1 /*
2  * Driver for the Asahi Kasei EMD Corporation AK8974
3  * and Aichi Steel AMI305 magnetometer chips.
4  * Based on a patch from Samu Onkalo and the AK8975 IIO driver.
5  *
6  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
7  * Copyright (c) 2010 NVIDIA Corporation.
8  * Copyright (C) 2016 Linaro Ltd.
9  *
10  * Author: Samu Onkalo <samu.p.onkalo@nokia.com>
11  * Author: Linus Walleij <linus.walleij@linaro.org>
12  */
13 #include <linux/module.h>
14 #include <linux/kernel.h>
15 #include <linux/i2c.h>
16 #include <linux/interrupt.h>
17 #include <linux/irq.h> /* For irq_get_irq_data() */
18 #include <linux/completion.h>
19 #include <linux/err.h>
20 #include <linux/mutex.h>
21 #include <linux/delay.h>
22 #include <linux/bitops.h>
23 #include <linux/regmap.h>
24 #include <linux/regulator/consumer.h>
25 #include <linux/pm_runtime.h>
26 
27 #include <linux/iio/iio.h>
28 #include <linux/iio/sysfs.h>
29 #include <linux/iio/buffer.h>
30 #include <linux/iio/trigger.h>
31 #include <linux/iio/trigger_consumer.h>
32 #include <linux/iio/triggered_buffer.h>
33 
34 /*
35  * 16-bit registers are little-endian. LSB is at the address defined below
36  * and MSB is at the next higher address.
37  */
38 
39 /* These registers are common for AK8974 and AMI305 */
40 #define AK8974_SELFTEST		0x0C
41 #define AK8974_SELFTEST_IDLE	0x55
42 #define AK8974_SELFTEST_OK	0xAA
43 
44 #define AK8974_INFO		0x0D
45 
46 #define AK8974_WHOAMI		0x0F
47 #define AK8974_WHOAMI_VALUE_AMI305 0x47
48 #define AK8974_WHOAMI_VALUE_AK8974 0x48
49 
50 #define AK8974_DATA_X		0x10
51 #define AK8974_DATA_Y		0x12
52 #define AK8974_DATA_Z		0x14
53 #define AK8974_INT_SRC		0x16
54 #define AK8974_STATUS		0x18
55 #define AK8974_INT_CLEAR	0x1A
56 #define AK8974_CTRL1		0x1B
57 #define AK8974_CTRL2		0x1C
58 #define AK8974_CTRL3		0x1D
59 #define AK8974_INT_CTRL		0x1E
60 #define AK8974_INT_THRES	0x26  /* Absolute any axis value threshold */
61 #define AK8974_PRESET		0x30
62 
63 /* AK8974-specific offsets */
64 #define AK8974_OFFSET_X		0x20
65 #define AK8974_OFFSET_Y		0x22
66 #define AK8974_OFFSET_Z		0x24
67 /* AMI305-specific offsets */
68 #define AMI305_OFFSET_X		0x6C
69 #define AMI305_OFFSET_Y		0x72
70 #define AMI305_OFFSET_Z		0x78
71 
72 /* Different temperature registers */
73 #define AK8974_TEMP		0x31
74 #define AMI305_TEMP		0x60
75 
76 #define AK8974_INT_X_HIGH	BIT(7) /* Axis over +threshold  */
77 #define AK8974_INT_Y_HIGH	BIT(6)
78 #define AK8974_INT_Z_HIGH	BIT(5)
79 #define AK8974_INT_X_LOW	BIT(4) /* Axis below -threshold	*/
80 #define AK8974_INT_Y_LOW	BIT(3)
81 #define AK8974_INT_Z_LOW	BIT(2)
82 #define AK8974_INT_RANGE	BIT(1) /* Range overflow (any axis) */
83 
84 #define AK8974_STATUS_DRDY	BIT(6) /* Data ready */
85 #define AK8974_STATUS_OVERRUN	BIT(5) /* Data overrun */
86 #define AK8974_STATUS_INT	BIT(4) /* Interrupt occurred */
87 
88 #define AK8974_CTRL1_POWER	BIT(7) /* 0 = standby; 1 = active */
89 #define AK8974_CTRL1_RATE	BIT(4) /* 0 = 10 Hz; 1 = 20 Hz	 */
90 #define AK8974_CTRL1_FORCE_EN	BIT(1) /* 0 = normal; 1 = force	 */
91 #define AK8974_CTRL1_MODE2	BIT(0) /* 0 */
