1 /*
2  * A sensor driver for the magnetometer AK8975.
3  *
4  * Magnetic compass sensor driver for monitoring magnetic flux information.
5  *
6  * Copyright (c) 2010, NVIDIA Corporation.
7  *
8  * This program is free software; you can redistribute it and/or modify
9  * it under the terms of the GNU General Public License as published by
10  * the Free Software Foundation; either version 2 of the License, or
11  * (at your option) any later version.
12  *
13  * This program is distributed in the hope that it will be useful, but WITHOUT
14  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
15  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
16  * more details.
17  *
18  * You should have received a copy of the GNU General Public License along
19  * with this program; if not, write to the Free Software Foundation, Inc.,
20  * 51 Franklin Street, Fifth Floor, Boston, MA	02110-1301, USA.
21  */
22 
23 #include <linux/module.h>
24 #include <linux/kernel.h>
25 #include <linux/slab.h>
26 #include <linux/i2c.h>
27 #include <linux/interrupt.h>
28 #include <linux/err.h>
29 #include <linux/mutex.h>
30 #include <linux/delay.h>
31 #include <linux/bitops.h>
32 #include <linux/gpio.h>
33 #include <linux/of_gpio.h>
34 #include <linux/acpi.h>
35 #include <linux/regulator/consumer.h>
36 #include <linux/pm_runtime.h>
37 
38 #include <linux/iio/iio.h>
39 #include <linux/iio/sysfs.h>
40 #include <linux/iio/buffer.h>
41 #include <linux/iio/trigger.h>
42 #include <linux/iio/trigger_consumer.h>
43 #include <linux/iio/triggered_buffer.h>
44 
45 #include <linux/iio/magnetometer/ak8975.h>
46 
47 /*
48  * Register definitions, as well as various shifts and masks to get at the
49  * individual fields of the registers.
50  */
51 #define AK8975_REG_WIA			0x00
52 #define AK8975_DEVICE_ID		0x48
53 
54 #define AK8975_REG_INFO			0x01
55 
56 #define AK8975_REG_ST1			0x02
57 #define AK8975_REG_ST1_DRDY_SHIFT	0
58 #define AK8975_REG_ST1_DRDY_MASK	(1 << AK8975_REG_ST1_DRDY_SHIFT)
59 
60 #define AK8975_REG_HXL			0x03
61 #define AK8975_REG_HXH			0x04
62 #define AK8975_REG_HYL			0x05
63 #define AK8975_REG_HYH			0x06
64 #define AK8975_REG_HZL			0x07
65 #define AK8975_REG_HZH			0x08
66 #define AK8975_REG_ST2			0x09
67 #define AK8975_REG_ST2_DERR_SHIFT	2
68 #define AK8975_REG_ST2_DERR_MASK	(1 << AK8975_REG_ST2_DERR_SHIFT)
69 
70 #define AK8975_REG_ST2_HOFL_SHIFT	3
71 #define AK8975_REG_ST2_HOFL_MASK	(1 << AK8975_REG_ST2_HOFL_SHIFT)
72 
73 #define AK8975_REG_CNTL			0x0A
74 #define AK8975_REG_CNTL_MODE_SHIFT	0
75 #define AK8975_REG_CNTL_MODE_MASK	(0xF << AK8975_REG_CNTL_MODE_SHIFT)
76 #define AK8975_REG_CNTL_MODE_POWER_DOWN	0x00
77 #define AK8975_REG_CNTL_MODE_ONCE	0x01
78 #define AK8975_REG_CNTL_MODE_SELF_TEST	0x08
79 #define AK8975_REG_CNTL_MODE_FUSE_ROM	0x0F
80 
