1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * A sensor driver for the magnetometer AK8975.
4  *
5  * Magnetic compass sensor driver for monitoring magnetic flux information.
6  *
7  * Copyright (c) 2010, NVIDIA Corporation.
8  */
9 
10 #include <linux/module.h>
11 #include <linux/mod_devicetable.h>
12 #include <linux/kernel.h>
13 #include <linux/slab.h>
14 #include <linux/i2c.h>
15 #include <linux/interrupt.h>
16 #include <linux/err.h>
17 #include <linux/mutex.h>
18 #include <linux/delay.h>
19 #include <linux/bitops.h>
20 #include <linux/gpio/consumer.h>
21 #include <linux/regulator/consumer.h>
22 #include <linux/pm_runtime.h>
23 
24 #include <linux/iio/iio.h>
25 #include <linux/iio/sysfs.h>
26 #include <linux/iio/buffer.h>
27 #include <linux/iio/trigger.h>
28 #include <linux/iio/trigger_consumer.h>
29 #include <linux/iio/triggered_buffer.h>
30 
31 /*
32  * Register definitions, as well as various shifts and masks to get at the
33  * individual fields of the registers.
34  */
35 #define AK8975_REG_WIA			0x00
36 #define AK8975_DEVICE_ID		0x48
37 
38 #define AK8975_REG_INFO			0x01
39 
40 #define AK8975_REG_ST1			0x02
41 #define AK8975_REG_ST1_DRDY_SHIFT	0
42 #define AK8975_REG_ST1_DRDY_MASK	(1 << AK8975_REG_ST1_DRDY_SHIFT)
43 
44 #define AK8975_REG_HXL			0x03
45 #define AK8975_REG_HXH			0x04
46 #define AK8975_REG_HYL			0x05
47 #define AK8975_REG_HYH			0x06
48 #define AK8975_REG_HZL			0x07
49 #define AK8975_REG_HZH			0x08
50 #define AK8975_REG_ST2			0x09
51 #define AK8975_REG_ST2_DERR_SHIFT	2
52 #define AK8975_REG_ST2_DERR_MASK	(1 << AK8975_REG_ST2_DERR_SHIFT)
53 
54 #define AK8975_REG_ST2_HOFL_SHIFT	3
55 #define AK8975_REG_ST2_HOFL_MASK	(1 << AK8975_REG_ST2_HOFL_SHIFT)
56 
57 #define AK8975_REG_CNTL			0x0A
58 #define AK8975_REG_CNTL_MODE_SHIFT	0
59 #define AK8975_REG_CNTL_MODE_MASK	(0xF << AK8975_REG_CNTL_MODE_SHIFT)
60 #define AK8975_REG_CNTL_MODE_POWER_DOWN	0x00
61 #define AK8975_REG_CNTL_MODE_ONCE	0x01
62 #define AK8975_REG_CNTL_MODE_SELF_TEST	0x08
63 #define AK8975_REG_CNTL_MODE_FUSE_ROM	0x0F
64 
65 #define AK8975_REG_RSVC			0x0B
66 #define AK8975_REG_ASTC			0x0C
67 #define AK8975_REG_TS1			0x0D
68 #define AK8975_REG_TS2			0x0E
69 #define AK8975_REG_I2CDIS		0x0F
70 #define AK8975_REG_ASAX			0x10
71 #define AK8975_REG_ASAY			0x11
72 #define AK8975_REG_ASAZ			0x12
73 
74 #define AK8975_MAX_REGS			AK8975_REG_ASAZ
75 
76 /*
77  * AK09912 Register definitions
78  */
79 #define AK09912_REG_WIA1		0x00
80 #define AK09912_REG_WIA2		0x01
81 #define AK09912_DEVICE_ID		0x04
82 #define AK09911_DEVICE_ID		0x05
83 
84 #define AK09911_REG_INFO1		0x02
85 #define AK09911_REG_INFO2		0x03
86 
87 #define AK09912_REG_ST1			0x10
88 
89 #define AK09912_REG_ST1_DRDY_SHIFT	0
90 #define AK09912_REG_ST1_DRDY_MASK	(1 << AK09912_REG_ST1_DRDY_SHIFT)
91 
92 #define AK09912_REG_HXL			0x11
93 #define AK09912_REG_HXH			0x12
94 #define AK09912_REG_HYL			0x13
95 #define AK09912_REG_HYH			0x14
96 #define AK09912_REG_HZL			0x15
97 #define AK09912_REG_HZH			0x16
98 #define AK09912_REG_TMPS		0x17
99 
100 #define AK09912_REG_ST2			0x18
101 #define AK09912_REG_ST2_HOFL_SHIFT	3
102 #define AK09912_REG_ST2_HOFL_MASK	(1 << AK09912_REG_ST2_HOFL_SHIFT)
103 
104 #define AK09912_REG_CNTL1		0x30
105 
106 #define AK09912_REG_CNTL2		0x31
107 #define AK09912_REG_CNTL_MODE_POWER_DOWN	0x00
108 #define AK09912_REG_CNTL_MODE_ONCE	0x01
109 #define AK09912_REG_CNTL_MODE_SELF_TEST	0x10
110 #define AK09912_REG_CNTL_MODE_FUSE_ROM	0x1F
111 #define AK09912_REG_CNTL2_MODE_SHIFT	0
112 #define AK09912_REG_CNTL2_MODE_MASK	(0x1F << AK09912_REG_CNTL2_MODE_SHIFT)
113 
114 #define AK09912_REG_CNTL3		0x32
115 
116 #define AK09912_REG_TS1			0x33
117 #define AK09912_REG_TS2			0x34
118 #define AK09912_REG_TS3			0x35
119 #define AK09912_REG_I2CDIS		0x36
120 #define AK09912_REG_TS4			0x37
121 
122 #define AK09912_REG_ASAX		0x60
123 #define AK09912_REG_ASAY		0x61
124 #define AK09912_REG_ASAZ		0x62
125 
126 #define AK09912_MAX_REGS		AK09912_REG_ASAZ
127 
128 /*
129  * Miscellaneous values.