92 
93 #define AK8974_CTRL2_INT_EN	BIT(4)  /* 1 = enable interrupts	      */
94 #define AK8974_CTRL2_DRDY_EN	BIT(3)  /* 1 = enable data ready signal */
95 #define AK8974_CTRL2_DRDY_POL	BIT(2)  /* 1 = data ready active high   */
96 #define AK8974_CTRL2_RESDEF	(AK8974_CTRL2_DRDY_POL)
97 
98 #define AK8974_CTRL3_RESET	BIT(7) /* Software reset		  */
99 #define AK8974_CTRL3_FORCE	BIT(6) /* Start forced measurement */
100 #define AK8974_CTRL3_SELFTEST	BIT(4) /* Set selftest register	  */
101 #define AK8974_CTRL3_RESDEF	0x00
102 
103 #define AK8974_INT_CTRL_XEN	BIT(7) /* Enable interrupt for this axis */
104 #define AK8974_INT_CTRL_YEN	BIT(6)
105 #define AK8974_INT_CTRL_ZEN	BIT(5)
106 #define AK8974_INT_CTRL_XYZEN	(BIT(7)|BIT(6)|BIT(5))
107 #define AK8974_INT_CTRL_POL	BIT(3) /* 0 = active low; 1 = active high */
108 #define AK8974_INT_CTRL_PULSE	BIT(1) /* 0 = latched; 1 = pulse (50 usec) */
109 #define AK8974_INT_CTRL_RESDEF	(AK8974_INT_CTRL_XYZEN | AK8974_INT_CTRL_POL)
110 
111 /* The AMI305 has elaborate FW version and serial number registers */
112 #define AMI305_VER		0xE8
113 #define AMI305_SN		0xEA
114 
115 #define AK8974_MAX_RANGE	2048
116 
117 #define AK8974_POWERON_DELAY	50
118 #define AK8974_ACTIVATE_DELAY	1
119 #define AK8974_SELFTEST_DELAY	1
120 /*
121  * Set the autosuspend to two orders of magnitude larger than the poweron
122  * delay to make sane reasonable power tradeoff savings (5 seconds in
123  * this case).
124  */
125 #define AK8974_AUTOSUSPEND_DELAY 5000
126 
127 #define AK8974_MEASTIME		3
128 
129 #define AK8974_PWR_ON		1
130 #define AK8974_PWR_OFF		0
131 
132 /**
133  * struct ak8974 - state container for the AK8974 driver
134  * @i2c: parent I2C client
135  * @orientation: mounting matrix, flipped axis etc
136  * @map: regmap to access the AK8974 registers over I2C
137  * @regs: the avdd and dvdd power regulators
138  * @name: the name of the part
139  * @variant: the whoami ID value (for selecting code paths)
140  * @lock: locks the magnetometer for exclusive use during a measurement
141  * @drdy_irq: uses the DRDY IRQ line
142  * @drdy_complete: completion for DRDY
143  * @drdy_active_low: the DRDY IRQ is active low
144  */
145 struct ak8974 {
146 	struct i2c_client *i2c;
147 	struct iio_mount_matrix orientation;
148 	struct regmap *map;
149 	struct regulator_bulk_data regs[2];
150 	const char *name;
151 	u8 variant;
152 	struct mutex lock;
153 	bool drdy_irq;
154 	struct completion drdy_complete;
155 	bool drdy_active_low;
156 };
157 
158 static const char ak8974_reg_avdd[] = "avdd";
159 static const char ak8974_reg_dvdd[] = "dvdd";
160 
161 static int ak8974_set_power(struct ak8974 *ak8974, bool mode)
162 {
163 	int ret;
164 	u8 val;
165 
166 	val = mode ? AK8974_CTRL1_POWER : 0;
167 	val |= AK8974_CTRL1_FORCE_EN;
168 	ret = regmap_write(ak8974->map, AK8974_CTRL1, val);
169 	if (ret < 0)
170 		return ret;
171 
172 	if (mode)
173 		msleep(AK8974_ACTIVATE_DELAY);
174 
175 	return 0;
176 }
177 
178 static int ak8974_reset(struct ak8974 *ak8974)
179 {
180 	int ret;
181 