81 #define AK8975_REG_RSVC			0x0B
82 #define AK8975_REG_ASTC			0x0C
83 #define AK8975_REG_TS1			0x0D
84 #define AK8975_REG_TS2			0x0E
85 #define AK8975_REG_I2CDIS		0x0F
86 #define AK8975_REG_ASAX			0x10
87 #define AK8975_REG_ASAY			0x11
88 #define AK8975_REG_ASAZ			0x12
89 
90 #define AK8975_MAX_REGS			AK8975_REG_ASAZ
91 
92 /*
93  * AK09912 Register definitions
94  */
95 #define AK09912_REG_WIA1		0x00
96 #define AK09912_REG_WIA2		0x01
97 #define AK09912_DEVICE_ID		0x04
98 #define AK09911_DEVICE_ID		0x05
99 
100 #define AK09911_REG_INFO1		0x02
101 #define AK09911_REG_INFO2		0x03
102 
103 #define AK09912_REG_ST1			0x10
104 
105 #define AK09912_REG_ST1_DRDY_SHIFT	0
106 #define AK09912_REG_ST1_DRDY_MASK	(1 << AK09912_REG_ST1_DRDY_SHIFT)
107 
108 #define AK09912_REG_HXL			0x11
109 #define AK09912_REG_HXH			0x12
110 #define AK09912_REG_HYL			0x13
111 #define AK09912_REG_HYH			0x14
112 #define AK09912_REG_HZL			0x15
113 #define AK09912_REG_HZH			0x16
114 #define AK09912_REG_TMPS		0x17
115 
116 #define AK09912_REG_ST2			0x18
117 #define AK09912_REG_ST2_HOFL_SHIFT	3
118 #define AK09912_REG_ST2_HOFL_MASK	(1 << AK09912_REG_ST2_HOFL_SHIFT)
119 
120 #define AK09912_REG_CNTL1		0x30
121 
122 #define AK09912_REG_CNTL2		0x31
123 #define AK09912_REG_CNTL_MODE_POWER_DOWN	0x00
124 #define AK09912_REG_CNTL_MODE_ONCE	0x01
125 #define AK09912_REG_CNTL_MODE_SELF_TEST	0x10
126 #define AK09912_REG_CNTL_MODE_FUSE_ROM	0x1F
127 #define AK09912_REG_CNTL2_MODE_SHIFT	0
128 #define AK09912_REG_CNTL2_MODE_MASK	(0x1F << AK09912_REG_CNTL2_MODE_SHIFT)
129 
130 #define AK09912_REG_CNTL3		0x32
131 
132 #define AK09912_REG_TS1			0x33
133 #define AK09912_REG_TS2			0x34
134 #define AK09912_REG_TS3			0x35
135 #define AK09912_REG_I2CDIS		0x36
136 #define AK09912_REG_TS4			0x37
137 
138 #define AK09912_REG_ASAX		0x60
139 #define AK09912_REG_ASAY		0x61
140 #define AK09912_REG_ASAZ		0x62
141 
142 #define AK09912_MAX_REGS		AK09912_REG_ASAZ
143 
144 /*
145  * Miscellaneous values.
146  */
147 #define AK8975_MAX_CONVERSION_TIMEOUT	500
148 #define AK8975_CONVERSION_DONE_POLL_TIME 10
149 #define AK8975_DATA_READY_TIMEOUT	((100*HZ)/1000)
150 
151 /*
152  * Precalculate scale factor (in Gauss units) for each axis and
153  * store in the device data.
154  *
155  * This scale factor is axis-dependent, and is derived from 3 calibration
156  * factors ASA(x), ASA(y), and ASA(z).
157  *
158  * These ASA values are read from the sensor device at start of day, and
159  * cached in the device context struct.
160  *
161  * Adjusting the flux value with the sensitivity adjustment value should be
162  * done via the following formula:
163  *
164  * Hadj = H * ( ( ( (ASA-128)*0.5 ) / 128 ) + 1 )
165  * where H is the raw value, ASA is the sensitivity adjustment, and Hadj
166  * is the resultant adjusted value.