130  */
131 #define AK8975_MAX_CONVERSION_TIMEOUT	500
132 #define AK8975_CONVERSION_DONE_POLL_TIME 10
133 #define AK8975_DATA_READY_TIMEOUT	((100*HZ)/1000)
134 
135 /*
136  * Precalculate scale factor (in Gauss units) for each axis and
137  * store in the device data.
138  *
139  * This scale factor is axis-dependent, and is derived from 3 calibration
140  * factors ASA(x), ASA(y), and ASA(z).
141  *
142  * These ASA values are read from the sensor device at start of day, and
143  * cached in the device context struct.
144  *
145  * Adjusting the flux value with the sensitivity adjustment value should be
146  * done via the following formula:
147  *
148  * Hadj = H * ( ( ( (ASA-128)*0.5 ) / 128 ) + 1 )
149  * where H is the raw value, ASA is the sensitivity adjustment, and Hadj
150  * is the resultant adjusted value.
151  *
152  * We reduce the formula to:
153  *
154  * Hadj = H * (ASA + 128) / 256
155  *
156  * H is in the range of -4096 to 4095.  The magnetometer has a range of
157  * +-1229uT.  To go from the raw value to uT is:
158  *
159  * HuT = H * 1229/4096, or roughly, 3/10.
160  *
161  * Since 1uT = 0.01 gauss, our final scale factor becomes:
162  *
163  * Hadj = H * ((ASA + 128) / 256) * 3/10 * 1/100
164  * Hadj = H * ((ASA + 128) * 0.003) / 256
165  *
166  * Since ASA doesn't change, we cache the resultant scale factor into the
167  * device context in ak8975_setup().
168  *
169  * Given we use IIO_VAL_INT_PLUS_MICRO bit when displaying the scale, we
170  * multiply the stored scale value by 1e6.
171  */
172 static long ak8975_raw_to_gauss(u16 data)
173 {
174 	return (((long)data + 128) * 3000) / 256;
175 }
176 
177 /*
178  * For AK8963 and AK09911, same calculation, but the device is less sensitive:
179  *
180  * H is in the range of +-8190.  The magnetometer has a range of
181  * +-4912uT.  To go from the raw value to uT is:
182  *
183  * HuT = H * 4912/8190, or roughly, 6/10, instead of 3/10.
184  */
185 
186 static long ak8963_09911_raw_to_gauss(u16 data)
187 {
188 	return (((long)data + 128) * 6000) / 256;
189 }
190 
191 /*
192  * For AK09912, same calculation, except the device is more sensitive:
193  *
194  * H is in the range of -32752 to 32752.  The magnetometer has a range of
195  * +-4912uT.  To go from the raw value to uT is:
196  *
197  * HuT = H * 4912/32752, or roughly, 3/20, instead of 3/10.
198  */
199 static long ak09912_raw_to_gauss(u16 data)
200 {
201 	return (((long)data + 128) * 1500) / 256;
202 }
203 
204 /* Compatible Asahi Kasei Compass parts */
205 enum asahi_compass_chipset {
206 	AKXXXX		= 0,
207 	AK8975,
208 	AK8963,
209 	AK09911,
210 	AK09912,
211 };
212 
213 enum ak_ctrl_reg_addr {
214 	ST1,
215 	ST2,
216 	CNTL,
217 	ASA_BASE,
218 	MAX_REGS,
219 	REGS_END,
220 };
221 
222 enum ak_ctrl_reg_mask {
223 	ST1_DRDY,
224 	ST2_HOFL,
225 	ST2_DERR,
226 	CNTL_MODE,
227 	MASK_END,
228 };
229 
230 enum ak_ctrl_mode {
231 	POWER_DOWN,
232 	MODE_ONCE,
233 	SELF_TEST,
234 	FUSE_ROM,
235 	MODE_END,
236 };
237 
238 struct ak_def {
239 	enum asahi_compass_chipset type;
240 	long (*raw_to_gauss)(u16 data);
241 	u16 range;
242 	u8 ctrl_regs[REGS_END];
243 	u8 ctrl_masks[MASK_END];
244 	u8 ctrl_modes[MODE_END];
245 	u8 data_regs[3];
246 };
247 
248 static const struct ak_def ak_def_array[] = {
249 	{
250 		.type = AK8975,
251 		.raw_to_gauss = ak8975_raw_to_gauss,
252 		.range = 4096,
253 		.ctrl_regs = {
254 			AK8975_REG_ST1,
255 			AK8975_REG_ST2,
256 			AK8975_REG_CNTL,
257 			AK8975_REG_ASAX,
258 			AK8975_MAX_REGS},
259 		.ctrl_masks = {
260 			AK8975_REG_ST1_DRDY_MASK,
261 			AK8975_REG_ST2_HOFL_MASK,
262 			AK8975_REG_ST2_DERR_MASK,
263 			AK8975_REG_CNTL_MODE_MASK},
