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/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>
24
25 #define MAX30100_DRV_NAME "max30100"
26
27 #define MAX30100_REG_INT_STATUS 0x00
28 #define MAX30100_REG_INT_STATUS_PWR_RDY BIT(0)
29 #define MAX30100_REG_INT_STATUS_SPO2_RDY BIT(4)
30 #define MAX30100_REG_INT_STATUS_HR_RDY BIT(5)
31 #define MAX30100_REG_INT_STATUS_FIFO_RDY BIT(7)
32
33 #define MAX30100_REG_INT_ENABLE 0x01
34 #define MAX30100_REG_INT_ENABLE_SPO2_EN BIT(0)
35 #define MAX30100_REG_INT_ENABLE_HR_EN BIT(1)
36 #define MAX30100_REG_INT_ENABLE_FIFO_EN BIT(3)
37 #define MAX30100_REG_INT_ENABLE_MASK 0xf0
38 #define MAX30100_REG_INT_ENABLE_MASK_SHIFT 4
39
40 #define MAX30100_REG_FIFO_WR_PTR 0x02
41 #define MAX30100_REG_FIFO_OVR_CTR 0x03
42 #define MAX30100_REG_FIFO_RD_PTR 0x04
43 #define MAX30100_REG_FIFO_DATA 0x05
44 #define MAX30100_REG_FIFO_DATA_ENTRY_COUNT 16
45 #define MAX30100_REG_FIFO_DATA_ENTRY_LEN 4
46
47 #define MAX30100_REG_MODE_CONFIG 0x06
48 #define MAX30100_REG_MODE_CONFIG_MODE_SPO2_EN BIT(0)
49 #define MAX30100_REG_MODE_CONFIG_MODE_HR_EN BIT(1)
50 #define MAX30100_REG_MODE_CONFIG_MODE_MASK 0x03
51 #define MAX30100_REG_MODE_CONFIG_TEMP_EN BIT(3)
52 #define MAX30100_REG_MODE_CONFIG_PWR BIT(7)
53
54 #define MAX30100_REG_SPO2_CONFIG 0x07
55 #define MAX30100_REG_SPO2_CONFIG_100HZ BIT(2)
56 #define MAX30100_REG_SPO2_CONFIG_HI_RES_EN BIT(6)
57 #define MAX30100_REG_SPO2_CONFIG_1600US 0x3
58
59 #define MAX30100_REG_LED_CONFIG 0x09
60 #define MAX30100_REG_LED_CONFIG_LED_MASK 0x0f
61 #define MAX30100_REG_LED_CONFIG_RED_LED_SHIFT 4
62
63 #define MAX30100_REG_LED_CONFIG_24MA 0x07
64 #define MAX30100_REG_LED_CONFIG_50MA 0x0f
65
66 #define MAX30100_REG_TEMP_INTEGER 0x16
67 #define MAX30100_REG_TEMP_FRACTION 0x17
68
69 struct max30100_data {
70 struct i2c_client *client;
71 struct iio_dev *indio_dev;
72 struct mutex lock;
73 struct regmap *regmap;
74
75 __be16 buffer[2]; /* 2 16-bit channels */
76 };
77
max30100_is_volatile_reg(struct device * dev,unsigned int reg)78 static bool max30100_is_volatile_reg(struct device *dev, unsigned int reg)
79 {
80 switch (reg) {
81 case MAX30100_REG_INT_STATUS:
82 case MAX30100_REG_MODE_CONFIG:
83 case MAX30100_REG_FIFO_WR_PTR:
84 case MAX30100_REG_FIFO_OVR_CTR:
85 case MAX30100_REG_FIFO_RD_PTR:
86 case MAX30100_REG_FIFO_DATA:
87 case MAX30100_REG_TEMP_INTEGER:
88 case MAX30100_REG_TEMP_FRACTION:
89 return true;
90 default:
91 return false;
92 }
93 }
94
95 static const struct regmap_config max30100_regmap_config = {
96 .name = "max30100_regmap",
97
98 .reg_bits = 8,
99 .val_bits = 8,
100
101 .max_register = MAX30100_REG_TEMP_FRACTION,
102 .cache_type = REGCACHE_FLAT,
103
104 .volatile_reg = max30100_is_volatile_reg,
105 };
106
107 static const unsigned int max30100_led_current_mapping[] = {
108 4400, 7600, 11000, 14200, 17400,
109 20800, 24000, 27100, 30600, 33800,
110 37000, 40200, 43600, 46800, 50000
111 };
112
113 static const unsigned long max30100_scan_masks[] = {0x3, 0};
114
115 static const struct iio_chan_spec max30100_channels[] = {
116 {
117 .type = IIO_INTENSITY,
118 .channel2 = IIO_MOD_LIGHT_IR,
119 .modified = 1,
120
121 .scan_index = 0,
122 .scan_type = {
123 .sign = 'u',
124 .realbits = 16,
125 .storagebits = 16,
126 .endianness = IIO_BE,
127 },
128 },
129 {
130 .type = IIO_INTENSITY,
131 .channel2 = IIO_MOD_LIGHT_RED,
132 .modified = 1,
133
134 .scan_index = 1,
135 .scan_type = {
136 .sign = 'u',
137 .realbits = 16,
138 .storagebits = 16,
139 .endianness = IIO_BE,
140 },
141 },
142 {
143 .type = IIO_TEMP,
144 .info_mask_separate =
