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/random.h>
24 #include <linux/regmap.h>
25 #include <linux/regulator/consumer.h>
26 #include <linux/pm_runtime.h>
27 
28 #include <linux/iio/iio.h>
29 #include <linux/iio/sysfs.h>
30 #include <linux/iio/buffer.h>
31 #include <linux/iio/trigger.h>
32 #include <linux/iio/trigger_consumer.h>
33 #include <linux/iio/triggered_buffer.h>
34 
35 /*
36  * 16-bit registers are little-endian. LSB is at the address defined below
37  * and MSB is at the next higher address.
38  */
39 
40 /* These registers are common for AK8974 and AMI30x */
41 #define AK8974_SELFTEST		0x0C
42 #define AK8974_SELFTEST_IDLE	0x55
43 #define AK8974_SELFTEST_OK	0xAA
44 
45 #define AK8974_INFO		0x0D
46 
47 #define AK8974_WHOAMI		0x0F
48 #define AK8974_WHOAMI_VALUE_AMI306 0x46
49 #define AK8974_WHOAMI_VALUE_AMI305 0x47
50 #define AK8974_WHOAMI_VALUE_AK8974 0x48
51 
52 #define AK8974_DATA_X		0x10
53 #define AK8974_DATA_Y		0x12
54 #define AK8974_DATA_Z		0x14
55 #define AK8974_INT_SRC		0x16
56 #define AK8974_STATUS		0x18
57 #define AK8974_INT_CLEAR	0x1A
58 #define AK8974_CTRL1		0x1B
59 #define AK8974_CTRL2		0x1C
60 #define AK8974_CTRL3		0x1D
61 #define AK8974_INT_CTRL		0x1E
62 #define AK8974_INT_THRES	0x26  /* Absolute any axis value threshold */
63 #define AK8974_PRESET		0x30
64 
65 /* AK8974-specific offsets */
66 #define AK8974_OFFSET_X		0x20
67 #define AK8974_OFFSET_Y		0x22
68 #define AK8974_OFFSET_Z		0x24
69 /* AMI305-specific offsets */
70 #define AMI305_OFFSET_X		0x6C
71 #define AMI305_OFFSET_Y		0x72
72 #define AMI305_OFFSET_Z		0x78
73 
74 /* Different temperature registers */
75 #define AK8974_TEMP		0x31
76 #define AMI305_TEMP		0x60
77 
78 /* AMI306-specific control register */
79 #define AMI306_CTRL4		0x5C
80 
81 /* AMI306 factory calibration data */
82 
83 /* fine axis sensitivity */
84 #define AMI306_FINEOUTPUT_X	0x90
85 #define AMI306_FINEOUTPUT_Y	0x92
86 #define AMI306_FINEOUTPUT_Z	0x94
87 
88 /* axis sensitivity */
89 #define AMI306_SENS_X		0x96
90 #define AMI306_SENS_Y		0x98
91 #define AMI306_SENS_Z		0x9A
92 
93 /* axis cross-interference */
94 #define AMI306_GAIN_PARA_XZ	0x9C
95 #define AMI306_GAIN_PARA_XY	0x9D
96 #define AMI306_GAIN_PARA_YZ	0x9E
97 #define AMI306_GAIN_PARA_YX	0x9F
98 #define AMI306_GAIN_PARA_ZY	0xA0
99 #define AMI306_GAIN_PARA_ZX	0xA1
100 
101 /* offset at ZERO magnetic field */
102 #define AMI306_OFFZERO_X	0xF8
103 #define AMI306_OFFZERO_Y	0xFA
104 #define AMI306_OFFZERO_Z	0xFC
105 
106 
107 #define AK8974_INT_X_HIGH	BIT(7) /* Axis over +threshold  */
108 #define AK8974_INT_Y_HIGH	BIT(6)
109 #define AK8974_INT_Z_HIGH	BIT(5)
110 #define AK8974_INT_X_LOW	BIT(4) /* Axis below -threshold	*/
111 #define AK8974_INT_Y_LOW	BIT(3)
112 #define AK8974_INT_Z_LOW	BIT(2)
113 #define AK8974_INT_RANGE	BIT(1) /* Range overflow (any axis) */
114 
115 #define AK8974_STATUS_DRDY	BIT(6) /* Data ready */
116 #define AK8974_STATUS_OVERRUN	BIT(5) /* Data overrun */
117 #define AK8974_STATUS_INT	BIT(4) /* Interrupt occurred */
118 
119 #define AK8974_CTRL1_POWER	BIT(7) /* 0 = standby; 1 = active */
120 #define AK8974_CTRL1_RATE	BIT(4) /* 0 = 10 Hz; 1 = 20 Hz	 */