264 		.ctrl_modes = {
265 			AK8975_REG_CNTL_MODE_POWER_DOWN,
266 			AK8975_REG_CNTL_MODE_ONCE,
267 			AK8975_REG_CNTL_MODE_SELF_TEST,
268 			AK8975_REG_CNTL_MODE_FUSE_ROM},
269 		.data_regs = {
270 			AK8975_REG_HXL,
271 			AK8975_REG_HYL,
272 			AK8975_REG_HZL},
273 	},
274 	{
275 		.type = AK8963,
276 		.raw_to_gauss = ak8963_09911_raw_to_gauss,
277 		.range = 8190,
278 		.ctrl_regs = {
279 			AK8975_REG_ST1,
280 			AK8975_REG_ST2,
281 			AK8975_REG_CNTL,
282 			AK8975_REG_ASAX,
283 			AK8975_MAX_REGS},
284 		.ctrl_masks = {
285 			AK8975_REG_ST1_DRDY_MASK,
286 			AK8975_REG_ST2_HOFL_MASK,
287 			0,
288 			AK8975_REG_CNTL_MODE_MASK},
289 		.ctrl_modes = {
290 			AK8975_REG_CNTL_MODE_POWER_DOWN,
291 			AK8975_REG_CNTL_MODE_ONCE,
292 			AK8975_REG_CNTL_MODE_SELF_TEST,
293 			AK8975_REG_CNTL_MODE_FUSE_ROM},
294 		.data_regs = {
295 			AK8975_REG_HXL,
296 			AK8975_REG_HYL,
297 			AK8975_REG_HZL},
298 	},
299 	{
300 		.type = AK09911,
301 		.raw_to_gauss = ak8963_09911_raw_to_gauss,
302 		.range = 8192,
303 		.ctrl_regs = {
304 			AK09912_REG_ST1,
305 			AK09912_REG_ST2,
306 			AK09912_REG_CNTL2,
307 			AK09912_REG_ASAX,
308 			AK09912_MAX_REGS},
309 		.ctrl_masks = {
310 			AK09912_REG_ST1_DRDY_MASK,
311 			AK09912_REG_ST2_HOFL_MASK,
312 			0,
313 			AK09912_REG_CNTL2_MODE_MASK},
314 		.ctrl_modes = {
315 			AK09912_REG_CNTL_MODE_POWER_DOWN,
316 			AK09912_REG_CNTL_MODE_ONCE,
317 			AK09912_REG_CNTL_MODE_SELF_TEST,
318 			AK09912_REG_CNTL_MODE_FUSE_ROM},
319 		.data_regs = {
320 			AK09912_REG_HXL,
321 			AK09912_REG_HYL,
322 			AK09912_REG_HZL},
323 	},
324 	{
325 		.type = AK09912,
326 		.raw_to_gauss = ak09912_raw_to_gauss,
327 		.range = 32752,
328 		.ctrl_regs = {
329 			AK09912_REG_ST1,
330 			AK09912_REG_ST2,
331 			AK09912_REG_CNTL2,
332 			AK09912_REG_ASAX,
333 			AK09912_MAX_REGS},
334 		.ctrl_masks = {
335 			AK09912_REG_ST1_DRDY_MASK,
336 			AK09912_REG_ST2_HOFL_MASK,
337 			0,
338 			AK09912_REG_CNTL2_MODE_MASK},
339 		.ctrl_modes = {
340 			AK09912_REG_CNTL_MODE_POWER_DOWN,
341 			AK09912_REG_CNTL_MODE_ONCE,
342 			AK09912_REG_CNTL_MODE_SELF_TEST,
343 			AK09912_REG_CNTL_MODE_FUSE_ROM},
344 		.data_regs = {
345 			AK09912_REG_HXL,
346 			AK09912_REG_HYL,
347 			AK09912_REG_HZL},
348 	}
349 };
350 
351 /*
352  * Per-instance context data for the device.
353  */
354 struct ak8975_data {
355 	struct i2c_client	*client;
356 	const struct ak_def	*def;
357 	struct mutex		lock;
358 	u8			asa[3];
359 	long			raw_to_gauss[3];
360 	struct gpio_desc	*eoc_gpiod;
361 	struct gpio_desc	*reset_gpiod;
362 	int			eoc_irq;
363 	wait_queue_head_t	data_ready_queue;
364 	unsigned long		flags;
365 	u8			cntl_cache;
366 	struct iio_mount_matrix orientation;
367 	struct regulator	*vdd;
368 	struct regulator	*vid;
369 
370 	/* Ensure natural alignment of timestamp */
371 	struct {
372 		s16 channels[3];
373 		s64 ts __aligned(8);
374 	} scan;
375 };
376 
377 /* Enable attached power regulator if any. */
378 static int ak8975_power_on(const struct ak8975_data *data)
379 {
380 	int ret;
381 
382 	ret = regulator_enable(data->vdd);
383 	if (ret) {
384 		dev_warn(&data->client->dev,
385 			 "Failed to enable specified Vdd supply\n");
386 		return ret;
387 	}
388 	ret = regulator_enable(data->vid);
389 	if (ret) {
390 		dev_warn(&data->client->dev,
391 			 "Failed to enable specified Vid supply\n");
392 		return ret;
393 	}
394 
395 	gpiod_set_value_cansleep(data->reset_gpiod, 0);
396 
397 	/*
398 	 * According to the datasheet the power supply rise time is 200us
399 	 * and the minimum wait time before mode setting is 100us, in
400 	 * total 300us. Add some margin and say minimum 500us here.
