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Release 4.8 drivers/iio/health/max30100.c

/*
 * max30100.c - Support for MAX30100 heart rate and pulse oximeter sensor
 *
 * Copyright (C) 2015 Matt Ranostay <mranostay@gmail.com>
 *
 * 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: 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/of.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; } }

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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); }

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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); }

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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); }

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static int max30100_buffer_predisable(struct iio_dev *indio_dev) { struct max30100_data *data = iio_priv(indio_dev); return max30100_set_powermode(data, false); }

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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; }

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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; }

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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; }

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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; }

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static int max30100_led_init(struct max30100_data *data) { struct device *dev = &data->client->dev; struct device_node *np = dev->of_node; unsigned int val[2]; int reg, ret; ret = of_property_read_u32_array(np, "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); }

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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); }

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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; }

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static int max30100_get_temp(struct max30100_data *data, int *val) { int ret; /* start acquisition */ ret = regmap_update_bits(data->regmap, MAX30100_REG_MODE_CONFIG, MAX30100_REG_MODE_CONFIG_TEMP_EN, MAX30100_REG_MODE_CONFIG_TEMP_EN); if (ret) return ret; usleep_range(35000, 50000); return max30100_read_temp(data, val); }

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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 */ mutex_lock(&indio_dev->mlock); if (!iio_buffer_enabled(indio_dev)) ret = -EAGAIN; else { ret = max30100_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; }

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static const struct iio_info max30100_info = { .driver_module = THIS_MODULE, .read_raw = max30100_read_raw, };
static int max30100_probe(struct i2c_client *client, const struct i2c_device_id *id) { struct max30100_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 = 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_BUFFER_SOFTWARE | INDIO_DIRECT_MODE); indio_dev->setup_ops = &max30100_buffer_setup_ops; 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); }

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static int 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); return 0; }

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static const struct i2c_device_id max30100_id[] = { { "max30100", 0 }, {} }; 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 = of_match_ptr(max30100_dt_ids), }, .probe = max30100_probe, .remove = max30100_remove, .id_table = max30100_id, }; module_i2c_driver(max30100_driver); MODULE_AUTHOR("Matt Ranostay <mranostay@gmail.com>"); MODULE_DESCRIPTION("MAX30100 heart rate and pulse oximeter sensor"); MODULE_LICENSE("GPL");

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