, 2018
  * Author: Matt Ranostay <matt.ranostay@konsulko.com>
  *
  * TODO: enable pulse length controls via device tree properties
  */

 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/interrupt.h>
 #include <linux/delay.h>
 #include <linux/err.h>
 #include <linux/irq.h>
 #include <linux/i2c.h>
 #include <linux/mutex.h>
 #include <linux/property.h>
 #include <linux/regmap.h>
 #include <linux/iio/iio.h>
 #include <linux/iio/buffer.h>
 #include <linux/iio/kfifo_buf.h>

 #define MAX30100_REGMAP_NAME	"max30100_regmap"
 #define MAX30100_DRV_NAME	"max30100"

 #define MAX30100_REG_INT_STATUS			0x00
 #define MAX30100_REG_INT_STATUS_PWR_RDY		BIT(0)
 #define MAX30100_REG_INT_STATUS_SPO2_RDY	BIT(4)
 #define MAX30100_REG_INT_STATUS_HR_RDY		BIT(5)
 #define MAX30100_REG_INT_STATUS_FIFO_RDY	BIT(7)

 #define MAX30100_REG_INT_ENABLE			0x01
 #define MAX30100_REG_INT_ENABLE_SPO2_EN		BIT(0)
 #define MAX30100_REG_INT_ENABLE_HR_EN		BIT(1)
 #define MAX30100_REG_INT_ENABLE_FIFO_EN		BIT(3)
 #define MAX30100_REG_INT_ENABLE_MASK		0xf0
 #define MAX30100_REG_INT_ENABLE_MASK_SHIFT	4

 #define MAX30100_REG_FIFO_WR_PTR		0x02
 #define MAX30100_REG_FIFO_OVR_CTR		0x03
 #define MAX30100_REG_FIFO_RD_PTR		0x04
 #define MAX30100_REG_FIFO_DATA			0x05
 #define MAX30100_REG_FIFO_DATA_ENTRY_COUNT	16
 #define MAX30100_REG_FIFO_DATA_ENTRY_LEN	4

 #define MAX30100_REG_MODE_CONFIG		0x06
 #define MAX30100_REG_MODE_CONFIG_MODE_SPO2_EN	BIT(0)
 #define MAX30100_REG_MODE_CONFIG_MODE_HR_EN	BIT(1)
 #define MAX30100_REG_MODE_CONFIG_MODE_MASK	0x03
 #define MAX30100_REG_MODE_CONFIG_TEMP_EN	BIT(3)
 #define MAX30100_REG_MODE_CONFIG_PWR		BIT(7)

 #define MAX30100_REG_SPO2_CONFIG		0x07
 #define MAX30100_REG_SPO2_CONFIG_100HZ		BIT(2)
 #define MAX30100_REG_SPO2_CONFIG_HI_RES_EN	BIT(6)
 #define MAX30100_REG_SPO2_CONFIG_1600US		0x3

 #define MAX30100_REG_LED_CONFIG			0x09
 #define MAX30100_REG_LED_CONFIG_LED_MASK	0x0f
 #define MAX30100_REG_LED_CONFIG_RED_LED_SHIFT	4

 #define MAX30100_REG_LED_CONFIG_24MA		0x07
 #define MAX30100_REG_LED_CONFIG_50MA		0x0f

 #define MAX30100_REG_TEMP_INTEGER		0x16
 #define MAX30100_REG_TEMP_FRACTION		0x17

 struct max30100_data {
 	struct i2c_client *client;
 	struct iio_dev *indio_dev;
 	struct mutex lock;
 	struct regmap *regmap;

 	__be16 buffer[2]; /* 2 16-bit channels */
 };

 static bool max30100_is_volatile_reg(struct device *dev, unsigned int reg)
 {
 	switch (reg) {
 	case MAX30100_REG_INT_STATUS:
 	case MAX30100_REG_MODE_CONFIG:
 	case MAX30100_REG_FIFO_WR_PTR:
 	case MAX30100_REG_FIFO_OVR_CTR:
 	case MAX30100_REG_FIFO_RD_PTR:
 	case MAX30100_REG_FIFO_DATA:
 	case MAX30100_REG_TEMP_INTEGER:
 	case MAX30100_REG_TEMP_FRACTION:
 		return true;
 	default:
 		return false;
 	}
 }

 static const struct regmap_config max30100_regmap_config = {
 	.name = MAX30100_REGMAP_NAME,

