1 // SPDX-License-Identifier: GPL-2.0+
3 * max30100.c - Support for MAX30100 heart rate and pulse oximeter sensor
5 * Copyright (C) 2015, 2018
6 * Author: Matt Ranostay <matt.ranostay@konsulko.com>
8 * TODO: enable pulse length controls via device tree properties
11 #include <linux/module.h>
12 #include <linux/init.h>
13 #include <linux/interrupt.h>
14 #include <linux/delay.h>
15 #include <linux/err.h>
16 #include <linux/irq.h>
17 #include <linux/i2c.h>
18 #include <linux/mutex.h>
19 #include <linux/property.h>
20 #include <linux/regmap.h>
21 #include <linux/iio/iio.h>
22 #include <linux/iio/buffer.h>
23 #include <linux/iio/kfifo_buf.h>
25 #define MAX30100_REGMAP_NAME "max30100_regmap"
26 #define MAX30100_DRV_NAME "max30100"
28 #define MAX30100_REG_INT_STATUS 0x00
29 #define MAX30100_REG_INT_STATUS_PWR_RDY BIT(0)
30 #define MAX30100_REG_INT_STATUS_SPO2_RDY BIT(4)
31 #define MAX30100_REG_INT_STATUS_HR_RDY BIT(5)
32 #define MAX30100_REG_INT_STATUS_FIFO_RDY BIT(7)
34 #define MAX30100_REG_INT_ENABLE 0x01
35 #define MAX30100_REG_INT_ENABLE_SPO2_EN BIT(0)
36 #define MAX30100_REG_INT_ENABLE_HR_EN BIT(1)
37 #define MAX30100_REG_INT_ENABLE_FIFO_EN BIT(3)
38 #define MAX30100_REG_INT_ENABLE_MASK 0xf0
39 #define MAX30100_REG_INT_ENABLE_MASK_SHIFT 4
41 #define MAX30100_REG_FIFO_WR_PTR 0x02
42 #define MAX30100_REG_FIFO_OVR_CTR 0x03
43 #define MAX30100_REG_FIFO_RD_PTR 0x04
44 #define MAX30100_REG_FIFO_DATA 0x05
45 #define MAX30100_REG_FIFO_DATA_ENTRY_COUNT 16
46 #define MAX30100_REG_FIFO_DATA_ENTRY_LEN 4
48 #define MAX30100_REG_MODE_CONFIG 0x06
49 #define MAX30100_REG_MODE_CONFIG_MODE_SPO2_EN BIT(0)
50 #define MAX30100_REG_MODE_CONFIG_MODE_HR_EN BIT(1)
51 #define MAX30100_REG_MODE_CONFIG_MODE_MASK 0x03
52 #define MAX30100_REG_MODE_CONFIG_TEMP_EN BIT(3)
53 #define MAX30100_REG_MODE_CONFIG_PWR BIT(7)
55 #define MAX30100_REG_SPO2_CONFIG 0x07
56 #define MAX30100_REG_SPO2_CONFIG_100HZ BIT(2)
57 #define MAX30100_REG_SPO2_CONFIG_HI_RES_EN BIT(6)
58 #define MAX30100_REG_SPO2_CONFIG_1600US 0x3
60 #define MAX30100_REG_LED_CONFIG 0x09
61 #define MAX30100_REG_LED_CONFIG_LED_MASK 0x0f
62 #define MAX30100_REG_LED_CONFIG_RED_LED_SHIFT 4
64 #define MAX30100_REG_LED_CONFIG_24MA 0x07
65 #define MAX30100_REG_LED_CONFIG_50MA 0x0f
67 #define MAX30100_REG_TEMP_INTEGER 0x16
68 #define MAX30100_REG_TEMP_FRACTION 0x17
70 struct max30100_data {
71 struct i2c_client *client;
72 struct iio_dev *indio_dev;
74 struct regmap *regmap;
76 __be16 buffer[2]; /* 2 16-bit channels */
79 static bool max30100_is_volatile_reg(struct device *dev, unsigned int reg)
82 case MAX30100_REG_INT_STATUS:
83 case MAX30100_REG_MODE_CONFIG:
84 case MAX30100_REG_FIFO_WR_PTR:
85 case MAX30100_REG_FIFO_OVR_CTR:
86 case MAX30100_REG_FIFO_RD_PTR:
87 case MAX30100_REG_FIFO_DATA:
88 case MAX30100_REG_TEMP_INTEGER:
89 case MAX30100_REG_TEMP_FRACTION:
96 static const struct regmap_config max30100_regmap_config = {
97 .name = MAX30100_REGMAP_NAME,
102 .max_register = MAX30100_REG_TEMP_FRACTION,
