diff options
Diffstat (limited to 'drivers/iio/health/max30100.c')
| -rw-r--r-- | drivers/iio/health/max30100.c | 453 |
1 files changed, 453 insertions, 0 deletions
diff --git a/drivers/iio/health/max30100.c b/drivers/iio/health/max30100.c new file mode 100644 index 000000000..9d1c81f91 --- /dev/null +++ b/drivers/iio/health/max30100.c @@ -0,0 +1,453 @@ +/* + * 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: allow LED current and 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/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_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 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); + } + + mutex_unlock(&data->lock); + + return IRQ_HANDLED; +} + +static int max30100_chip_init(struct max30100_data *data) +{ + int ret; + + /* RED IR LED = 24mA, IR LED = 50mA */ + ret = regmap_write(data->regmap, MAX30100_REG_LED_CONFIG, + (MAX30100_REG_LED_CONFIG_24MA << + MAX30100_REG_LED_CONFIG_RED_LED_SHIFT) | + MAX30100_REG_LED_CONFIG_50MA); + 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, ®); + if (ret < 0) + return ret; + *val = reg << 4; + + ret = regmap_read(data->regmap, MAX30100_REG_TEMP_FRACTION, ®); + 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_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); +} + +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; +} + +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); +} + +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; +} + +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"); |