 	.reg_bits = 8,
 	.val_bits = 8,

 	.max_register = MAX30100_REG_TEMP_FRACTION,
 	.cache_type = REGCACHE_FLAT,

 	.volatile_reg = max30100_is_volatile_reg,
 };

 static const unsigned int max30100_led_current_mapping[] = {
 	4400, 7600, 11000, 14200, 17400,
 	20800, 24000, 27100, 30600, 33800,
 	37000, 40200, 43600, 46800, 50000
 };

 static const unsigned long max30100_scan_masks[] = {0x3, 0};

 static const struct iio_chan_spec max30100_channels[] = {
 	{
 		.type = IIO_INTENSITY,
 		.channel2 = IIO_MOD_LIGHT_IR,
 		.modified = 1,

 		.scan_index = 0,
 		.scan_type = {
 			.sign = 'u',
 			.realbits = 16,
 			.storagebits = 16,
 			.endianness = IIO_BE,
 		},
 	},
 	{
 		.type = IIO_INTENSITY,
 		.channel2 = IIO_MOD_LIGHT_RED,
 		.modified = 1,

 		.scan_index = 1,
 		.scan_type = {
 			.sign = 'u',
 			.realbits = 16,
 			.storagebits = 16,
 			.endianness = IIO_BE,
 		},
 	},
 	{
 		.type = IIO_TEMP,
 		.info_mask_separate =
 			BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),
 		.scan_index = -1,
 	},
 };

 static int max30100_set_powermode(struct max30100_data *data, bool state)
 {
 	return regmap_update_bits(data->regmap, MAX30100_REG_MODE_CONFIG,
 				  MAX30100_REG_MODE_CONFIG_PWR,
 				  state ? 0 : MAX30100_REG_MODE_CONFIG_PWR);
 }

 static int max30100_clear_fifo(struct max30100_data *data)
 {
 	int ret;

 	ret = regmap_write(data->regmap, MAX30100_REG_FIFO_WR_PTR, 0);
 	if (ret)
 		return ret;

 	ret = regmap_write(data->regmap, MAX30100_REG_FIFO_OVR_CTR, 0);
 	if (ret)
 		return ret;

 	return regmap_write(data->regmap, MAX30100_REG_FIFO_RD_PTR, 0);
 }

 static int max30100_buffer_postenable(struct iio_dev *indio_dev)
 {
 	struct max30100_data *data = iio_priv(indio_dev);
 	int ret;

 	ret = max30100_set_powermode(data, true);
 	if (ret)
 		return ret;

 	return max30100_clear_fifo(data);
 }

 static int max30100_buffer_predisable(struct iio_dev *indio_dev)
 {
 	struct max30100_data *data = iio_priv(indio_dev);

 	return max30100_set_powermode(data, false);
 }

 static const struct iio_buffer_setup_ops max30100_buffer_setup_ops = {
 	.postenable = max30100_buffer_postenable,
 	.predisable = max30100_buffer_predisable,
 };

 static inline int max30100_fifo_count(struct max30100_data *data)
 {
 	unsigned int val;
 	int ret;

 	ret = regmap_read(data->regmap, MAX30100_REG_INT_STATUS, &val);
 	if (ret)
 		return ret;

 	/* FIFO is almost full */
 	if (val & MAX30100_REG_INT_STATUS_FIFO_RDY)
 		return MAX30100_REG_FIFO_DATA_ENTRY_COUNT - 1;

 	return 0;
 }

 static int max30100_read_measurement(struct max30100_data *data)
 {
 	int ret;

 	ret = i2c_smbus_read_i2c_block_data(data->client,
 					    MAX30100_REG_FIFO_DATA,
 					    MAX30100_REG_FIFO_DATA_ENTRY_LEN,
 					    (u8 *) &data->buffer);

 	return (ret == MAX30100_REG_FIFO_DATA_ENTRY_LEN) ? 0 : ret;
 }

 static irqreturn_t max30100_interrupt_handler(int irq, void *private)
 {
 	struct iio_dev *indio_dev = private;
 	struct max30100_data *data = iio_priv(indio_dev);
 	int ret, cnt = 0;

 	mutex_lock(&data->lock);

 	while (cnt || (cnt = max30100_fifo_count(data)) > 0) {
 		ret = max30100_read_measurement(data);
 		if (ret)
 			break;

 		iio_push_to_buffers(data->indio_dev, data->buffer);
 		cnt--;
 	}

 	mutex_unlock(&data->lock);

 	return IRQ_HANDLED;
 }

 static int max30100_get_current_idx(unsigned int val, int *reg)
 {
 	int idx;