145 BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),
146 .scan_index = -1,
147 },
148 };
149
max30100_set_powermode(struct max30100_data * data,bool state)150 static int max30100_set_powermode(struct max30100_data *data, bool state)
151 {
152 return regmap_update_bits(data->regmap, MAX30100_REG_MODE_CONFIG,
153 MAX30100_REG_MODE_CONFIG_PWR,
154 state ? 0 : MAX30100_REG_MODE_CONFIG_PWR);
155 }
156
max30100_clear_fifo(struct max30100_data * data)157 static int max30100_clear_fifo(struct max30100_data *data)
158 {
159 int ret;
160
161 ret = regmap_write(data->regmap, MAX30100_REG_FIFO_WR_PTR, 0);
162 if (ret)
163 return ret;
164
165 ret = regmap_write(data->regmap, MAX30100_REG_FIFO_OVR_CTR, 0);
166 if (ret)
167 return ret;
168
169 return regmap_write(data->regmap, MAX30100_REG_FIFO_RD_PTR, 0);
170 }
171
max30100_buffer_postenable(struct iio_dev * indio_dev)172 static int max30100_buffer_postenable(struct iio_dev *indio_dev)
173 {
174 struct max30100_data *data = iio_priv(indio_dev);
175 int ret;
176
177 ret = max30100_set_powermode(data, true);
178 if (ret)
179 return ret;
180
181 return max30100_clear_fifo(data);
182 }
183
max30100_buffer_predisable(struct iio_dev * indio_dev)184 static int max30100_buffer_predisable(struct iio_dev *indio_dev)
185 {
186 struct max30100_data *data = iio_priv(indio_dev);
187
188 return max30100_set_powermode(data, false);
189 }
190
191 static const struct iio_buffer_setup_ops max30100_buffer_setup_ops = {
192 .postenable = max30100_buffer_postenable,
193 .predisable = max30100_buffer_predisable,
194 };
195
max30100_fifo_count(struct max30100_data * data)196 static inline int max30100_fifo_count(struct max30100_data *data)
197 {
198 unsigned int val;
199 int ret;
200
201 ret = regmap_read(data->regmap, MAX30100_REG_INT_STATUS, &val);
202 if (ret)
203 return ret;
204
205 /* FIFO is almost full */
206 if (val & MAX30100_REG_INT_STATUS_FIFO_RDY)
207 return MAX30100_REG_FIFO_DATA_ENTRY_COUNT - 1;
208
209 return 0;
210 }
211
max30100_read_measurement(struct max30100_data * data)212 static int max30100_read_measurement(struct max30100_data *data)
213 {
214 int ret;
215
216 ret = i2c_smbus_read_i2c_block_data(data->client,
217 MAX30100_REG_FIFO_DATA,
218 MAX30100_REG_FIFO_DATA_ENTRY_LEN,
219 (u8 *) &data->buffer);
220
221 return (ret == MAX30100_REG_FIFO_DATA_ENTRY_LEN) ? 0 : ret;
222 }
223
max30100_interrupt_handler(int irq,void * private)224 static irqreturn_t max30100_interrupt_handler(int irq, void *private)
225 {
226 struct iio_dev *indio_dev = private;
227 struct max30100_data *data = iio_priv(indio_dev);
228 int ret, cnt = 0;
229
230 mutex_lock(&data->lock);
231
232 while (cnt || (cnt = max30100_fifo_count(data)) > 0) {
233 ret = max30100_read_measurement(data);
234 if (ret)
235 break;
236
237 iio_push_to_buffers(data->indio_dev, data->buffer);
238 cnt--;
239 }
240
241 mutex_unlock(&data->lock);
242
243 return IRQ_HANDLED;
244 }
245
max30100_get_current_idx(unsigned int val,int * reg)246 static int max30100_get_current_idx(unsigned int val, int *reg)
247 {
248 int idx;
249
250 /* LED turned off */
251 if (val == 0) {
252 *reg = 0;
253 return 0;
254 }
255
256 for (idx = 0; idx < ARRAY_SIZE(max30100_led_current_mapping); idx++) {
257 if (max30100_led_current_mapping[idx] == val) {
258 *reg = idx + 1;
259 return 0;
260 }
261 }
262
263 return -EINVAL;
264 }
265
max30100_led_init(struct max30100_data * data)266 static int max30100_led_init(struct max30100_data *data)
267 {
268 struct device *dev = &data->client->dev;
269 unsigned int val[2];
270 int reg, ret;
271
