2 * max30102.c - Support for MAX30102 heart rate and pulse oximeter sensor
4 * Copyright (C) 2017 Matt Ranostay <matt@ranostay.consulting>
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: proximity power saving feature
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>
28 #include <linux/regmap.h>
29 #include <linux/iio/iio.h>
30 #include <linux/iio/buffer.h>
31 #include <linux/iio/kfifo_buf.h>
33 #define MAX30102_REGMAP_NAME "max30102_regmap"
34 #define MAX30102_DRV_NAME "max30102"
36 #define MAX30102_REG_INT_STATUS 0x00
37 #define MAX30102_REG_INT_STATUS_PWR_RDY BIT(0)
38 #define MAX30102_REG_INT_STATUS_PROX_INT BIT(4)
39 #define MAX30102_REG_INT_STATUS_ALC_OVF BIT(5)
40 #define MAX30102_REG_INT_STATUS_PPG_RDY BIT(6)
41 #define MAX30102_REG_INT_STATUS_FIFO_RDY BIT(7)
43 #define MAX30102_REG_INT_ENABLE 0x02
44 #define MAX30102_REG_INT_ENABLE_PROX_INT_EN BIT(4)
45 #define MAX30102_REG_INT_ENABLE_ALC_OVF_EN BIT(5)
46 #define MAX30102_REG_INT_ENABLE_PPG_EN BIT(6)
47 #define MAX30102_REG_INT_ENABLE_FIFO_EN BIT(7)
48 #define MAX30102_REG_INT_ENABLE_MASK 0xf0
49 #define MAX30102_REG_INT_ENABLE_MASK_SHIFT 4
51 #define MAX30102_REG_FIFO_WR_PTR 0x04
52 #define MAX30102_REG_FIFO_OVR_CTR 0x05
53 #define MAX30102_REG_FIFO_RD_PTR 0x06
54 #define MAX30102_REG_FIFO_DATA 0x07
55 #define MAX30102_REG_FIFO_DATA_ENTRY_LEN 6
57 #define MAX30102_REG_FIFO_CONFIG 0x08
58 #define MAX30102_REG_FIFO_CONFIG_AVG_4SAMPLES BIT(1)
59 #define MAX30102_REG_FIFO_CONFIG_AVG_SHIFT 5
60 #define MAX30102_REG_FIFO_CONFIG_AFULL BIT(0)
62 #define MAX30102_REG_MODE_CONFIG 0x09
63 #define MAX30102_REG_MODE_CONFIG_MODE_SPO2_EN BIT(0)
64 #define MAX30102_REG_MODE_CONFIG_MODE_HR_EN BIT(1)
65 #define MAX30102_REG_MODE_CONFIG_MODE_MASK 0x03
66 #define MAX30102_REG_MODE_CONFIG_PWR BIT(7)
68 #define MAX30102_REG_SPO2_CONFIG 0x0a
69 #define MAX30102_REG_SPO2_CONFIG_PULSE_411_US 0x03
70 #define MAX30102_REG_SPO2_CONFIG_SR_400HZ 0x03
71 #define MAX30102_REG_SPO2_CONFIG_SR_MASK 0x07
72 #define MAX30102_REG_SPO2_CONFIG_SR_MASK_SHIFT 2
73 #define MAX30102_REG_SPO2_CONFIG_ADC_4096_STEPS BIT(0)
74 #define MAX30102_REG_SPO2_CONFIG_ADC_MASK_SHIFT 5
76 #define MAX30102_REG_RED_LED_CONFIG 0x0c
77 #define MAX30102_REG_IR_LED_CONFIG 0x0d
79 #define MAX30102_REG_TEMP_CONFIG 0x21
80 #define MAX30102_REG_TEMP_CONFIG_TEMP_EN BIT(0)
82 #define MAX30102_REG_TEMP_INTEGER 0x1f
83 #define MAX30102_REG_TEMP_FRACTION 0x20
85 struct max30102_data {
86 struct i2c_client *client;
87 struct iio_dev *indio_dev;
89 struct regmap *regmap;
92 __be32 processed_buffer[2]; /* 2 x 18-bit (padded to 32-bits) */
95 static const struct regmap_config max30102_regmap_config = {
96 .name = MAX30102_REGMAP_NAME,
102 static const unsigned long max30102_scan_masks[] = {0x3, 0};
104 static const struct iio_chan_spec max30102_channels[] = {
106 .type = IIO_INTENSITY,
107 .channel2 = IIO_MOD_LIGHT_RED,
116 .endianness = IIO_BE,
120 .type = IIO_INTENSITY,
121 .channel2 = IIO_MOD_LIGHT_IR,
130 .endianness = IIO_BE,
135 .info_mask_separate =
136 BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),
141 static int max30102_set_powermode(struct max30102_data *data, bool state)
143 return regmap_update_bits(data->regmap, MAX30102_REG_MODE_CONFIG,
144 MAX30102_REG_MODE_CONFIG_PWR,
145 state ? 0 : MAX30102_REG_MODE_CONFIG_PWR);
148 static int max30102_buffer_postenable(struct iio_dev *indio_dev)
150 struct max30102_data *data = iio_priv(indio_dev);
152 return max30102_set_powermode(data, true);
155 static int max30102_buffer_predisable(struct iio_dev *indio_dev)