103 .cache_type = REGCACHE_FLAT,
105 .volatile_reg = max30100_is_volatile_reg,
108 static const unsigned int max30100_led_current_mapping[] = {
109 4400, 7600, 11000, 14200, 17400,
110 20800, 24000, 27100, 30600, 33800,
111 37000, 40200, 43600, 46800, 50000
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);
242 mutex_unlock(&data->lock);
247 static int max30100_get_current_idx(unsigned int val, int *reg)
257 for (idx = 0; idx < ARRAY_SIZE(max30100_led_current_mapping); idx++) {
258 if (max30100_led_current_mapping[idx] == val) {
267 static int max30100_led_init(struct max30100_data *data)
269 struct device *dev = &data->client->dev;
273 ret = device_property_read_u32_array(dev, "maxim,led-current-microamp",
274 (unsigned int *) &val, 2);
276 /* Default to 24 mA RED LED, 50 mA IR LED */
277 reg = (MAX30100_REG_LED_CONFIG_24MA <<
278 MAX30100_REG_LED_CONFIG_RED_LED_SHIFT) |
279 MAX30100_REG_LED_CONFIG_50MA;
280 dev_warn(dev, "no led-current-microamp set");
282 return regmap_write(data->regmap, MAX30100_REG_LED_CONFIG, reg);
285 /* RED LED current */
286 ret = max30100_get_current_idx(val[0], ®);
288 dev_err(dev, "invalid RED current setting %d", val[0]);
292 ret = regmap_update_bits(data->regmap, MAX30100_REG_LED_CONFIG,
293 MAX30100_REG_LED_CONFIG_LED_MASK <<
294 MAX30100_REG_LED_CONFIG_RED_LED_SHIFT,
295 reg << MAX30100_REG_LED_CONFIG_RED_LED_SHIFT);
300 ret = max30100_get_current_idx(val[1], ®);
302 dev_err(dev, "invalid IR current setting %d", val[1]);
306 return regmap_update_bits(data->regmap, MAX30100_REG_LED_CONFIG,
307 MAX30100_REG_LED_CONFIG_LED_MASK, reg);
310 static int max30100_chip_init(struct max30100_data *data)
314 /* setup LED current settings */
315 ret = max30100_led_init(data);
319 /* enable hi-res SPO2 readings at 100Hz */
320 ret = regmap_write(data->regmap, MAX30100_REG_SPO2_CONFIG,
321 MAX30100_REG_SPO2_CONFIG_HI_RES_EN |
322 MAX30100_REG_SPO2_CONFIG_100HZ);
326 /* enable SPO2 mode */
327 ret = regmap_update_bits(data->regmap, MAX30100_REG_MODE_CONFIG,
328 MAX30100_REG_MODE_CONFIG_MODE_MASK,
329 MAX30100_REG_MODE_CONFIG_MODE_HR_EN |
330 MAX30100_REG_MODE_CONFIG_MODE_SPO2_EN);
334 /* enable FIFO interrupt */
335 return regmap_update_bits(data->regmap, MAX30100_REG_INT_ENABLE,
336 MAX30100_REG_INT_ENABLE_MASK,
337 MAX30100_REG_INT_ENABLE_FIFO_EN
338 << MAX30100_REG_INT_ENABLE_MASK_SHIFT);
341 static int max30100_read_temp(struct max30100_data *data, int *val)
346 ret = regmap_read(data->regmap, MAX30100_REG_TEMP_INTEGER, ®);
351 ret = regmap_read(data->regmap, MAX30100_REG_TEMP_FRACTION, ®);
356 *val = sign_extend32(*val, 11);
361 static int max30100_get_temp(struct max30100_data *data, int *val)
365 /* start acquisition */
366 ret = regmap_update_bits(data->regmap, MAX30100_REG_MODE_CONFIG,
367 MAX30100_REG_MODE_CONFIG_TEMP_EN,
368 MAX30100_REG_MODE_CONFIG_TEMP_EN);
374 return max30100_read_temp(data, val);
377 static int max30100_read_raw(struct iio_dev *indio_dev,