272 ret = device_property_read_u32_array(dev, "maxim,led-current-microamp",
273 (unsigned int *) &val, 2);
274 if (ret) {
275 /* Default to 24 mA RED LED, 50 mA IR LED */
276 reg = (MAX30100_REG_LED_CONFIG_24MA <<
277 MAX30100_REG_LED_CONFIG_RED_LED_SHIFT) |
278 MAX30100_REG_LED_CONFIG_50MA;
279 dev_warn(dev, "no led-current-microamp set");
280
281 return regmap_write(data->regmap, MAX30100_REG_LED_CONFIG, reg);
282 }
283
284 /* RED LED current */
285 ret = max30100_get_current_idx(val[0], ®);
286 if (ret) {
287 dev_err(dev, "invalid RED current setting %d", val[0]);
288 return ret;
289 }
290
291 ret = regmap_update_bits(data->regmap, MAX30100_REG_LED_CONFIG,
292 MAX30100_REG_LED_CONFIG_LED_MASK <<
293 MAX30100_REG_LED_CONFIG_RED_LED_SHIFT,
294 reg << MAX30100_REG_LED_CONFIG_RED_LED_SHIFT);
295 if (ret)
296 return ret;
297
298 /* IR LED current */
299 ret = max30100_get_current_idx(val[1], ®);
300 if (ret) {
301 dev_err(dev, "invalid IR current setting %d", val[1]);
302 return ret;
303 }
304
305 return regmap_update_bits(data->regmap, MAX30100_REG_LED_CONFIG,
306 MAX30100_REG_LED_CONFIG_LED_MASK, reg);
307 }
308
max30100_chip_init(struct max30100_data * data)309 static int max30100_chip_init(struct max30100_data *data)
310 {
311 int ret;
312
313 /* setup LED current settings */
314 ret = max30100_led_init(data);
315 if (ret)
316 return ret;
317
318 /* enable hi-res SPO2 readings at 100Hz */
319 ret = regmap_write(data->regmap, MAX30100_REG_SPO2_CONFIG,
320 MAX30100_REG_SPO2_CONFIG_HI_RES_EN |
321 MAX30100_REG_SPO2_CONFIG_100HZ);
322 if (ret)
323 return ret;
324
325 /* enable SPO2 mode */
326 ret = regmap_update_bits(data->regmap, MAX30100_REG_MODE_CONFIG,
327 MAX30100_REG_MODE_CONFIG_MODE_MASK,
328 MAX30100_REG_MODE_CONFIG_MODE_HR_EN |
329 MAX30100_REG_MODE_CONFIG_MODE_SPO2_EN);
330 if (ret)
331 return ret;
332
333 /* enable FIFO interrupt */
334 return regmap_update_bits(data->regmap, MAX30100_REG_INT_ENABLE,
335 MAX30100_REG_INT_ENABLE_MASK,
336 MAX30100_REG_INT_ENABLE_FIFO_EN
337 << MAX30100_REG_INT_ENABLE_MASK_SHIFT);
338 }
339
max30100_read_temp(struct max30100_data * data,int * val)340 static int max30100_read_temp(struct max30100_data *data, int *val)
341 {
342 int ret;
343 unsigned int reg;
344
345 ret = regmap_read(data->regmap, MAX30100_REG_TEMP_INTEGER, ®);
346 if (ret < 0)
347 return ret;
348 *val = reg << 4;
349
350 ret = regmap_read(data->regmap, MAX30100_REG_TEMP_FRACTION, ®);
351 if (ret < 0)
352 return ret;
353
354 *val |= reg & 0xf;
355 *val = sign_extend32(*val, 11);
356
357 return 0;
358 }
359
max30100_get_temp(struct max30100_data * data,int * val)360 static int max30100_get_temp(struct max30100_data *data, int *val)
361 {
362 int ret;
363
364 /* start acquisition */
365 ret = regmap_set_bits(data->regmap, MAX30100_REG_MODE_CONFIG,
366 MAX30100_REG_MODE_CONFIG_TEMP_EN);
367 if (ret)
368 return ret;
369
370 msleep(35);
371
372 return max30100_read_temp(data, val);
373 }
374
max30100_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)375 static int max30100_read_raw(struct iio_dev *indio_dev,
376 struct iio_chan_spec const *chan,
377 int *val, int *val2, long mask)
378 {
379 struct max30100_data *data = iio_priv(indio_dev);
380 int ret = -EINVAL;
381
382 switch (mask) {
383 case IIO_CHAN_INFO_RAW:
384 /*
385 * Temperature reading can only be acquired while engine
386 * is running
387 */
388 if (iio_device_claim_buffer_mode(indio_dev)) {
389 /*
390 * Replacing -EBUSY or other error code
391 * returned by iio_device_claim_buffer_mode()
392 * because user space may rely on the current
393 * one.