121 #define AK8974_CTRL1_FORCE_EN	BIT(1) /* 0 = normal; 1 = force	 */
122 #define AK8974_CTRL1_MODE2	BIT(0) /* 0 */
123 
124 #define AK8974_CTRL2_INT_EN	BIT(4)  /* 1 = enable interrupts	      */
125 #define AK8974_CTRL2_DRDY_EN	BIT(3)  /* 1 = enable data ready signal */
126 #define AK8974_CTRL2_DRDY_POL	BIT(2)  /* 1 = data ready active high   */
127 #define AK8974_CTRL2_RESDEF	(AK8974_CTRL2_DRDY_POL)
128 
129 #define AK8974_CTRL3_RESET	BIT(7) /* Software reset		  */
130 #define AK8974_CTRL3_FORCE	BIT(6) /* Start forced measurement */
131 #define AK8974_CTRL3_SELFTEST	BIT(4) /* Set selftest register	  */
132 #define AK8974_CTRL3_RESDEF	0x00
133 
134 #define AK8974_INT_CTRL_XEN	BIT(7) /* Enable interrupt for this axis */
135 #define AK8974_INT_CTRL_YEN	BIT(6)
136 #define AK8974_INT_CTRL_ZEN	BIT(5)
137 #define AK8974_INT_CTRL_XYZEN	(BIT(7)|BIT(6)|BIT(5))
138 #define AK8974_INT_CTRL_POL	BIT(3) /* 0 = active low; 1 = active high */
139 #define AK8974_INT_CTRL_PULSE	BIT(1) /* 0 = latched; 1 = pulse (50 usec) */
140 #define AK8974_INT_CTRL_RESDEF	(AK8974_INT_CTRL_XYZEN | AK8974_INT_CTRL_POL)
141 
142 /* The AMI305 has elaborate FW version and serial number registers */
143 #define AMI305_VER		0xE8
144 #define AMI305_SN		0xEA
145 
146 #define AK8974_MAX_RANGE	2048
147 
148 #define AK8974_POWERON_DELAY	50
149 #define AK8974_ACTIVATE_DELAY	1
150 #define AK8974_SELFTEST_DELAY	1
151 /*
152  * Set the autosuspend to two orders of magnitude larger than the poweron
153  * delay to make sane reasonable power tradeoff savings (5 seconds in
154  * this case).
155  */
156 #define AK8974_AUTOSUSPEND_DELAY 5000
157 
158 #define AK8974_MEASTIME		3
159 
160 #define AK8974_PWR_ON		1
161 #define AK8974_PWR_OFF		0
162 
163 /**
164  * struct ak8974 - state container for the AK8974 driver
165  * @i2c: parent I2C client
166  * @orientation: mounting matrix, flipped axis etc
167  * @map: regmap to access the AK8974 registers over I2C
168  * @regs: the avdd and dvdd power regulators
169  * @name: the name of the part
170  * @variant: the whoami ID value (for selecting code paths)
171  * @lock: locks the magnetometer for exclusive use during a measurement
172  * @drdy_irq: uses the DRDY IRQ line
173  * @drdy_complete: completion for DRDY
174  * @drdy_active_low: the DRDY IRQ is active low
175  */
176 struct ak8974 {
177 	struct i2c_client *i2c;
178 	struct iio_mount_matrix orientation;
179 	struct regmap *map;
180 	struct regulator_bulk_data regs[2];
181 	const char *name;
182 	u8 variant;
183 	struct mutex lock;
184 	bool drdy_irq;
185 	struct completion drdy_complete;
186 	bool drdy_active_low;
187 };
188 
189 static const char ak8974_reg_avdd[] = "avdd";
190 static const char ak8974_reg_dvdd[] = "dvdd";
191 
192 static int ak8974_get_u16_val(struct ak8974 *ak8974, u8 reg, u16 *val)
193 {
194 	int ret;
195 	__le16 bulk;
196 
197 	ret = regmap_bulk_read(ak8974->map, reg, &bulk, 2);
198 	if (ret)
199 		return ret;
200 	*val = le16_to_cpu(bulk);
201 
202 	return 0;
203 }
204 
205 static int ak8974_set_u16_val(struct ak8974 *ak8974, u8 reg, u16 val)
206 {
207 	__le16 bulk = cpu_to_le16(val);
208 
209 	return regmap_bulk_write(ak8974->map, reg, &bulk, 2);
210 }
211 