182 	/* Power on to get register access. Sets CTRL1 reg to reset state */
183 	ret = ak8974_set_power(ak8974, AK8974_PWR_ON);
184 	if (ret)
185 		return ret;
186 	ret = regmap_write(ak8974->map, AK8974_CTRL2, AK8974_CTRL2_RESDEF);
187 	if (ret)
188 		return ret;
189 	ret = regmap_write(ak8974->map, AK8974_CTRL3, AK8974_CTRL3_RESDEF);
190 	if (ret)
191 		return ret;
192 	ret = regmap_write(ak8974->map, AK8974_INT_CTRL,
193 			   AK8974_INT_CTRL_RESDEF);
194 	if (ret)
195 		return ret;
196 
197 	/* After reset, power off is default state */
198 	return ak8974_set_power(ak8974, AK8974_PWR_OFF);
199 }
200 
201 static int ak8974_configure(struct ak8974 *ak8974)
202 {
203 	int ret;
204 
205 	ret = regmap_write(ak8974->map, AK8974_CTRL2, AK8974_CTRL2_DRDY_EN |
206 			   AK8974_CTRL2_INT_EN);
207 	if (ret)
208 		return ret;
209 	ret = regmap_write(ak8974->map, AK8974_CTRL3, 0);
210 	if (ret)
211 		return ret;
212 	ret = regmap_write(ak8974->map, AK8974_INT_CTRL, AK8974_INT_CTRL_POL);
213 	if (ret)
214 		return ret;
215 
216 	return regmap_write(ak8974->map, AK8974_PRESET, 0);
217 }
218 
219 static int ak8974_trigmeas(struct ak8974 *ak8974)
220 {
221 	unsigned int clear;
222 	u8 mask;
223 	u8 val;
224 	int ret;
225 
226 	/* Clear any previous measurement overflow status */
227 	ret = regmap_read(ak8974->map, AK8974_INT_CLEAR, &clear);
228 	if (ret)
229 		return ret;
230 
231 	/* If we have a DRDY IRQ line, use it */
232 	if (ak8974->drdy_irq) {
233 		mask = AK8974_CTRL2_INT_EN |
234 			AK8974_CTRL2_DRDY_EN |
235 			AK8974_CTRL2_DRDY_POL;
236 		val = AK8974_CTRL2_DRDY_EN;
237 
238 		if (!ak8974->drdy_active_low)
239 			val |= AK8974_CTRL2_DRDY_POL;
240 
241 		init_completion(&ak8974->drdy_complete);
242 		ret = regmap_update_bits(ak8974->map, AK8974_CTRL2,
243 					 mask, val);
244 		if (ret)
245 			return ret;
246 	}
247 
248 	/* Force a measurement */
249 	return regmap_update_bits(ak8974->map,
250 				  AK8974_CTRL3,
251 				  AK8974_CTRL3_FORCE,
252 				  AK8974_CTRL3_FORCE);
253 }
254 
255 static int ak8974_await_drdy(struct ak8974 *ak8974)
256 {
257 	int timeout = 2;
258 	unsigned int val;
259 	int ret;
260 
261 	if (ak8974->drdy_irq) {
262 		ret = wait_for_completion_timeout(&ak8974->drdy_complete,
263 					1 + msecs_to_jiffies(1000));
264 		if (!ret) {
265 			dev_err(&ak8974->i2c->dev,
266 				"timeout waiting for DRDY IRQ\n");
267 			return -ETIMEDOUT;
268 		}
269 		return 0;
270 	}
271 
272 	/* Default delay-based poll loop */
273 	do {
274 		msleep(AK8974_MEASTIME);
275 		ret = regmap_read(ak8974->map, AK8974_STATUS, &val);
276 		if (ret < 0)
277 			return ret;
278 		if (val & AK8974_STATUS_DRDY)
279 			return 0;
280 	} while (--timeout);
281 
282 	dev_err(&ak8974->i2c->dev, "timeout waiting for DRDY\n");
283 	return -ETIMEDOUT;
284 }
285 
286 static int ak8974_getresult(struct ak8974 *ak8974, __le16 *result)
287 {
288 	unsigned int src;
289 	int ret;
290 
291 	ret = ak8974_await_drdy(ak8974);
292 	if (ret)
293 		return ret;
294 	ret = regmap_read(ak8974->map, AK8974_INT_SRC, &src);
295 	if (ret < 0)
296 		return ret;
297 
