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4d33615d MR |
1 | /* |
2 | * max30100.c - Support for MAX30100 heart rate and pulse oximeter sensor | |
3 | * | |
4 | * Copyright (C) 2015 Matt Ranostay <mranostay@gmail.com> | |
5 | * | |
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. | |
10 | * | |
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. | |
15 | * | |
b11a3460 | 16 | * TODO: enable pulse length controls via device tree properties |
4d33615d MR |
17 | */ |
18 | ||
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> | |
b11a3460 | 27 | #include <linux/of.h> |
4d33615d MR |
28 | #include <linux/regmap.h> |
29 | #include <linux/iio/iio.h> | |
30 | #include <linux/iio/buffer.h> | |
31 | #include <linux/iio/kfifo_buf.h> | |
32 | ||
33 | #define MAX30100_REGMAP_NAME "max30100_regmap" | |
34 | #define MAX30100_DRV_NAME "max30100" | |
35 | ||
36 | #define MAX30100_REG_INT_STATUS 0x00 | |
37 | #define MAX30100_REG_INT_STATUS_PWR_RDY BIT(0) | |
38 | #define MAX30100_REG_INT_STATUS_SPO2_RDY BIT(4) | |
39 | #define MAX30100_REG_INT_STATUS_HR_RDY BIT(5) | |
40 | #define MAX30100_REG_INT_STATUS_FIFO_RDY BIT(7) | |
41 | ||
42 | #define MAX30100_REG_INT_ENABLE 0x01 | |
43 | #define MAX30100_REG_INT_ENABLE_SPO2_EN BIT(0) | |
44 | #define MAX30100_REG_INT_ENABLE_HR_EN BIT(1) | |
45 | #define MAX30100_REG_INT_ENABLE_FIFO_EN BIT(3) | |
46 | #define MAX30100_REG_INT_ENABLE_MASK 0xf0 | |
47 | #define MAX30100_REG_INT_ENABLE_MASK_SHIFT 4 | |
48 | ||
49 | #define MAX30100_REG_FIFO_WR_PTR 0x02 | |
50 | #define MAX30100_REG_FIFO_OVR_CTR 0x03 | |
51 | #define MAX30100_REG_FIFO_RD_PTR 0x04 | |
52 | #define MAX30100_REG_FIFO_DATA 0x05 | |
53 | #define MAX30100_REG_FIFO_DATA_ENTRY_COUNT 16 | |
54 | #define MAX30100_REG_FIFO_DATA_ENTRY_LEN 4 | |
55 | ||
56 | #define MAX30100_REG_MODE_CONFIG 0x06 | |
57 | #define MAX30100_REG_MODE_CONFIG_MODE_SPO2_EN BIT(0) | |
58 | #define MAX30100_REG_MODE_CONFIG_MODE_HR_EN BIT(1) | |
59 | #define MAX30100_REG_MODE_CONFIG_MODE_MASK 0x03 | |
60 | #define MAX30100_REG_MODE_CONFIG_TEMP_EN BIT(3) | |
61 | #define MAX30100_REG_MODE_CONFIG_PWR BIT(7) | |
62 | ||
63 | #define MAX30100_REG_SPO2_CONFIG 0x07 | |
64 | #define MAX30100_REG_SPO2_CONFIG_100HZ BIT(2) | |
65 | #define MAX30100_REG_SPO2_CONFIG_HI_RES_EN BIT(6) | |
66 | #define MAX30100_REG_SPO2_CONFIG_1600US 0x3 | |
67 | ||
68 | #define MAX30100_REG_LED_CONFIG 0x09 | |
b11a3460 | 69 | #define MAX30100_REG_LED_CONFIG_LED_MASK 0x0f |
4d33615d MR |
70 | #define MAX30100_REG_LED_CONFIG_RED_LED_SHIFT 4 |
71 | ||
72 | #define MAX30100_REG_LED_CONFIG_24MA 0x07 | |
73 | #define MAX30100_REG_LED_CONFIG_50MA 0x0f | |
74 | ||
75 | #define MAX30100_REG_TEMP_INTEGER 0x16 | |
76 | #define MAX30100_REG_TEMP_FRACTION 0x17 | |
77 | ||
78 | struct max30100_data { | |
79 | struct i2c_client *client; | |