167  *
168  * We reduce the formula to:
169  *
170  * Hadj = H * (ASA + 128) / 256
171  *
172  * H is in the range of -4096 to 4095.  The magnetometer has a range of
173  * +-1229uT.  To go from the raw value to uT is:
174  *
175  * HuT = H * 1229/4096, or roughly, 3/10.
176  *
177  * Since 1uT = 0.01 gauss, our final scale factor becomes:
178  *
179  * Hadj = H * ((ASA + 128) / 256) * 3/10 * 1/100
180  * Hadj = H * ((ASA + 128) * 0.003) / 256
181  *
182  * Since ASA doesn't change, we cache the resultant scale factor into the
183  * device context in ak8975_setup().
184  *
185  * Given we use IIO_VAL_INT_PLUS_MICRO bit when displaying the scale, we
186  * multiply the stored scale value by 1e6.
187  */
188 static long ak8975_raw_to_gauss(u16 data)
189 {
190 	return (((long)data + 128) * 3000) / 256;
191 }
192 
193 /*
194  * For AK8963 and AK09911, same calculation, but the device is less sensitive:
195  *
196  * H is in the range of +-8190.  The magnetometer has a range of
197  * +-4912uT.  To go from the raw value to uT is:
198  *
199  * HuT = H * 4912/8190, or roughly, 6/10, instead of 3/10.
200  */
201 
202 static long ak8963_09911_raw_to_gauss(u16 data)
203 {
204 	return (((long)data + 128) * 6000) / 256;
205 }
206 
207 /*
208  * For AK09912, same calculation, except the device is more sensitive:
209  *
210  * H is in the range of -32752 to 32752.  The magnetometer has a range of
211  * +-4912uT.  To go from the raw value to uT is:
212  *
213  * HuT = H * 4912/32752, or roughly, 3/20, instead of 3/10.
214  */
215 static long ak09912_raw_to_gauss(u16 data)
216 {
217 	return (((long)data + 128) * 1500) / 256;
218 }
219 
220 /* Compatible Asahi Kasei Compass parts */
221 enum asahi_compass_chipset {
222 	AK8975,
223 	AK8963,
224 	AK09911,
225 	AK09912,
226 	AK_MAX_TYPE
227 };
228 
229 enum ak_ctrl_reg_addr {
230 	ST1,
231 	ST2,
232 	CNTL,
233 	ASA_BASE,
234 	MAX_REGS,
235 	REGS_END,
236 };
237 
238 enum ak_ctrl_reg_mask {
239 	ST1_DRDY,
240 	ST2_HOFL,
241 	ST2_DERR,
242 	CNTL_MODE,
243 	MASK_END,
244 };
245 
246 enum ak_ctrl_mode {
247 	POWER_DOWN,
248 	MODE_ONCE,
249 	SELF_TEST,
250 	FUSE_ROM,
251 	MODE_END,
252 };
253 
254 struct ak_def {
255 	enum asahi_compass_chipset type;
256 	long (*raw_to_gauss)(u16 data);
257 	u16 range;
258 	u8 ctrl_regs[REGS_END];
259 	u8 ctrl_masks[MASK_END];
260 	u8 ctrl_modes[MODE_END];
261 	u8 data_regs[3];
262 };
263 
264 static const struct ak_def ak_def_array[AK_MAX_TYPE] = {
265 	{
266 		.type = AK8975,
267 		.raw_to_gauss = ak8975_raw_to_gauss,
268 		.range = 4096,
269 		.ctrl_regs = {
