xref: /openbmc/linux/drivers/iio/health/afe4404.c (revision ae108c48)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * AFE4404 Heart Rate Monitors and Low-Cost Pulse Oximeters
4  *
5  * Copyright (C) 2015-2016 Texas Instruments Incorporated - https://www.ti.com/
6  *	Andrew F. Davis <afd@ti.com>
7  */
8 
9 #include <linux/device.h>
10 #include <linux/err.h>
11 #include <linux/interrupt.h>
12 #include <linux/i2c.h>
13 #include <linux/kernel.h>
14 #include <linux/module.h>
15 #include <linux/regmap.h>
16 #include <linux/sysfs.h>
17 #include <linux/regulator/consumer.h>
18 
19 #include <linux/iio/iio.h>
20 #include <linux/iio/sysfs.h>
21 #include <linux/iio/buffer.h>
22 #include <linux/iio/trigger.h>
23 #include <linux/iio/triggered_buffer.h>
24 #include <linux/iio/trigger_consumer.h>
25 
26 #include "afe440x.h"
27 
28 #define AFE4404_DRIVER_NAME		"afe4404"
29 
30 /* AFE4404 registers */
31 #define AFE4404_TIA_GAIN_SEP		0x20
32 #define AFE4404_TIA_GAIN		0x21
33 #define AFE4404_PROG_TG_STC		0x34
34 #define AFE4404_PROG_TG_ENDC		0x35
35 #define AFE4404_LED3LEDSTC		0x36
36 #define AFE4404_LED3LEDENDC		0x37
37 #define AFE4404_CLKDIV_PRF		0x39
38 #define AFE4404_OFFDAC			0x3a
39 #define AFE4404_DEC			0x3d
40 #define AFE4404_AVG_LED2_ALED2VAL	0x3f
41 #define AFE4404_AVG_LED1_ALED1VAL	0x40
42 
43 /* AFE4404 CONTROL2 register fields */
44 #define AFE440X_CONTROL2_OSC_ENABLE	BIT(9)
45 
46 enum afe4404_fields {
47 	/* Gains */
48 	F_TIA_GAIN_SEP, F_TIA_CF_SEP,
49 	F_TIA_GAIN, TIA_CF,
50 
51 	/* LED Current */
52 	F_ILED1, F_ILED2, F_ILED3,
53 
54 	/* Offset DAC */
55 	F_OFFDAC_AMB2, F_OFFDAC_LED1, F_OFFDAC_AMB1, F_OFFDAC_LED2,
56 
57 	/* sentinel */
58 	F_MAX_FIELDS
59 };
60 
61 static const struct reg_field afe4404_reg_fields[] = {
62 	/* Gains */
63 	[F_TIA_GAIN_SEP]	= REG_FIELD(AFE4404_TIA_GAIN_SEP, 0, 2),
64 	[F_TIA_CF_SEP]		= REG_FIELD(AFE4404_TIA_GAIN_SEP, 3, 5),
65 	[F_TIA_GAIN]		= REG_FIELD(AFE4404_TIA_GAIN, 0, 2),
66 	[TIA_CF]		= REG_FIELD(AFE4404_TIA_GAIN, 3, 5),
67 	/* LED Current */
68 	[F_ILED1]		= REG_FIELD(AFE440X_LEDCNTRL, 0, 5),
69 	[F_ILED2]		= REG_FIELD(AFE440X_LEDCNTRL, 6, 11),
70 	[F_ILED3]		= REG_FIELD(AFE440X_LEDCNTRL, 12, 17),
71 	/* Offset DAC */
72 	[F_OFFDAC_AMB2]		= REG_FIELD(AFE4404_OFFDAC, 0, 4),
73 	[F_OFFDAC_LED1]		= REG_FIELD(AFE4404_OFFDAC, 5, 9),
74 	[F_OFFDAC_AMB1]		= REG_FIELD(AFE4404_OFFDAC, 10, 14),
75 	[F_OFFDAC_LED2]		= REG_FIELD(AFE4404_OFFDAC, 15, 19),
76 };
77 
78 /**
79  * struct afe4404_data - AFE4404 device instance data
80  * @dev: Device structure
81  * @regmap: Register map of the device
82  * @fields: Register fields of the device
83  * @regulator: Pointer to the regulator for the IC
84  * @trig: IIO trigger for this device
85  * @irq: ADC_RDY line interrupt number
86  * @buffer: Used to construct a scan to push to the iio buffer.