 	/* LED turned off */
 	if (val == 0) {
 		*reg = 0;
 		return 0;
 	}

 	for (idx = 0; idx < ARRAY_SIZE(max30100_led_current_mapping); idx++) {
 		if (max30100_led_current_mapping[idx] == val) {
 			*reg = idx + 1;
 			return 0;
 		}
 	}

 	return -EINVAL;
 }

 static int max30100_led_init(struct max30100_data *data)
 {
 	struct device *dev = &data->client->dev;
 	unsigned int val[2];
 	int reg, ret;

 	ret = device_property_read_u32_array(dev, "maxim,led-current-microamp",
 					(unsigned int *) &val, 2);
 	if (ret) {
 		/* Default to 24 mA RED LED, 50 mA IR LED */
 		reg = (MAX30100_REG_LED_CONFIG_24MA <<
 			MAX30100_REG_LED_CONFIG_RED_LED_SHIFT) |
 			MAX30100_REG_LED_CONFIG_50MA;
 		dev_warn(dev, "no led-current-microamp set");

 		return regmap_write(data->regmap, MAX30100_REG_LED_CONFIG, reg);
 	}

 	/* RED LED current */
 	ret = max30100_get_current_idx(val[0], &reg);
 	if (ret) {
 		dev_err(dev, "invalid RED current setting %d", val[0]);
 		return ret;
 	}

 	ret = regmap_update_bits(data->regmap, MAX30100_REG_LED_CONFIG,
 		MAX30100_REG_LED_CONFIG_LED_MASK <<
 		MAX30100_REG_LED_CONFIG_RED_LED_SHIFT,
 		reg << MAX30100_REG_LED_CONFIG_RED_LED_SHIFT);
 	if (ret)
 		return ret;

 	/* IR LED current */
 	ret = max30100_get_current_idx(val[1], &reg);
 	if (ret) {
 		dev_err(dev, "invalid IR current setting %d", val[1]);
 		return ret;
 	}

 	return regmap_update_bits(data->regmap, MAX30100_REG_LED_CONFIG,
 		MAX30100_REG_LED_CONFIG_LED_MASK, reg);
 }

 static int max30100_chip_init(struct max30100_data *data)
 {
 	int ret;

 	/* setup LED current settings */
 	ret = max30100_led_init(data);
 	if (ret)
 		return ret;

 	/* enable hi-res SPO2 readings at 100Hz */
 	ret = regmap_write(data->regmap, MAX30100_REG_SPO2_CONFIG,
 				 MAX30100_REG_SPO2_CONFIG_HI_RES_EN |
 				 MAX30100_REG_SPO2_CONFIG_100HZ);
 	if (ret)
 		return ret;

 	/* enable SPO2 mode */
 	ret = regmap_update_bits(data->regmap, MAX30100_REG_MODE_CONFIG,
 				 MAX30100_REG_MODE_CONFIG_MODE_MASK,
 				 MAX30100_REG_MODE_CONFIG_MODE_HR_EN |
 				 MAX30100_REG_MODE_CONFIG_MODE_SPO2_EN);
 	if (ret)
 		return ret;

 	/* enable FIFO interrupt */
 	return regmap_update_bits(data->regmap, MAX30100_REG_INT_ENABLE,
 				 MAX30100_REG_INT_ENABLE_MASK,
 				 MAX30100_REG_INT_ENABLE_FIFO_EN
 				 << MAX30100_REG_INT_ENABLE_MASK_SHIFT);
 }

 static int max30100_read_temp(struct max30100_data *data, int *val)
 {
 	int ret;
 	unsigned int reg;

 	ret = regmap_read(data->regmap, MAX30100_REG_TEMP_INTEGER, &reg);
 	if (ret < 0)
 		return ret;
 	*val = reg << 4;

 	ret = regmap_read(data->regmap, MAX30100_REG_TEMP_FRACTION, &reg);
 	if (ret < 0)
 		return ret;

 	*val |= reg & 0xf;
 	*val = sign_extend32(*val, 11);

 	return 0;
 }

 static int max30100_get_temp(struct max30100_data *data, int *val)
 {
 	int ret;