270 			AK8975_REG_ST1,
271 			AK8975_REG_ST2,
272 			AK8975_REG_CNTL,
273 			AK8975_REG_ASAX,
274 			AK8975_MAX_REGS},
275 		.ctrl_masks = {
276 			AK8975_REG_ST1_DRDY_MASK,
277 			AK8975_REG_ST2_HOFL_MASK,
278 			AK8975_REG_ST2_DERR_MASK,
279 			AK8975_REG_CNTL_MODE_MASK},
280 		.ctrl_modes = {
281 			AK8975_REG_CNTL_MODE_POWER_DOWN,
282 			AK8975_REG_CNTL_MODE_ONCE,
283 			AK8975_REG_CNTL_MODE_SELF_TEST,
284 			AK8975_REG_CNTL_MODE_FUSE_ROM},
285 		.data_regs = {
286 			AK8975_REG_HXL,
287 			AK8975_REG_HYL,
288 			AK8975_REG_HZL},
289 	},
290 	{
291 		.type = AK8963,
292 		.raw_to_gauss = ak8963_09911_raw_to_gauss,
293 		.range = 8190,
294 		.ctrl_regs = {
295 			AK8975_REG_ST1,
296 			AK8975_REG_ST2,
297 			AK8975_REG_CNTL,
298 			AK8975_REG_ASAX,
299 			AK8975_MAX_REGS},
300 		.ctrl_masks = {
301 			AK8975_REG_ST1_DRDY_MASK,
302 			AK8975_REG_ST2_HOFL_MASK,
303 			0,
304 			AK8975_REG_CNTL_MODE_MASK},
305 		.ctrl_modes = {
306 			AK8975_REG_CNTL_MODE_POWER_DOWN,
307 			AK8975_REG_CNTL_MODE_ONCE,
308 			AK8975_REG_CNTL_MODE_SELF_TEST,
309 			AK8975_REG_CNTL_MODE_FUSE_ROM},
310 		.data_regs = {
311 			AK8975_REG_HXL,
312 			AK8975_REG_HYL,
313 			AK8975_REG_HZL},
314 	},
315 	{
316 		.type = AK09911,
317 		.raw_to_gauss = ak8963_09911_raw_to_gauss,
318 		.range = 8192,
319 		.ctrl_regs = {
320 			AK09912_REG_ST1,
321 			AK09912_REG_ST2,
322 			AK09912_REG_CNTL2,
323 			AK09912_REG_ASAX,
324 			AK09912_MAX_REGS},
325 		.ctrl_masks = {
326 			AK09912_REG_ST1_DRDY_MASK,
327 			AK09912_REG_ST2_HOFL_MASK,
328 			0,
329 			AK09912_REG_CNTL2_MODE_MASK},
330 		.ctrl_modes = {
331 			AK09912_REG_CNTL_MODE_POWER_DOWN,
332 			AK09912_REG_CNTL_MODE_ONCE,
333 			AK09912_REG_CNTL_MODE_SELF_TEST,
334 			AK09912_REG_CNTL_MODE_FUSE_ROM},
335 		.data_regs = {
336 			AK09912_REG_HXL,
337 			AK09912_REG_HYL,
338 			AK09912_REG_HZL},
339 	},
340 	{
341 		.type = AK09912,
342 		.raw_to_gauss = ak09912_raw_to_gauss,
343 		.range = 32752,
344 		.ctrl_regs = {
345 			AK09912_REG_ST1,
346 			AK09912_REG_ST2,
347 			AK09912_REG_CNTL2,
348 			AK09912_REG_ASAX,
349 			AK09912_MAX_REGS},
350 		.ctrl_masks = {
351 			AK09912_REG_ST1_DRDY_MASK,
352 			AK09912_REG_ST2_HOFL_MASK,
353 			0,
354 			AK09912_REG_CNTL2_MODE_MASK},
355 		.ctrl_modes = {
356 			AK09912_REG_CNTL_MODE_POWER_DOWN,
357 			AK09912_REG_CNTL_MODE_ONCE,
358 			AK09912_REG_CNTL_MODE_SELF_TEST,
359 			AK09912_REG_CNTL_MODE_FUSE_ROM},
360 		.data_regs = {
361 			AK09912_REG_HXL,
362 			AK09912_REG_HYL,
363 			AK09912_REG_HZL},
364 	}
365 };
366 
367 /*
368  * Per-instance context data for the device.