212 static int ak8974_set_power(struct ak8974 *ak8974, bool mode)
213 {
214 	int ret;
215 	u8 val;
216 
217 	val = mode ? AK8974_CTRL1_POWER : 0;
218 	val |= AK8974_CTRL1_FORCE_EN;
219 	ret = regmap_write(ak8974->map, AK8974_CTRL1, val);
220 	if (ret < 0)
221 		return ret;
222 
223 	if (mode)
224 		msleep(AK8974_ACTIVATE_DELAY);
225 
226 	return 0;
227 }
228 
229 static int ak8974_reset(struct ak8974 *ak8974)
230 {
231 	int ret;
232 
233 	/* Power on to get register access. Sets CTRL1 reg to reset state */
234 	ret = ak8974_set_power(ak8974, AK8974_PWR_ON);
235 	if (ret)
236 		return ret;
237 	ret = regmap_write(ak8974->map, AK8974_CTRL2, AK8974_CTRL2_RESDEF);
238 	if (ret)
239 		return ret;
240 	ret = regmap_write(ak8974->map, AK8974_CTRL3, AK8974_CTRL3_RESDEF);
241 	if (ret)
242 		return ret;
243 	ret = regmap_write(ak8974->map, AK8974_INT_CTRL,
244 			   AK8974_INT_CTRL_RESDEF);
245 	if (ret)
246 		return ret;
247 
248 	/* After reset, power off is default state */
249 	return ak8974_set_power(ak8974, AK8974_PWR_OFF);
250 }
251 
252 static int ak8974_configure(struct ak8974 *ak8974)
253 {
254 	int ret;
255 
256 	ret = regmap_write(ak8974->map, AK8974_CTRL2, AK8974_CTRL2_DRDY_EN |
257 			   AK8974_CTRL2_INT_EN);
258 	if (ret)
259 		return ret;
260 	ret = regmap_write(ak8974->map, AK8974_CTRL3, 0);
261 	if (ret)
262 		return ret;
263 	if (ak8974->variant == AK8974_WHOAMI_VALUE_AMI306) {
264 		/* magic from datasheet: set high-speed measurement mode */
265 		ret = ak8974_set_u16_val(ak8974, AMI306_CTRL4, 0xA07E);
266 		if (ret)
267 			return ret;
268 	}
269 	ret = regmap_write(ak8974->map, AK8974_INT_CTRL, AK8974_INT_CTRL_POL);
270 	if (ret)
271 		return ret;
272 
273 	return regmap_write(ak8974->map, AK8974_PRESET, 0);
274 }
275 
276 static int ak8974_trigmeas(struct ak8974 *ak8974)
277 {
278 	unsigned int clear;
279 	u8 mask;
280 	u8 val;
281 	int ret;
282 
283 	/* Clear any previous measurement overflow status */
284 	ret = regmap_read(ak8974->map, AK8974_INT_CLEAR, &clear);
285 	if (ret)
286 		return ret;
287 
288 	/* If we have a DRDY IRQ line, use it */
289 	if (ak8974->drdy_irq) {
290 		mask = AK8974_CTRL2_INT_EN |
291 			AK8974_CTRL2_DRDY_EN |
292 			AK8974_CTRL2_DRDY_POL;
293 		val = AK8974_CTRL2_DRDY_EN;
294 
295 		if (!ak8974->drdy_active_low)
296 			val |= AK8974_CTRL2_DRDY_POL;
297 
298 		init_completion(&ak8974->drdy_complete);
299 		ret = regmap_update_bits(ak8974->map, AK8974_CTRL2,
300 					 mask, val);
301 		if (ret)
302 			return ret;
303 	}
304 
305 	/* Force a measurement */
306 	return regmap_update_bits(ak8974->map,
307 				  AK8974_CTRL3,
308 				  AK8974_CTRL3_FORCE,
309 				  AK8974_CTRL3_FORCE);
310 }
311 
312 static int ak8974_await_drdy(struct ak8974 *ak8974)
313 {
314 	int timeout = 2;
315 	unsigned int val;
316 	int ret;
317 
318 	if (ak8974->drdy_irq) {
319 		ret = wait_for_completion_timeout(&ak8974->drdy_complete,
320 					1 + msecs_to_jiffies(1000));
321 		if (!ret) {
322 			dev_err(&ak8974->i2c->dev,
323 				"timeout waiting for DRDY IRQ\n");
324 			return -ETIMEDOUT;
325 		}
326 		return 0;
327 	}
328 
329 	/* Default delay-based poll loop */
330 	do {
331 		msleep(AK8974_MEASTIME);
