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linux/drivers/iio/health/max30102.c

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/*
* 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)
{
int 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)
return ret;
msleep(35);
return max30102_read_temp(data, val);
}
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 while engine
* is running
*/
mutex_lock(&indio_dev->mlock);
if (!iio_buffer_enabled(indio_dev))
ret = -EBUSY;
else {
ret = max30102_get_temp(data, val);
if (!ret)
ret = IIO_VAL_INT;
}
mutex_unlock(&indio_dev->mlock);
break;
case IIO_CHAN_INFO_SCALE:
*val = 1; /* 0.0625 */
*val2 = 16;
ret = IIO_VAL_FRACTIONAL;
break;
}
return ret;
}
static const struct iio_info max30102_info = {
.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");
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