--- /dev/null
+/*
+ * 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");
projects / deliverable / linux.git / commitdiff