332 		ret = regmap_read(ak8974->map, AK8974_STATUS, &val);
333 		if (ret < 0)
334 			return ret;
335 		if (val & AK8974_STATUS_DRDY)
336 			return 0;
337 	} while (--timeout);
338 
339 	dev_err(&ak8974->i2c->dev, "timeout waiting for DRDY\n");
340 	return -ETIMEDOUT;
341 }
342 
343 static int ak8974_getresult(struct ak8974 *ak8974, __le16 *result)
344 {
345 	unsigned int src;
346 	int ret;
347 
348 	ret = ak8974_await_drdy(ak8974);
349 	if (ret)
350 		return ret;
351 	ret = regmap_read(ak8974->map, AK8974_INT_SRC, &src);
352 	if (ret < 0)
353 		return ret;
354 
355 	/* Out of range overflow! Strong magnet close? */
356 	if (src & AK8974_INT_RANGE) {
357 		dev_err(&ak8974->i2c->dev,
358 			"range overflow in sensor\n");
359 		return -ERANGE;
360 	}
361 
362 	ret = regmap_bulk_read(ak8974->map, AK8974_DATA_X, result, 6);
363 	if (ret)
364 		return ret;
365 
366 	return ret;
367 }
368 
369 static irqreturn_t ak8974_drdy_irq(int irq, void *d)
370 {
371 	struct ak8974 *ak8974 = d;
372 
373 	if (!ak8974->drdy_irq)
374 		return IRQ_NONE;
375 
376 	/* TODO: timestamp here to get good measurement stamps */
377 	return IRQ_WAKE_THREAD;
378 }
379 
380 static irqreturn_t ak8974_drdy_irq_thread(int irq, void *d)
381 {
382 	struct ak8974 *ak8974 = d;
383 	unsigned int val;
384 	int ret;
385 
386 	/* Check if this was a DRDY from us */
387 	ret = regmap_read(ak8974->map, AK8974_STATUS, &val);
388 	if (ret < 0) {
389 		dev_err(&ak8974->i2c->dev, "error reading DRDY status\n");
390 		return IRQ_HANDLED;
391 	}
392 	if (val & AK8974_STATUS_DRDY) {
393 		/* Yes this was our IRQ */
394 		complete(&ak8974->drdy_complete);
395 		return IRQ_HANDLED;
396 	}
397 
398 	/* We may be on a shared IRQ, let the next client check */
399 	return IRQ_NONE;
400 }
401 
402 static int ak8974_selftest(struct ak8974 *ak8974)
403 {
404 	struct device *dev = &ak8974->i2c->dev;
405 	unsigned int val;
406 	int ret;
407 
408 	ret = regmap_read(ak8974->map, AK8974_SELFTEST, &val);
409 	if (ret)
410 		return ret;
411 	if (val != AK8974_SELFTEST_IDLE) {
412 		dev_err(dev, "selftest not idle before test\n");
413 		return -EIO;
414 	}
415 
416 	/* Trigger self-test */
417 	ret = regmap_update_bits(ak8974->map,
418 			AK8974_CTRL3,
419 			AK8974_CTRL3_SELFTEST,
420 			AK8974_CTRL3_SELFTEST);
421 	if (ret) {
422 		dev_err(dev, "could not write CTRL3\n");
423 		return ret;
424 	}
425 
426 	msleep(AK8974_SELFTEST_DELAY);
427 
428 	ret = regmap_read(ak8974->map, AK8974_SELFTEST, &val);
429 	if (ret)
430 		return ret;
431 	if (val != AK8974_SELFTEST_OK) {
432 		dev_err(dev, "selftest result NOT OK (%02x)\n", val);
433 		return -EIO;
434 	}
435 
436 	ret = regmap_read(ak8974->map, AK8974_SELFTEST, &val);
437 	if (ret)
438 		return ret;
439 	if (val != AK8974_SELFTEST_IDLE) {
440 		dev_err(dev, "selftest not idle after test (%02x)\n", val);
441 		return -EIO;
442 	}
443 	dev_dbg(dev, "passed self-test\n");
444 
445 	return 0;
446 }
447 
448 static void ak8974_read_calib_data(struct ak8974 *ak8974, unsigned int reg,
449 				   __le16 *tab, size_t tab_size)
450 {
451 	int ret = regmap_bulk_read(ak8974->map, reg, tab, tab_size);
452 	if (ret) {
453 		memset(tab, 0xFF, tab_size);