401 	 */
402 	usleep_range(500, 1000);
403 	return 0;
404 }
405 
406 /* Disable attached power regulator if any. */
407 static void ak8975_power_off(const struct ak8975_data *data)
408 {
409 	gpiod_set_value_cansleep(data->reset_gpiod, 1);
410 
411 	regulator_disable(data->vid);
412 	regulator_disable(data->vdd);
413 }
414 
415 /*
416  * Return 0 if the i2c device is the one we expect.
417  * return a negative error number otherwise
418  */
419 static int ak8975_who_i_am(struct i2c_client *client,
420 			   enum asahi_compass_chipset type)
421 {
422 	u8 wia_val[2];
423 	int ret;
424 
425 	/*
426 	 * Signature for each device:
427 	 * Device   |  WIA1      |  WIA2
428 	 * AK09912  |  DEVICE_ID |  AK09912_DEVICE_ID
429 	 * AK09911  |  DEVICE_ID |  AK09911_DEVICE_ID
430 	 * AK8975   |  DEVICE_ID |  NA
431 	 * AK8963   |  DEVICE_ID |  NA
432 	 */
433 	ret = i2c_smbus_read_i2c_block_data_or_emulated(
434 			client, AK09912_REG_WIA1, 2, wia_val);
435 	if (ret < 0) {
436 		dev_err(&client->dev, "Error reading WIA\n");
437 		return ret;
438 	}
439 
440 	if (wia_val[0] != AK8975_DEVICE_ID)
441 		return -ENODEV;
442 
443 	switch (type) {
444 	case AK8975:
445 	case AK8963:
446 		return 0;
447 	case AK09911:
448 		if (wia_val[1] == AK09911_DEVICE_ID)
449 			return 0;
450 		break;
451 	case AK09912:
452 		if (wia_val[1] == AK09912_DEVICE_ID)
453 			return 0;
454 		break;
455 	default:
456 		dev_err(&client->dev, "Type %d unknown\n", type);
457 	}
458 	return -ENODEV;
459 }
460 
461 /*
462  * Helper function to write to CNTL register.
463  */
464 static int ak8975_set_mode(struct ak8975_data *data, enum ak_ctrl_mode mode)
465 {
466 	u8 regval;
467 	int ret;
468 
469 	regval = (data->cntl_cache & ~data->def->ctrl_masks[CNTL_MODE]) |
470 		 data->def->ctrl_modes[mode];
471 	ret = i2c_smbus_write_byte_data(data->client,
472 					data->def->ctrl_regs[CNTL], regval);
473 	if (ret < 0) {
474 		return ret;
475 	}
476 	data->cntl_cache = regval;
477 	/* After mode change wait atleast 100us */
478 	usleep_range(100, 500);
479 
480 	return 0;
481 }
482 
483 /*
484  * Handle data ready irq
485  */
486 static irqreturn_t ak8975_irq_handler(int irq, void *data)
487 {
488 	struct ak8975_data *ak8975 = data;
489 
490 	set_bit(0, &ak8975->flags);
491 	wake_up(&ak8975->data_ready_queue);
492 
493 	return IRQ_HANDLED;
494 }
495 
496 /*
497  * Install data ready interrupt handler
498  */
499 static int ak8975_setup_irq(struct ak8975_data *data)
500 {
501 	struct i2c_client *client = data->client;
502 	int rc;
503 	int irq;
504 
505 	init_waitqueue_head(&data->data_ready_queue);
506 	clear_bit(0, &data->flags);
507 	if (client->irq)
508 		irq = client->irq;
509 	else
510 		irq = gpiod_to_irq(data->eoc_gpiod);
511 
512 	rc = devm_request_irq(&client->dev, irq, ak8975_irq_handler,
513 			      IRQF_TRIGGER_RISING | IRQF_ONESHOT,
514 			      dev_name(&client->dev), data);
515 	if (rc < 0) {
516 		dev_err(&client->dev, "irq %d request failed: %d\n", irq, rc);
517 		return rc;
518 	}
519 
520 	data->eoc_irq = irq;
521 
522 	return rc;
523 }
524 
525 
526 /*
527  * Perform some start-of-day setup, including reading the asa calibration
528  * values and caching them.
