1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * max30100.c - Support for MAX30100 heart rate and pulse oximeter sensor
4 *
5 * Copyright (C) 2015, 2018
6 * Author: Matt Ranostay <matt.ranostay@konsulko.com>
7 *
8 * TODO: enable pulse length controls via device tree properties
9 */
10
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/of.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>
24
25 #define MAX30100_REGMAP_NAME "max30100_regmap"
26 #define MAX30100_DRV_NAME "max30100"
27
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)
33
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
40
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
47
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)
54
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
59
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
63
64 #define MAX30100_REG_LED_CONFIG_24MA 0x07
65 #define MAX30100_REG_LED_CONFIG_50MA 0x0f
66
67 #define MAX30100_REG_TEMP_INTEGER 0x16
68 #define MAX30100_REG_TEMP_FRACTION 0x17
69
70 struct max30100_data {
71 struct i2c_client *client;
72 struct iio_dev *indio_dev;
73 struct mutex lock;
74 struct regmap *regmap;
75
76 __be16 buffer[2]; /* 2 16-bit channels */
77 };
78
max30100_is_volatile_reg(struct device * dev,unsigned int reg)79 static bool max30100_is_volatile_reg(struct device *dev, unsigned int reg)
80 {
81 switch (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:
90 return true;
91 default:
92 return false;
93 }
94 }
95
96 static const struct regmap_config max30100_regmap_config = {
97 .name = MAX30100_REGMAP_NAME,
98
99 .reg_bits = 8,
100 .val_bits = 8,
101
102 .max_register = MAX30100_REG_TEMP_FRACTION,
103 .cache_type = REGCACHE_FLAT,
104
105 .volatile_reg = max30100_is_volatile_reg,
106 };
107
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
112 };
113
114 static const unsigned long max30100_scan_masks[] = {0x3, 0};
115
116 static const struct iio_chan_spec max30100_channels[] = {
117 {
118 .type = IIO_INTENSITY,
119 .channel2 = IIO_MOD_LIGHT_IR,
120 .modified = 1,
121
122 .scan_index = 0,
123 .scan_type = {
124 .sign = 'u',
125 .realbits = 16,
126 .storagebits = 16,
127 .endianness = IIO_BE,
128 },
129 },
130 {
131 .type = IIO_INTENSITY,
132 .channel2 = IIO_MOD_LIGHT_RED,
133 .modified = 1,
134
135 .scan_index = 1,
136 .scan_type = {
137 .sign = 'u',
138 .realbits = 16,
139 .storagebits = 16,
140 .endianness = IIO_BE,
141 },
142 },
143 {
144 .type = IIO_TEMP,
145 .info_mask_separate =
146 BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),
147 .scan_index = -1,
148 },
149 };
150
max30100_set_powermode(struct max30100_data * data,bool state)151 static int max30100_set_powermode(struct max30100_data *data, bool state)
152 {
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);
156 }
157
max30100_clear_fifo(struct max30100_data * data)158 static int max30100_clear_fifo(struct max30100_data *data)
159 {
160 int ret;
161
162 ret = regmap_write(data->regmap, MAX30100_REG_FIFO_WR_PTR, 0);
163 if (ret)
164 return ret;
165
166 ret = regmap_write(data->regmap, MAX30100_REG_FIFO_OVR_CTR, 0);
167 if (ret)
168 return ret;
169
170 return regmap_write(data->regmap, MAX30100_REG_FIFO_RD_PTR, 0);
171 }