454 		dev_warn(&ak8974->i2c->dev,
455 			 "can't read calibration data (regs %u..%zu): %d\n",
456 			 reg, reg + tab_size - 1, ret);
457 	} else {
458 		add_device_randomness(tab, tab_size);
459 	}
460 }
461 
462 static int ak8974_detect(struct ak8974 *ak8974)
463 {
464 	unsigned int whoami;
465 	const char *name;
466 	int ret;
467 	unsigned int fw;
468 	u16 sn;
469 
470 	ret = regmap_read(ak8974->map, AK8974_WHOAMI, &whoami);
471 	if (ret)
472 		return ret;
473 
474 	name = "ami305";
475 
476 	switch (whoami) {
477 	case AK8974_WHOAMI_VALUE_AMI306:
478 		name = "ami306";
479 		/* fall-through */
480 	case AK8974_WHOAMI_VALUE_AMI305:
481 		ret = regmap_read(ak8974->map, AMI305_VER, &fw);
482 		if (ret)
483 			return ret;
484 		fw &= 0x7f; /* only bits 0 thru 6 valid */
485 		ret = ak8974_get_u16_val(ak8974, AMI305_SN, &sn);
486 		if (ret)
487 			return ret;
488 		add_device_randomness(&sn, sizeof(sn));
489 		dev_info(&ak8974->i2c->dev,
490 			 "detected %s, FW ver %02x, S/N: %04x\n",
491 			 name, fw, sn);
492 		break;
493 	case AK8974_WHOAMI_VALUE_AK8974:
494 		name = "ak8974";
495 		dev_info(&ak8974->i2c->dev, "detected AK8974\n");
496 		break;
497 	default:
498 		dev_err(&ak8974->i2c->dev, "unsupported device (%02x) ",
499 			whoami);
500 		return -ENODEV;
501 	}
502 
503 	ak8974->name = name;
504 	ak8974->variant = whoami;
505 
506 	if (whoami == AK8974_WHOAMI_VALUE_AMI306) {
507 		__le16 fab_data1[9], fab_data2[3];
508 		int i;
509 
510 		ak8974_read_calib_data(ak8974, AMI306_FINEOUTPUT_X,
511 				       fab_data1, sizeof(fab_data1));
512 		ak8974_read_calib_data(ak8974, AMI306_OFFZERO_X,
513 				       fab_data2, sizeof(fab_data2));
514 
515 		for (i = 0; i < 3; ++i) {
516 			static const char axis[3] = "XYZ";
517 			static const char pgaxis[6] = "ZYZXYX";
518 			unsigned offz = le16_to_cpu(fab_data2[i]) & 0x7F;
519 			unsigned fine = le16_to_cpu(fab_data1[i]);
520 			unsigned sens = le16_to_cpu(fab_data1[i + 3]);
521 			unsigned pgain1 = le16_to_cpu(fab_data1[i + 6]);
522 			unsigned pgain2 = pgain1 >> 8;
523 
524 			pgain1 &= 0xFF;
525 
526 			dev_info(&ak8974->i2c->dev,
527 				 "factory calibration for axis %c: offz=%u sens=%u fine=%u pga%c=%u pga%c=%u\n",
528 				 axis[i], offz, sens, fine, pgaxis[i * 2],
529 				 pgain1, pgaxis[i * 2 + 1], pgain2);
530 		}
531 	}
532 
533 	return 0;
534 }
535 
536 static int ak8974_read_raw(struct iio_dev *indio_dev,
537 			   struct iio_chan_spec const *chan,
538 			   int *val, int *val2,
539 			   long mask)
540 {
541 	struct ak8974 *ak8974 = iio_priv(indio_dev);
542 	__le16 hw_values[3];
543 	int ret = -EINVAL;
544 
545 	pm_runtime_get_sync(&ak8974->i2c->dev);
546 	mutex_lock(&ak8974->lock);
547 
548 	switch (mask) {
549 	case IIO_CHAN_INFO_RAW:
550 		if (chan->address > 2) {
551 			dev_err(&ak8974->i2c->dev, "faulty channel address\n");
552 			ret = -EIO;
553 			goto out_unlock;
554 		}
555 		ret = ak8974_trigmeas(ak8974);
556 		if (ret)
557 			goto out_unlock;
558 		ret = ak8974_getresult(ak8974, hw_values);
559 		if (ret)
560 			goto out_unlock;
561 
562 		/*
563 		 * We read all axes and discard all but one, for optimized
564 		 * reading, use the triggered buffer.