298 	/* Out of range overflow! Strong magnet close? */
299 	if (src & AK8974_INT_RANGE) {
300 		dev_err(&ak8974->i2c->dev,
301 			"range overflow in sensor\n");
302 		return -ERANGE;
303 	}
304 
305 	ret = regmap_bulk_read(ak8974->map, AK8974_DATA_X, result, 6);
306 	if (ret)
307 		return ret;
308 
309 	return ret;
310 }
311 
312 static irqreturn_t ak8974_drdy_irq(int irq, void *d)
313 {
314 	struct ak8974 *ak8974 = d;
315 
316 	if (!ak8974->drdy_irq)
317 		return IRQ_NONE;
318 
319 	/* TODO: timestamp here to get good measurement stamps */
320 	return IRQ_WAKE_THREAD;
321 }
322 
323 static irqreturn_t ak8974_drdy_irq_thread(int irq, void *d)
324 {
325 	struct ak8974 *ak8974 = d;
326 	unsigned int val;
327 	int ret;
328 
329 	/* Check if this was a DRDY from us */
330 	ret = regmap_read(ak8974->map, AK8974_STATUS, &val);
331 	if (ret < 0) {
332 		dev_err(&ak8974->i2c->dev, "error reading DRDY status\n");
333 		return IRQ_HANDLED;
334 	}
335 	if (val & AK8974_STATUS_DRDY) {
336 		/* Yes this was our IRQ */
337 		complete(&ak8974->drdy_complete);
338 		return IRQ_HANDLED;
339 	}
340 
341 	/* We may be on a shared IRQ, let the next client check */
342 	return IRQ_NONE;
343 }
344 
345 static int ak8974_selftest(struct ak8974 *ak8974)
346 {
347 	struct device *dev = &ak8974->i2c->dev;
348 	unsigned int val;
349 	int ret;
350 
351 	ret = regmap_read(ak8974->map, AK8974_SELFTEST, &val);
352 	if (ret)
353 		return ret;
354 	if (val != AK8974_SELFTEST_IDLE) {
355 		dev_err(dev, "selftest not idle before test\n");
356 		return -EIO;
357 	}
358 
359 	/* Trigger self-test */
360 	ret = regmap_update_bits(ak8974->map,
361 			AK8974_CTRL3,
362 			AK8974_CTRL3_SELFTEST,
363 			AK8974_CTRL3_SELFTEST);
364 	if (ret) {
365 		dev_err(dev, "could not write CTRL3\n");
366 		return ret;
367 	}
368 
369 	msleep(AK8974_SELFTEST_DELAY);
370 
371 	ret = regmap_read(ak8974->map, AK8974_SELFTEST, &val);
372 	if (ret)
373 		return ret;
374 	if (val != AK8974_SELFTEST_OK) {
375 		dev_err(dev, "selftest result NOT OK (%02x)\n", val);
376 		return -EIO;
377 	}
378 
379 	ret = regmap_read(ak8974->map, AK8974_SELFTEST, &val);
380 	if (ret)
381 		return ret;
382 	if (val != AK8974_SELFTEST_IDLE) {
383 		dev_err(dev, "selftest not idle after test (%02x)\n", val);
384 		return -EIO;
385 	}
386 	dev_dbg(dev, "passed self-test\n");
387 
388 	return 0;
389 }
390 
391 static int ak8974_get_u16_val(struct ak8974 *ak8974, u8 reg, u16 *val)
392 {
393 	int ret;
394 	__le16 bulk;
395 
396 	ret = regmap_bulk_read(ak8974->map, reg, &bulk, 2);
397 	if (ret)
398 		return ret;
399 	*val = le16_to_cpu(bulk);
400 
401 	return 0;
402 }
403 
404 static int ak8974_detect(struct ak8974 *ak8974)
405 {
406 	unsigned int whoami;
407 	const char *name;
408 	int ret;
409 	unsigned int fw;
410 	u16 sn;
411 
412 	ret = regmap_read(ak8974->map, AK8974_WHOAMI, &whoami);
413 	if (ret)
414 		return ret;
415 
416 	switch (whoami) {
417 	case AK8974_WHOAMI_VALUE_AMI305:
418 		name = "ami305";
419 		ret = regmap_read(ak8974->map, AMI305_VER, &fw);
420 		if (ret)
421 			return ret;