172
max30100_buffer_postenable(struct iio_dev * indio_dev)173 static int max30100_buffer_postenable(struct iio_dev *indio_dev)
174 {
175 struct max30100_data *data = iio_priv(indio_dev);
176 int ret;
177
178 ret = max30100_set_powermode(data, true);
179 if (ret)
180 return ret;
181
182 return max30100_clear_fifo(data);
183 }
184
max30100_buffer_predisable(struct iio_dev * indio_dev)185 static int max30100_buffer_predisable(struct iio_dev *indio_dev)
186 {
187 struct max30100_data *data = iio_priv(indio_dev);
188
189 return max30100_set_powermode(data, false);
190 }
191
192 static const struct iio_buffer_setup_ops max30100_buffer_setup_ops = {
193 .postenable = max30100_buffer_postenable,
194 .predisable = max30100_buffer_predisable,
195 };
196
max30100_fifo_count(struct max30100_data * data)197 static inline int max30100_fifo_count(struct max30100_data *data)
198 {
199 unsigned int val;
200 int ret;
201
202 ret = regmap_read(data->regmap, MAX30100_REG_INT_STATUS, &val);
203 if (ret)
204 return ret;
205
206 /* FIFO is almost full */
207 if (val & MAX30100_REG_INT_STATUS_FIFO_RDY)
208 return MAX30100_REG_FIFO_DATA_ENTRY_COUNT - 1;
209
210 return 0;
211 }
212
max30100_read_measurement(struct max30100_data * data)213 static int max30100_read_measurement(struct max30100_data *data)
214 {
215 int ret;
216
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);
221
222 return (ret == MAX30100_REG_FIFO_DATA_ENTRY_LEN) ? 0 : ret;
223 }
224
max30100_interrupt_handler(int irq,void * private)225 static irqreturn_t max30100_interrupt_handler(int irq, void *private)
226 {
227 struct iio_dev *indio_dev = private;
228 struct max30100_data *data = iio_priv(indio_dev);
229 int ret, cnt = 0;
230
231 mutex_lock(&data->lock);
232
233 while (cnt || (cnt = max30100_fifo_count(data)) > 0) {
234 ret = max30100_read_measurement(data);
235 if (ret)
236 break;
237
238 iio_push_to_buffers(data->indio_dev, data->buffer);
239 cnt--;
240 }
241
242 mutex_unlock(&data->lock);
243
244 return IRQ_HANDLED;
245 }
246
max30100_get_current_idx(unsigned int val,int * reg)247 static int max30100_get_current_idx(unsigned int val, int *reg)
248 {
249 int idx;
250
251 /* LED turned off */
252 if (val == 0) {
253 *reg = 0;
254 return 0;
255 }
256
257 for (idx = 0; idx < ARRAY_SIZE(max30100_led_current_mapping); idx++) {
258 if (max30100_led_current_mapping[idx] == val) {
259 *reg = idx + 1;
260 return 0;
261 }
262 }
263
264 return -EINVAL;
265 }
266
max30100_led_init(struct max30100_data * data)267 static int max30100_led_init(struct max30100_data *data)
268 {
269 struct device *dev = &data->client->dev;
270 struct device_node *np = dev->of_node;
271 unsigned int val[2];
272 int reg, ret;
273
274 ret = of_property_read_u32_array(np, "maxim,led-current-microamp",
275 (unsigned int *) &val, 2);
276 if (ret) {
277 /* Default to 24 mA RED LED, 50 mA IR LED */
278 reg = (MAX30100_REG_LED_CONFIG_24MA <<
279 MAX30100_REG_LED_CONFIG_RED_LED_SHIFT) |
280 MAX30100_REG_LED_CONFIG_50MA;
281 dev_warn(dev, "no led-current-microamp set");
282
283 return regmap_write(data->regmap, MAX30100_REG_LED_CONFIG, reg);
284 }
285
286 /* RED LED current */
287 ret = max30100_get_current_idx(val[0], ®);
288 if (ret) {