 	/* start acquisition */
 	ret = regmap_set_bits(data->regmap, MAX30100_REG_MODE_CONFIG,
 			      MAX30100_REG_MODE_CONFIG_TEMP_EN);
 	if (ret)
 		return ret;

 	msleep(35);

 	return max30100_read_temp(data, val);
 }

 static int max30100_read_raw(struct iio_dev *indio_dev,
 			     struct iio_chan_spec const *chan,
 			     int *val, int *val2, long mask)
 {
 	struct max30100_data *data = iio_priv(indio_dev);
 	int ret = -EINVAL;

 	switch (mask) {
 	case IIO_CHAN_INFO_RAW:
 		/*
 		 * Temperature reading can only be acquired while engine
 		 * is running
 		 */
 		if (iio_device_claim_buffer_mode(indio_dev)) {
 			/*
 			 * Replacing -EBUSY or other error code
 			 * returned by iio_device_claim_buffer_mode()
 			 * because user space may rely on the current
 			 * one.
 			 */
 			ret = -EAGAIN;
 		} else {
 			ret = max30100_get_temp(data, val);
 			if (!ret)
 				ret = IIO_VAL_INT;

 			iio_device_release_buffer_mode(indio_dev);
 		}
 		break;
 	case IIO_CHAN_INFO_SCALE:
 		*val = 1;  /* 0.0625 */
 		*val2 = 16;
 		ret = IIO_VAL_FRACTIONAL;
 		break;
 	}

 	return ret;
 }

 static const struct iio_info max30100_info = {
 	.read_raw = max30100_read_raw,
 };

 static int max30100_probe(struct i2c_client *client)
 {
 	struct max30100_data *data;
 	struct iio_dev *indio_dev;
 	int ret;

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

 	indio_dev->name = MAX30100_DRV_NAME;
 	indio_dev->channels = max30100_channels;
 	indio_dev->info = &max30100_info;
 	indio_dev->num_channels = ARRAY_SIZE(max30100_channels);
 	indio_dev->available_scan_masks = max30100_scan_masks;
 	indio_dev->modes = INDIO_DIRECT_MODE;

 	ret = devm_iio_kfifo_buffer_setup(&client->dev, indio_dev,
 					  &max30100_buffer_setup_ops);
 	if (ret)
 		return ret;

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

 	mutex_init(&data->lock);
 	i2c_set_clientdata(client, indio_dev);

 	data->regmap = devm_regmap_init_i2c(client, &max30100_regmap_config);
 	if (IS_ERR(data->regmap)) {
 		dev_err(&client->dev, "regmap initialization failed.\n");
 		return PTR_ERR(data->regmap);
 	}
 	max30100_set_powermode(data, false);

 	ret = max30100_chip_init(data);
 	if (ret)
 		return ret;

 	if (client->irq <= 0) {
 		dev_err(&client->dev, "no valid irq defined\n");
 		return -EINVAL;
 	}
 	ret = devm_request_threaded_irq(&client->dev, client->irq,
 					NULL, max30100_interrupt_handler,
 					IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
 					"max30100_irq", indio_dev);
 	if (ret) {
 		dev_err(&client->dev, "request irq (%d) failed\n", client->irq);
 		return ret;
 	}

 	return iio_device_register(indio_dev);
 }

 static void max30100_remove(struct i2c_client *client)
 {
 	struct iio_dev *indio_dev = i2c_get_clientdata(client);
 	struct max30100_data *data = iio_priv(indio_dev);

 	iio_device_unregister(indio_dev);
 	max30100_set_powermode(data, false);
 }

 static const struct i2c_device_id max30100_id[] = {
 	{ "max30100" },
 	{}
 };
 MODULE_DEVICE_TABLE(i2c, max30100_id);

 static const struct of_device_id max30100_dt_ids[] = {
 	{ .compatible = "maxim,max30100" },
 	{ }
 };
 MODULE_DEVICE_TABLE(of, max30100_dt_ids);

 static struct i2c_driver max30100_driver = {
 	.driver = {
 		.name	= MAX30100_DRV_NAME,
 		.of_match_table	= max30100_dt_ids,
 	},
 	.probe		= max30100_probe,
 	.remove		= max30100_remove,
 	.id_table	= max30100_id,
 };
 module_i2c_driver(max30100_driver);