422 		fw &= 0x7f; /* only bits 0 thru 6 valid */
423 		ret = ak8974_get_u16_val(ak8974, AMI305_SN, &sn);
424 		if (ret)
425 			return ret;
426 		dev_info(&ak8974->i2c->dev,
427 			 "detected %s, FW ver %02x, S/N: %04x\n",
428 			 name, fw, sn);
429 		break;
430 	case AK8974_WHOAMI_VALUE_AK8974:
431 		name = "ak8974";
432 		dev_info(&ak8974->i2c->dev, "detected AK8974\n");
433 		break;
434 	default:
435 		dev_err(&ak8974->i2c->dev, "unsupported device (%02x) ",
436 			whoami);
437 		return -ENODEV;
438 	}
439 
440 	ak8974->name = name;
441 	ak8974->variant = whoami;
442 
443 	return 0;
444 }
445 
446 static int ak8974_read_raw(struct iio_dev *indio_dev,
447 			   struct iio_chan_spec const *chan,
448 			   int *val, int *val2,
449 			   long mask)
450 {
451 	struct ak8974 *ak8974 = iio_priv(indio_dev);
452 	__le16 hw_values[3];
453 	int ret = -EINVAL;
454 
455 	pm_runtime_get_sync(&ak8974->i2c->dev);
456 	mutex_lock(&ak8974->lock);
457 
458 	switch (mask) {
459 	case IIO_CHAN_INFO_RAW:
460 		if (chan->address > 2) {
461 			dev_err(&ak8974->i2c->dev, "faulty channel address\n");
462 			ret = -EIO;
463 			goto out_unlock;
464 		}
465 		ret = ak8974_trigmeas(ak8974);
466 		if (ret)
467 			goto out_unlock;
468 		ret = ak8974_getresult(ak8974, hw_values);
469 		if (ret)
470 			goto out_unlock;
471 
472 		/*
473 		 * We read all axes and discard all but one, for optimized
474 		 * reading, use the triggered buffer.
475 		 */
476 		*val = le16_to_cpu(hw_values[chan->address]);
477 
478 		ret = IIO_VAL_INT;
479 	}
480 
481  out_unlock:
482 	mutex_unlock(&ak8974->lock);
483 	pm_runtime_mark_last_busy(&ak8974->i2c->dev);
484 	pm_runtime_put_autosuspend(&ak8974->i2c->dev);
485 
486 	return ret;
487 }
488 
489 static void ak8974_fill_buffer(struct iio_dev *indio_dev)
490 {
491 	struct ak8974 *ak8974 = iio_priv(indio_dev);
492 	int ret;
493 	__le16 hw_values[8]; /* Three axes + 64bit padding */
494 
495 	pm_runtime_get_sync(&ak8974->i2c->dev);
496 	mutex_lock(&ak8974->lock);
497 
498 	ret = ak8974_trigmeas(ak8974);
499 	if (ret) {
500 		dev_err(&ak8974->i2c->dev, "error triggering measure\n");
501 		goto out_unlock;
502 	}
503 	ret = ak8974_getresult(ak8974, hw_values);
504 	if (ret) {
505 		dev_err(&ak8974->i2c->dev, "error getting measures\n");
506 		goto out_unlock;
507 	}
508 
509 	iio_push_to_buffers_with_timestamp(indio_dev, hw_values,
510 					   iio_get_time_ns(indio_dev));
511 
512  out_unlock:
513 	mutex_unlock(&ak8974->lock);
514 	pm_runtime_mark_last_busy(&ak8974->i2c->dev);
515 	pm_runtime_put_autosuspend(&ak8974->i2c->dev);
516 }
517 
518 static irqreturn_t ak8974_handle_trigger(int irq, void *p)
519 {
520 	const struct iio_poll_func *pf = p;
521 	struct iio_dev *indio_dev = pf->indio_dev;
522 
523 	ak8974_fill_buffer(indio_dev);
524 	iio_trigger_notify_done(indio_dev->trig);
525 
526 	return IRQ_HANDLED;
527 }
528 
529 static const struct iio_mount_matrix *
530 ak8974_get_mount_matrix(const struct iio_dev *indio_dev,
531 			const struct iio_chan_spec *chan)
532 {
533 	struct ak8974 *ak8974 = iio_priv(indio_dev);
534 