80 | struct iio_dev *indio_dev; | |
81 | struct mutex lock; | |
82 | struct regmap *regmap; | |
83 | ||
84 | __be16 buffer[2]; /* 2 16-bit channels */ | |
85 | }; | |
86 | ||
87 | static bool max30100_is_volatile_reg(struct device *dev, unsigned int reg) | |
88 | { | |
89 | switch (reg) { | |
90 | case MAX30100_REG_INT_STATUS: | |
91 | case MAX30100_REG_MODE_CONFIG: | |
92 | case MAX30100_REG_FIFO_WR_PTR: | |
93 | case MAX30100_REG_FIFO_OVR_CTR: | |
94 | case MAX30100_REG_FIFO_RD_PTR: | |
95 | case MAX30100_REG_FIFO_DATA: | |
96 | case MAX30100_REG_TEMP_INTEGER: | |
97 | case MAX30100_REG_TEMP_FRACTION: | |
98 | return true; | |
99 | default: | |
100 | return false; | |
101 | } | |
102 | } | |
103 | ||
104 | static const struct regmap_config max30100_regmap_config = { | |
105 | .name = MAX30100_REGMAP_NAME, | |
106 | ||
107 | .reg_bits = 8, | |
108 | .val_bits = 8, | |
109 | ||
110 | .max_register = MAX30100_REG_TEMP_FRACTION, | |
111 | .cache_type = REGCACHE_FLAT, | |
112 | ||
113 | .volatile_reg = max30100_is_volatile_reg, | |
114 | }; | |
115 | ||
b11a3460 MR |
116 | static const unsigned int max30100_led_current_mapping[] = { |
117 | 4400, 7600, 11000, 14200, 17400, | |
118 | 20800, 24000, 27100, 30600, 33800, | |
119 | 37000, 40200, 43600, 46800, 50000 | |
120 | }; | |
121 | ||
4d33615d MR |
122 | static const unsigned long max30100_scan_masks[] = {0x3, 0}; |
123 | ||
124 | static const struct iio_chan_spec max30100_channels[] = { | |
125 | { | |
126 | .type = IIO_INTENSITY, | |
127 | .channel2 = IIO_MOD_LIGHT_IR, | |
128 | .modified = 1, | |
129 | ||
130 | .scan_index = 0, | |
131 | .scan_type = { | |
132 | .sign = 'u', | |
133 | .realbits = 16, | |
134 | .storagebits = 16, | |
135 | .endianness = IIO_BE, | |
136 | }, | |
137 | }, | |
138 | { | |
139 | .type = IIO_INTENSITY, | |
140 | .channel2 = IIO_MOD_LIGHT_RED, | |
141 | .modified = 1, | |
142 | ||
143 | .scan_index = 1, | |
144 | .scan_type = { | |
145 | .sign = 'u', | |
146 | .realbits = 16, | |
147 | .storagebits = 16, | |
148 | .endianness = IIO_BE, | |
149 | }, | |
150 | }, | |
151 | { | |
152 | .type = IIO_TEMP, | |
153 | .info_mask_separate = | |
154 | BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE), | |
155 | .scan_index = -1, | |
156 | }, | |
157 | }; | |
158 | ||
159 | static int max30100_set_powermode(struct max30100_data *data, bool state) | |
160 | { | |
161 | return regmap_update_bits(data->regmap, MAX30100_REG_MODE_CONFIG, | |
162 | MAX30100_REG_MODE_CONFIG_PWR, | |
163 | state ? 0 : MAX30100_REG_MODE_CONFIG_PWR); | |
164 | } | |
165 | ||
166 | static int max30100_clear_fifo(struct max30100_data *data) | |
167 | { | |
168 | int ret; | |
169 | ||
170 | ret = regmap_write(data->regmap, MAX30100_REG_FIFO_WR_PTR, 0); | |
171 | if (ret) | |
172 | return ret; | |
173 | ||