394 */
395 ret = -EAGAIN;
396 } else {
397 ret = max30100_get_temp(data, val);
398 if (!ret)
399 ret = IIO_VAL_INT;
400
401 iio_device_release_buffer_mode(indio_dev);
402 }
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)418 static int max30100_probe(struct i2c_client *client)
419 {
420 struct max30100_data *data;
421 struct iio_dev *indio_dev;
422 int ret;
423
424 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
425 if (!indio_dev)
426 return -ENOMEM;
427
428 indio_dev->name = MAX30100_DRV_NAME;
429 indio_dev->channels = max30100_channels;
430 indio_dev->info = &max30100_info;
431 indio_dev->num_channels = ARRAY_SIZE(max30100_channels);
432 indio_dev->available_scan_masks = max30100_scan_masks;
433 indio_dev->modes = INDIO_DIRECT_MODE;
434
435 ret = devm_iio_kfifo_buffer_setup(&client->dev, indio_dev,
436 &max30100_buffer_setup_ops);
437 if (ret)
438 return ret;
439
440 data = iio_priv(indio_dev);
441 data->indio_dev = indio_dev;
442 data->client = client;
443
444 mutex_init(&data->lock);
445 i2c_set_clientdata(client, indio_dev);
446
447 data->regmap = devm_regmap_init_i2c(client, &max30100_regmap_config);
448 if (IS_ERR(data->regmap)) {
449 dev_err(&client->dev, "regmap initialization failed.\n");
450 return PTR_ERR(data->regmap);
451 }
452 max30100_set_powermode(data, false);
453
454 ret = max30100_chip_init(data);
455 if (ret)
456 return ret;
457
458 if (client->irq <= 0) {
459 dev_err(&client->dev, "no valid irq defined\n");
460 return -EINVAL;
461 }
462 ret = devm_request_threaded_irq(&client->dev, client->irq,
463 NULL, max30100_interrupt_handler,
464 IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
465 "max30100_irq", indio_dev);
466 if (ret) {
467 dev_err(&client->dev, "request irq (%d) failed\n", client->irq);
468 return ret;
469 }
470
471 return iio_device_register(indio_dev);
472 }
473
max30100_remove(struct i2c_client * client)474 static void max30100_remove(struct i2c_client *client)
475 {
476 struct iio_dev *indio_dev = i2c_get_clientdata(client);
477 struct max30100_data *data = iio_priv(indio_dev);
478
479 iio_device_unregister(indio_dev);
480 max30100_set_powermode(data, false);
481 }
482
483 static const struct i2c_device_id max30100_id[] = {
484 { "max30100" },
485 { }
486 };
487 MODULE_DEVICE_TABLE(i2c, max30100_id);
488
489 static const struct of_device_id max30100_dt_ids[] = {
490 { .compatible = "maxim,max30100" },
491 { }
492 };
493 MODULE_DEVICE_TABLE(of, max30100_dt_ids);
494
495 static struct i2c_driver max30100_driver = {
496 .driver = {
497 .name = MAX30100_DRV_NAME,
498 .of_match_table = max30100_dt_ids,
499 },
500 .probe = max30100_probe,
501 .remove = max30100_remove,
502 .id_table = max30100_id,
503 };
504 module_i2c_driver(max30100_driver);
505
506 MODULE_AUTHOR("Matt Ranostay <matt.ranostay@konsulko.com>");
507 MODULE_DESCRIPTION("MAX30100 heart rate and pulse oximeter sensor");
508 MODULE_LICENSE("GPL");
509