529  */
530 static int ak8975_setup(struct i2c_client *client)
531 {
532 	struct iio_dev *indio_dev = i2c_get_clientdata(client);
533 	struct ak8975_data *data = iio_priv(indio_dev);
534 	int ret;
535 
536 	/* Write the fused rom access mode. */
537 	ret = ak8975_set_mode(data, FUSE_ROM);
538 	if (ret < 0) {
539 		dev_err(&client->dev, "Error in setting fuse access mode\n");
540 		return ret;
541 	}
542 
543 	/* Get asa data and store in the device data. */
544 	ret = i2c_smbus_read_i2c_block_data_or_emulated(
545 			client, data->def->ctrl_regs[ASA_BASE],
546 			3, data->asa);
547 	if (ret < 0) {
548 		dev_err(&client->dev, "Not able to read asa data\n");
549 		return ret;
550 	}
551 
552 	/* After reading fuse ROM data set power-down mode */
553 	ret = ak8975_set_mode(data, POWER_DOWN);
554 	if (ret < 0) {
555 		dev_err(&client->dev, "Error in setting power-down mode\n");
556 		return ret;
557 	}
558 
559 	if (data->eoc_gpiod || client->irq > 0) {
560 		ret = ak8975_setup_irq(data);
561 		if (ret < 0) {
562 			dev_err(&client->dev,
563 				"Error setting data ready interrupt\n");
564 			return ret;
565 		}
566 	}
567 
568 	data->raw_to_gauss[0] = data->def->raw_to_gauss(data->asa[0]);
569 	data->raw_to_gauss[1] = data->def->raw_to_gauss(data->asa[1]);
570 	data->raw_to_gauss[2] = data->def->raw_to_gauss(data->asa[2]);
571 
572 	return 0;
573 }
574 
575 static int wait_conversion_complete_gpio(struct ak8975_data *data)
576 {
577 	struct i2c_client *client = data->client;
578 	u32 timeout_ms = AK8975_MAX_CONVERSION_TIMEOUT;
579 	int ret;
580 
581 	/* Wait for the conversion to complete. */
582 	while (timeout_ms) {
583 		msleep(AK8975_CONVERSION_DONE_POLL_TIME);
584 		if (gpiod_get_value(data->eoc_gpiod))
585 			break;
586 		timeout_ms -= AK8975_CONVERSION_DONE_POLL_TIME;
587 	}
588 	if (!timeout_ms) {
589 		dev_err(&client->dev, "Conversion timeout happened\n");
590 		return -EINVAL;
591 	}
592 
593 	ret = i2c_smbus_read_byte_data(client, data->def->ctrl_regs[ST1]);
594 	if (ret < 0)
595 		dev_err(&client->dev, "Error in reading ST1\n");
596 
597 	return ret;
598 }
599 
600 static int wait_conversion_complete_polled(struct ak8975_data *data)
601 {
602 	struct i2c_client *client = data->client;
603 	u8 read_status;
604 	u32 timeout_ms = AK8975_MAX_CONVERSION_TIMEOUT;
605 	int ret;
606 
607 	/* Wait for the conversion to complete. */
608 	while (timeout_ms) {
609 		msleep(AK8975_CONVERSION_DONE_POLL_TIME);
610 		ret = i2c_smbus_read_byte_data(client,
611 					       data->def->ctrl_regs[ST1]);
612 		if (ret < 0) {
613 			dev_err(&client->dev, "Error in reading ST1\n");
614 			return ret;
615 		}
616 		read_status = ret;
617 		if (read_status)
618 			break;
619 		timeout_ms -= AK8975_CONVERSION_DONE_POLL_TIME;
620 	}
621 	if (!timeout_ms) {
622 		dev_err(&client->dev, "Conversion timeout happened\n");
623 		return -EINVAL;
624 	}
625 
626 	return read_status;
627 }
628 
629 /* Returns 0 if the end of conversion interrupt occured or -ETIME otherwise */
630 static int wait_conversion_complete_interrupt(struct ak8975_data *data)
631 {
632 	int ret;
633 
634 	ret = wait_event_timeout(data->data_ready_queue,
635 				 test_bit(0, &data->flags),
636 				 AK8975_DATA_READY_TIMEOUT);
637 	clear_bit(0, &data->flags);
638 
639 	return ret > 0 ? 0 : -ETIME;
640 }
641 
642 static int ak8975_start_read_axis(struct ak8975_data *data,
643 				  const struct i2c_client *client)
644 {
645 	/* Set up the device for taking a sample. */
646 	int ret = ak8975_set_mode(data, MODE_ONCE);
647 
648 	if (ret < 0) {
649 		dev_err(&client->dev, "Error in setting operating mode\n");
650 		return ret;
651 	}
652 
653 	/* Wait for the conversion to complete. */
654 	if (data->eoc_irq)
655 		ret = wait_conversion_complete_interrupt(data);
656 	else if (data->eoc_gpiod)
657 		ret = wait_conversion_complete_gpio(data);
658 	else
659 		ret = wait_conversion_complete_polled(data);
660 	if (ret < 0)
661 		return ret;
662 
663 	/* This will be executed only for non-interrupt based waiting case */
664 	if (ret & data->def->ctrl_masks[ST1_DRDY]) {
665 		ret = i2c_smbus_read_byte_data(client,
