drivers/iio/health/max30102.c - LeafOS-Devices/android_kernel_samsung_gta4xl - Gitiles

 /*
  * max30102.c - Support for MAX30102 heart rate and pulse oximeter sensor
  *
  * Copyright (C) 2017 Matt Ranostay <matt@ranostay.consulting>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation; either version 2 of the License, or
  * (at your option) any later version.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  * GNU General Public License for more details.
  *
  * TODO: proximity power saving feature
  */

 #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/of.h>
 #include <linux/regmap.h>
 #include <linux/iio/iio.h>
 #include <linux/iio/buffer.h>
 #include <linux/iio/kfifo_buf.h>

 #define MAX30102_REGMAP_NAME	"max30102_regmap"
 #define MAX30102_DRV_NAME	"max30102"

 #define MAX30102_REG_INT_STATUS			0x00
 #define MAX30102_REG_INT_STATUS_PWR_RDY		BIT(0)
 #define MAX30102_REG_INT_STATUS_PROX_INT	BIT(4)
 #define MAX30102_REG_INT_STATUS_ALC_OVF		BIT(5)
 #define MAX30102_REG_INT_STATUS_PPG_RDY		BIT(6)
 #define MAX30102_REG_INT_STATUS_FIFO_RDY	BIT(7)

 #define MAX30102_REG_INT_ENABLE			0x02
 #define MAX30102_REG_INT_ENABLE_PROX_INT_EN	BIT(4)
 #define MAX30102_REG_INT_ENABLE_ALC_OVF_EN	BIT(5)
 #define MAX30102_REG_INT_ENABLE_PPG_EN		BIT(6)
 #define MAX30102_REG_INT_ENABLE_FIFO_EN		BIT(7)
 #define MAX30102_REG_INT_ENABLE_MASK		0xf0
 #define MAX30102_REG_INT_ENABLE_MASK_SHIFT	4

 #define MAX30102_REG_FIFO_WR_PTR		0x04
 #define MAX30102_REG_FIFO_OVR_CTR		0x05
 #define MAX30102_REG_FIFO_RD_PTR		0x06
 #define MAX30102_REG_FIFO_DATA			0x07
 #define MAX30102_REG_FIFO_DATA_ENTRY_LEN	6

 #define MAX30102_REG_FIFO_CONFIG		0x08
 #define MAX30102_REG_FIFO_CONFIG_AVG_4SAMPLES	BIT(1)
 #define MAX30102_REG_FIFO_CONFIG_AVG_SHIFT	5
 #define MAX30102_REG_FIFO_CONFIG_AFULL		BIT(0)

 #define MAX30102_REG_MODE_CONFIG		0x09
 #define MAX30102_REG_MODE_CONFIG_MODE_SPO2_EN	BIT(0)
 #define MAX30102_REG_MODE_CONFIG_MODE_HR_EN	BIT(1)
 #define MAX30102_REG_MODE_CONFIG_MODE_MASK	0x03
 #define MAX30102_REG_MODE_CONFIG_PWR		BIT(7)

 #define MAX30102_REG_SPO2_CONFIG		0x0a
 #define MAX30102_REG_SPO2_CONFIG_PULSE_411_US	0x03
 #define MAX30102_REG_SPO2_CONFIG_SR_400HZ	0x03
 #define MAX30102_REG_SPO2_CONFIG_SR_MASK	0x07
 #define MAX30102_REG_SPO2_CONFIG_SR_MASK_SHIFT	2
 #define MAX30102_REG_SPO2_CONFIG_ADC_4096_STEPS	BIT(0)
 #define MAX30102_REG_SPO2_CONFIG_ADC_MASK_SHIFT	5

 #define MAX30102_REG_RED_LED_CONFIG		0x0c
 #define MAX30102_REG_IR_LED_CONFIG		0x0d

 #define MAX30102_REG_TEMP_CONFIG		0x21
 #define MAX30102_REG_TEMP_CONFIG_TEMP_EN	BIT(0)