369  */
370 struct ak8975_data {
371 	struct i2c_client	*client;
372 	const struct ak_def	*def;
373 	struct mutex		lock;
374 	u8			asa[3];
375 	long			raw_to_gauss[3];
376 	int			eoc_gpio;
377 	int			eoc_irq;
378 	wait_queue_head_t	data_ready_queue;
379 	unsigned long		flags;
380 	u8			cntl_cache;
381 	struct iio_mount_matrix orientation;
382 	struct regulator	*vdd;
383 	struct regulator	*vid;
384 };
385 
386 /* Enable attached power regulator if any. */
387 static int ak8975_power_on(const struct ak8975_data *data)
388 {
389 	int ret;
390 
391 	ret = regulator_enable(data->vdd);
392 	if (ret) {
393 		dev_warn(&data->client->dev,
394 			 "Failed to enable specified Vdd supply\n");
395 		return ret;
396 	}
397 	ret = regulator_enable(data->vid);
398 	if (ret) {
399 		dev_warn(&data->client->dev,
400 			 "Failed to enable specified Vid supply\n");
401 		return ret;
402 	}
403 	/*
404 	 * According to the datasheet the power supply rise time i 200us
405 	 * and the minimum wait time before mode setting is 100us, in
406 	 * total 300 us. Add some margin and say minimum 500us here.
407 	 */
408 	usleep_range(500, 1000);
409 	return 0;
410 }
411 
412 /* Disable attached power regulator if any. */
413 static void ak8975_power_off(const struct ak8975_data *data)
414 {
415 	regulator_disable(data->vid);
416 	regulator_disable(data->vdd);
417 }
418 
419 /*
420  * Return 0 if the i2c device is the one we expect.
421  * return a negative error number otherwise
422  */
423 static int ak8975_who_i_am(struct i2c_client *client,
424 			   enum asahi_compass_chipset type)
425 {
426 	u8 wia_val[2];
427 	int ret;
428 
429 	/*
430 	 * Signature for each device:
431 	 * Device   |  WIA1      |  WIA2
432 	 * AK09912  |  DEVICE_ID |  AK09912_DEVICE_ID
433 	 * AK09911  |  DEVICE_ID |  AK09911_DEVICE_ID
434 	 * AK8975   |  DEVICE_ID |  NA
435 	 * AK8963   |  DEVICE_ID |  NA
436 	 */
437 	ret = i2c_smbus_read_i2c_block_data_or_emulated(
438 			client, AK09912_REG_WIA1, 2, wia_val);
439 	if (ret < 0) {
440 		dev_err(&client->dev, "Error reading WIA\n");
441 		return ret;
442 	}
443 
444 	if (wia_val[0] != AK8975_DEVICE_ID)
445 		return -ENODEV;
446 
447 	switch (type) {
448 	case AK8975:
449 	case AK8963:
450 		return 0;
451 	case AK09911:
452 		if (wia_val[1] == AK09911_DEVICE_ID)
453 			return 0;
454 		break;
455 	case AK09912:
456 		if (wia_val[1] == AK09912_DEVICE_ID)
457 			return 0;
458 		break;
459 	default:
460 		dev_err(&client->dev, "Type %d unknown\n", type);
461 	}
462 	return -ENODEV;
463 }
464 
465 /*
466  * Helper function to write to CNTL register.