289 dev_err(dev, "invalid RED current setting %d", val[0]);
290 return ret;
291 }
292
293 ret = regmap_update_bits(data->regmap, MAX30100_REG_LED_CONFIG,
294 MAX30100_REG_LED_CONFIG_LED_MASK <<
295 MAX30100_REG_LED_CONFIG_RED_LED_SHIFT,
296 reg << MAX30100_REG_LED_CONFIG_RED_LED_SHIFT);
297 if (ret)
298 return ret;
299
300 /* IR LED current */
301 ret = max30100_get_current_idx(val[1], ®);
302 if (ret) {
303 dev_err(dev, "invalid IR current setting %d", val[1]);
304 return ret;
305 }
306
307 return regmap_update_bits(data->regmap, MAX30100_REG_LED_CONFIG,
308 MAX30100_REG_LED_CONFIG_LED_MASK, reg);
309 }
310
max30100_chip_init(struct max30100_data * data)311 static int max30100_chip_init(struct max30100_data *data)
312 {
313 int ret;
314
315 /* setup LED current settings */
316 ret = max30100_led_init(data);
317 if (ret)
318 return ret;
319
320 /* enable hi-res SPO2 readings at 100Hz */
321 ret = regmap_write(data->regmap, MAX30100_REG_SPO2_CONFIG,
322 MAX30100_REG_SPO2_CONFIG_HI_RES_EN |
323 MAX30100_REG_SPO2_CONFIG_100HZ);
324 if (ret)
325 return ret;
326
327 /* enable SPO2 mode */
328 ret = regmap_update_bits(data->regmap, MAX30100_REG_MODE_CONFIG,
329 MAX30100_REG_MODE_CONFIG_MODE_MASK,
330 MAX30100_REG_MODE_CONFIG_MODE_HR_EN |
331 MAX30100_REG_MODE_CONFIG_MODE_SPO2_EN);
332 if (ret)
333 return ret;
334
335 /* enable FIFO interrupt */
336 return regmap_update_bits(data->regmap, MAX30100_REG_INT_ENABLE,
337 MAX30100_REG_INT_ENABLE_MASK,
338 MAX30100_REG_INT_ENABLE_FIFO_EN
339 << MAX30100_REG_INT_ENABLE_MASK_SHIFT);
340 }
341
max30100_read_temp(struct max30100_data * data,int * val)342 static int max30100_read_temp(struct max30100_data *data, int *val)
343 {
344 int ret;
345 unsigned int reg;
346
347 ret = regmap_read(data->regmap, MAX30100_REG_TEMP_INTEGER, ®);
348 if (ret < 0)
349 return ret;
350 *val = reg << 4;
351
352 ret = regmap_read(data->regmap, MAX30100_REG_TEMP_FRACTION, ®);
353 if (ret < 0)
354 return ret;
355
356 *val |= reg & 0xf;
357 *val = sign_extend32(*val, 11);
358
359 return 0;
360 }
361
max30100_get_temp(struct max30100_data * data,int * val)362 static int max30100_get_temp(struct max30100_data *data, int *val)
363 {
364 int ret;
365
366 /* start acquisition */
367 ret = regmap_update_bits(data->regmap, MAX30100_REG_MODE_CONFIG,
368 MAX30100_REG_MODE_CONFIG_TEMP_EN,
369 MAX30100_REG_MODE_CONFIG_TEMP_EN);
370 if (ret)
371 return ret;
372
373 msleep(35);
374
375 return max30100_read_temp(data, val);
376 }
377
max30100_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)378 static int max30100_read_raw(struct iio_dev *indio_dev,
379 struct iio_chan_spec const *chan,
380 int *val, int *val2, long mask)
381 {
382 struct max30100_data *data = iio_priv(indio_dev);
383 int ret = -EINVAL;
384
385 switch (mask) {
386 case IIO_CHAN_INFO_RAW:
387 /*
388 * Temperature reading can only be acquired while engine
389 * is running
390 */
391 mutex_lock(&indio_dev->mlock);
392
393 if (!iio_buffer_enabled(indio_dev))
394 ret = -EAGAIN;
395 else {
396 ret = max30100_get_temp(data, val);
397 if (!ret)
398 ret = IIO_VAL_INT;
399
400 }
401
402 mutex_unlock(&indio_dev->mlock);
403 break;
404 case IIO_CHAN_INFO_SCALE:
405 *val = 1; /* 0.0625 */