174 | ret = regmap_write(data->regmap, MAX30100_REG_FIFO_OVR_CTR, 0); | |
175 | if (ret) | |
176 | return ret; | |
177 | ||
178 | return regmap_write(data->regmap, MAX30100_REG_FIFO_RD_PTR, 0); | |
179 | } | |
180 | ||
181 | static int max30100_buffer_postenable(struct iio_dev *indio_dev) | |
182 | { | |
183 | struct max30100_data *data = iio_priv(indio_dev); | |
184 | int ret; | |
185 | ||
186 | ret = max30100_set_powermode(data, true); | |
187 | if (ret) | |
188 | return ret; | |
189 | ||
190 | return max30100_clear_fifo(data); | |
191 | } | |
192 | ||
193 | static int max30100_buffer_predisable(struct iio_dev *indio_dev) | |
194 | { | |
195 | struct max30100_data *data = iio_priv(indio_dev); | |
196 | ||
197 | return max30100_set_powermode(data, false); | |
198 | } | |
199 | ||
200 | static const struct iio_buffer_setup_ops max30100_buffer_setup_ops = { | |
201 | .postenable = max30100_buffer_postenable, | |
202 | .predisable = max30100_buffer_predisable, | |
203 | }; | |
204 | ||
205 | static inline int max30100_fifo_count(struct max30100_data *data) | |
206 | { | |
207 | unsigned int val; | |
208 | int ret; | |
209 | ||
210 | ret = regmap_read(data->regmap, MAX30100_REG_INT_STATUS, &val); | |
211 | if (ret) | |
212 | return ret; | |
213 | ||
214 | /* FIFO is almost full */ | |
215 | if (val & MAX30100_REG_INT_STATUS_FIFO_RDY) | |
216 | return MAX30100_REG_FIFO_DATA_ENTRY_COUNT - 1; | |
217 | ||
218 | return 0; | |
219 | } | |
220 | ||
221 | static int max30100_read_measurement(struct max30100_data *data) | |
222 | { | |
223 | int ret; | |
224 | ||
225 | ret = i2c_smbus_read_i2c_block_data(data->client, | |
226 | MAX30100_REG_FIFO_DATA, | |
227 | MAX30100_REG_FIFO_DATA_ENTRY_LEN, | |
228 | (u8 *) &data->buffer); | |
229 | ||
230 | return (ret == MAX30100_REG_FIFO_DATA_ENTRY_LEN) ? 0 : ret; | |
231 | } | |
232 | ||
233 | static irqreturn_t max30100_interrupt_handler(int irq, void *private) | |
234 | { | |
235 | struct iio_dev *indio_dev = private; | |
236 | struct max30100_data *data = iio_priv(indio_dev); | |
237 | int ret, cnt = 0; | |
238 | ||
239 | mutex_lock(&data->lock); | |
240 | ||
828f84ee | 241 | while (cnt || (cnt = max30100_fifo_count(data)) > 0) { |
4d33615d MR |
242 | ret = max30100_read_measurement(data); |
243 | if (ret) | |
244 | break; | |
245 | ||
246 | iio_push_to_buffers(data->indio_dev, data->buffer); | |
b74fccad | 247 | cnt--; |
4d33615d MR |
248 | } |
249 | ||
250 | mutex_unlock(&data->lock); | |
251 | ||
252 | return IRQ_HANDLED; | |
253 | } | |
254 | ||
b11a3460 MR |
255 | static int max30100_get_current_idx(unsigned int val, int *reg) |
256 | { | |
257 | int idx; | |
258 | ||
259 | /* LED turned off */ | |
260 | if (val == 0) { | |
261 | *reg = 0; | |
262 | return 0; | |
263 | } | |
264 | ||
265 | for (idx = 0; idx < ARRAY_SIZE(max30100_led_current_mapping); idx++) { | |