467  */
468 static int ak8975_set_mode(struct ak8975_data *data, enum ak_ctrl_mode mode)
469 {
470 	u8 regval;
471 	int ret;
472 
473 	regval = (data->cntl_cache & ~data->def->ctrl_masks[CNTL_MODE]) |
474 		 data->def->ctrl_modes[mode];
475 	ret = i2c_smbus_write_byte_data(data->client,
476 					data->def->ctrl_regs[CNTL], regval);
477 	if (ret < 0) {
478 		return ret;
479 	}
480 	data->cntl_cache = regval;
481 	/* After mode change wait atleast 100us */
482 	usleep_range(100, 500);
483 
484 	return 0;
485 }
486 
487 /*
488  * Handle data ready irq
489  */
490 static irqreturn_t ak8975_irq_handler(int irq, void *data)
491 {
492 	struct ak8975_data *ak8975 = data;
493 
494 	set_bit(0, &ak8975->flags);
495 	wake_up(&ak8975->data_ready_queue);
496 
497 	return IRQ_HANDLED;
498 }
499 
500 /*
501  * Install data ready interrupt handler
502  */
503 static int ak8975_setup_irq(struct ak8975_data *data)
504 {
505 	struct i2c_client *client = data->client;
506 	int rc;
507 	int irq;
508 
509 	init_waitqueue_head(&data->data_ready_queue);
510 	clear_bit(0, &data->flags);
511 	if (client->irq)
512 		irq = client->irq;
513 	else
514 		irq = gpio_to_irq(data->eoc_gpio);
515 
516 	rc = devm_request_irq(&client->dev, irq, ak8975_irq_handler,
517 			      IRQF_TRIGGER_RISING | IRQF_ONESHOT,
518 			      dev_name(&client->dev), data);
519 	if (rc < 0) {
520 		dev_err(&client->dev,
521 			"irq %d request failed, (gpio %d): %d\n",
522 			irq, data->eoc_gpio, rc);
523 		return rc;
524 	}
525 
526 	data->eoc_irq = irq;
527 
528 	return rc;
529 }
530 
531 
532 /*
533  * Perform some start-of-day setup, including reading the asa calibration
534  * values and caching them.
535  */
536 static int ak8975_setup(struct i2c_client *client)
537 {
538 	struct iio_dev *indio_dev = i2c_get_clientdata(client);
539 	struct ak8975_data *data = iio_priv(indio_dev);
540 	int ret;
541 
542 	/* Write the fused rom access mode. */
543 	ret = ak8975_set_mode(data, FUSE_ROM);
544 	if (ret < 0) {
545 		dev_err(&client->dev, "Error in setting fuse access mode\n");
546 		return ret;
547 	}
548 
549 	/* Get asa data and store in the device data. */
550 	ret = i2c_smbus_read_i2c_block_data_or_emulated(
551 			client, data->def->ctrl_regs[ASA_BASE],
552 			3, data->asa);
553 	if (ret < 0) {
554 		dev_err(&client->dev, "Not able to read asa data\n");
555 		return ret;
556 	}
557 
558 	/* After reading fuse ROM data set power-down mode */
559 	ret = ak8975_set_mode(data, POWER_DOWN);
560 	if (ret < 0) {
561 		dev_err(&client->dev, "Error in setting power-down mode\n");
562 		return ret;
563 	}
564 
565 	if (data->eoc_gpio > 0 || client->irq > 0) {
566 		ret = ak8975_setup_irq(data);
567 		if (ret < 0) {
568 			dev_err(&client->dev,
569 				"Error setting data ready interrupt\n");
570 			return ret;
571 		}
572 	}
573 
574 	data->raw_to_gauss[0] = data->def->raw_to_gauss(data->asa[0]);
575 	data->raw_to_gauss[1] = data->def->raw_to_gauss(data->asa[1]);
576 	data->raw_to_gauss[2] = data->def->raw_to_gauss(data->asa[2]);
577 
578 	return 0;
579 }
580 
581 static int wait_conversion_complete_gpio(struct ak8975_data *data)
582 {
583 	struct i2c_client *client = data->client;
