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
, bool en
)
337 ret
= max30102_set_powermode(data
, true);
342 /* start acquisition */
343 ret
= regmap_update_bits(data
->regmap
, MAX30102_REG_TEMP_CONFIG
,
344 MAX30102_REG_TEMP_CONFIG_TEMP_EN
,
345 MAX30102_REG_TEMP_CONFIG_TEMP_EN
);
350 ret
= max30102_read_temp(data
, val
);
354 max30102_set_powermode(data
, false);
359 static int max30102_read_raw(struct iio_dev
*indio_dev
,
360 struct iio_chan_spec
const *chan
,
361 int *val
, int *val2
, long mask
)
363 struct max30102_data
*data
= iio_priv(indio_dev
);
367 case IIO_CHAN_INFO_RAW
:
369 * Temperature reading can only be acquired when not in
370 * shutdown; leave shutdown briefly when buffer not running
372 mutex_lock(&indio_dev
->mlock
);
373 if (!iio_buffer_enabled(indio_dev
))
374 ret
= max30102_get_temp(data
, val
, true);
376 ret
= max30102_get_temp(data
, val
, false);
377 mutex_unlock(&indio_dev
->mlock
);
383 case IIO_CHAN_INFO_SCALE
:
384 *val
= 1000; /* 62.5 */
386 ret
= IIO_VAL_FRACTIONAL
;
393 static const struct iio_info max30102_info
= {
394 .driver_module
= THIS_MODULE
,
395 .read_raw
= max30102_read_raw
,
398 static int max30102_probe(struct i2c_client
*client
,
399 const struct i2c_device_id
*id
)
401 struct max30102_data
*data
;
402 struct iio_buffer
*buffer
;
403 struct iio_dev
*indio_dev
;
406 indio_dev
= devm_iio_device_alloc(&client
->dev
, sizeof(*data
));
410 buffer
= devm_iio_kfifo_allocate(&client
->dev
);
414 iio_device_attach_buffer(indio_dev
, buffer
);
416 indio_dev
->name
= MAX30102_DRV_NAME
;
417 indio_dev
->channels
= max30102_channels
;
418 indio_dev
->info
= &max30102_info
;
419 indio_dev
->num_channels
= ARRAY_SIZE(max30102_channels
);
420 indio_dev
->available_scan_masks
= max30102_scan_masks
;
421 indio_dev
->modes
= (INDIO_BUFFER_SOFTWARE
| INDIO_DIRECT_MODE
);
422 indio_dev
->setup_ops
= &max30102_buffer_setup_ops
;
423 indio_dev
->dev
.parent
= &client
->dev
;
425 data
= iio_priv(indio_dev
);
426 data
->indio_dev
= indio_dev
;
427 data
->client
= client
;
429 mutex_init(&data
->lock
);
430 i2c_set_clientdata(client
, indio_dev
);
432 data
->regmap
= devm_regmap_init_i2c(client
, &max30102_regmap_config
);
433 if (IS_ERR(data
->regmap
)) {
434 dev_err(&client
->dev
, "regmap initialization failed.\n");
435 return PTR_ERR(data
->regmap
);
437 max30102_set_powermode(data
, false);
439 ret
= max30102_chip_init(data
);
443 if (client
->irq
<= 0) {
444 dev_err(&client
->dev
, "no valid irq defined\n");
448 ret
= devm_request_threaded_irq(&client
->dev
, client
->irq
,
449 NULL
, max30102_interrupt_handler
,
450 IRQF_TRIGGER_FALLING
| IRQF_ONESHOT
,
451 "max30102_irq", indio_dev
);
453 dev_err(&client
->dev
, "request irq (%d) failed\n", client
->irq
);
457 return iio_device_register(indio_dev
);
460 static int max30102_remove(struct i2c_client
*client
)
462 struct iio_dev
*indio_dev
= i2c_get_clientdata(client
);
463 struct max30102_data
*data
= iio_priv(indio_dev
);
465 iio_device_unregister(indio_dev
);
466 max30102_set_powermode(data
, false);
471 static const struct i2c_device_id max30102_id
[] = {
475 MODULE_DEVICE_TABLE(i2c
, max30102_id
);
477 static const struct of_device_id max30102_dt_ids
[] = {
478 { .compatible
= "maxim,max30102" },
481 MODULE_DEVICE_TABLE(of
, max30102_dt_ids
);
483 static struct i2c_driver max30102_driver
= {
485 .name
= MAX30102_DRV_NAME
,
486 .of_match_table
= of_match_ptr(max30102_dt_ids
),
488 .probe
= max30102_probe
,
489 .remove
= max30102_remove
,
490 .id_table
= max30102_id
,
492 module_i2c_driver(max30102_driver
);
494 MODULE_AUTHOR("Matt Ranostay <matt@ranostay.consulting>");
495 MODULE_DESCRIPTION("MAX30102 heart rate and pulse oximeter sensor");
496 MODULE_LICENSE("GPL");