87  */
88 struct afe4404_data {
89 	struct device *dev;
90 	struct regmap *regmap;
91 	struct regmap_field *fields[F_MAX_FIELDS];
92 	struct regulator *regulator;
93 	struct iio_trigger *trig;
94 	int irq;
95 	s32 buffer[10] __aligned(8);
96 };
97 
98 enum afe4404_chan_id {
99 	LED2 = 1,
100 	ALED2,
101 	LED1,
102 	ALED1,
103 	LED2_ALED2,
104 	LED1_ALED1,
105 };
106 
107 static const unsigned int afe4404_channel_values[] = {
108 	[LED2] = AFE440X_LED2VAL,
109 	[ALED2] = AFE440X_ALED2VAL,
110 	[LED1] = AFE440X_LED1VAL,
111 	[ALED1] = AFE440X_ALED1VAL,
112 	[LED2_ALED2] = AFE440X_LED2_ALED2VAL,
113 	[LED1_ALED1] = AFE440X_LED1_ALED1VAL,
114 };
115 
116 static const unsigned int afe4404_channel_leds[] = {
117 	[LED2] = F_ILED2,
118 	[ALED2] = F_ILED3,
119 	[LED1] = F_ILED1,
120 };
121 
122 static const unsigned int afe4404_channel_offdacs[] = {
123 	[LED2] = F_OFFDAC_LED2,
124 	[ALED2] = F_OFFDAC_AMB2,
125 	[LED1] = F_OFFDAC_LED1,
126 	[ALED1] = F_OFFDAC_AMB1,
127 };
128 
129 static const struct iio_chan_spec afe4404_channels[] = {
130 	/* ADC values */
131 	AFE440X_INTENSITY_CHAN(LED2, BIT(IIO_CHAN_INFO_OFFSET)),
132 	AFE440X_INTENSITY_CHAN(ALED2, BIT(IIO_CHAN_INFO_OFFSET)),
133 	AFE440X_INTENSITY_CHAN(LED1, BIT(IIO_CHAN_INFO_OFFSET)),
134 	AFE440X_INTENSITY_CHAN(ALED1, BIT(IIO_CHAN_INFO_OFFSET)),
135 	AFE440X_INTENSITY_CHAN(LED2_ALED2, 0),
136 	AFE440X_INTENSITY_CHAN(LED1_ALED1, 0),
137 	/* LED current */
138 	AFE440X_CURRENT_CHAN(LED2),
139 	AFE440X_CURRENT_CHAN(ALED2),
140 	AFE440X_CURRENT_CHAN(LED1),
141 };
142 
143 static const struct afe440x_val_table afe4404_res_table[] = {
144 	{ .integer = 500000, .fract = 0 },
145 	{ .integer = 250000, .fract = 0 },
146 	{ .integer = 100000, .fract = 0 },
147 	{ .integer = 50000, .fract = 0 },
148 	{ .integer = 25000, .fract = 0 },
149 	{ .integer = 10000, .fract = 0 },
150 	{ .integer = 1000000, .fract = 0 },
151 	{ .integer = 2000000, .fract = 0 },
152 };
153 AFE440X_TABLE_ATTR(in_intensity_resistance_available, afe4404_res_table);
154 
155 static const struct afe440x_val_table afe4404_cap_table[] = {
156 	{ .integer = 0, .fract = 5000 },
157 	{ .integer = 0, .fract = 2500 },
158 	{ .integer = 0, .fract = 10000 },
159 	{ .integer = 0, .fract = 7500 },
160 	{ .integer = 0, .fract = 20000 },
161 	{ .integer = 0, .fract = 17500 },
162 	{ .integer = 0, .fract = 25000 },
163 	{ .integer = 0, .fract = 22500 },
164 };
165 AFE440X_TABLE_ATTR(in_intensity_capacitance_available, afe4404_cap_table);
166 
167 static ssize_t afe440x_show_register(struct device *dev,
168 				     struct device_attribute *attr,
169 				     char *buf)
170 {
171 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
172 	struct afe4404_data *afe = iio_priv(indio_dev);
173 	struct afe440x_attr *afe440x_attr = to_afe440x_attr(attr);