 MODULE_AUTHOR("Matt Ranostay <matt.ranostay@konsulko.com>");
 MODULE_DESCRIPTION("MAX30100 heart rate and pulse oximeter sensor");
 MODULE_LICENSE("GPL");
	// SPDX-License-Identifier: GPL-2.0+
	/*
	* max30100.c - Support for MAX30100 heart rate and pulse oximeter sensor
	*
	* Copyright (C) 2015, 2018
	* Author: Matt Ranostay <matt.ranostay@konsulko.com>
	*
	* TODO: enable pulse length controls via device tree properties
	*/

	#include <linux/module.h>
	#include <linux/init.h>
	#include <linux/interrupt.h>
	#include <linux/delay.h>
	#include <linux/err.h>
	#include <linux/irq.h>
	#include <linux/i2c.h>
	#include <linux/mutex.h>
	#include <linux/property.h>
	#include <linux/regmap.h>
	#include <linux/iio/iio.h>
	#include <linux/iio/buffer.h>
	#include <linux/iio/kfifo_buf.h>

	#define MAX30100_REGMAP_NAME "max30100_regmap"
	#define MAX30100_DRV_NAME "max30100"

	#define MAX30100_REG_INT_STATUS 0x00
	#define MAX30100_REG_INT_STATUS_PWR_RDY BIT(0)
	#define MAX30100_REG_INT_STATUS_SPO2_RDY BIT(4)
	#define MAX30100_REG_INT_STATUS_HR_RDY BIT(5)
	#define MAX30100_REG_INT_STATUS_FIFO_RDY BIT(7)

	#define MAX30100_REG_INT_ENABLE 0x01
	#define MAX30100_REG_INT_ENABLE_SPO2_EN BIT(0)
	#define MAX30100_REG_INT_ENABLE_HR_EN BIT(1)
	#define MAX30100_REG_INT_ENABLE_FIFO_EN BIT(3)
	#define MAX30100_REG_INT_ENABLE_MASK 0xf0
	#define MAX30100_REG_INT_ENABLE_MASK_SHIFT 4

	#define MAX30100_REG_FIFO_WR_PTR 0x02
	#define MAX30100_REG_FIFO_OVR_CTR 0x03
	#define MAX30100_REG_FIFO_RD_PTR 0x04
	#define MAX30100_REG_FIFO_DATA 0x05
	#define MAX30100_REG_FIFO_DATA_ENTRY_COUNT 16
	#define MAX30100_REG_FIFO_DATA_ENTRY_LEN 4

	#define MAX30100_REG_MODE_CONFIG 0x06
	#define MAX30100_REG_MODE_CONFIG_MODE_SPO2_EN BIT(0)
	#define MAX30100_REG_MODE_CONFIG_MODE_HR_EN BIT(1)
	#define MAX30100_REG_MODE_CONFIG_MODE_MASK 0x03
	#define MAX30100_REG_MODE_CONFIG_TEMP_EN BIT(3)
	#define MAX30100_REG_MODE_CONFIG_PWR BIT(7)

	#define MAX30100_REG_SPO2_CONFIG 0x07
	#define MAX30100_REG_SPO2_CONFIG_100HZ BIT(2)
	#define MAX30100_REG_SPO2_CONFIG_HI_RES_EN BIT(6)
	#define MAX30100_REG_SPO2_CONFIG_1600US 0x3

	#define MAX30100_REG_LED_CONFIG 0x09
	#define MAX30100_REG_LED_CONFIG_LED_MASK 0x0f
	#define MAX30100_REG_LED_CONFIG_RED_LED_SHIFT 4

	#define MAX30100_REG_LED_CONFIG_24MA 0x07
	#define MAX30100_REG_LED_CONFIG_50MA 0x0f

	#define MAX30100_REG_TEMP_INTEGER 0x16
	#define MAX30100_REG_TEMP_FRACTION 0x17

	struct max30100_data {
	struct i2c_client *client;
	struct iio_dev *indio_dev;
	struct mutex lock;
	struct regmap *regmap;