 #define MAX30102_REG_TEMP_INTEGER		0x1f
 #define MAX30102_REG_TEMP_FRACTION		0x20

 struct max30102_data {
 	struct i2c_client *client;
 	struct iio_dev *indio_dev;
 	struct mutex lock;
 	struct regmap *regmap;

 	u8 buffer[8];
 	__be32 processed_buffer[2]; /* 2 x 18-bit (padded to 32-bits) */
 };

 static const struct regmap_config max30102_regmap_config = {
 	.name = MAX30102_REGMAP_NAME,

 	.reg_bits = 8,
 	.val_bits = 8,
 };

 static const unsigned long max30102_scan_masks[] = {0x3, 0};

 static const struct iio_chan_spec max30102_channels[] = {
 	{
 		.type = IIO_INTENSITY,
 		.channel2 = IIO_MOD_LIGHT_RED,
 		.modified = 1,

 		.scan_index = 0,
 		.scan_type = {
 			.sign = 'u',
 			.shift = 8,
 			.realbits = 18,
 			.storagebits = 32,
 			.endianness = IIO_BE,
 		},
 	},
 	{
 		.type = IIO_INTENSITY,
 		.channel2 = IIO_MOD_LIGHT_IR,
 		.modified = 1,

 		.scan_index = 1,
 		.scan_type = {
 			.sign = 'u',
 			.shift = 8,
 			.realbits = 18,
 			.storagebits = 32,
 			.endianness = IIO_BE,
 		},
 	},
 	{
 		.type = IIO_TEMP,
 		.info_mask_separate =
 			BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),
 		.scan_index = -1,
 	},
 };

 static int max30102_set_powermode(struct max30102_data *data, bool state)
 {
 	return regmap_update_bits(data->regmap, MAX30102_REG_MODE_CONFIG,
 				  MAX30102_REG_MODE_CONFIG_PWR,
 				  state ? 0 : MAX30102_REG_MODE_CONFIG_PWR);
 }

 static int max30102_buffer_postenable(struct iio_dev *indio_dev)
 {
 	struct max30102_data *data = iio_priv(indio_dev);

 	return max30102_set_powermode(data, true);
 }

 static int max30102_buffer_predisable(struct iio_dev *indio_dev)
 {
 	struct max30102_data *data = iio_priv(indio_dev);

 	return max30102_set_powermode(data, false);
 }

 static const struct iio_buffer_setup_ops max30102_buffer_setup_ops = {
 	.postenable = max30102_buffer_postenable,
 	.predisable = max30102_buffer_predisable,
 };

 static inline int max30102_fifo_count(struct max30102_data *data)
 {
 	unsigned int val;
 	int ret;

 	ret = regmap_read(data->regmap, MAX30102_REG_INT_STATUS, &val);
 	if (ret)
 		return ret;

 	/* FIFO has one sample slot left */
 	if (val & MAX30102_REG_INT_STATUS_FIFO_RDY)
 		return 1;

 	return 0;
 }

 static int max30102_read_measurement(struct max30102_data *data)
 {
 	int ret;
 	u8 *buffer = (u8 *) &data->buffer;

 	ret = i2c_smbus_read_i2c_block_data(data->client,
 					    MAX30102_REG_FIFO_DATA,
 					    MAX30102_REG_FIFO_DATA_ENTRY_LEN,
 					    buffer);

 	memcpy(&data->processed_buffer[0], &buffer[0], 3);
 	memcpy(&data->processed_buffer[1], &buffer[3], 3);

 	return (ret == MAX30102_REG_FIFO_DATA_ENTRY_LEN) ? 0 : -EINVAL;
 }

 static irqreturn_t max30102_interrupt_handler(int irq, void *private)
 {
 	struct iio_dev *indio_dev = private;
 	struct max30102_data *data = iio_priv(indio_dev);
 	int ret, cnt = 0;

 	mutex_lock(&data->lock);

 	while (cnt || (cnt = max30102_fifo_count(data)) > 0) {
 		ret = max30102_read_measurement(data);
 		if (ret)
 			break;