406 *val2 = 16;
407 ret = IIO_VAL_FRACTIONAL;
408 break;
409 }
410
411 return ret;
412 }
413
414 static const struct iio_info max30100_info = {
415 .read_raw = max30100_read_raw,
416 };
417
max30100_probe(struct i2c_client * client,const struct i2c_device_id * id)418 static int max30100_probe(struct i2c_client *client,
419 const struct i2c_device_id *id)
420 {
421 struct max30100_data *data;
422 struct iio_buffer *buffer;
423 struct iio_dev *indio_dev;
424 int ret;
425
426 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
427 if (!indio_dev)
428 return -ENOMEM;
429
430 buffer = devm_iio_kfifo_allocate(&client->dev);
431 if (!buffer)
432 return -ENOMEM;
433
434 iio_device_attach_buffer(indio_dev, buffer);
435
436 indio_dev->name = MAX30100_DRV_NAME;
437 indio_dev->channels = max30100_channels;
438 indio_dev->info = &max30100_info;
439 indio_dev->num_channels = ARRAY_SIZE(max30100_channels);
440 indio_dev->available_scan_masks = max30100_scan_masks;
441 indio_dev->modes = (INDIO_BUFFER_SOFTWARE | INDIO_DIRECT_MODE);
442 indio_dev->setup_ops = &max30100_buffer_setup_ops;
443 indio_dev->dev.parent = &client->dev;
444
445 data = iio_priv(indio_dev);
446 data->indio_dev = indio_dev;
447 data->client = client;
448
449 mutex_init(&data->lock);
450 i2c_set_clientdata(client, indio_dev);
451
452 data->regmap = devm_regmap_init_i2c(client, &max30100_regmap_config);
453 if (IS_ERR(data->regmap)) {
454 dev_err(&client->dev, "regmap initialization failed.\n");
455 return PTR_ERR(data->regmap);
456 }
457 max30100_set_powermode(data, false);
458
459 ret = max30100_chip_init(data);
460 if (ret)
461 return ret;
462
463 if (client->irq <= 0) {
464 dev_err(&client->dev, "no valid irq defined\n");
465 return -EINVAL;
466 }
467 ret = devm_request_threaded_irq(&client->dev, client->irq,
468 NULL, max30100_interrupt_handler,
469 IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
470 "max30100_irq", indio_dev);
471 if (ret) {
472 dev_err(&client->dev, "request irq (%d) failed\n", client->irq);
473 return ret;
474 }
475
476 return iio_device_register(indio_dev);
477 }
478
max30100_remove(struct i2c_client * client)479 static int max30100_remove(struct i2c_client *client)
480 {
481 struct iio_dev *indio_dev = i2c_get_clientdata(client);
482 struct max30100_data *data = iio_priv(indio_dev);
483
484 iio_device_unregister(indio_dev);
485 max30100_set_powermode(data, false);
486
487 return 0;
488 }
489
490 static const struct i2c_device_id max30100_id[] = {
491 { "max30100", 0 },
492 {}
493 };
494 MODULE_DEVICE_TABLE(i2c, max30100_id);
495
496 static const struct of_device_id max30100_dt_ids[] = {
497 { .compatible = "maxim,max30100" },
498 { }
499 };
500 MODULE_DEVICE_TABLE(of, max30100_dt_ids);
501
502 static struct i2c_driver max30100_driver = {
503 .driver = {
504 .name = MAX30100_DRV_NAME,
505 .of_match_table = of_match_ptr(max30100_dt_ids),
506 },
507 .probe = max30100_probe,
508 .remove = max30100_remove,
509 .id_table = max30100_id,
510 };
511 module_i2c_driver(max30100_driver);
512
513 MODULE_AUTHOR("Matt Ranostay <matt.ranostay@konsulko.com>");
514 MODULE_DESCRIPTION("MAX30100 heart rate and pulse oximeter sensor");
515 MODULE_LICENSE("GPL");
516