	__be16 buffer[2]; /* 2 16-bit channels */
	};

	static bool max30100_is_volatile_reg(struct device *dev, unsigned int reg)
	{
	switch (reg) {
	case MAX30100_REG_INT_STATUS:
	case MAX30100_REG_MODE_CONFIG:
	case MAX30100_REG_FIFO_WR_PTR:
	case MAX30100_REG_FIFO_OVR_CTR:
	case MAX30100_REG_FIFO_RD_PTR:
	case MAX30100_REG_FIFO_DATA:
	case MAX30100_REG_TEMP_INTEGER:
	case MAX30100_REG_TEMP_FRACTION:
	return true;
	default:
	return false;
	}
	}

	static const struct regmap_config max30100_regmap_config = {
	.name = MAX30100_REGMAP_NAME,

	.reg_bits = 8,
	.val_bits = 8,

	.max_register = MAX30100_REG_TEMP_FRACTION,
	.cache_type = REGCACHE_FLAT,

	.volatile_reg = max30100_is_volatile_reg,
	};

	static const unsigned int max30100_led_current_mapping[] = {
	4400, 7600, 11000, 14200, 17400,
	20800, 24000, 27100, 30600, 33800,
	37000, 40200, 43600, 46800, 50000
	};

	static const unsigned long max30100_scan_masks[] = {0x3, 0};

	static const struct iio_chan_spec max30100_channels[] = {
	{
	.type = IIO_INTENSITY,
	.channel2 = IIO_MOD_LIGHT_IR,
	.modified = 1,

	.scan_index = 0,
	.scan_type = {
	.sign = 'u',
	.realbits = 16,
	.storagebits = 16,
	.endianness = IIO_BE,
	},
	},
	{
	.type = IIO_INTENSITY,
	.channel2 = IIO_MOD_LIGHT_RED,
	.modified = 1,

	.scan_index = 1,
	.scan_type = {
	.sign = 'u',
	.realbits = 16,
	.storagebits = 16,
	.endianness = IIO_BE,
	},
	},
	{
	.type = IIO_TEMP,
	.info_mask_separate =
	BIT(IIO_CHAN_INFO_RAW) \| BIT(IIO_CHAN_INFO_SCALE),
	.scan_index = -1,
	},
	};

	static int max30100_set_powermode(struct max30100_data *data, bool state)
	{
	return regmap_update_bits(data->regmap, MAX30100_REG_MODE_CONFIG,
	MAX30100_REG_MODE_CONFIG_PWR,
	state ? 0 : MAX30100_REG_MODE_CONFIG_PWR);
	}

	static int max30100_clear_fifo(struct max30100_data *data)
	{
	int ret;

	ret = regmap_write(data->regmap, MAX30100_REG_FIFO_WR_PTR, 0);
	if (ret)
	return ret;

	ret = regmap_write(data->regmap, MAX30100_REG_FIFO_OVR_CTR, 0);
	if (ret)
	return ret;

	return regmap_write(data->regmap, MAX30100_REG_FIFO_RD_PTR, 0);
	}

	static int max30100_buffer_postenable(struct iio_dev *indio_dev)
	{
	struct max30100_data *data = iio_priv(indio_dev);
	int ret;

	ret = max30100_set_powermode(data, true);
	if (ret)
	return ret;

	return max30100_clear_fifo(data);
	}

	static int max30100_buffer_predisable(struct iio_dev *indio_dev)
	{
	struct max30100_data *data = iio_priv(indio_dev);

	return max30100_set_powermode(data, false);
	}

	static const struct iio_buffer_setup_ops max30100_buffer_setup_ops = {
	.postenable = max30100_buffer_postenable,
	.predisable = max30100_buffer_predisable,
	};

	static inline int max30100_fifo_count(struct max30100_data *data)
	{
	unsigned int val;
	int ret;

	ret = regmap_read(data->regmap, MAX30100_REG_INT_STATUS, &val);
	if (ret)
	return ret;

	/* FIFO is almost full */
	if (val & MAX30100_REG_INT_STATUS_FIFO_RDY)
	return MAX30100_REG_FIFO_DATA_ENTRY_COUNT - 1;

	return 0;
	}

	static int max30100_read_measurement(struct max30100_data *data)
	{
	int ret;

	ret = i2c_smbus_read_i2c_block_data(data->client,
	MAX30100_REG_FIFO_DATA,
	MAX30100_REG_FIFO_DATA_ENTRY_LEN,
	(u8 *) &data->buffer);

	return (ret == MAX30100_REG_FIFO_DATA_ENTRY_LEN) ? 0 : ret;
	}

	static irqreturn_t max30100_interrupt_handler(int irq, void *private)
	{
	struct iio_dev *indio_dev = private;
	struct max30100_data *data = iio_priv(indio_dev);
	int ret, cnt = 0;

	mutex_lock(&data->lock);

	while (cnt \|\| (cnt = max30100_fifo_count(data)) > 0) {
	ret = max30100_read_measurement(data);
	if (ret)
	break;

	iio_push_to_buffers(data->indio_dev, data->buffer);
	cnt--;
	}

	mutex_unlock(&data->lock);

	return IRQ_HANDLED;
	}

	static int max30100_get_current_idx(unsigned int val, int *reg)
	{
	int idx;