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

 	mutex_unlock(&data->lock);

 	return IRQ_HANDLED;
 }

 static int max30102_get_current_idx(unsigned int val, int *reg)
 {
 	/* each step is 0.200 mA */
 	*reg = val / 200;

 	return *reg > 0xff ? -EINVAL : 0;
 }

 static int max30102_led_init(struct max30102_data *data)
 {
 	struct device *dev = &data->client->dev;
 	struct device_node *np = dev->of_node;
 	unsigned int val;
 	int reg, ret;

 	ret = of_property_read_u32(np, "maxim,red-led-current-microamp", &val);
 	if (ret) {
 		dev_info(dev, "no red-led-current-microamp set\n");

 		/* Default to 7 mA RED LED */
 		val = 7000;
 	}

 	ret = max30102_get_current_idx(val, &reg);
 	if (ret) {
 		dev_err(dev, "invalid RED LED current setting %d\n", val);
 		return ret;
 	}

 	ret = regmap_write(data->regmap, MAX30102_REG_RED_LED_CONFIG, reg);
 	if (ret)
 		return ret;

 	ret = of_property_read_u32(np, "maxim,ir-led-current-microamp", &val);
 	if (ret) {
 		dev_info(dev, "no ir-led-current-microamp set\n");

 		/* Default to 7 mA IR LED */
 		val = 7000;
 	}

 	ret = max30102_get_current_idx(val, &reg);
 	if (ret) {
 		dev_err(dev, "invalid IR LED current setting %d", val);
 		return ret;
 	}

 	return regmap_write(data->regmap, MAX30102_REG_IR_LED_CONFIG, reg);
 }

 static int max30102_chip_init(struct max30102_data *data)
 {
 	int ret;

 	/* setup LED current settings */
 	ret = max30102_led_init(data);
 	if (ret)
 		return ret;

 	/* enable 18-bit HR + SPO2 readings at 400Hz */
 	ret = regmap_write(data->regmap, MAX30102_REG_SPO2_CONFIG,
 				(MAX30102_REG_SPO2_CONFIG_ADC_4096_STEPS
 				 << MAX30102_REG_SPO2_CONFIG_ADC_MASK_SHIFT) |
 				(MAX30102_REG_SPO2_CONFIG_SR_400HZ
 				 << MAX30102_REG_SPO2_CONFIG_SR_MASK_SHIFT) |
 				 MAX30102_REG_SPO2_CONFIG_PULSE_411_US);
 	if (ret)
 		return ret;

 	/* enable SPO2 mode */
 	ret = regmap_update_bits(data->regmap, MAX30102_REG_MODE_CONFIG,
 				 MAX30102_REG_MODE_CONFIG_MODE_MASK,
 				 MAX30102_REG_MODE_CONFIG_MODE_HR_EN |
 				 MAX30102_REG_MODE_CONFIG_MODE_SPO2_EN);
 	if (ret)
 		return ret;

 	/* average 4 samples + generate FIFO interrupt */
 	ret = regmap_write(data->regmap, MAX30102_REG_FIFO_CONFIG,
 				(MAX30102_REG_FIFO_CONFIG_AVG_4SAMPLES
 				 << MAX30102_REG_FIFO_CONFIG_AVG_SHIFT) |
 				 MAX30102_REG_FIFO_CONFIG_AFULL);
 	if (ret)
 		return ret;

 	/* enable FIFO interrupt */
 	return regmap_update_bits(data->regmap, MAX30102_REG_INT_ENABLE,
 				 MAX30102_REG_INT_ENABLE_MASK,
 				 MAX30102_REG_INT_ENABLE_FIFO_EN);
 }

 static int max30102_read_temp(struct max30102_data *data, int *val)
 {
 	int ret;
 	unsigned int reg;

 	ret = regmap_read(data->regmap, MAX30102_REG_TEMP_INTEGER, &reg);
 	if (ret < 0)
 		return ret;
 	*val = reg << 4;

 	ret = regmap_read(data->regmap, MAX30102_REG_TEMP_FRACTION, &reg);
 	if (ret < 0)
 		return ret;

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

 	return 0;
 }

 static int max30102_get_temp(struct max30102_data *data, int *val, bool en)
 {
 	int ret;

 	if (en) {
 		ret = max30102_set_powermode(data, true);
 		if (ret)
 			return ret;
 	}