666 					       data->def->ctrl_regs[ST2]);
667 		if (ret < 0) {
668 			dev_err(&client->dev, "Error in reading ST2\n");
669 			return ret;
670 		}
671 		if (ret & (data->def->ctrl_masks[ST2_DERR] |
672 			   data->def->ctrl_masks[ST2_HOFL])) {
673 			dev_err(&client->dev, "ST2 status error 0x%x\n", ret);
674 			return -EINVAL;
675 		}
676 	}
677 
678 	return 0;
679 }
680 
681 /* Retrieve raw flux value for one of the x, y, or z axis.  */
682 static int ak8975_read_axis(struct iio_dev *indio_dev, int index, int *val)
683 {
684 	struct ak8975_data *data = iio_priv(indio_dev);
685 	const struct i2c_client *client = data->client;
686 	const struct ak_def *def = data->def;
687 	__le16 rval;
688 	u16 buff;
689 	int ret;
690 
691 	pm_runtime_get_sync(&data->client->dev);
692 
693 	mutex_lock(&data->lock);
694 
695 	ret = ak8975_start_read_axis(data, client);
696 	if (ret)
697 		goto exit;
698 
699 	ret = i2c_smbus_read_i2c_block_data_or_emulated(
700 			client, def->data_regs[index],
701 			sizeof(rval), (u8*)&rval);
702 	if (ret < 0)
703 		goto exit;
704 
705 	mutex_unlock(&data->lock);
706 
707 	pm_runtime_mark_last_busy(&data->client->dev);
708 	pm_runtime_put_autosuspend(&data->client->dev);
709 
710 	/* Swap bytes and convert to valid range. */
711 	buff = le16_to_cpu(rval);
712 	*val = clamp_t(s16, buff, -def->range, def->range);
713 	return IIO_VAL_INT;
714 
715 exit:
716 	mutex_unlock(&data->lock);
717 	dev_err(&client->dev, "Error in reading axis\n");
718 	return ret;
719 }
720 
721 static int ak8975_read_raw(struct iio_dev *indio_dev,
722 			   struct iio_chan_spec const *chan,
723 			   int *val, int *val2,
724 			   long mask)
725 {
726 	struct ak8975_data *data = iio_priv(indio_dev);
727 
728 	switch (mask) {
729 	case IIO_CHAN_INFO_RAW:
730 		return ak8975_read_axis(indio_dev, chan->address, val);
731 	case IIO_CHAN_INFO_SCALE:
732 		*val = 0;
733 		*val2 = data->raw_to_gauss[chan->address];
734 		return IIO_VAL_INT_PLUS_MICRO;
735 	}
736 	return -EINVAL;
737 }
738 
739 static const struct iio_mount_matrix *
740 ak8975_get_mount_matrix(const struct iio_dev *indio_dev,
741 			const struct iio_chan_spec *chan)
742 {
743 	struct ak8975_data *data = iio_priv(indio_dev);
744 
745 	return &data->orientation;
746 }
747 
748 static const struct iio_chan_spec_ext_info ak8975_ext_info[] = {
749 	IIO_MOUNT_MATRIX(IIO_SHARED_BY_DIR, ak8975_get_mount_matrix),
750 	{ }
751 };
752 
753 #define AK8975_CHANNEL(axis, index)					\
754 	{								\
755 		.type = IIO_MAGN,					\
756 		.modified = 1,						\
757 		.channel2 = IIO_MOD_##axis,				\
758 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |		\
759 			     BIT(IIO_CHAN_INFO_SCALE),			\
760 		.address = index,					\
761 		.scan_index = index,					\
762 		.scan_type = {						\
763 			.sign = 's',					\
764 			.realbits = 16,					\
765 			.storagebits = 16,				\
766 			.endianness = IIO_CPU				\
767 		},							\
768 		.ext_info = ak8975_ext_info,				\
769 	}
770 
771 static const struct iio_chan_spec ak8975_channels[] = {
772 	AK8975_CHANNEL(X, 0), AK8975_CHANNEL(Y, 1), AK8975_CHANNEL(Z, 2),
773 	IIO_CHAN_SOFT_TIMESTAMP(3),
774 };
775 
776 static const unsigned long ak8975_scan_masks[] = { 0x7, 0 };
777 
778 static const struct iio_info ak8975_info = {
779 	.read_raw = &ak8975_read_raw,
780 };
781 
782 static const struct acpi_device_id ak_acpi_match[] = {
783 	{"AK8975", AK8975},
784 	{"AK8963", AK8963},
785 	{"INVN6500", AK8963},
786 	{"AK009911", AK09911},
787 	{"AK09911", AK09911},
788 	{"AKM9911", AK09911},
789 	{"AK09912", AK09912},
790 	{ }
791 };
792 MODULE_DEVICE_TABLE(acpi, ak_acpi_match);
793 
794 static void ak8975_fill_buffer(struct iio_dev *indio_dev)
795 {
796 	struct ak8975_data *data = iio_priv(indio_dev);
797 	const struct i2c_client *client = data->client;
798 	const struct ak_def *def = data->def;
799 	int ret;
800 	__le16 fval[3];
801 
802 	mutex_lock(&data->lock);
803 
804 	ret = ak8975_start_read_axis(data, client);
805 	if (ret)
806 		goto unlock;
807 
808 	/*
809 	 * For each axis, read the flux value from the appropriate register
810 	 * (the register is specified in the iio device attributes).