378 struct iio_chan_spec const *chan,
379 int *val, int *val2, long mask)
381 struct max30100_data *data = iio_priv(indio_dev);
385 case IIO_CHAN_INFO_RAW:
387 * Temperature reading can only be acquired while engine
390 if (iio_device_claim_buffer_mode(indio_dev)) {
392 * Replacing -EBUSY or other error code
393 * returned by iio_device_claim_buffer_mode()
394 * because user space may rely on the current
399 ret = max30100_get_temp(data, val);
403 iio_device_release_buffer_mode(indio_dev);
406 case IIO_CHAN_INFO_SCALE:
407 *val = 1; /* 0.0625 */
409 ret = IIO_VAL_FRACTIONAL;
416 static const struct iio_info max30100_info = {
417 .read_raw = max30100_read_raw,
420 static int max30100_probe(struct i2c_client *client)
422 struct max30100_data *data;
423 struct iio_dev *indio_dev;
426 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
430 indio_dev->name = MAX30100_DRV_NAME;
431 indio_dev->channels = max30100_channels;
432 indio_dev->info = &max30100_info;
433 indio_dev->num_channels = ARRAY_SIZE(max30100_channels);
434 indio_dev->available_scan_masks = max30100_scan_masks;
435 indio_dev->modes = INDIO_DIRECT_MODE;
437 ret = devm_iio_kfifo_buffer_setup(&client->dev, indio_dev,
438 &max30100_buffer_setup_ops);
442 data = iio_priv(indio_dev);
443 data->indio_dev = indio_dev;
444 data->client = client;
446 mutex_init(&data->lock);
447 i2c_set_clientdata(client, indio_dev);
449 data->regmap = devm_regmap_init_i2c(client, &max30100_regmap_config);
450 if (IS_ERR(data->regmap)) {
451 dev_err(&client->dev, "regmap initialization failed.\n");
452 return PTR_ERR(data->regmap);
454 max30100_set_powermode(data, false);
456 ret = max30100_chip_init(data);
460 if (client->irq <= 0) {
461 dev_err(&client->dev, "no valid irq defined\n");
464 ret = devm_request_threaded_irq(&client->dev, client->irq,
465 NULL, max30100_interrupt_handler,
466 IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
467 "max30100_irq", indio_dev);
469 dev_err(&client->dev, "request irq (%d) failed\n", client->irq);
473 return iio_device_register(indio_dev);
476 static void max30100_remove(struct i2c_client *client)
478 struct iio_dev *indio_dev = i2c_get_clientdata(client);
479 struct max30100_data *data = iio_priv(indio_dev);
481 iio_device_unregister(indio_dev);
482 max30100_set_powermode(data, false);
485 static const struct i2c_device_id max30100_id[] = {
489 MODULE_DEVICE_TABLE(i2c, max30100_id);
491 static const struct of_device_id max30100_dt_ids[] = {
492 { .compatible = "maxim,max30100" },
495 MODULE_DEVICE_TABLE(of, max30100_dt_ids);
497 static struct i2c_driver max30100_driver = {
499 .name = MAX30100_DRV_NAME,
500 .of_match_table = max30100_dt_ids,
502 .probe = max30100_probe,
503 .remove = max30100_remove,
504 .id_table = max30100_id,
506 module_i2c_driver(max30100_driver);
508 MODULE_AUTHOR("Matt Ranostay <matt.ranostay@konsulko.com>");
509 MODULE_DESCRIPTION("MAX30100 heart rate and pulse oximeter sensor");
510 MODULE_LICENSE("GPL");