 	/* start acquisition */
 	ret = regmap_update_bits(data->regmap, MAX30102_REG_TEMP_CONFIG,
 				 MAX30102_REG_TEMP_CONFIG_TEMP_EN,
 				 MAX30102_REG_TEMP_CONFIG_TEMP_EN);
 	if (ret)
 		goto out;

 	msleep(35);
 	ret = max30102_read_temp(data, val);

 out:
 	if (en)
 		max30102_set_powermode(data, false);

 	return ret;
 }

 static int max30102_read_raw(struct iio_dev *indio_dev,
 			     struct iio_chan_spec const *chan,
 			     int *val, int *val2, long mask)
 {
 	struct max30102_data *data = iio_priv(indio_dev);
 	int ret = -EINVAL;

 	switch (mask) {
 	case IIO_CHAN_INFO_RAW:
 		/*
 		 * Temperature reading can only be acquired when not in
 		 * shutdown; leave shutdown briefly when buffer not running
 		 */
 		mutex_lock(&indio_dev->mlock);
 		if (!iio_buffer_enabled(indio_dev))
 			ret = max30102_get_temp(data, val, true);
 		else
 			ret = max30102_get_temp(data, val, false);
 		mutex_unlock(&indio_dev->mlock);
 		if (ret)
 			return ret;

 		ret = IIO_VAL_INT;
 		break;
 	case IIO_CHAN_INFO_SCALE:
 		*val = 1000;  /* 62.5 */
 		*val2 = 16;
 		ret = IIO_VAL_FRACTIONAL;
 		break;
 	}

 	return ret;
 }

 static const struct iio_info max30102_info = {
 	.driver_module = THIS_MODULE,
 	.read_raw = max30102_read_raw,
 };

 static int max30102_probe(struct i2c_client *client,
 			  const struct i2c_device_id *id)
 {
 	struct max30102_data *data;
 	struct iio_buffer *buffer;
 	struct iio_dev *indio_dev;
 	int ret;

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

 	buffer = devm_iio_kfifo_allocate(&client->dev);
 	if (!buffer)
 		return -ENOMEM;

 	iio_device_attach_buffer(indio_dev, buffer);

 	indio_dev->name = MAX30102_DRV_NAME;
 	indio_dev->channels = max30102_channels;
 	indio_dev->info = &max30102_info;
 	indio_dev->num_channels = ARRAY_SIZE(max30102_channels);
 	indio_dev->available_scan_masks = max30102_scan_masks;
 	indio_dev->modes = (INDIO_BUFFER_SOFTWARE | INDIO_DIRECT_MODE);
 	indio_dev->setup_ops = &max30102_buffer_setup_ops;
 	indio_dev->dev.parent = &client->dev;

 	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, &max30102_regmap_config);
 	if (IS_ERR(data->regmap)) {
 		dev_err(&client->dev, "regmap initialization failed.\n");
 		return PTR_ERR(data->regmap);
 	}
 	max30102_set_powermode(data, false);

 	ret = max30102_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, max30102_interrupt_handler,
 					IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
 					"max30102_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 int max30102_remove(struct i2c_client *client)
 {
 	struct iio_dev *indio_dev = i2c_get_clientdata(client);
 	struct max30102_data *data = iio_priv(indio_dev);

 	iio_device_unregister(indio_dev);
 	max30102_set_powermode(data, false);

 	return 0;
 }

 static const struct i2c_device_id max30102_id[] = {
 	{ "max30102", 0 },
 	{}
 };
 MODULE_DEVICE_TABLE(i2c, max30102_id);

 static const struct of_device_id max30102_dt_ids[] = {
 	{ .compatible = "maxim,max30102" },
 	{ }
 };
 MODULE_DEVICE_TABLE(of, max30102_dt_ids);

 static struct i2c_driver max30102_driver = {
 	.driver = {
 		.name	= MAX30102_DRV_NAME,
 		.of_match_table	= of_match_ptr(max30102_dt_ids),
 	},
 	.probe		= max30102_probe,
 	.remove		= max30102_remove,
 	.id_table	= max30102_id,
 };
 module_i2c_driver(max30102_driver);