266 | if (max30100_led_current_mapping[idx] == val) { | |
267 | *reg = idx + 1; | |
268 | return 0; | |
269 | } | |
270 | } | |
271 | ||
272 | return -EINVAL; | |
273 | } | |
274 | ||
275 | static int max30100_led_init(struct max30100_data *data) | |
276 | { | |
277 | struct device *dev = &data->client->dev; | |
278 | struct device_node *np = dev->of_node; | |
279 | unsigned int val[2]; | |
280 | int reg, ret; | |
281 | ||
282 | ret = of_property_read_u32_array(np, "maxim,led-current-microamp", | |
283 | (unsigned int *) &val, 2); | |
284 | if (ret) { | |
285 | /* Default to 24 mA RED LED, 50 mA IR LED */ | |
286 | reg = (MAX30100_REG_LED_CONFIG_24MA << | |
287 | MAX30100_REG_LED_CONFIG_RED_LED_SHIFT) | | |
288 | MAX30100_REG_LED_CONFIG_50MA; | |
289 | dev_warn(dev, "no led-current-microamp set"); | |
290 | ||
291 | return regmap_write(data->regmap, MAX30100_REG_LED_CONFIG, reg); | |
292 | } | |
293 | ||
294 | /* RED LED current */ | |
295 | ret = max30100_get_current_idx(val[0], ®); | |
296 | if (ret) { | |
297 | dev_err(dev, "invalid RED current setting %d", val[0]); | |
298 | return ret; | |
299 | } | |
300 | ||
301 | ret = regmap_update_bits(data->regmap, MAX30100_REG_LED_CONFIG, | |
302 | MAX30100_REG_LED_CONFIG_LED_MASK << | |
303 | MAX30100_REG_LED_CONFIG_RED_LED_SHIFT, | |
304 | reg << MAX30100_REG_LED_CONFIG_RED_LED_SHIFT); | |
305 | if (ret) | |
306 | return ret; | |
307 | ||
308 | /* IR LED current */ | |
309 | ret = max30100_get_current_idx(val[1], ®); | |
310 | if (ret) { | |
311 | dev_err(dev, "invalid IR current setting %d", val[1]); | |
312 | return ret; | |
313 | } | |
314 | ||
315 | return regmap_update_bits(data->regmap, MAX30100_REG_LED_CONFIG, | |
316 | MAX30100_REG_LED_CONFIG_LED_MASK, reg); | |
317 | } | |
318 | ||
4d33615d MR |
319 | static int max30100_chip_init(struct max30100_data *data) |
320 | { | |
321 | int ret; | |
322 | ||
b11a3460 MR |
323 | /* setup LED current settings */ |
324 | ret = max30100_led_init(data); | |
4d33615d MR |
325 | if (ret) |
326 | return ret; | |
327 | ||
328 | /* enable hi-res SPO2 readings at 100Hz */ | |
329 | ret = regmap_write(data->regmap, MAX30100_REG_SPO2_CONFIG, | |
330 | MAX30100_REG_SPO2_CONFIG_HI_RES_EN | | |
331 | MAX30100_REG_SPO2_CONFIG_100HZ); | |
332 | if (ret) | |
333 | return ret; | |
334 | ||
335 | /* enable SPO2 mode */ | |
336 | ret = regmap_update_bits(data->regmap, MAX30100_REG_MODE_CONFIG, | |
337 | MAX30100_REG_MODE_CONFIG_MODE_MASK, | |
338 | MAX30100_REG_MODE_CONFIG_MODE_HR_EN | | |
339 | MAX30100_REG_MODE_CONFIG_MODE_SPO2_EN); | |
340 | if (ret) | |
341 | return ret; | |
342 | ||
343 | /* enable FIFO interrupt */ | |
344 | return regmap_update_bits(data->regmap, MAX30100_REG_INT_ENABLE, | |
345 | MAX30100_REG_INT_ENABLE_MASK, | |
346 | MAX30100_REG_INT_ENABLE_FIFO_EN | |