157 struct max30102_data *data = iio_priv(indio_dev);
159 return max30102_set_powermode(data, false);
162 static const struct iio_buffer_setup_ops max30102_buffer_setup_ops = {
163 .postenable = max30102_buffer_postenable,
164 .predisable = max30102_buffer_predisable,
167 static inline int max30102_fifo_count(struct max30102_data *data)
172 ret = regmap_read(data->regmap, MAX30102_REG_INT_STATUS, &val);
176 /* FIFO has one sample slot left */
177 if (val & MAX30102_REG_INT_STATUS_FIFO_RDY)
183 static int max30102_read_measurement(struct max30102_data *data)
186 u8 *buffer = (u8 *) &data->buffer;
188 ret = i2c_smbus_read_i2c_block_data(data->client,
189 MAX30102_REG_FIFO_DATA,
190 MAX30102_REG_FIFO_DATA_ENTRY_LEN,
193 memcpy(&data->processed_buffer[0], &buffer[0], 3);
194 memcpy(&data->processed_buffer[1], &buffer[3], 3);
196 return (ret == MAX30102_REG_FIFO_DATA_ENTRY_LEN) ? 0 : -EINVAL;
199 static irqreturn_t max30102_interrupt_handler(int irq, void *private)
201 struct iio_dev *indio_dev = private;
202 struct max30102_data *data = iio_priv(indio_dev);
205 mutex_lock(&data->lock);
207 while (cnt || (cnt = max30102_fifo_count(data)) > 0) {
208 ret = max30102_read_measurement(data);
212 iio_push_to_buffers(data->indio_dev, data->processed_buffer);
216 mutex_unlock(&data->lock);
221 static int max30102_get_current_idx(unsigned int val, int *reg)
223 /* each step is 0.200 mA */
226 return *reg > 0xff ? -EINVAL : 0;
229 static int max30102_led_init(struct max30102_data *data)
231 struct device *dev = &data->client->dev;
232 struct device_node *np = dev->of_node;
236 ret = of_property_read_u32(np, "maxim,red-led-current-microamp", &val);
238 dev_info(dev, "no red-led-current-microamp set\n");
240 /* Default to 7 mA RED LED */
244 ret = max30102_get_current_idx(val, ®);
246 dev_err(dev, "invalid RED LED current setting %d\n", val);
250 ret = regmap_write(data->regmap, MAX30102_REG_RED_LED_CONFIG, reg);
254 ret = of_property_read_u32(np, "maxim,ir-led-current-microamp", &val);
256 dev_info(dev, "no ir-led-current-microamp set\n");
258 /* Default to 7 mA IR LED */
262 ret = max30102_get_current_idx(val, ®);
264 dev_err(dev, "invalid IR LED current setting %d", val);
268 return regmap_write(data->regmap, MAX30102_REG_IR_LED_CONFIG, reg);
271 static int max30102_chip_init(struct max30102_data *data)
275 /* setup LED current settings */
276 ret = max30102_led_init(data);
280 /* enable 18-bit HR + SPO2 readings at 400Hz */
281 ret = regmap_write(data->regmap, MAX30102_REG_SPO2_CONFIG,
282 (MAX30102_REG_SPO2_CONFIG_ADC_4096_STEPS
283 << MAX30102_REG_SPO2_CONFIG_ADC_MASK_SHIFT) |
284 (MAX30102_REG_SPO2_CONFIG_SR_400HZ
285 << MAX30102_REG_SPO2_CONFIG_SR_MASK_SHIFT) |
286 MAX30102_REG_SPO2_CONFIG_PULSE_411_US);
290 /* enable SPO2 mode */
291 ret = regmap_update_bits(data->regmap, MAX30102_REG_MODE_CONFIG,
292 MAX30102_REG_MODE_CONFIG_MODE_MASK,
293 MAX30102_REG_MODE_CONFIG_MODE_HR_EN |
294 MAX30102_REG_MODE_CONFIG_MODE_SPO2_EN);
298 /* average 4 samples + generate FIFO interrupt */
299 ret = regmap_write(data->regmap, MAX30102_REG_FIFO_CONFIG,
300 (MAX30102_REG_FIFO_CONFIG_AVG_4SAMPLES
301 << MAX30102_REG_FIFO_CONFIG_AVG_SHIFT) |
302 MAX30102_REG_FIFO_CONFIG_AFULL);
306 /* enable FIFO interrupt */
307 return regmap_update_bits(data->regmap, MAX30102_REG_INT_ENABLE,
308 MAX30102_REG_INT_ENABLE_MASK,
309 MAX30102_REG_INT_ENABLE_FIFO_EN);
312 static int max30102_read_temp(struct max30102_data *data, int *val)
317 ret = regmap_read(data->regmap, MAX30102_REG_TEMP_INTEGER, ®);