174 	unsigned int reg_val;
175 	int vals[2];
176 	int ret;
177 
178 	ret = regmap_field_read(afe->fields[afe440x_attr->field], &reg_val);
179 	if (ret)
180 		return ret;
181 
182 	if (reg_val >= afe440x_attr->table_size)
183 		return -EINVAL;
184 
185 	vals[0] = afe440x_attr->val_table[reg_val].integer;
186 	vals[1] = afe440x_attr->val_table[reg_val].fract;
187 
188 	return iio_format_value(buf, IIO_VAL_INT_PLUS_MICRO, 2, vals);
189 }
190 
191 static ssize_t afe440x_store_register(struct device *dev,
192 				      struct device_attribute *attr,
193 				      const char *buf, size_t count)
194 {
195 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
196 	struct afe4404_data *afe = iio_priv(indio_dev);
197 	struct afe440x_attr *afe440x_attr = to_afe440x_attr(attr);
198 	int val, integer, fract, ret;
199 
200 	ret = iio_str_to_fixpoint(buf, 100000, &integer, &fract);
201 	if (ret)
202 		return ret;
203 
204 	for (val = 0; val < afe440x_attr->table_size; val++)
205 		if (afe440x_attr->val_table[val].integer == integer &&
206 		    afe440x_attr->val_table[val].fract == fract)
207 			break;
208 	if (val == afe440x_attr->table_size)
209 		return -EINVAL;
210 
211 	ret = regmap_field_write(afe->fields[afe440x_attr->field], val);
212 	if (ret)
213 		return ret;
214 
215 	return count;
216 }
217 
218 static AFE440X_ATTR(in_intensity1_resistance, F_TIA_GAIN_SEP, afe4404_res_table);
219 static AFE440X_ATTR(in_intensity1_capacitance, F_TIA_CF_SEP, afe4404_cap_table);
220 
221 static AFE440X_ATTR(in_intensity2_resistance, F_TIA_GAIN_SEP, afe4404_res_table);
222 static AFE440X_ATTR(in_intensity2_capacitance, F_TIA_CF_SEP, afe4404_cap_table);
223 
224 static AFE440X_ATTR(in_intensity3_resistance, F_TIA_GAIN, afe4404_res_table);
225 static AFE440X_ATTR(in_intensity3_capacitance, TIA_CF, afe4404_cap_table);
226 
227 static AFE440X_ATTR(in_intensity4_resistance, F_TIA_GAIN, afe4404_res_table);
228 static AFE440X_ATTR(in_intensity4_capacitance, TIA_CF, afe4404_cap_table);
229 
230 static struct attribute *afe440x_attributes[] = {
231 	&dev_attr_in_intensity_resistance_available.attr,
232 	&dev_attr_in_intensity_capacitance_available.attr,
233 	&afe440x_attr_in_intensity1_resistance.dev_attr.attr,
234 	&afe440x_attr_in_intensity1_capacitance.dev_attr.attr,
235 	&afe440x_attr_in_intensity2_resistance.dev_attr.attr,
236 	&afe440x_attr_in_intensity2_capacitance.dev_attr.attr,
237 	&afe440x_attr_in_intensity3_resistance.dev_attr.attr,
238 	&afe440x_attr_in_intensity3_capacitance.dev_attr.attr,
239 	&afe440x_attr_in_intensity4_resistance.dev_attr.attr,
240 	&afe440x_attr_in_intensity4_capacitance.dev_attr.attr,
241 	NULL
242 };
243 
244 static const struct attribute_group afe440x_attribute_group = {