 MODULE_AUTHOR("Matt Ranostay <matt@ranostay.consulting>");
 MODULE_DESCRIPTION("MAX30102 heart rate and pulse oximeter sensor");
 MODULE_LICENSE("GPL");
	/*
	* max30102.c - Support for MAX30102 heart rate and pulse oximeter sensor
	*
	* Copyright (C) 2017 Matt Ranostay <matt@ranostay.consulting>
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License as published by
	* the Free Software Foundation; either version 2 of the License, or
	* (at your option) any later version.
	*
	* This program is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU General Public License for more details.
	*
	* TODO: proximity power saving feature
	*/

	#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/of.h>
	#include <linux/regmap.h>
	#include <linux/iio/iio.h>
	#include <linux/iio/buffer.h>
	#include <linux/iio/kfifo_buf.h>

	#define MAX30102_REGMAP_NAME "max30102_regmap"
	#define MAX30102_DRV_NAME "max30102"

	#define MAX30102_REG_INT_STATUS 0x00
	#define MAX30102_REG_INT_STATUS_PWR_RDY BIT(0)
	#define MAX30102_REG_INT_STATUS_PROX_INT BIT(4)
	#define MAX30102_REG_INT_STATUS_ALC_OVF BIT(5)
	#define MAX30102_REG_INT_STATUS_PPG_RDY BIT(6)
	#define MAX30102_REG_INT_STATUS_FIFO_RDY BIT(7)

	#define MAX30102_REG_INT_ENABLE 0x02
	#define MAX30102_REG_INT_ENABLE_PROX_INT_EN BIT(4)
	#define MAX30102_REG_INT_ENABLE_ALC_OVF_EN BIT(5)
	#define MAX30102_REG_INT_ENABLE_PPG_EN BIT(6)
	#define MAX30102_REG_INT_ENABLE_FIFO_EN BIT(7)
	#define MAX30102_REG_INT_ENABLE_MASK 0xf0
	#define MAX30102_REG_INT_ENABLE_MASK_SHIFT 4

	#define MAX30102_REG_FIFO_WR_PTR 0x04
	#define MAX30102_REG_FIFO_OVR_CTR 0x05
	#define MAX30102_REG_FIFO_RD_PTR 0x06
	#define MAX30102_REG_FIFO_DATA 0x07
	#define MAX30102_REG_FIFO_DATA_ENTRY_LEN 6

	#define MAX30102_REG_FIFO_CONFIG 0x08
	#define MAX30102_REG_FIFO_CONFIG_AVG_4SAMPLES BIT(1)
	#define MAX30102_REG_FIFO_CONFIG_AVG_SHIFT 5
	#define MAX30102_REG_FIFO_CONFIG_AFULL BIT(0)

	#define MAX30102_REG_MODE_CONFIG 0x09
	#define MAX30102_REG_MODE_CONFIG_MODE_SPO2_EN BIT(0)
	#define MAX30102_REG_MODE_CONFIG_MODE_HR_EN BIT(1)
	#define MAX30102_REG_MODE_CONFIG_MODE_MASK 0x03
	#define MAX30102_REG_MODE_CONFIG_PWR BIT(7)

	#define MAX30102_REG_SPO2_CONFIG 0x0a
	#define MAX30102_REG_SPO2_CONFIG_PULSE_411_US 0x03
	#define MAX30102_REG_SPO2_CONFIG_SR_400HZ 0x03
	#define MAX30102_REG_SPO2_CONFIG_SR_MASK 0x07
	#define MAX30102_REG_SPO2_CONFIG_SR_MASK_SHIFT 2
	#define MAX30102_REG_SPO2_CONFIG_ADC_4096_STEPS BIT(0)
	#define MAX30102_REG_SPO2_CONFIG_ADC_MASK_SHIFT 5

	#define MAX30102_REG_RED_LED_CONFIG 0x0c
	#define MAX30102_REG_IR_LED_CONFIG 0x0d

	#define MAX30102_REG_TEMP_CONFIG 0x21
	#define MAX30102_REG_TEMP_CONFIG_TEMP_EN BIT(0)