811 	 */
812 	ret = i2c_smbus_read_i2c_block_data_or_emulated(client,
813 							def->data_regs[0],
814 							3 * sizeof(fval[0]),
815 							(u8 *)fval);
816 	if (ret < 0)
817 		goto unlock;
818 
819 	mutex_unlock(&data->lock);
820 
821 	/* Clamp to valid range. */
822 	data->scan.channels[0] = clamp_t(s16, le16_to_cpu(fval[0]), -def->range, def->range);
823 	data->scan.channels[1] = clamp_t(s16, le16_to_cpu(fval[1]), -def->range, def->range);
824 	data->scan.channels[2] = clamp_t(s16, le16_to_cpu(fval[2]), -def->range, def->range);
825 
826 	iio_push_to_buffers_with_timestamp(indio_dev, &data->scan,
827 					   iio_get_time_ns(indio_dev));
828 
829 	return;
830 
831 unlock:
832 	mutex_unlock(&data->lock);
833 	dev_err(&client->dev, "Error in reading axes block\n");
834 }
835 
836 static irqreturn_t ak8975_handle_trigger(int irq, void *p)
837 {
838 	const struct iio_poll_func *pf = p;
839 	struct iio_dev *indio_dev = pf->indio_dev;
840 
841 	ak8975_fill_buffer(indio_dev);
842 	iio_trigger_notify_done(indio_dev->trig);
843 	return IRQ_HANDLED;
844 }
845 
846 static int ak8975_probe(struct i2c_client *client,
847 			const struct i2c_device_id *id)
848 {
849 	struct ak8975_data *data;
850 	struct iio_dev *indio_dev;
851 	struct gpio_desc *eoc_gpiod;
852 	struct gpio_desc *reset_gpiod;
853 	const void *match;
854 	unsigned int i;
855 	int err;
856 	enum asahi_compass_chipset chipset;
857 	const char *name = NULL;
858 
859 	/*
860 	 * Grab and set up the supplied GPIO.
861 	 * We may not have a GPIO based IRQ to scan, that is fine, we will
862 	 * poll if so.
863 	 */
864 	eoc_gpiod = devm_gpiod_get_optional(&client->dev, NULL, GPIOD_IN);
865 	if (IS_ERR(eoc_gpiod))
866 		return PTR_ERR(eoc_gpiod);
867 	if (eoc_gpiod)
868 		gpiod_set_consumer_name(eoc_gpiod, "ak_8975");
869 
870 	/*
871 	 * According to AK09911 datasheet, if reset GPIO is provided then
872 	 * deassert reset on ak8975_power_on() and assert reset on
873 	 * ak8975_power_off().
874 	 */
875 	reset_gpiod = devm_gpiod_get_optional(&client->dev,
876 					      "reset", GPIOD_OUT_HIGH);
877 	if (IS_ERR(reset_gpiod))
878 		return PTR_ERR(reset_gpiod);
879 
880 	/* Register with IIO */
881 	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
882 	if (indio_dev == NULL)
883 		return -ENOMEM;
884 
885 	data = iio_priv(indio_dev);
886 	i2c_set_clientdata(client, indio_dev);
887 
888 	data->client = client;
889 	data->eoc_gpiod = eoc_gpiod;
890 	data->reset_gpiod = reset_gpiod;
891 	data->eoc_irq = 0;
892 
893 	err = iio_read_mount_matrix(&client->dev, "mount-matrix", &data->orientation);
894 	if (err)
895 		return err;
896 
897 	/* id will be NULL when enumerated via ACPI */
898 	match = device_get_match_data(&client->dev);
899 	if (match) {
900 		chipset = (enum asahi_compass_chipset)(match);
901 		name = dev_name(&client->dev);
902 	} else if (id) {
903 		chipset = (enum asahi_compass_chipset)(id->driver_data);
904 		name = id->name;
905 	} else
906 		return -ENOSYS;
907 
908 	for (i = 0; i < ARRAY_SIZE(ak_def_array); i++)
909 		if (ak_def_array[i].type == chipset)
910 			break;
911 
912 	if (i == ARRAY_SIZE(ak_def_array)) {
913 		dev_err(&client->dev, "AKM device type unsupported: %d\n",
914 			chipset);
915 		return -ENODEV;
916 	}
917 
918 	data->def = &ak_def_array[i];
919 
920 	/* Fetch the regulators */
921 	data->vdd = devm_regulator_get(&client->dev, "vdd");
922 	if (IS_ERR(data->vdd))
923 		return PTR_ERR(data->vdd);
924 	data->vid = devm_regulator_get(&client->dev, "vid");
925 	if (IS_ERR(data->vid))
926 		return PTR_ERR(data->vid);
927 
928 	err = ak8975_power_on(data);
929 	if (err)
930 		return err;
931 
932 	err = ak8975_who_i_am(client, data->def->type);
933 	if (err < 0) {
934 		dev_err(&client->dev, "Unexpected device\n");
935 		goto power_off;
936 	}
937 	dev_dbg(&client->dev, "Asahi compass chip %s\n", name);
938 
939 	/* Perform some basic start-of-day setup of the device. */
940 	err = ak8975_setup(client);
941 	if (err < 0) {
942 		dev_err(&client->dev, "%s initialization fails\n", name);
943 		goto power_off;
944 	}
945 
946 	mutex_init(&data->lock);
947 	indio_dev->channels = ak8975_channels;
948 	indio_dev->num_channels = ARRAY_SIZE(ak8975_channels);
949 	indio_dev->info = &ak8975_info;
950 	indio_dev->available_scan_masks = ak8975_scan_masks;
951 	indio_dev->modes = INDIO_DIRECT_MODE;
952 	indio_dev->name = name;
953 
954 	err = iio_triggered_buffer_setup(indio_dev, NULL, ak8975_handle_trigger,
955 					 NULL);
956 	if (err) {
957 		dev_err(&client->dev, "triggered buffer setup failed\n");
958 		goto power_off;
959 	}
960 
961 	err = iio_device_register(indio_dev);
962 	if (err) {
963 		dev_err(&client->dev, "device register failed\n");
964 		goto cleanup_buffer;
965 	}
966 
967 	/* Enable runtime PM */
968 	pm_runtime_get_noresume(&client->dev);
969 	pm_runtime_set_active(&client->dev);
970 	pm_runtime_enable(&client->dev);
971 	/*
972 	 * The device comes online in 500us, so add two orders of magnitude
973 	 * of delay before autosuspending: 50 ms.
