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_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
70struct 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
79static 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
96static 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
108static 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
114static const unsigned long max30100_scan_masks[] = {0x3, 0};
115
116static 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
151static 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
158static 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
173static 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
185static 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
192static const struct iio_buffer_setup_ops max30100_buffer_setup_ops = {
193	.postenable = max30100_buffer_postenable,
194	.predisable = max30100_buffer_predisable,
195};
196
197static 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
213static 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
225static 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
247static 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
267static int max30100_led_init(struct max30100_data *data)
268{
269	struct device *dev = &data->client->dev;
270	unsigned int val[2];
271	int reg, ret;
272
273	ret = device_property_read_u32_array(dev, "maxim,led-current-microamp",
274					(unsigned int *) &val, 2);
275	if (ret) {
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");
281
282		return regmap_write(data->regmap, MAX30100_REG_LED_CONFIG, reg);
283	}
284
285	/* RED LED current */
286	ret = max30100_get_current_idx(val[0], &reg);
287	if (ret) {
288		dev_err(dev, "invalid RED current setting %d", val[0]);
289		return ret;
290	}
291
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);
296	if (ret)
297		return ret;
298
299	/* IR LED current */
300	ret = max30100_get_current_idx(val[1], &reg);
301	if (ret) {
302		dev_err(dev, "invalid IR current setting %d", val[1]);
303		return ret;
304	}
305
306	return regmap_update_bits(data->regmap, MAX30100_REG_LED_CONFIG,
307		MAX30100_REG_LED_CONFIG_LED_MASK, reg);
308}
309
310static int max30100_chip_init(struct max30100_data *data)
311{
312	int ret;
313
314	/* setup LED current settings */
315	ret = max30100_led_init(data);
316	if (ret)
317		return ret;
318
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);
323	if (ret)
324		return ret;
325
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);
331	if (ret)
332		return ret;
333
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);
339}
340
341static int max30100_read_temp(struct max30100_data *data, int *val)
342{
343	int ret;
344	unsigned int reg;
345
346	ret = regmap_read(data->regmap, MAX30100_REG_TEMP_INTEGER, &reg);
347	if (ret < 0)
348		return ret;
349	*val = reg << 4;
350
351	ret = regmap_read(data->regmap, MAX30100_REG_TEMP_FRACTION, &reg);
352	if (ret < 0)
353		return ret;
354
355	*val |= reg & 0xf;
356	*val = sign_extend32(*val, 11);
357
358	return 0;
359}
360
361static int max30100_get_temp(struct max30100_data *data, int *val)
362{
363	int ret;
364
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);
369	if (ret)
370		return ret;
371
372	msleep(35);
373
374	return max30100_read_temp(data, val);
375}
376
377static int max30100_read_raw(struct iio_dev *indio_dev,
378			     struct iio_chan_spec const *chan,
379			     int *val, int *val2, long mask)
380{
381	struct max30100_data *data = iio_priv(indio_dev);
382	int ret = -EINVAL;
383
384	switch (mask) {
385	case IIO_CHAN_INFO_RAW:
386		/*
387		 * Temperature reading can only be acquired while engine
388		 * is running
389		 */
390		mutex_lock(&indio_dev->mlock);
391
392		if (!iio_buffer_enabled(indio_dev))
393			ret = -EAGAIN;
394		else {
395			ret = max30100_get_temp(data, val);
396			if (!ret)
397				ret = IIO_VAL_INT;
398
399		}
400
401		mutex_unlock(&indio_dev->mlock);
402		break;
403	case IIO_CHAN_INFO_SCALE:
404		*val = 1;  /* 0.0625 */
405		*val2 = 16;
406		ret = IIO_VAL_FRACTIONAL;
407		break;
408	}
409
410	return ret;
411}
412
413static const struct iio_info max30100_info = {
414	.read_raw = max30100_read_raw,
415};
416
417static int max30100_probe(struct i2c_client *client,
418			  const struct i2c_device_id *id)
419{
420	struct max30100_data *data;
421	struct iio_buffer *buffer;
422	struct iio_dev *indio_dev;
423	int ret;
424
425	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
426	if (!indio_dev)
427		return -ENOMEM;
428
429	buffer = devm_iio_kfifo_allocate(&client->dev);
430	if (!buffer)
431		return -ENOMEM;
432
433	iio_device_attach_buffer(indio_dev, buffer);
434
435	indio_dev->name = MAX30100_DRV_NAME;
436	indio_dev->channels = max30100_channels;
437	indio_dev->info = &max30100_info;
438	indio_dev->num_channels = ARRAY_SIZE(max30100_channels);
439	indio_dev->available_scan_masks = max30100_scan_masks;
440	indio_dev->modes = (INDIO_BUFFER_SOFTWARE | INDIO_DIRECT_MODE);
441	indio_dev->setup_ops = &max30100_buffer_setup_ops;
442
443	data = iio_priv(indio_dev);
444	data->indio_dev = indio_dev;
445	data->client = client;
446
447	mutex_init(&data->lock);
448	i2c_set_clientdata(client, indio_dev);
449
450	data->regmap = devm_regmap_init_i2c(client, &max30100_regmap_config);
451	if (IS_ERR(data->regmap)) {
452		dev_err(&client->dev, "regmap initialization failed.\n");
453		return PTR_ERR(data->regmap);
454	}
455	max30100_set_powermode(data, false);
456
457	ret = max30100_chip_init(data);
458	if (ret)
459		return ret;
460
461	if (client->irq <= 0) {
462		dev_err(&client->dev, "no valid irq defined\n");
463		return -EINVAL;
464	}
465	ret = devm_request_threaded_irq(&client->dev, client->irq,
466					NULL, max30100_interrupt_handler,
467					IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
468					"max30100_irq", indio_dev);
469	if (ret) {
470		dev_err(&client->dev, "request irq (%d) failed\n", client->irq);
471		return ret;
472	}
473
474	return iio_device_register(indio_dev);
475}
476
477static int max30100_remove(struct i2c_client *client)
478{
479	struct iio_dev *indio_dev = i2c_get_clientdata(client);
480	struct max30100_data *data = iio_priv(indio_dev);
481
482	iio_device_unregister(indio_dev);
483	max30100_set_powermode(data, false);
484
485	return 0;
486}
487
488static const struct i2c_device_id max30100_id[] = {
489	{ "max30100", 0 },
490	{}
491};
492MODULE_DEVICE_TABLE(i2c, max30100_id);
493
494static const struct of_device_id max30100_dt_ids[] = {
495	{ .compatible = "maxim,max30100" },
496	{ }
497};
498MODULE_DEVICE_TABLE(of, max30100_dt_ids);
499
500static struct i2c_driver max30100_driver = {
501	.driver = {
502		.name	= MAX30100_DRV_NAME,
503		.of_match_table	= max30100_dt_ids,
504	},
505	.probe		= max30100_probe,
506	.remove		= max30100_remove,
507	.id_table	= max30100_id,
508};
509module_i2c_driver(max30100_driver);
510
511MODULE_AUTHOR("Matt Ranostay <matt.ranostay@konsulko.com>");
512MODULE_DESCRIPTION("MAX30100 heart rate and pulse oximeter sensor");
513MODULE_LICENSE("GPL");
514