565 		 */
566 		*val = le16_to_cpu(hw_values[chan->address]);
567 
568 		ret = IIO_VAL_INT;
569 	}
570 
571  out_unlock:
572 	mutex_unlock(&ak8974->lock);
573 	pm_runtime_mark_last_busy(&ak8974->i2c->dev);
574 	pm_runtime_put_autosuspend(&ak8974->i2c->dev);
575 
576 	return ret;
577 }
578 
579 static void ak8974_fill_buffer(struct iio_dev *indio_dev)
580 {
581 	struct ak8974 *ak8974 = iio_priv(indio_dev);
582 	int ret;
583 	__le16 hw_values[8]; /* Three axes + 64bit padding */
584 
585 	pm_runtime_get_sync(&ak8974->i2c->dev);
586 	mutex_lock(&ak8974->lock);
587 
588 	ret = ak8974_trigmeas(ak8974);
589 	if (ret) {
590 		dev_err(&ak8974->i2c->dev, "error triggering measure\n");
591 		goto out_unlock;
592 	}
593 	ret = ak8974_getresult(ak8974, hw_values);
594 	if (ret) {
595 		dev_err(&ak8974->i2c->dev, "error getting measures\n");
596 		goto out_unlock;
597 	}
598 
599 	iio_push_to_buffers_with_timestamp(indio_dev, hw_values,
600 					   iio_get_time_ns(indio_dev));
601 
602  out_unlock:
603 	mutex_unlock(&ak8974->lock);
604 	pm_runtime_mark_last_busy(&ak8974->i2c->dev);
605 	pm_runtime_put_autosuspend(&ak8974->i2c->dev);
606 }
607 
608 static irqreturn_t ak8974_handle_trigger(int irq, void *p)
609 {
610 	const struct iio_poll_func *pf = p;
611 	struct iio_dev *indio_dev = pf->indio_dev;
612 
613 	ak8974_fill_buffer(indio_dev);
614 	iio_trigger_notify_done(indio_dev->trig);
615 
616 	return IRQ_HANDLED;
617 }
618 
619 static const struct iio_mount_matrix *
620 ak8974_get_mount_matrix(const struct iio_dev *indio_dev,
621 			const struct iio_chan_spec *chan)
622 {
623 	struct ak8974 *ak8974 = iio_priv(indio_dev);
624 
625 	return &ak8974->orientation;
626 }
627 
628 static const struct iio_chan_spec_ext_info ak8974_ext_info[] = {
629 	IIO_MOUNT_MATRIX(IIO_SHARED_BY_DIR, ak8974_get_mount_matrix),
630 	{ },
631 };
632 
633 #define AK8974_AXIS_CHANNEL(axis, index)				\
634 	{								\
635 		.type = IIO_MAGN,					\
636 		.modified = 1,						\
637 		.channel2 = IIO_MOD_##axis,				\
638 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),		\
639 		.ext_info = ak8974_ext_info,				\
640 		.address = index,					\
641 		.scan_index = index,					\
642 		.scan_type = {						\
643 			.sign = 's',					\
644 			.realbits = 16,					\
645 			.storagebits = 16,				\
646 			.endianness = IIO_LE				\
647 		},							\
648 	}
649 
650 static const struct iio_chan_spec ak8974_channels[] = {
651 	AK8974_AXIS_CHANNEL(X, 0),
652 	AK8974_AXIS_CHANNEL(Y, 1),
653 	AK8974_AXIS_CHANNEL(Z, 2),
654 	IIO_CHAN_SOFT_TIMESTAMP(3),
655 };
656 
657 static const unsigned long ak8974_scan_masks[] = { 0x7, 0 };
658 
659 static const struct iio_info ak8974_info = {
660 	.read_raw = &ak8974_read_raw,
661 };
662 
663 static bool ak8974_writeable_reg(struct device *dev, unsigned int reg)
664 {
665 	struct i2c_client *i2c = to_i2c_client(dev);
666 	struct iio_dev *indio_dev = i2c_get_clientdata(i2c);
667 	struct ak8974 *ak8974 = iio_priv(indio_dev);
668 
669 	switch (reg) {
670 	case AK8974_CTRL1:
671 	case AK8974_CTRL2:
672 	case AK8974_CTRL3:
673 	case AK8974_INT_CTRL:
674 	case AK8974_INT_THRES:
675 	case AK8974_INT_THRES + 1:
676 	case AK8974_PRESET:
677 	case AK8974_PRESET + 1:
678 		return true;
679 	case AK8974_OFFSET_X:
680 	case AK8974_OFFSET_X + 1:
681 	case AK8974_OFFSET_Y:
682 	case AK8974_OFFSET_Y + 1:
683 	case AK8974_OFFSET_Z:
684 	case AK8974_OFFSET_Z + 1:
685 		if (ak8974->variant == AK8974_WHOAMI_VALUE_AK8974)
686 			return true;
687 		return false;
688 	case AMI305_OFFSET_X:
689 	case AMI305_OFFSET_X + 1:
690 	case AMI305_OFFSET_Y:
691 	case AMI305_OFFSET_Y + 1:
692 	case AMI305_OFFSET_Z:
693 	case AMI305_OFFSET_Z + 1:
694 		return ak8974->variant == AK8974_WHOAMI_VALUE_AMI305 ||