245 	.attrs = afe440x_attributes
246 };
247 
248 static int afe4404_read_raw(struct iio_dev *indio_dev,
249 			    struct iio_chan_spec const *chan,
250 			    int *val, int *val2, long mask)
251 {
252 	struct afe4404_data *afe = iio_priv(indio_dev);
253 	unsigned int value_reg = afe4404_channel_values[chan->address];
254 	unsigned int led_field = afe4404_channel_leds[chan->address];
255 	unsigned int offdac_field = afe4404_channel_offdacs[chan->address];
256 	int ret;
257 
258 	switch (chan->type) {
259 	case IIO_INTENSITY:
260 		switch (mask) {
261 		case IIO_CHAN_INFO_RAW:
262 			ret = regmap_read(afe->regmap, value_reg, val);
263 			if (ret)
264 				return ret;
265 			return IIO_VAL_INT;
266 		case IIO_CHAN_INFO_OFFSET:
267 			ret = regmap_field_read(afe->fields[offdac_field], val);
268 			if (ret)
269 				return ret;
270 			return IIO_VAL_INT;
271 		}
272 		break;
273 	case IIO_CURRENT:
274 		switch (mask) {
275 		case IIO_CHAN_INFO_RAW:
276 			ret = regmap_field_read(afe->fields[led_field], val);
277 			if (ret)
278 				return ret;
279 			return IIO_VAL_INT;
280 		case IIO_CHAN_INFO_SCALE:
281 			*val = 0;
282 			*val2 = 800000;
283 			return IIO_VAL_INT_PLUS_MICRO;
284 		}
285 		break;
286 	default:
287 		break;
288 	}
289 
290 	return -EINVAL;
291 }
292 
293 static int afe4404_write_raw(struct iio_dev *indio_dev,
294 			     struct iio_chan_spec const *chan,
295 			     int val, int val2, long mask)
296 {
297 	struct afe4404_data *afe = iio_priv(indio_dev);
298 	unsigned int led_field = afe4404_channel_leds[chan->address];
299 	unsigned int offdac_field = afe4404_channel_offdacs[chan->address];
300 
301 	switch (chan->type) {
302 	case IIO_INTENSITY:
303 		switch (mask) {
304 		case IIO_CHAN_INFO_OFFSET:
305 			return regmap_field_write(afe->fields[offdac_field], val);
306 		}
307 		break;
308 	case IIO_CURRENT:
309 		switch (mask) {
310 		case IIO_CHAN_INFO_RAW:
311 			return regmap_field_write(afe->fields[led_field], val);
312 		}
313 		break;
314 	default:
315 		break;
316 	}
317 
318 	return -EINVAL;
319 }
320 
321 static const struct iio_info afe4404_iio_info = {
322 	.attrs = &afe440x_attribute_group,
323 	.read_raw = afe4404_read_raw,
324 	.write_raw = afe4404_write_raw,
325 };
326 
327 static irqreturn_t afe4404_trigger_handler(int irq, void *private)
328 {
329 	struct iio_poll_func *pf = private;
330 	struct iio_dev *indio_dev = pf->indio_dev;
331 	struct afe4404_data *afe = iio_priv(indio_dev);
332 	int ret, bit, i = 0;
333 
334 	for_each_set_bit(bit, indio_dev->active_scan_mask,
335 			 indio_dev->masklength) {
336 		ret = regmap_read(afe->regmap, afe4404_channel_values[bit],
337 				  &afe->buffer[i++]);
338 		if (ret)
339 			goto err;
340 	}
341 
342 	iio_push_to_buffers_with_timestamp(indio_dev, afe->buffer,