535 	return &ak8974->orientation;
536 }
537 
538 static const struct iio_chan_spec_ext_info ak8974_ext_info[] = {
539 	IIO_MOUNT_MATRIX(IIO_SHARED_BY_DIR, ak8974_get_mount_matrix),
540 	{ },
541 };
542 
543 #define AK8974_AXIS_CHANNEL(axis, index)				\
544 	{								\
545 		.type = IIO_MAGN,					\
546 		.modified = 1,						\
547 		.channel2 = IIO_MOD_##axis,				\
548 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),		\
549 		.ext_info = ak8974_ext_info,				\
550 		.address = index,					\
551 		.scan_index = index,					\
552 		.scan_type = {						\
553 			.sign = 's',					\
554 			.realbits = 16,					\
555 			.storagebits = 16,				\
556 			.endianness = IIO_LE				\
557 		},							\
558 	}
559 
560 static const struct iio_chan_spec ak8974_channels[] = {
561 	AK8974_AXIS_CHANNEL(X, 0),
562 	AK8974_AXIS_CHANNEL(Y, 1),
563 	AK8974_AXIS_CHANNEL(Z, 2),
564 	IIO_CHAN_SOFT_TIMESTAMP(3),
565 };
566 
567 static const unsigned long ak8974_scan_masks[] = { 0x7, 0 };
568 
569 static const struct iio_info ak8974_info = {
570 	.read_raw = &ak8974_read_raw,
571 	.driver_module = THIS_MODULE,
572 };
573 
574 static bool ak8974_writeable_reg(struct device *dev, unsigned int reg)
575 {
576 	struct i2c_client *i2c = to_i2c_client(dev);
577 	struct iio_dev *indio_dev = i2c_get_clientdata(i2c);
578 	struct ak8974 *ak8974 = iio_priv(indio_dev);
579 
580 	switch (reg) {
581 	case AK8974_CTRL1:
582 	case AK8974_CTRL2:
583 	case AK8974_CTRL3:
584 	case AK8974_INT_CTRL:
585 	case AK8974_INT_THRES:
586 	case AK8974_INT_THRES + 1:
587 	case AK8974_PRESET:
588 	case AK8974_PRESET + 1:
589 		return true;
590 	case AK8974_OFFSET_X:
591 	case AK8974_OFFSET_X + 1:
592 	case AK8974_OFFSET_Y:
593 	case AK8974_OFFSET_Y + 1:
594 	case AK8974_OFFSET_Z:
595 	case AK8974_OFFSET_Z + 1:
596 		if (ak8974->variant == AK8974_WHOAMI_VALUE_AK8974)
597 			return true;
598 		return false;
599 	case AMI305_OFFSET_X:
600 	case AMI305_OFFSET_X + 1:
601 	case AMI305_OFFSET_Y:
602 	case AMI305_OFFSET_Y + 1:
603 	case AMI305_OFFSET_Z:
604 	case AMI305_OFFSET_Z + 1:
605 		if (ak8974->variant == AK8974_WHOAMI_VALUE_AMI305)
606 			return true;
607 		return false;
608 	default:
609 		return false;
610 	}
611 }
612 
613 static const struct regmap_config ak8974_regmap_config = {
614 	.reg_bits = 8,
615 	.val_bits = 8,
616 	.max_register = 0xff,
617 	.writeable_reg = ak8974_writeable_reg,
618 };
619 
620 static int ak8974_probe(struct i2c_client *i2c,
621 			const struct i2c_device_id *id)
622 {
623 	struct iio_dev *indio_dev;
624 	struct ak8974 *ak8974;
625 	unsigned long irq_trig;
626 	int irq = i2c->irq;
627 	int ret;
628 
629 	/* Register with IIO */
630 	indio_dev = devm_iio_device_alloc(&i2c->dev, sizeof(*ak8974));
631 	if (indio_dev == NULL)
632 		return -ENOMEM;
633 
634 	ak8974 = iio_priv(indio_dev);
635 	i2c_set_clientdata(i2c, indio_dev);
636 	ak8974->i2c = i2c;
637 	mutex_init(&ak8974->lock);
638 
639 	ret = of_iio_read_mount_matrix(&i2c->dev,
640 				       "mount-matrix",
641 				       &ak8974->orientation);
642 	if (ret)
643 		return ret;
644 
645 	ak8974->regs[0].supply = ak8974_reg_avdd;