	#define MAX30102_REG_TEMP_INTEGER 0x1f
	#define MAX30102_REG_TEMP_FRACTION 0x20

	struct max30102_data {
	struct i2c_client *client;
	struct iio_dev *indio_dev;
	struct mutex lock;
	struct regmap *regmap;

	u8 buffer[8];
	__be32 processed_buffer[2]; /* 2 x 18-bit (padded to 32-bits) */
	};

	static const struct regmap_config max30102_regmap_config = {
	.name = MAX30102_REGMAP_NAME,

	.reg_bits = 8,
	.val_bits = 8,
	};

	static const unsigned long max30102_scan_masks[] = {0x3, 0};

	static const struct iio_chan_spec max30102_channels[] = {
	{
	.type = IIO_INTENSITY,
	.channel2 = IIO_MOD_LIGHT_RED,
	.modified = 1,

	.scan_index = 0,
	.scan_type = {
	.sign = 'u',
	.shift = 8,
	.realbits = 18,
	.storagebits = 32,
	.endianness = IIO_BE,
	},
	},
	{
	.type = IIO_INTENSITY,
	.channel2 = IIO_MOD_LIGHT_IR,
	.modified = 1,

	.scan_index = 1,
	.scan_type = {
	.sign = 'u',
	.shift = 8,
	.realbits = 18,
	.storagebits = 32,
	.endianness = IIO_BE,
	},
	},
	{
	.type = IIO_TEMP,
	.info_mask_separate =
	BIT(IIO_CHAN_INFO_RAW) \| BIT(IIO_CHAN_INFO_SCALE),
	.scan_index = -1,
	},
	};

	static int max30102_set_powermode(struct max30102_data *data, bool state)
	{
	return regmap_update_bits(data->regmap, MAX30102_REG_MODE_CONFIG,
	MAX30102_REG_MODE_CONFIG_PWR,
	state ? 0 : MAX30102_REG_MODE_CONFIG_PWR);
	}

	static int max30102_buffer_postenable(struct iio_dev *indio_dev)
	{
	struct max30102_data *data = iio_priv(indio_dev);

	return max30102_set_powermode(data, true);
	}

	static int max30102_buffer_predisable(struct iio_dev *indio_dev)
	{
	struct max30102_data *data = iio_priv(indio_dev);

	return max30102_set_powermode(data, false);
	}

	static const struct iio_buffer_setup_ops max30102_buffer_setup_ops = {
	.postenable = max30102_buffer_postenable,
	.predisable = max30102_buffer_predisable,
	};

	static inline int max30102_fifo_count(struct max30102_data *data)
	{
	unsigned int val;
	int ret;

	ret = regmap_read(data->regmap, MAX30102_REG_INT_STATUS, &val);
	if (ret)
	return ret;

	/* FIFO has one sample slot left */
	if (val & MAX30102_REG_INT_STATUS_FIFO_RDY)
	return 1;

	return 0;
	}

	static int max30102_read_measurement(struct max30102_data *data)
	{
	int ret;
	u8 buffer = (u8 ) &data->buffer;

	ret = i2c_smbus_read_i2c_block_data(data->client,
	MAX30102_REG_FIFO_DATA,
	MAX30102_REG_FIFO_DATA_ENTRY_LEN,
	buffer);

	memcpy(&data->processed_buffer[0], &buffer[0], 3);
	memcpy(&data->processed_buffer[1], &buffer[3], 3);

	return (ret == MAX30102_REG_FIFO_DATA_ENTRY_LEN) ? 0 : -EINVAL;
	}

	static irqreturn_t max30102_interrupt_handler(int irq, void *private)
	{
	struct iio_dev *indio_dev = private;
	struct max30102_data *data = iio_priv(indio_dev);
	int ret, cnt = 0;

	mutex_lock(&data->lock);

	while (cnt \|\| (cnt = max30102_fifo_count(data)) > 0) {
	ret = max30102_read_measurement(data);
	if (ret)
	break;