584 	u32 timeout_ms = AK8975_MAX_CONVERSION_TIMEOUT;
585 	int ret;
586 
587 	/* Wait for the conversion to complete. */
588 	while (timeout_ms) {
589 		msleep(AK8975_CONVERSION_DONE_POLL_TIME);
590 		if (gpio_get_value(data->eoc_gpio))
591 			break;
592 		timeout_ms -= AK8975_CONVERSION_DONE_POLL_TIME;
593 	}
594 	if (!timeout_ms) {
595 		dev_err(&client->dev, "Conversion timeout happened\n");
596 		return -EINVAL;
597 	}
598 
599 	ret = i2c_smbus_read_byte_data(client, data->def->ctrl_regs[ST1]);
600 	if (ret < 0)
601 		dev_err(&client->dev, "Error in reading ST1\n");
602 
603 	return ret;
604 }
605 
606 static int wait_conversion_complete_polled(struct ak8975_data *data)
607 {
608 	struct i2c_client *client = data->client;
609 	u8 read_status;
610 	u32 timeout_ms = AK8975_MAX_CONVERSION_TIMEOUT;
611 	int ret;
612 
613 	/* Wait for the conversion to complete. */
614 	while (timeout_ms) {
615 		msleep(AK8975_CONVERSION_DONE_POLL_TIME);
616 		ret = i2c_smbus_read_byte_data(client,
617 					       data->def->ctrl_regs[ST1]);
618 		if (ret < 0) {
619 			dev_err(&client->dev, "Error in reading ST1\n");
620 			return ret;
621 		}
622 		read_status = ret;
623 		if (read_status)
624 			break;
625 		timeout_ms -= AK8975_CONVERSION_DONE_POLL_TIME;
626 	}
627 	if (!timeout_ms) {
628 		dev_err(&client->dev, "Conversion timeout happened\n");
629 		return -EINVAL;
630 	}
631 
632 	return read_status;
633 }
634 
635 /* Returns 0 if the end of conversion interrupt occured or -ETIME otherwise */
636 static int wait_conversion_complete_interrupt(struct ak8975_data *data)
637 {
638 	int ret;
639 
640 	ret = wait_event_timeout(data->data_ready_queue,
641 				 test_bit(0, &data->flags),
642 				 AK8975_DATA_READY_TIMEOUT);
643 	clear_bit(0, &data->flags);
644 
645 	return ret > 0 ? 0 : -ETIME;
646 }
647 
648 static int ak8975_start_read_axis(struct ak8975_data *data,
649 				  const struct i2c_client *client)
650 {
651 	/* Set up the device for taking a sample. */
652 	int ret = ak8975_set_mode(data, MODE_ONCE);
653 
654 	if (ret < 0) {
655 		dev_err(&client->dev, "Error in setting operating mode\n");
656 		return ret;
657 	}
658 
659 	/* Wait for the conversion to complete. */
660 	if (data->eoc_irq)
661 		ret = wait_conversion_complete_interrupt(data);
662 	else if (gpio_is_valid(data->eoc_gpio))
663 		ret = wait_conversion_complete_gpio(data);
664 	else
665 		ret = wait_conversion_complete_polled(data);
666 	if (ret < 0)
667 		return ret;
668 
669 	/* This will be executed only for non-interrupt based waiting case */
670 	if (ret & data->def->ctrl_masks[ST1_DRDY]) {
671 		ret = i2c_smbus_read_byte_data(client,
672 					       data->def->ctrl_regs[ST2]);
673 		if (ret < 0) {
674 			dev_err(&client->dev, "Error in reading ST2\n");
675 			return ret;
676 		}
677 		if (ret & (data->def->ctrl_masks[ST2_DERR] |
678 			   data->def->ctrl_masks[ST2_HOFL])) {
679 			dev_err(&client->dev, "ST2 status error 0x%x\n", ret);
680 			return -EINVAL;
681 		}
682 	}
683 
684 	return 0;
685 }
686 
687 /* Retrieve raw flux value for one of the x, y, or z axis.  */
688 static int ak8975_read_axis(struct iio_dev *indio_dev, int index, int *val)
689 {
690 	struct ak8975_data *data = iio_priv(indio_dev);