347 | << MAX30100_REG_INT_ENABLE_MASK_SHIFT); | |
348 | } | |
349 | ||
350 | static int max30100_read_temp(struct max30100_data *data, int *val) | |
351 | { | |
352 | int ret; | |
353 | unsigned int reg; | |
354 | ||
355 | ret = regmap_read(data->regmap, MAX30100_REG_TEMP_INTEGER, ®); | |
356 | if (ret < 0) | |
357 | return ret; | |
358 | *val = reg << 4; | |
359 | ||
360 | ret = regmap_read(data->regmap, MAX30100_REG_TEMP_FRACTION, ®); | |
361 | if (ret < 0) | |
362 | return ret; | |
363 | ||
364 | *val |= reg & 0xf; | |
365 | *val = sign_extend32(*val, 11); | |
366 | ||
367 | return 0; | |
368 | } | |
369 | ||
370 | static int max30100_get_temp(struct max30100_data *data, int *val) | |
371 | { | |
372 | int ret; | |
373 | ||
374 | /* start acquisition */ | |
375 | ret = regmap_update_bits(data->regmap, MAX30100_REG_MODE_CONFIG, | |
376 | MAX30100_REG_MODE_CONFIG_TEMP_EN, | |
377 | MAX30100_REG_MODE_CONFIG_TEMP_EN); | |
378 | if (ret) | |
379 | return ret; | |
380 | ||
18e2452a | 381 | msleep(35); |
4d33615d MR |
382 | |
383 | return max30100_read_temp(data, val); | |
384 | } | |
385 | ||
386 | static int max30100_read_raw(struct iio_dev *indio_dev, | |
387 | struct iio_chan_spec const *chan, | |
388 | int *val, int *val2, long mask) | |
389 | { | |
390 | struct max30100_data *data = iio_priv(indio_dev); | |
391 | int ret = -EINVAL; | |
392 | ||
393 | switch (mask) { | |
394 | case IIO_CHAN_INFO_RAW: | |
395 | /* | |
396 | * Temperature reading can only be acquired while engine | |
397 | * is running | |
398 | */ | |
399 | mutex_lock(&indio_dev->mlock); | |
400 | ||
401 | if (!iio_buffer_enabled(indio_dev)) | |
402 | ret = -EAGAIN; | |
403 | else { | |
404 | ret = max30100_get_temp(data, val); | |
405 | if (!ret) | |
406 | ret = IIO_VAL_INT; | |
407 | ||
408 | } | |
409 | ||
410 | mutex_unlock(&indio_dev->mlock); | |
411 | break; | |
412 | case IIO_CHAN_INFO_SCALE: | |
413 | *val = 1; /* 0.0625 */ | |
414 | *val2 = 16; | |
415 | ret = IIO_VAL_FRACTIONAL; | |
416 | break; | |
417 | } | |
418 | ||
419 | return ret; | |
420 | } | |
421 | ||
422 | static const struct iio_info max30100_info = { | |
423 | .driver_module = THIS_MODULE, | |
424 | .read_raw = max30100_read_raw, | |
425 | }; | |
426 | ||
427 | static int max30100_probe(struct i2c_client *client, | |
428 | const struct i2c_device_id *id) | |
429 | { | |
430 | struct max30100_data *data; | |
431 | struct iio_buffer *buffer; | |
432 | struct iio_dev *indio_dev; | |
433 | int ret; | |
434 | ||
435 | indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data)); | |
436 | if (!indio_dev) | |
437 | return -ENOMEM; | |
438 | ||
439 | buffer = devm_iio_kfifo_allocate(&client->dev); | |
440 | if (!buffer) | |
441 | return -ENOMEM; | |
442 | ||
443 | iio_device_attach_buffer(indio_dev, buffer); | |
444 | ||