343 					   pf->timestamp);
344 err:
345 	iio_trigger_notify_done(indio_dev->trig);
346 
347 	return IRQ_HANDLED;
348 }
349 
350 /* Default timings from data-sheet */
351 #define AFE4404_TIMING_PAIRS			\
352 	{ AFE440X_PRPCOUNT,	39999	},	\
353 	{ AFE440X_LED2LEDSTC,	0	},	\
354 	{ AFE440X_LED2LEDENDC,	398	},	\
355 	{ AFE440X_LED2STC,	80	},	\
356 	{ AFE440X_LED2ENDC,	398	},	\
357 	{ AFE440X_ADCRSTSTCT0,	5600	},	\
358 	{ AFE440X_ADCRSTENDCT0,	5606	},	\
359 	{ AFE440X_LED2CONVST,	5607	},	\
360 	{ AFE440X_LED2CONVEND,	6066	},	\
361 	{ AFE4404_LED3LEDSTC,	400	},	\
362 	{ AFE4404_LED3LEDENDC,	798	},	\
363 	{ AFE440X_ALED2STC,	480	},	\
364 	{ AFE440X_ALED2ENDC,	798	},	\
365 	{ AFE440X_ADCRSTSTCT1,	6068	},	\
366 	{ AFE440X_ADCRSTENDCT1,	6074	},	\
367 	{ AFE440X_ALED2CONVST,	6075	},	\
368 	{ AFE440X_ALED2CONVEND,	6534	},	\
369 	{ AFE440X_LED1LEDSTC,	800	},	\
370 	{ AFE440X_LED1LEDENDC,	1198	},	\
371 	{ AFE440X_LED1STC,	880	},	\
372 	{ AFE440X_LED1ENDC,	1198	},	\
373 	{ AFE440X_ADCRSTSTCT2,	6536	},	\
374 	{ AFE440X_ADCRSTENDCT2,	6542	},	\
375 	{ AFE440X_LED1CONVST,	6543	},	\
376 	{ AFE440X_LED1CONVEND,	7003	},	\
377 	{ AFE440X_ALED1STC,	1280	},	\
378 	{ AFE440X_ALED1ENDC,	1598	},	\
379 	{ AFE440X_ADCRSTSTCT3,	7005	},	\
380 	{ AFE440X_ADCRSTENDCT3,	7011	},	\
381 	{ AFE440X_ALED1CONVST,	7012	},	\
382 	{ AFE440X_ALED1CONVEND,	7471	},	\
383 	{ AFE440X_PDNCYCLESTC,	7671	},	\
384 	{ AFE440X_PDNCYCLEENDC,	39199	}
385 
386 static const struct reg_sequence afe4404_reg_sequences[] = {
387 	AFE4404_TIMING_PAIRS,
388 	{ AFE440X_CONTROL1, AFE440X_CONTROL1_TIMEREN },
389 	{ AFE4404_TIA_GAIN_SEP, AFE440X_TIAGAIN_ENSEPGAIN },
390 	{ AFE440X_CONTROL2, AFE440X_CONTROL2_OSC_ENABLE	},
391 };
392 
393 static const struct regmap_range afe4404_yes_ranges[] = {
394 	regmap_reg_range(AFE440X_LED2VAL, AFE440X_LED1_ALED1VAL),
395 	regmap_reg_range(AFE4404_AVG_LED2_ALED2VAL, AFE4404_AVG_LED1_ALED1VAL),
396 };
397 
398 static const struct regmap_access_table afe4404_volatile_table = {
399 	.yes_ranges = afe4404_yes_ranges,
400 	.n_yes_ranges = ARRAY_SIZE(afe4404_yes_ranges),
401 };
402 
403 static const struct regmap_config afe4404_regmap_config = {
404 	.reg_bits = 8,
405 	.val_bits = 24,
406 
407 	.max_register = AFE4404_AVG_LED1_ALED1VAL,
408 	.cache_type = REGCACHE_RBTREE,
409 	.volatile_table = &afe4404_volatile_table,
410 };
411 
412 static const struct of_device_id afe4404_of_match[] = {
413 	{ .compatible = "ti,afe4404", },
414 	{ /* sentinel */ }
415 };
416 MODULE_DEVICE_TABLE(of, afe4404_of_match);
417 
418 static int afe4404_suspend(struct device *dev)
419 {
420 	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
421 	struct afe4404_data *afe = iio_priv(indio_dev);
422 	int ret;
423 
424 	ret = regmap_update_bits(afe->regmap, AFE440X_CONTROL2,