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

	mutex_unlock(&data->lock);

	return IRQ_HANDLED;
	}

	static int max30102_get_current_idx(unsigned int val, int *reg)
	{
	/* each step is 0.200 mA */
	*reg = val / 200;

	return *reg > 0xff ? -EINVAL : 0;
	}

	static int max30102_led_init(struct max30102_data *data)
	{
	struct device *dev = &data->client->dev;
	struct device_node *np = dev->of_node;
	unsigned int val;
	int reg, ret;

	ret = of_property_read_u32(np, "maxim,red-led-current-microamp", &val);
	if (ret) {
	dev_info(dev, "no red-led-current-microamp set\n");

	/* Default to 7 mA RED LED */
	val = 7000;
	}

	ret = max30102_get_current_idx(val, &reg);
	if (ret) {
	dev_err(dev, "invalid RED LED current setting %d\n", val);
	return ret;
	}

	ret = regmap_write(data->regmap, MAX30102_REG_RED_LED_CONFIG, reg);
	if (ret)
	return ret;

	ret = of_property_read_u32(np, "maxim,ir-led-current-microamp", &val);
	if (ret) {
	dev_info(dev, "no ir-led-current-microamp set\n");

	/* Default to 7 mA IR LED */
	val = 7000;
	}

	ret = max30102_get_current_idx(val, &reg);
	if (ret) {
	dev_err(dev, "invalid IR LED current setting %d", val);
	return ret;
	}

	return regmap_write(data->regmap, MAX30102_REG_IR_LED_CONFIG, reg);
	}

	static int max30102_chip_init(struct max30102_data *data)
	{
	int ret;

	/* setup LED current settings */
	ret = max30102_led_init(data);
	if (ret)
	return ret;

	/* enable 18-bit HR + SPO2 readings at 400Hz */
	ret = regmap_write(data->regmap, MAX30102_REG_SPO2_CONFIG,
	(MAX30102_REG_SPO2_CONFIG_ADC_4096_STEPS
	<< MAX30102_REG_SPO2_CONFIG_ADC_MASK_SHIFT) \|
	(MAX30102_REG_SPO2_CONFIG_SR_400HZ
	<< MAX30102_REG_SPO2_CONFIG_SR_MASK_SHIFT) \|
	MAX30102_REG_SPO2_CONFIG_PULSE_411_US);
	if (ret)
	return ret;

	/* enable SPO2 mode */
	ret = regmap_update_bits(data->regmap, MAX30102_REG_MODE_CONFIG,
	MAX30102_REG_MODE_CONFIG_MODE_MASK,
	MAX30102_REG_MODE_CONFIG_MODE_HR_EN \|
	MAX30102_REG_MODE_CONFIG_MODE_SPO2_EN);
	if (ret)
	return ret;

	/* average 4 samples + generate FIFO interrupt */
	ret = regmap_write(data->regmap, MAX30102_REG_FIFO_CONFIG,
	(MAX30102_REG_FIFO_CONFIG_AVG_4SAMPLES
	<< MAX30102_REG_FIFO_CONFIG_AVG_SHIFT) \|
	MAX30102_REG_FIFO_CONFIG_AFULL);
	if (ret)
	return ret;

	/* enable FIFO interrupt */
	return regmap_update_bits(data->regmap, MAX30102_REG_INT_ENABLE,
	MAX30102_REG_INT_ENABLE_MASK,
	MAX30102_REG_INT_ENABLE_FIFO_EN);
	}

	static int max30102_read_temp(struct max30102_data data, int val)
	{
	int ret;
	unsigned int reg;

	ret = regmap_read(data->regmap, MAX30102_REG_TEMP_INTEGER, &reg);
	if (ret < 0)
	return ret;
	*val = reg << 4;

	ret = regmap_read(data->regmap, MAX30102_REG_TEMP_FRACTION, &reg);
	if (ret < 0)
	return ret;