322 ret = regmap_read(data->regmap, MAX30102_REG_TEMP_FRACTION, ®);
327 *val = sign_extend32(*val, 11);
332 static int max30102_get_temp(struct max30102_data *data, int *val)
336 /* start acquisition */
337 ret = regmap_update_bits(data->regmap, MAX30102_REG_TEMP_CONFIG,
338 MAX30102_REG_TEMP_CONFIG_TEMP_EN,
339 MAX30102_REG_TEMP_CONFIG_TEMP_EN);
345 return max30102_read_temp(data, val);
348 static int max30102_read_raw(struct iio_dev *indio_dev,
349 struct iio_chan_spec const *chan,
350 int *val, int *val2, long mask)
352 struct max30102_data *data = iio_priv(indio_dev);
356 case IIO_CHAN_INFO_RAW:
358 * Temperature reading can only be acquired while engine
361 mutex_lock(&indio_dev->mlock);
363 if (!iio_buffer_enabled(indio_dev))
366 ret = max30102_get_temp(data, val);
371 mutex_unlock(&indio_dev->mlock);
373 case IIO_CHAN_INFO_SCALE:
374 *val = 1; /* 0.0625 */
376 ret = IIO_VAL_FRACTIONAL;
383 static const struct iio_info max30102_info = {
384 .driver_module = THIS_MODULE,
385 .read_raw = max30102_read_raw,
388 static int max30102_probe(struct i2c_client *client,
389 const struct i2c_device_id *id)
391 struct max30102_data *data;
392 struct iio_buffer *buffer;
393 struct iio_dev *indio_dev;
396 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
400 buffer = devm_iio_kfifo_allocate(&client->dev);
404 iio_device_attach_buffer(indio_dev, buffer);
406 indio_dev->name = MAX30102_DRV_NAME;
407 indio_dev->channels = max30102_channels;
408 indio_dev->info = &max30102_info;
409 indio_dev->num_channels = ARRAY_SIZE(max30102_channels);
410 indio_dev->available_scan_masks = max30102_scan_masks;
411 indio_dev->modes = (INDIO_BUFFER_SOFTWARE | INDIO_DIRECT_MODE);
412 indio_dev->setup_ops = &max30102_buffer_setup_ops;
413 indio_dev->dev.parent = &client->dev;
415 data = iio_priv(indio_dev);
416 data->indio_dev = indio_dev;
417 data->client = client;
419 mutex_init(&data->lock);
420 i2c_set_clientdata(client, indio_dev);
422 data->regmap = devm_regmap_init_i2c(client, &max30102_regmap_config);
423 if (IS_ERR(data->regmap)) {
424 dev_err(&client->dev, "regmap initialization failed.\n");
425 return PTR_ERR(data->regmap);
427 max30102_set_powermode(data, false);
429 ret = max30102_chip_init(data);
433 if (client->irq <= 0) {
434 dev_err(&client->dev, "no valid irq defined\n");
438 ret = devm_request_threaded_irq(&client->dev, client->irq,
439 NULL, max30102_interrupt_handler,
440 IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
441 "max30102_irq", indio_dev);
443 dev_err(&client->dev, "request irq (%d) failed\n", client->irq);
447 return iio_device_register(indio_dev);
450 static int max30102_remove(struct i2c_client *client)
452 struct iio_dev *indio_dev = i2c_get_clientdata(client);
453 struct max30102_data *data = iio_priv(indio_dev);
455 iio_device_unregister(indio_dev);
456 max30102_set_powermode(data, false);
461 static const struct i2c_device_id max30102_id[] = {
465 MODULE_DEVICE_TABLE(i2c, max30102_id);
467 static const struct of_device_id max30102_dt_ids[] = {
468 { .compatible = "maxim,max30102" },
471 MODULE_DEVICE_TABLE(of, max30102_dt_ids);
473 static struct i2c_driver max30102_driver = {
475 .name = MAX30102_DRV_NAME,
476 .of_match_table = of_match_ptr(max30102_dt_ids),
478 .probe = max30102_probe,
479 .remove = max30102_remove,
480 .id_table = max30102_id,
482 module_i2c_driver(max30102_driver);
484 MODULE_AUTHOR("Matt Ranostay <matt@ranostay.consulting>");
485 MODULE_DESCRIPTION("MAX30102 heart rate and pulse oximeter sensor");
486 MODULE_LICENSE("GPL");