425 				 AFE440X_CONTROL2_PDN_AFE,
426 				 AFE440X_CONTROL2_PDN_AFE);
427 	if (ret)
428 		return ret;
429 
430 	ret = regulator_disable(afe->regulator);
431 	if (ret) {
432 		dev_err(dev, "Unable to disable regulator\n");
433 		return ret;
434 	}
435 
436 	return 0;
437 }
438 
439 static int afe4404_resume(struct device *dev)
440 {
441 	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
442 	struct afe4404_data *afe = iio_priv(indio_dev);
443 	int ret;
444 
445 	ret = regulator_enable(afe->regulator);
446 	if (ret) {
447 		dev_err(dev, "Unable to enable regulator\n");
448 		return ret;
449 	}
450 
451 	ret = regmap_update_bits(afe->regmap, AFE440X_CONTROL2,
452 				 AFE440X_CONTROL2_PDN_AFE, 0);
453 	if (ret)
454 		return ret;
455 
456 	return 0;
457 }
458 
459 static DEFINE_SIMPLE_DEV_PM_OPS(afe4404_pm_ops, afe4404_suspend,
460 				afe4404_resume);
461 
462 static int afe4404_probe(struct i2c_client *client,
463 			 const struct i2c_device_id *id)
464 {
465 	struct iio_dev *indio_dev;
466 	struct afe4404_data *afe;
467 	int i, ret;
468 
469 	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*afe));
470 	if (!indio_dev)
471 		return -ENOMEM;
472 
473 	afe = iio_priv(indio_dev);
474 	i2c_set_clientdata(client, indio_dev);
475 
476 	afe->dev = &client->dev;
477 	afe->irq = client->irq;
478 
479 	afe->regmap = devm_regmap_init_i2c(client, &afe4404_regmap_config);
480 	if (IS_ERR(afe->regmap)) {
481 		dev_err(afe->dev, "Unable to allocate register map\n");
482 		return PTR_ERR(afe->regmap);
483 	}
484 
485 	for (i = 0; i < F_MAX_FIELDS; i++) {
486 		afe->fields[i] = devm_regmap_field_alloc(afe->dev, afe->regmap,
487 							 afe4404_reg_fields[i]);
488 		if (IS_ERR(afe->fields[i])) {
489 			dev_err(afe->dev, "Unable to allocate regmap fields\n");
490 			return PTR_ERR(afe->fields[i]);
491 		}
492 	}
493 
494 	afe->regulator = devm_regulator_get(afe->dev, "tx_sup");
495 	if (IS_ERR(afe->regulator))
496 		return dev_err_probe(afe->dev, PTR_ERR(afe->regulator),
497 				     "Unable to get regulator\n");
498 
499 	ret = regulator_enable(afe->regulator);
500 	if (ret) {
501 		dev_err(afe->dev, "Unable to enable regulator\n");
502 		return ret;
503 	}
504 
505 	ret = regmap_write(afe->regmap, AFE440X_CONTROL0,
506 			   AFE440X_CONTROL0_SW_RESET);
507 	if (ret) {
508 		dev_err(afe->dev, "Unable to reset device\n");
509 		goto disable_reg;
510 	}
511 
512 	ret = regmap_multi_reg_write(afe->regmap, afe4404_reg_sequences,
513 				     ARRAY_SIZE(afe4404_reg_sequences));
514 	if (ret) {
515 		dev_err(afe->dev, "Unable to set register defaults\n");
516 		goto disable_reg;
517 	}
518 
519 	indio_dev->modes = INDIO_DIRECT_MODE;
520 	indio_dev->channels = afe4404_channels;
521 	indio_dev->num_channels = ARRAY_SIZE(afe4404_channels);
