2 * max30100.c - Support for MAX30100 heart rate and pulse oximeter sensor
4 * Copyright (C) 2015 Matt Ranostay <mranostay@gmail.com>
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * TODO: allow LED current and pulse length controls via device tree properties
19 #include <linux/module.h>
20 #include <linux/init.h>
21 #include <linux/interrupt.h>
22 #include <linux/delay.h>
23 #include <linux/err.h>
24 #include <linux/irq.h>
25 #include <linux/i2c.h>
26 #include <linux/mutex.h>
27 #include <linux/regmap.h>
28 #include <linux/iio/iio.h>
29 #include <linux/iio/buffer.h>
30 #include <linux/iio/kfifo_buf.h>
32 #define MAX30100_REGMAP_NAME "max30100_regmap"
33 #define MAX30100_DRV_NAME "max30100"
35 #define MAX30100_REG_INT_STATUS 0x00
36 #define MAX30100_REG_INT_STATUS_PWR_RDY BIT(0)
37 #define MAX30100_REG_INT_STATUS_SPO2_RDY BIT(4)
38 #define MAX30100_REG_INT_STATUS_HR_RDY BIT(5)
39 #define MAX30100_REG_INT_STATUS_FIFO_RDY BIT(7)
41 #define MAX30100_REG_INT_ENABLE 0x01
42 #define MAX30100_REG_INT_ENABLE_SPO2_EN BIT(0)
43 #define MAX30100_REG_INT_ENABLE_HR_EN BIT(1)
44 #define MAX30100_REG_INT_ENABLE_FIFO_EN BIT(3)
45 #define MAX30100_REG_INT_ENABLE_MASK 0xf0
46 #define MAX30100_REG_INT_ENABLE_MASK_SHIFT 4
48 #define MAX30100_REG_FIFO_WR_PTR 0x02
49 #define MAX30100_REG_FIFO_OVR_CTR 0x03
50 #define MAX30100_REG_FIFO_RD_PTR 0x04
51 #define MAX30100_REG_FIFO_DATA 0x05
52 #define MAX30100_REG_FIFO_DATA_ENTRY_COUNT 16
53 #define MAX30100_REG_FIFO_DATA_ENTRY_LEN 4
55 #define MAX30100_REG_MODE_CONFIG 0x06
56 #define MAX30100_REG_MODE_CONFIG_MODE_SPO2_EN BIT(0)
57 #define MAX30100_REG_MODE_CONFIG_MODE_HR_EN BIT(1)
58 #define MAX30100_REG_MODE_CONFIG_MODE_MASK 0x03
59 #define MAX30100_REG_MODE_CONFIG_TEMP_EN BIT(3)
60 #define MAX30100_REG_MODE_CONFIG_PWR BIT(7)
62 #define MAX30100_REG_SPO2_CONFIG 0x07
63 #define MAX30100_REG_SPO2_CONFIG_100HZ BIT(2)
64 #define MAX30100_REG_SPO2_CONFIG_HI_RES_EN BIT(6)
65 #define MAX30100_REG_SPO2_CONFIG_1600US 0x3
67 #define MAX30100_REG_LED_CONFIG 0x09
68 #define MAX30100_REG_LED_CONFIG_RED_LED_SHIFT 4
70 #define MAX30100_REG_LED_CONFIG_24MA 0x07
71 #define MAX30100_REG_LED_CONFIG_50MA 0x0f
73 #define MAX30100_REG_TEMP_INTEGER 0x16
74 #define MAX30100_REG_TEMP_FRACTION 0x17
76 struct max30100_data {
77 struct i2c_client *client;
78 struct iio_dev *indio_dev;
80 struct regmap *regmap;
82 __be16 buffer[2]; /* 2 16-bit channels */
85 static bool max30100_is_volatile_reg(struct device *dev, unsigned int reg)
88 case MAX30100_REG_INT_STATUS:
89 case MAX30100_REG_MODE_CONFIG:
90 case MAX30100_REG_FIFO_WR_PTR:
91 case MAX30100_REG_FIFO_OVR_CTR:
92 case MAX30100_REG_FIFO_RD_PTR:
93 case MAX30100_REG_FIFO_DATA:
94 case MAX30100_REG_TEMP_INTEGER:
95 case MAX30100_REG_TEMP_FRACTION:
102 static const struct regmap_config max30100_regmap_config = {
103 .name = MAX30100_REGMAP_NAME,
108 .max_register = MAX30100_REG_TEMP_FRACTION,
109 .cache_type = REGCACHE_FLAT,
111 .volatile_reg = max30100_is_volatile_reg,
114 static const unsigned long max30100_scan_masks[] = {0x3, 0};
116 static const struct iio_chan_spec max30100_channels[] = {
118 .type = IIO_INTENSITY,
119 .channel2 = IIO_MOD_LIGHT_IR,
127 .endianness = IIO_BE,
131 .type = IIO_INTENSITY,
132 .channel2 = IIO_MOD_LIGHT_RED,
140 .endianness = IIO_BE,
145 .info_mask_separate =