974 	 */
975 	pm_runtime_set_autosuspend_delay(&client->dev, 50);
976 	pm_runtime_use_autosuspend(&client->dev);
977 	pm_runtime_put(&client->dev);
978 
979 	return 0;
980 
981 cleanup_buffer:
982 	iio_triggered_buffer_cleanup(indio_dev);
983 power_off:
984 	ak8975_power_off(data);
985 	return err;
986 }
987 
988 static int ak8975_remove(struct i2c_client *client)
989 {
990 	struct iio_dev *indio_dev = i2c_get_clientdata(client);
991 	struct ak8975_data *data = iio_priv(indio_dev);
992 
993 	pm_runtime_get_sync(&client->dev);
994 	pm_runtime_put_noidle(&client->dev);
995 	pm_runtime_disable(&client->dev);
996 	iio_device_unregister(indio_dev);
997 	iio_triggered_buffer_cleanup(indio_dev);
998 	ak8975_set_mode(data, POWER_DOWN);
999 	ak8975_power_off(data);
1000 
1001 	return 0;
1002 }
1003 
1004 #ifdef CONFIG_PM
1005 static int ak8975_runtime_suspend(struct device *dev)
1006 {
1007 	struct i2c_client *client = to_i2c_client(dev);
1008 	struct iio_dev *indio_dev = i2c_get_clientdata(client);
1009 	struct ak8975_data *data = iio_priv(indio_dev);
1010 	int ret;
1011 
1012 	/* Set the device in power down if it wasn't already */
1013 	ret = ak8975_set_mode(data, POWER_DOWN);
1014 	if (ret < 0) {
1015 		dev_err(&client->dev, "Error in setting power-down mode\n");
1016 		return ret;
1017 	}
1018 	/* Next cut the regulators */
1019 	ak8975_power_off(data);
1020 
1021 	return 0;
1022 }
1023 
1024 static int ak8975_runtime_resume(struct device *dev)
1025 {
1026 	struct i2c_client *client = to_i2c_client(dev);
1027 	struct iio_dev *indio_dev = i2c_get_clientdata(client);
1028 	struct ak8975_data *data = iio_priv(indio_dev);
1029 	int ret;
1030 
1031 	/* Take up the regulators */
1032 	ak8975_power_on(data);
1033 	/*
1034 	 * We come up in powered down mode, the reading routines will
1035 	 * put us in the mode to read values later.
1036 	 */
1037 	ret = ak8975_set_mode(data, POWER_DOWN);
1038 	if (ret < 0) {
1039 		dev_err(&client->dev, "Error in setting power-down mode\n");
1040 		return ret;
1041 	}
1042 
1043 	return 0;
1044 }
1045 #endif /* CONFIG_PM */
1046 
1047 static const struct dev_pm_ops ak8975_dev_pm_ops = {
1048 	SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
1049 				pm_runtime_force_resume)
1050 	SET_RUNTIME_PM_OPS(ak8975_runtime_suspend,
1051 			   ak8975_runtime_resume, NULL)
1052 };
1053 
1054 static const struct i2c_device_id ak8975_id[] = {
1055 	{"ak8975", AK8975},
1056 	{"ak8963", AK8963},
1057 	{"AK8963", AK8963},
1058 	{"ak09911", AK09911},
1059 	{"ak09912", AK09912},
1060 	{}
1061 };
1062 
1063 MODULE_DEVICE_TABLE(i2c, ak8975_id);
1064 
1065 static const struct of_device_id ak8975_of_match[] = {
1066 	{ .compatible = "asahi-kasei,ak8975", },
1067 	{ .compatible = "ak8975", },
1068 	{ .compatible = "asahi-kasei,ak8963", },
1069 	{ .compatible = "ak8963", },
1070 	{ .compatible = "asahi-kasei,ak09911", },
1071 	{ .compatible = "ak09911", },
1072 	{ .compatible = "asahi-kasei,ak09912", },
1073 	{ .compatible = "ak09912", },
1074 	{}
1075 };
1076 MODULE_DEVICE_TABLE(of, ak8975_of_match);
1077 
1078 static struct i2c_driver ak8975_driver = {
1079 	.driver = {
1080 		.name	= "ak8975",
1081 		.pm = &ak8975_dev_pm_ops,
1082 		.of_match_table = ak8975_of_match,
1083 		.acpi_match_table = ak_acpi_match,
1084 	},
1085 	.probe		= ak8975_probe,
1086 	.remove		= ak8975_remove,
1087 	.id_table	= ak8975_id,
1088 };
1089 module_i2c_driver(ak8975_driver);
1090 
1091 MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
1092 MODULE_DESCRIPTION("AK8975 magnetometer driver");
1093 MODULE_LICENSE("GPL");
1094