695 		       ak8974->variant == AK8974_WHOAMI_VALUE_AMI306;
696 	case AMI306_CTRL4:
697 	case AMI306_CTRL4 + 1:
698 		return ak8974->variant == AK8974_WHOAMI_VALUE_AMI306;
699 	default:
700 		return false;
701 	}
702 }
703 
704 static bool ak8974_precious_reg(struct device *dev, unsigned int reg)
705 {
706 	return reg == AK8974_INT_CLEAR;
707 }
708 
709 static const struct regmap_config ak8974_regmap_config = {
710 	.reg_bits = 8,
711 	.val_bits = 8,
712 	.max_register = 0xff,
713 	.writeable_reg = ak8974_writeable_reg,
714 	.precious_reg = ak8974_precious_reg,
715 };
716 
717 static int ak8974_probe(struct i2c_client *i2c,
718 			const struct i2c_device_id *id)
719 {
720 	struct iio_dev *indio_dev;
721 	struct ak8974 *ak8974;
722 	unsigned long irq_trig;
723 	int irq = i2c->irq;
724 	int ret;
725 
726 	/* Register with IIO */
727 	indio_dev = devm_iio_device_alloc(&i2c->dev, sizeof(*ak8974));
728 	if (indio_dev == NULL)
729 		return -ENOMEM;
730 
731 	ak8974 = iio_priv(indio_dev);
732 	i2c_set_clientdata(i2c, indio_dev);
733 	ak8974->i2c = i2c;
734 	mutex_init(&ak8974->lock);
735 
736 	ret = of_iio_read_mount_matrix(&i2c->dev,
737 				       "mount-matrix",
738 				       &ak8974->orientation);
739 	if (ret)
740 		return ret;
741 
742 	ak8974->regs[0].supply = ak8974_reg_avdd;
743 	ak8974->regs[1].supply = ak8974_reg_dvdd;
744 
745 	ret = devm_regulator_bulk_get(&i2c->dev,
746 				      ARRAY_SIZE(ak8974->regs),
747 				      ak8974->regs);
748 	if (ret < 0) {
749 		dev_err(&i2c->dev, "cannot get regulators\n");
750 		return ret;
751 	}
752 
753 	ret = regulator_bulk_enable(ARRAY_SIZE(ak8974->regs), ak8974->regs);
754 	if (ret < 0) {
755 		dev_err(&i2c->dev, "cannot enable regulators\n");
756 		return ret;
757 	}
758 
759 	/* Take runtime PM online */
760 	pm_runtime_get_noresume(&i2c->dev);
761 	pm_runtime_set_active(&i2c->dev);
762 	pm_runtime_enable(&i2c->dev);
763 
764 	ak8974->map = devm_regmap_init_i2c(i2c, &ak8974_regmap_config);
765 	if (IS_ERR(ak8974->map)) {
766 		dev_err(&i2c->dev, "failed to allocate register map\n");
767 		return PTR_ERR(ak8974->map);
768 	}
769 
770 	ret = ak8974_set_power(ak8974, AK8974_PWR_ON);
771 	if (ret) {
772 		dev_err(&i2c->dev, "could not power on\n");
773 		goto power_off;
774 	}
775 
776 	ret = ak8974_detect(ak8974);
777 	if (ret) {
778 		dev_err(&i2c->dev, "neither AK8974 nor AMI30x found\n");
779 		goto power_off;
780 	}
781 
782 	ret = ak8974_selftest(ak8974);
783 	if (ret)
784 		dev_err(&i2c->dev, "selftest failed (continuing anyway)\n");
785 
786 	ret = ak8974_reset(ak8974);
787 	if (ret) {
788 		dev_err(&i2c->dev, "AK8974 reset failed\n");
789 		goto power_off;
790 	}
791 
792 	pm_runtime_set_autosuspend_delay(&i2c->dev,
793 					 AK8974_AUTOSUSPEND_DELAY);
794 	pm_runtime_use_autosuspend(&i2c->dev);
795 	pm_runtime_put(&i2c->dev);
796 
797 	indio_dev->dev.parent = &i2c->dev;
798 	indio_dev->channels = ak8974_channels;
799 	indio_dev->num_channels = ARRAY_SIZE(ak8974_channels);
800 	indio_dev->info = &ak8974_info;
801 	indio_dev->available_scan_masks = ak8974_scan_masks;
802 	indio_dev->modes = INDIO_DIRECT_MODE;
803 	indio_dev->name = ak8974->name;
804 
805 	ret = iio_triggered_buffer_setup(indio_dev, NULL,
806 					 ak8974_handle_trigger,
807 					 NULL);
808 	if (ret) {
809 		dev_err(&i2c->dev, "triggered buffer setup failed\n");
810 		goto disable_pm;
811 	}
812 
813 	/* If we have a valid DRDY IRQ, make use of it */
814 	if (irq > 0) {
815 		irq_trig = irqd_get_trigger_type(irq_get_irq_data(irq));
816 		if (irq_trig == IRQF_TRIGGER_RISING) {
817 			dev_info(&i2c->dev, "enable rising edge DRDY IRQ\n");
818 		} else if (irq_trig == IRQF_TRIGGER_FALLING) {
819 			ak8974->drdy_active_low = true;