	/* LED turned off */
	if (val == 0) {
	*reg = 0;
	return 0;
	}

	for (idx = 0; idx < ARRAY_SIZE(max30100_led_current_mapping); idx++) {
	if (max30100_led_current_mapping[idx] == val) {
	*reg = idx + 1;
	return 0;
	}
	}

	return -EINVAL;
	}

	static int max30100_led_init(struct max30100_data *data)
	{
	struct device *dev = &data->client->dev;
	unsigned int val[2];
	int reg, ret;

	ret = device_property_read_u32_array(dev, "maxim,led-current-microamp",
	(unsigned int *) &val, 2);
	if (ret) {
	/* Default to 24 mA RED LED, 50 mA IR LED */
	reg = (MAX30100_REG_LED_CONFIG_24MA <<
	MAX30100_REG_LED_CONFIG_RED_LED_SHIFT) \|
	MAX30100_REG_LED_CONFIG_50MA;
	dev_warn(dev, "no led-current-microamp set");

	return regmap_write(data->regmap, MAX30100_REG_LED_CONFIG, reg);
	}

	/* RED LED current */
	ret = max30100_get_current_idx(val[0], &reg);
	if (ret) {
	dev_err(dev, "invalid RED current setting %d", val[0]);
	return ret;
	}

	ret = regmap_update_bits(data->regmap, MAX30100_REG_LED_CONFIG,
	MAX30100_REG_LED_CONFIG_LED_MASK <<
	MAX30100_REG_LED_CONFIG_RED_LED_SHIFT,
	reg << MAX30100_REG_LED_CONFIG_RED_LED_SHIFT);
	if (ret)
	return ret;

	/* IR LED current */
	ret = max30100_get_current_idx(val[1], &reg);
	if (ret) {
	dev_err(dev, "invalid IR current setting %d", val[1]);
	return ret;
	}

	return regmap_update_bits(data->regmap, MAX30100_REG_LED_CONFIG,
	MAX30100_REG_LED_CONFIG_LED_MASK, reg);
	}

	static int max30100_chip_init(struct max30100_data *data)
	{
	int ret;

	/* setup LED current settings */
	ret = max30100_led_init(data);
	if (ret)
	return ret;

	/* enable hi-res SPO2 readings at 100Hz */
	ret = regmap_write(data->regmap, MAX30100_REG_SPO2_CONFIG,
	MAX30100_REG_SPO2_CONFIG_HI_RES_EN \|
	MAX30100_REG_SPO2_CONFIG_100HZ);
	if (ret)
	return ret;

	/* enable SPO2 mode */
	ret = regmap_update_bits(data->regmap, MAX30100_REG_MODE_CONFIG,
	MAX30100_REG_MODE_CONFIG_MODE_MASK,
	MAX30100_REG_MODE_CONFIG_MODE_HR_EN \|
	MAX30100_REG_MODE_CONFIG_MODE_SPO2_EN);
	if (ret)
	return ret;

	/* enable FIFO interrupt */
	return regmap_update_bits(data->regmap, MAX30100_REG_INT_ENABLE,
	MAX30100_REG_INT_ENABLE_MASK,
	MAX30100_REG_INT_ENABLE_FIFO_EN
	<< MAX30100_REG_INT_ENABLE_MASK_SHIFT);
	}

	static int max30100_read_temp(struct max30100_data data, int val)
	{
	int ret;
	unsigned int reg;

	ret = regmap_read(data->regmap, MAX30100_REG_TEMP_INTEGER, &reg);
	if (ret < 0)
	return ret;
	*val = reg << 4;

	ret = regmap_read(data->regmap, MAX30100_REG_TEMP_FRACTION, &reg);
	if (ret < 0)
	return ret;

	*val \|= reg & 0xf;
	val = sign_extend32(val, 11);

	return 0;
	}

	static int max30100_get_temp(struct max30100_data data, int val)
	{
	int ret;