146 BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),
151 static int max30100_set_powermode(struct max30100_data *data, bool state)
153 return regmap_update_bits(data->regmap, MAX30100_REG_MODE_CONFIG,
154 MAX30100_REG_MODE_CONFIG_PWR,
155 state ? 0 : MAX30100_REG_MODE_CONFIG_PWR);
158 static int max30100_clear_fifo(struct max30100_data *data)
162 ret = regmap_write(data->regmap, MAX30100_REG_FIFO_WR_PTR, 0);
166 ret = regmap_write(data->regmap, MAX30100_REG_FIFO_OVR_CTR, 0);
170 return regmap_write(data->regmap, MAX30100_REG_FIFO_RD_PTR, 0);
173 static int max30100_buffer_postenable(struct iio_dev *indio_dev)
175 struct max30100_data *data = iio_priv(indio_dev);
178 ret = max30100_set_powermode(data, true);
182 return max30100_clear_fifo(data);
185 static int max30100_buffer_predisable(struct iio_dev *indio_dev)
187 struct max30100_data *data = iio_priv(indio_dev);
189 return max30100_set_powermode(data, false);
192 static const struct iio_buffer_setup_ops max30100_buffer_setup_ops = {
193 .postenable = max30100_buffer_postenable,
194 .predisable = max30100_buffer_predisable,
197 static inline int max30100_fifo_count(struct max30100_data *data)
202 ret = regmap_read(data->regmap, MAX30100_REG_INT_STATUS, &val);
206 /* FIFO is almost full */
207 if (val & MAX30100_REG_INT_STATUS_FIFO_RDY)
208 return MAX30100_REG_FIFO_DATA_ENTRY_COUNT - 1;
213 static int max30100_read_measurement(struct max30100_data *data)
217 ret = i2c_smbus_read_i2c_block_data(data->client,
218 MAX30100_REG_FIFO_DATA,
219 MAX30100_REG_FIFO_DATA_ENTRY_LEN,
220 (u8 *) &data->buffer);
222 return (ret == MAX30100_REG_FIFO_DATA_ENTRY_LEN) ? 0 : ret;
225 static irqreturn_t max30100_interrupt_handler(int irq, void *private)
227 struct iio_dev *indio_dev = private;
228 struct max30100_data *data = iio_priv(indio_dev);
231 mutex_lock(&data->lock);
233 while (cnt-- || (cnt = max30100_fifo_count(data) > 0)) {
234 ret = max30100_read_measurement(data);
238 iio_push_to_buffers(data->indio_dev, data->buffer);
241 mutex_unlock(&data->lock);
246 static int max30100_chip_init(struct max30100_data *data)
250 /* RED IR LED = 24mA, IR LED = 50mA */
251 ret = regmap_write(data->regmap, MAX30100_REG_LED_CONFIG,
252 (MAX30100_REG_LED_CONFIG_24MA <<
253 MAX30100_REG_LED_CONFIG_RED_LED_SHIFT) |
254 MAX30100_REG_LED_CONFIG_50MA);
258 /* enable hi-res SPO2 readings at 100Hz */
259 ret = regmap_write(data->regmap, MAX30100_REG_SPO2_CONFIG,
260 MAX30100_REG_SPO2_CONFIG_HI_RES_EN |
261 MAX30100_REG_SPO2_CONFIG_100HZ);
265 /* enable SPO2 mode */
266 ret = regmap_update_bits(data->regmap, MAX30100_REG_MODE_CONFIG,
267 MAX30100_REG_MODE_CONFIG_MODE_MASK,
268 MAX30100_REG_MODE_CONFIG_MODE_HR_EN |
269 MAX30100_REG_MODE_CONFIG_MODE_SPO2_EN);
273 /* enable FIFO interrupt */
274 return regmap_update_bits(data->regmap, MAX30100_REG_INT_ENABLE,
275 MAX30100_REG_INT_ENABLE_MASK,
276 MAX30100_REG_INT_ENABLE_FIFO_EN
277 << MAX30100_REG_INT_ENABLE_MASK_SHIFT);
280 static int max30100_read_temp(struct max30100_data *data, int *val)
285 ret = regmap_read(data->regmap, MAX30100_REG_TEMP_INTEGER, ®);
290 ret = regmap_read(data->regmap, MAX30100_REG_TEMP_FRACTION, ®);
295 *val = sign_extend32(*val, 11);
300 static int max30100_get_temp(struct max30100_data *data, int *val)
304 /* start acquisition */