820 			dev_info(&i2c->dev, "enable falling edge DRDY IRQ\n");
821 		} else {
822 			irq_trig = IRQF_TRIGGER_RISING;
823 		}
824 		irq_trig |= IRQF_ONESHOT;
825 		irq_trig |= IRQF_SHARED;
826 
827 		ret = devm_request_threaded_irq(&i2c->dev,
828 						irq,
829 						ak8974_drdy_irq,
830 						ak8974_drdy_irq_thread,
831 						irq_trig,
832 						ak8974->name,
833 						ak8974);
834 		if (ret) {
835 			dev_err(&i2c->dev, "unable to request DRDY IRQ "
836 				"- proceeding without IRQ\n");
837 			goto no_irq;
838 		}
839 		ak8974->drdy_irq = true;
840 	}
841 
842 no_irq:
843 	ret = iio_device_register(indio_dev);
844 	if (ret) {
845 		dev_err(&i2c->dev, "device register failed\n");
846 		goto cleanup_buffer;
847 	}
848 
849 	return 0;
850 
851 cleanup_buffer:
852 	iio_triggered_buffer_cleanup(indio_dev);
853 disable_pm:
854 	pm_runtime_put_noidle(&i2c->dev);
855 	pm_runtime_disable(&i2c->dev);
856 	ak8974_set_power(ak8974, AK8974_PWR_OFF);
857 power_off:
858 	regulator_bulk_disable(ARRAY_SIZE(ak8974->regs), ak8974->regs);
859 
860 	return ret;
861 }
862 
863 static int ak8974_remove(struct i2c_client *i2c)
864 {
865 	struct iio_dev *indio_dev = i2c_get_clientdata(i2c);
866 	struct ak8974 *ak8974 = iio_priv(indio_dev);
867 
868 	iio_device_unregister(indio_dev);
869 	iio_triggered_buffer_cleanup(indio_dev);
870 	pm_runtime_get_sync(&i2c->dev);
871 	pm_runtime_put_noidle(&i2c->dev);
872 	pm_runtime_disable(&i2c->dev);
873 	ak8974_set_power(ak8974, AK8974_PWR_OFF);
874 	regulator_bulk_disable(ARRAY_SIZE(ak8974->regs), ak8974->regs);
875 
876 	return 0;
877 }
878 
879 static int __maybe_unused ak8974_runtime_suspend(struct device *dev)
880 {
881 	struct ak8974 *ak8974 =
882 		iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
883 
884 	ak8974_set_power(ak8974, AK8974_PWR_OFF);
885 	regulator_bulk_disable(ARRAY_SIZE(ak8974->regs), ak8974->regs);
886 
887 	return 0;
888 }
889 
890 static int __maybe_unused ak8974_runtime_resume(struct device *dev)
891 {
892 	struct ak8974 *ak8974 =
893 		iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
894 	int ret;
895 
896 	ret = regulator_bulk_enable(ARRAY_SIZE(ak8974->regs), ak8974->regs);
897 	if (ret)
898 		return ret;
899 	msleep(AK8974_POWERON_DELAY);
900 	ret = ak8974_set_power(ak8974, AK8974_PWR_ON);
901 	if (ret)
902 		goto out_regulator_disable;
903 
904 	ret = ak8974_configure(ak8974);
905 	if (ret)
906 		goto out_disable_power;
907 
908 	return 0;
909 
910 out_disable_power:
911 	ak8974_set_power(ak8974, AK8974_PWR_OFF);
912 out_regulator_disable:
913 	regulator_bulk_disable(ARRAY_SIZE(ak8974->regs), ak8974->regs);
914 
915 	return ret;
916 }
917 
918 static const struct dev_pm_ops ak8974_dev_pm_ops = {
919 	SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
920 				pm_runtime_force_resume)
921 	SET_RUNTIME_PM_OPS(ak8974_runtime_suspend,
922 			   ak8974_runtime_resume, NULL)
923 };
924 
925 static const struct i2c_device_id ak8974_id[] = {
926 	{"ami305", 0 },
927 	{"ami306", 0 },
928 	{"ak8974", 0 },
929 	{}
930 };
931 MODULE_DEVICE_TABLE(i2c, ak8974_id);
932 
933 static const struct of_device_id ak8974_of_match[] = {
934 	{ .compatible = "asahi-kasei,ak8974", },
935 	{}
936 };
937 MODULE_DEVICE_TABLE(of, ak8974_of_match);
938 
939 static struct i2c_driver ak8974_driver = {
940 	.driver	 = {
941 		.name	= "ak8974",
942 		.pm = &ak8974_dev_pm_ops,
943 		.of_match_table = of_match_ptr(ak8974_of_match),
944 	},
945 	.probe	  = ak8974_probe,
946 	.remove	  = ak8974_remove,
947 	.id_table = ak8974_id,
948 };
949 module_i2c_driver(ak8974_driver);
950 
951 MODULE_DESCRIPTION("AK8974 and AMI30x 3-axis magnetometer driver");
952 MODULE_AUTHOR("Samu Onkalo");
953 MODULE_AUTHOR("Linus Walleij");
954 MODULE_LICENSE("GPL v2");
955