646 	ak8974->regs[1].supply = ak8974_reg_dvdd;
647 
648 	ret = devm_regulator_bulk_get(&i2c->dev,
649 				      ARRAY_SIZE(ak8974->regs),
650 				      ak8974->regs);
651 	if (ret < 0) {
652 		dev_err(&i2c->dev, "cannot get regulators\n");
653 		return ret;
654 	}
655 
656 	ret = regulator_bulk_enable(ARRAY_SIZE(ak8974->regs), ak8974->regs);
657 	if (ret < 0) {
658 		dev_err(&i2c->dev, "cannot enable regulators\n");
659 		return ret;
660 	}
661 
662 	/* Take runtime PM online */
663 	pm_runtime_get_noresume(&i2c->dev);
664 	pm_runtime_set_active(&i2c->dev);
665 	pm_runtime_enable(&i2c->dev);
666 
667 	ak8974->map = devm_regmap_init_i2c(i2c, &ak8974_regmap_config);
668 	if (IS_ERR(ak8974->map)) {
669 		dev_err(&i2c->dev, "failed to allocate register map\n");
670 		return PTR_ERR(ak8974->map);
671 	}
672 
673 	ret = ak8974_set_power(ak8974, AK8974_PWR_ON);
674 	if (ret) {
675 		dev_err(&i2c->dev, "could not power on\n");
676 		goto power_off;
677 	}
678 
679 	ret = ak8974_detect(ak8974);
680 	if (ret) {
681 		dev_err(&i2c->dev, "neither AK8974 nor AMI305 found\n");
682 		goto power_off;
683 	}
684 
685 	ret = ak8974_selftest(ak8974);
686 	if (ret)
687 		dev_err(&i2c->dev, "selftest failed (continuing anyway)\n");
688 
689 	ret = ak8974_reset(ak8974);
690 	if (ret) {
691 		dev_err(&i2c->dev, "AK8974 reset failed\n");
692 		goto power_off;
693 	}
694 
695 	pm_runtime_set_autosuspend_delay(&i2c->dev,
696 					 AK8974_AUTOSUSPEND_DELAY);
697 	pm_runtime_use_autosuspend(&i2c->dev);
698 	pm_runtime_put(&i2c->dev);
699 
700 	indio_dev->dev.parent = &i2c->dev;
701 	indio_dev->channels = ak8974_channels;
702 	indio_dev->num_channels = ARRAY_SIZE(ak8974_channels);
703 	indio_dev->info = &ak8974_info;
704 	indio_dev->available_scan_masks = ak8974_scan_masks;
705 	indio_dev->modes = INDIO_DIRECT_MODE;
706 	indio_dev->name = ak8974->name;
707 
708 	ret = iio_triggered_buffer_setup(indio_dev, NULL,
709 					 ak8974_handle_trigger,
710 					 NULL);
711 	if (ret) {
712 		dev_err(&i2c->dev, "triggered buffer setup failed\n");
713 		goto disable_pm;
714 	}
715 
716 	/* If we have a valid DRDY IRQ, make use of it */
717 	if (irq > 0) {
718 		irq_trig = irqd_get_trigger_type(irq_get_irq_data(irq));
719 		if (irq_trig == IRQF_TRIGGER_RISING) {
720 			dev_info(&i2c->dev, "enable rising edge DRDY IRQ\n");
721 		} else if (irq_trig == IRQF_TRIGGER_FALLING) {
722 			ak8974->drdy_active_low = true;
723 			dev_info(&i2c->dev, "enable falling edge DRDY IRQ\n");
724 		} else {
725 			irq_trig = IRQF_TRIGGER_RISING;
726 		}
727 		irq_trig |= IRQF_ONESHOT;
728 		irq_trig |= IRQF_SHARED;
729 
730 		ret = devm_request_threaded_irq(&i2c->dev,
731 						irq,
732 						ak8974_drdy_irq,
733 						ak8974_drdy_irq_thread,
734 						irq_trig,
735 						ak8974->name,
736 						ak8974);
737 		if (ret) {
738 			dev_err(&i2c->dev, "unable to request DRDY IRQ "
739 				"- proceeding without IRQ\n");
740 			goto no_irq;
741 		}
742 		ak8974->drdy_irq = true;
743 	}
744 
745 no_irq:
746 	ret = iio_device_register(indio_dev);
747 	if (ret) {