305 ret = regmap_update_bits(data->regmap, MAX30100_REG_MODE_CONFIG,
306 MAX30100_REG_MODE_CONFIG_TEMP_EN,
307 MAX30100_REG_MODE_CONFIG_TEMP_EN);
311 usleep_range(35000, 50000);
313 return max30100_read_temp(data, val);
316 static int max30100_read_raw(struct iio_dev *indio_dev,
317 struct iio_chan_spec const *chan,
318 int *val, int *val2, long mask)
320 struct max30100_data *data = iio_priv(indio_dev);
324 case IIO_CHAN_INFO_RAW:
326 * Temperature reading can only be acquired while engine
329 mutex_lock(&indio_dev->mlock);
331 if (!iio_buffer_enabled(indio_dev))
334 ret = max30100_get_temp(data, val);
340 mutex_unlock(&indio_dev->mlock);
342 case IIO_CHAN_INFO_SCALE:
343 *val = 1; /* 0.0625 */
345 ret = IIO_VAL_FRACTIONAL;
352 static const struct iio_info max30100_info = {
353 .driver_module = THIS_MODULE,
354 .read_raw = max30100_read_raw,
357 static int max30100_probe(struct i2c_client *client,
358 const struct i2c_device_id *id)
360 struct max30100_data *data;
361 struct iio_buffer *buffer;
362 struct iio_dev *indio_dev;
365 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
369 buffer = devm_iio_kfifo_allocate(&client->dev);
373 iio_device_attach_buffer(indio_dev, buffer);
375 indio_dev->name = MAX30100_DRV_NAME;
376 indio_dev->channels = max30100_channels;
377 indio_dev->info = &max30100_info;
378 indio_dev->num_channels = ARRAY_SIZE(max30100_channels);
379 indio_dev->available_scan_masks = max30100_scan_masks;
380 indio_dev->modes = (INDIO_BUFFER_SOFTWARE | INDIO_DIRECT_MODE);
381 indio_dev->setup_ops = &max30100_buffer_setup_ops;
383 data = iio_priv(indio_dev);
384 data->indio_dev = indio_dev;
385 data->client = client;
387 mutex_init(&data->lock);
388 i2c_set_clientdata(client, indio_dev);
390 data->regmap = devm_regmap_init_i2c(client, &max30100_regmap_config);
391 if (IS_ERR(data->regmap)) {
392 dev_err(&client->dev, "regmap initialization failed.\n");
393 return PTR_ERR(data->regmap);
395 max30100_set_powermode(data, false);
397 ret = max30100_chip_init(data);
401 if (client->irq <= 0) {
402 dev_err(&client->dev, "no valid irq defined\n");
405 ret = devm_request_threaded_irq(&client->dev, client->irq,
406 NULL, max30100_interrupt_handler,
407 IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
408 "max30100_irq", indio_dev);
410 dev_err(&client->dev, "request irq (%d) failed\n", client->irq);
414 return iio_device_register(indio_dev);
417 static int max30100_remove(struct i2c_client *client)
419 struct iio_dev *indio_dev = i2c_get_clientdata(client);
420 struct max30100_data *data = iio_priv(indio_dev);
422 iio_device_unregister(indio_dev);
423 max30100_set_powermode(data, false);
428 static const struct i2c_device_id max30100_id[] = {
432 MODULE_DEVICE_TABLE(i2c, max30100_id);
434 static const struct of_device_id max30100_dt_ids[] = {
435 { .compatible = "maxim,max30100" },
438 MODULE_DEVICE_TABLE(of, max30100_dt_ids);
440 static struct i2c_driver max30100_driver = {
442 .name = MAX30100_DRV_NAME,
443 .of_match_table = of_match_ptr(max30100_dt_ids),
445 .probe = max30100_probe,
446 .remove = max30100_remove,
447 .id_table = max30100_id,
449 module_i2c_driver(max30100_driver);
451 MODULE_AUTHOR("Matt Ranostay <mranostay@gmail.com>");
452 MODULE_DESCRIPTION("MAX30100 heart rate and pulse oximeter sensor");
453 MODULE_LICENSE("GPL");