522 	indio_dev->name = AFE4404_DRIVER_NAME;
523 	indio_dev->info = &afe4404_iio_info;
524 
525 	if (afe->irq > 0) {
526 		afe->trig = devm_iio_trigger_alloc(afe->dev,
527 						   "%s-dev%d",
528 						   indio_dev->name,
529 						   iio_device_id(indio_dev));
530 		if (!afe->trig) {
531 			dev_err(afe->dev, "Unable to allocate IIO trigger\n");
532 			ret = -ENOMEM;
533 			goto disable_reg;
534 		}
535 
536 		iio_trigger_set_drvdata(afe->trig, indio_dev);
537 
538 		ret = iio_trigger_register(afe->trig);
539 		if (ret) {
540 			dev_err(afe->dev, "Unable to register IIO trigger\n");
541 			goto disable_reg;
542 		}
543 
544 		ret = devm_request_threaded_irq(afe->dev, afe->irq,
545 						iio_trigger_generic_data_rdy_poll,
546 						NULL, IRQF_ONESHOT,
547 						AFE4404_DRIVER_NAME,
548 						afe->trig);
549 		if (ret) {
550 			dev_err(afe->dev, "Unable to request IRQ\n");
551 			goto disable_reg;
552 		}
553 	}
554 
555 	ret = iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time,
556 					 afe4404_trigger_handler, NULL);
557 	if (ret) {
558 		dev_err(afe->dev, "Unable to setup buffer\n");
559 		goto unregister_trigger;
560 	}
561 
562 	ret = iio_device_register(indio_dev);
563 	if (ret) {
564 		dev_err(afe->dev, "Unable to register IIO device\n");
565 		goto unregister_triggered_buffer;
566 	}
567 
568 	return 0;
569 
570 unregister_triggered_buffer:
571 	iio_triggered_buffer_cleanup(indio_dev);
572 unregister_trigger:
573 	if (afe->irq > 0)
574 		iio_trigger_unregister(afe->trig);
575 disable_reg:
576 	regulator_disable(afe->regulator);
577 
578 	return ret;
579 }
580 
581 static void afe4404_remove(struct i2c_client *client)
582 {
583 	struct iio_dev *indio_dev = i2c_get_clientdata(client);
584 	struct afe4404_data *afe = iio_priv(indio_dev);
585 	int ret;
586 
587 	iio_device_unregister(indio_dev);
588 
589 	iio_triggered_buffer_cleanup(indio_dev);
590 
591 	if (afe->irq > 0)
592 		iio_trigger_unregister(afe->trig);
593 
594 	ret = regulator_disable(afe->regulator);
595 	if (ret)
596 		dev_err(afe->dev, "Unable to disable regulator\n");
597 }
598 
599 static const struct i2c_device_id afe4404_ids[] = {
600 	{ "afe4404", 0 },
601 	{ /* sentinel */ }
602 };
603 MODULE_DEVICE_TABLE(i2c, afe4404_ids);
604 
605 static struct i2c_driver afe4404_i2c_driver = {
606 	.driver = {
607 		.name = AFE4404_DRIVER_NAME,
608 		.of_match_table = afe4404_of_match,
609 		.pm = pm_sleep_ptr(&afe4404_pm_ops),
610 	},
611 	.probe = afe4404_probe,
612 	.remove = afe4404_remove,
613 	.id_table = afe4404_ids,
614 };
615 module_i2c_driver(afe4404_i2c_driver);
616 
617 MODULE_AUTHOR("Andrew F. Davis <afd@ti.com>");
618 MODULE_DESCRIPTION("TI AFE4404 Heart Rate Monitor and Pulse Oximeter AFE");
619 MODULE_LICENSE("GPL v2");
620