748 		dev_err(&i2c->dev, "device register failed\n");
749 		goto cleanup_buffer;
750 	}
751 
752 	return 0;
753 
754 cleanup_buffer:
755 	iio_triggered_buffer_cleanup(indio_dev);
756 disable_pm:
757 	pm_runtime_put_noidle(&i2c->dev);
758 	pm_runtime_disable(&i2c->dev);
759 	ak8974_set_power(ak8974, AK8974_PWR_OFF);
760 power_off:
761 	regulator_bulk_disable(ARRAY_SIZE(ak8974->regs), ak8974->regs);
762 
763 	return ret;
764 }
765 
766 static int ak8974_remove(struct i2c_client *i2c)
767 {
768 	struct iio_dev *indio_dev = i2c_get_clientdata(i2c);
769 	struct ak8974 *ak8974 = iio_priv(indio_dev);
770 
771 	iio_device_unregister(indio_dev);
772 	iio_triggered_buffer_cleanup(indio_dev);
773 	pm_runtime_get_sync(&i2c->dev);
774 	pm_runtime_put_noidle(&i2c->dev);
775 	pm_runtime_disable(&i2c->dev);
776 	ak8974_set_power(ak8974, AK8974_PWR_OFF);
777 	regulator_bulk_disable(ARRAY_SIZE(ak8974->regs), ak8974->regs);
778 
779 	return 0;
780 }
781 
782 static int __maybe_unused ak8974_runtime_suspend(struct device *dev)
783 {
784 	struct ak8974 *ak8974 =
785 		iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
786 
787 	ak8974_set_power(ak8974, AK8974_PWR_OFF);
788 	regulator_bulk_disable(ARRAY_SIZE(ak8974->regs), ak8974->regs);
789 
790 	return 0;
791 }
792 
793 static int __maybe_unused ak8974_runtime_resume(struct device *dev)
794 {
795 	struct ak8974 *ak8974 =
796 		iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
797 	int ret;
798 
799 	ret = regulator_bulk_enable(ARRAY_SIZE(ak8974->regs), ak8974->regs);
800 	if (ret)
801 		return ret;
802 	msleep(AK8974_POWERON_DELAY);
803 	ret = ak8974_set_power(ak8974, AK8974_PWR_ON);
804 	if (ret)
805 		goto out_regulator_disable;
806 
807 	ret = ak8974_configure(ak8974);
808 	if (ret)
809 		goto out_disable_power;
810 
811 	return 0;
812 
813 out_disable_power:
814 	ak8974_set_power(ak8974, AK8974_PWR_OFF);
815 out_regulator_disable:
816 	regulator_bulk_disable(ARRAY_SIZE(ak8974->regs), ak8974->regs);
817 
818 	return ret;
819 }
820 
821 static const struct dev_pm_ops ak8974_dev_pm_ops = {
822 	SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
823 				pm_runtime_force_resume)
824 	SET_RUNTIME_PM_OPS(ak8974_runtime_suspend,
825 			   ak8974_runtime_resume, NULL)
826 };
827 
828 static const struct i2c_device_id ak8974_id[] = {
829 	{"ami305", 0 },
830 	{"ak8974", 0 },
831 	{}
832 };
833 MODULE_DEVICE_TABLE(i2c, ak8974_id);
834 
835 static const struct of_device_id ak8974_of_match[] = {
836 	{ .compatible = "asahi-kasei,ak8974", },
837 	{}
838 };
839 MODULE_DEVICE_TABLE(of, ak8974_of_match);
840 
841 static struct i2c_driver ak8974_driver = {
842 	.driver	 = {
843 		.name	= "ak8974",
844 		.pm = &ak8974_dev_pm_ops,
845 		.of_match_table = of_match_ptr(ak8974_of_match),
846 	},
847 	.probe	  = ak8974_probe,
848 	.remove	  = ak8974_remove,
849 	.id_table = ak8974_id,
850 };
851 module_i2c_driver(ak8974_driver);
852 
853 MODULE_DESCRIPTION("AK8974 and AMI305 3-axis magnetometer driver");
854 MODULE_AUTHOR("Samu Onkalo");
855 MODULE_AUTHOR("Linus Walleij");
856 MODULE_LICENSE("GPL v2");
857