445 | indio_dev->name = MAX30100_DRV_NAME; | |
446 | indio_dev->channels = max30100_channels; | |
447 | indio_dev->info = &max30100_info; | |
448 | indio_dev->num_channels = ARRAY_SIZE(max30100_channels); | |
449 | indio_dev->available_scan_masks = max30100_scan_masks; | |
450 | indio_dev->modes = (INDIO_BUFFER_SOFTWARE | INDIO_DIRECT_MODE); | |
451 | indio_dev->setup_ops = &max30100_buffer_setup_ops; | |
452 | ||
453 | data = iio_priv(indio_dev); | |
454 | data->indio_dev = indio_dev; | |
455 | data->client = client; | |
456 | ||
457 | mutex_init(&data->lock); | |
458 | i2c_set_clientdata(client, indio_dev); | |
459 | ||
460 | data->regmap = devm_regmap_init_i2c(client, &max30100_regmap_config); | |
461 | if (IS_ERR(data->regmap)) { | |
462 | dev_err(&client->dev, "regmap initialization failed.\n"); | |
463 | return PTR_ERR(data->regmap); | |
464 | } | |
465 | max30100_set_powermode(data, false); | |
466 | ||
467 | ret = max30100_chip_init(data); | |
468 | if (ret) | |
469 | return ret; | |
470 | ||
471 | if (client->irq <= 0) { | |
472 | dev_err(&client->dev, "no valid irq defined\n"); | |
473 | return -EINVAL; | |
474 | } | |
475 | ret = devm_request_threaded_irq(&client->dev, client->irq, | |
476 | NULL, max30100_interrupt_handler, | |
477 | IRQF_TRIGGER_FALLING | IRQF_ONESHOT, | |
478 | "max30100_irq", indio_dev); | |
479 | if (ret) { | |
480 | dev_err(&client->dev, "request irq (%d) failed\n", client->irq); | |
481 | return ret; | |
482 | } | |
483 | ||
484 | return iio_device_register(indio_dev); | |
485 | } | |
486 | ||
487 | static int max30100_remove(struct i2c_client *client) | |
488 | { | |
489 | struct iio_dev *indio_dev = i2c_get_clientdata(client); | |
490 | struct max30100_data *data = iio_priv(indio_dev); | |
491 | ||
492 | iio_device_unregister(indio_dev); | |
493 | max30100_set_powermode(data, false); | |
494 | ||
495 | return 0; | |
496 | } | |
497 | ||
498 | static const struct i2c_device_id max30100_id[] = { | |
499 | { "max30100", 0 }, | |
500 | {} | |
501 | }; | |
502 | MODULE_DEVICE_TABLE(i2c, max30100_id); | |
503 | ||
504 | static const struct of_device_id max30100_dt_ids[] = { | |
505 | { .compatible = "maxim,max30100" }, | |
506 | { } | |
507 | }; | |
508 | MODULE_DEVICE_TABLE(of, max30100_dt_ids); | |
509 | ||
510 | static struct i2c_driver max30100_driver = { | |
511 | .driver = { | |
512 | .name = MAX30100_DRV_NAME, | |
513 | .of_match_table = of_match_ptr(max30100_dt_ids), | |
514 | }, | |
515 | .probe = max30100_probe, | |
516 | .remove = max30100_remove, | |
517 | .id_table = max30100_id, | |
518 | }; | |
519 | module_i2c_driver(max30100_driver); | |
520 | ||
521 | MODULE_AUTHOR("Matt Ranostay <mranostay@gmail.com>"); | |
522 | MODULE_DESCRIPTION("MAX30100 heart rate and pulse oximeter sensor"); | |
523 | MODULE_LICENSE("GPL"); |