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

	return 0;
	}

	static int max30102_get_temp(struct max30102_data data, int val, bool en)
	{
	int ret;

	if (en) {
	ret = max30102_set_powermode(data, true);
	if (ret)
	return ret;
	}

	/* start acquisition */
	ret = regmap_update_bits(data->regmap, MAX30102_REG_TEMP_CONFIG,
	MAX30102_REG_TEMP_CONFIG_TEMP_EN,
	MAX30102_REG_TEMP_CONFIG_TEMP_EN);
	if (ret)
	goto out;

	msleep(35);
	ret = max30102_read_temp(data, val);

	out:
	if (en)
	max30102_set_powermode(data, false);

	return ret;
	}

	static int max30102_read_raw(struct iio_dev *indio_dev,
	struct iio_chan_spec const *chan,
	int val, int val2, long mask)
	{
	struct max30102_data *data = iio_priv(indio_dev);
	int ret = -EINVAL;

	switch (mask) {
	case IIO_CHAN_INFO_RAW:
	/*
	* Temperature reading can only be acquired when not in
	* shutdown; leave shutdown briefly when buffer not running
	*/
	mutex_lock(&indio_dev->mlock);
	if (!iio_buffer_enabled(indio_dev))
	ret = max30102_get_temp(data, val, true);
	else
	ret = max30102_get_temp(data, val, false);
	mutex_unlock(&indio_dev->mlock);
	if (ret)
	return ret;

	ret = IIO_VAL_INT;
	break;
	case IIO_CHAN_INFO_SCALE:
	val = 1000; / 62.5 */
	*val2 = 16;
	ret = IIO_VAL_FRACTIONAL;
	break;
	}

	return ret;
	}

	static const struct iio_info max30102_info = {
	.driver_module = THIS_MODULE,
	.read_raw = max30102_read_raw,
	};

	static int max30102_probe(struct i2c_client *client,
	const struct i2c_device_id *id)
	{
	struct max30102_data *data;
	struct iio_buffer *buffer;
	struct iio_dev *indio_dev;
	int ret;

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

	buffer = devm_iio_kfifo_allocate(&client->dev);
	if (!buffer)
	return -ENOMEM;

	iio_device_attach_buffer(indio_dev, buffer);

	indio_dev->name = MAX30102_DRV_NAME;
	indio_dev->channels = max30102_channels;
	indio_dev->info = &max30102_info;
	indio_dev->num_channels = ARRAY_SIZE(max30102_channels);
	indio_dev->available_scan_masks = max30102_scan_masks;
	indio_dev->modes = (INDIO_BUFFER_SOFTWARE \| INDIO_DIRECT_MODE);
	indio_dev->setup_ops = &max30102_buffer_setup_ops;
	indio_dev->dev.parent = &client->dev;

	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, &max30102_regmap_config);
	if (IS_ERR(data->regmap)) {
	dev_err(&client->dev, "regmap initialization failed.\n");
	return PTR_ERR(data->regmap);
	}
	max30102_set_powermode(data, false);

	ret = max30102_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, max30102_interrupt_handler,
	IRQF_TRIGGER_FALLING \| IRQF_ONESHOT,
	"max30102_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 int max30102_remove(struct i2c_client *client)
	{
	struct iio_dev *indio_dev = i2c_get_clientdata(client);
	struct max30102_data *data = iio_priv(indio_dev);

	iio_device_unregister(indio_dev);
	max30102_set_powermode(data, false);

	return 0;
	}

	static const struct i2c_device_id max30102_id[] = {
	{ "max30102", 0 },
	{}
	};
	MODULE_DEVICE_TABLE(i2c, max30102_id);

	static const struct of_device_id max30102_dt_ids[] = {
	{ .compatible = "maxim,max30102" },
	{ }
	};
	MODULE_DEVICE_TABLE(of, max30102_dt_ids);

	static struct i2c_driver max30102_driver = {
	.driver = {
	.name = MAX30102_DRV_NAME,
	.of_match_table = of_match_ptr(max30102_dt_ids),
	},
	.probe = max30102_probe,
	.remove = max30102_remove,
	.id_table = max30102_id,
	};
	module_i2c_driver(max30102_driver);

	MODULE_AUTHOR("Matt Ranostay <matt@ranostay.consulting>");
	MODULE_DESCRIPTION("MAX30102 heart rate and pulse oximeter sensor");
	MODULE_LICENSE("GPL");