	/* start acquisition */
	ret = regmap_set_bits(data->regmap, MAX30100_REG_MODE_CONFIG,
	MAX30100_REG_MODE_CONFIG_TEMP_EN);
	if (ret)
	return ret;

	msleep(35);

	return max30100_read_temp(data, val);
	}

	static int max30100_read_raw(struct iio_dev *indio_dev,
	struct iio_chan_spec const *chan,
	int val, int val2, long mask)
	{
	struct max30100_data *data = iio_priv(indio_dev);
	int ret = -EINVAL;

	switch (mask) {
	case IIO_CHAN_INFO_RAW:
	/*
	* Temperature reading can only be acquired while engine
	* is running
	*/
	if (iio_device_claim_buffer_mode(indio_dev)) {
	/*
	* Replacing -EBUSY or other error code
	* returned by iio_device_claim_buffer_mode()
	* because user space may rely on the current
	* one.
	*/
	ret = -EAGAIN;
	} else {
	ret = max30100_get_temp(data, val);
	if (!ret)
	ret = IIO_VAL_INT;

	iio_device_release_buffer_mode(indio_dev);
	}
	break;
	case IIO_CHAN_INFO_SCALE:
	val = 1; / 0.0625 */
	*val2 = 16;
	ret = IIO_VAL_FRACTIONAL;
	break;
	}

	return ret;
	}

	static const struct iio_info max30100_info = {
	.read_raw = max30100_read_raw,
	};

	static int max30100_probe(struct i2c_client *client)
	{
	struct max30100_data *data;
	struct iio_dev *indio_dev;
	int ret;

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

	indio_dev->name = MAX30100_DRV_NAME;
	indio_dev->channels = max30100_channels;
	indio_dev->info = &max30100_info;
	indio_dev->num_channels = ARRAY_SIZE(max30100_channels);
	indio_dev->available_scan_masks = max30100_scan_masks;
	indio_dev->modes = INDIO_DIRECT_MODE;

	ret = devm_iio_kfifo_buffer_setup(&client->dev, indio_dev,
	&max30100_buffer_setup_ops);
	if (ret)
	return ret;

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

	mutex_init(&data->lock);
	i2c_set_clientdata(client, indio_dev);

	data->regmap = devm_regmap_init_i2c(client, &max30100_regmap_config);
	if (IS_ERR(data->regmap)) {
	dev_err(&client->dev, "regmap initialization failed.\n");
	return PTR_ERR(data->regmap);
	}
	max30100_set_powermode(data, false);

	ret = max30100_chip_init(data);
	if (ret)
	return ret;

	if (client->irq <= 0) {
	dev_err(&client->dev, "no valid irq defined\n");
	return -EINVAL;
	}
	ret = devm_request_threaded_irq(&client->dev, client->irq,
	NULL, max30100_interrupt_handler,
	IRQF_TRIGGER_FALLING \| IRQF_ONESHOT,
	"max30100_irq", indio_dev);
	if (ret) {
	dev_err(&client->dev, "request irq (%d) failed\n", client->irq);
	return ret;
	}

	return iio_device_register(indio_dev);
	}

	static void max30100_remove(struct i2c_client *client)
	{
	struct iio_dev *indio_dev = i2c_get_clientdata(client);
	struct max30100_data *data = iio_priv(indio_dev);

	iio_device_unregister(indio_dev);
	max30100_set_powermode(data, false);
	}

	static const struct i2c_device_id max30100_id[] = {
	{ "max30100" },
	{}
	};
	MODULE_DEVICE_TABLE(i2c, max30100_id);

	static const struct of_device_id max30100_dt_ids[] = {
	{ .compatible = "maxim,max30100" },
	{ }
	};
	MODULE_DEVICE_TABLE(of, max30100_dt_ids);

	static struct i2c_driver max30100_driver = {
	.driver = {
	.name = MAX30100_DRV_NAME,
	.of_match_table = max30100_dt_ids,
	},
	.probe = max30100_probe,
	.remove = max30100_remove,
	.id_table = max30100_id,
	};
	module_i2c_driver(max30100_driver);

	MODULE_AUTHOR("Matt Ranostay <matt.ranostay@konsulko.com>");
	MODULE_DESCRIPTION("MAX30100 heart rate and pulse oximeter sensor");
	MODULE_LICENSE("GPL");