691 	const struct i2c_client *client = data->client;
692 	const struct ak_def *def = data->def;
693 	__le16 rval;
694 	u16 buff;
695 	int ret;
696 
697 	pm_runtime_get_sync(&data->client->dev);
698 
699 	mutex_lock(&data->lock);
700 
701 	ret = ak8975_start_read_axis(data, client);
702 	if (ret)
703 		goto exit;
704 
705 	ret = i2c_smbus_read_i2c_block_data_or_emulated(
706 			client, def->data_regs[index],
707 			sizeof(rval), (u8*)&rval);
708 	if (ret < 0)
709 		goto exit;
710 
711 	mutex_unlock(&data->lock);
712 
713 	pm_runtime_mark_last_busy(&data->client->dev);
714 	pm_runtime_put_autosuspend(&data->client->dev);
715 
716 	/* Swap bytes and convert to valid range. */
717 	buff = le16_to_cpu(rval);
718 	*val = clamp_t(s16, buff, -def->range, def->range);
719 	return IIO_VAL_INT;
720 
721 exit:
722 	mutex_unlock(&data->lock);
723 	dev_err(&client->dev, "Error in reading axis\n");
724 	return ret;
725 }
726 
727 static int ak8975_read_raw(struct iio_dev *indio_dev,
728 			   struct iio_chan_spec const *chan,
729 			   int *val, int *val2,
730 			   long mask)
731 {
732 	struct ak8975_data *data = iio_priv(indio_dev);
733 
734 	switch (mask) {
735 	case IIO_CHAN_INFO_RAW:
736 		return ak8975_read_axis(indio_dev, chan->address, val);
737 	case IIO_CHAN_INFO_SCALE:
738 		*val = 0;
739 		*val2 = data->raw_to_gauss[chan->address];
740 		return IIO_VAL_INT_PLUS_MICRO;
741 	}
742 	return -EINVAL;
743 }
744 
745 static const struct iio_mount_matrix *
746 ak8975_get_mount_matrix(const struct iio_dev *indio_dev,
747 			const struct iio_chan_spec *chan)
748 {
749 	return &((struct ak8975_data *)iio_priv(indio_dev))->orientation;
750 }
751 
752 static const struct iio_chan_spec_ext_info ak8975_ext_info[] = {
753 	IIO_MOUNT_MATRIX(IIO_SHARED_BY_DIR, ak8975_get_mount_matrix),
754 	{ },
755 };
756 
757 #define AK8975_CHANNEL(axis, index)					\
758 	{								\
759 		.type = IIO_MAGN,					\
760 		.modified = 1,						\
761 		.channel2 = IIO_MOD_##axis,				\
762 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |		\
763 			     BIT(IIO_CHAN_INFO_SCALE),			\
764 		.address = index,					\
765 		.scan_index = index,					\
766 		.scan_type = {						\
767 			.sign = 's',					\
768 			.realbits = 16,					\
769 			.storagebits = 16,				\
770 			.endianness = IIO_CPU				\
771 		},							\
772 		.ext_info = ak8975_ext_info,				\
773 	}
774 
775 static const struct iio_chan_spec ak8975_channels[] = {
776 	AK8975_CHANNEL(X, 0), AK8975_CHANNEL(Y, 1), AK8975_CHANNEL(Z, 2),
777 	IIO_CHAN_SOFT_TIMESTAMP(3),
778 };
779 
780 static const unsigned long ak8975_scan_masks[] = { 0x7, 0 };
781 
782 static const struct iio_info ak8975_info = {
783 	.read_raw = &ak8975_read_raw,
784 };
785 
786 #ifdef CONFIG_ACPI
787 static const struct acpi_device_id ak_acpi_match[] = {
788 	{"AK8975", AK8975},
789 	{"AK8963", AK8963},
790 	{"INVN6500", AK8963},
791 	{"AK009911", AK09911},
792 	{"AK09911", AK09911},
793 	{"AK09912", AK09912},
794 	{ },
795 };
796 MODULE_DEVICE_TABLE(acpi, ak_acpi_match);
797 #endif
798 
799 static const char *ak8975_match_acpi_device(struct device *dev,
800 					    enum asahi_compass_chipset *chipset)
801 {
802 	const struct acpi_device_id *id;
803 
804 	id = acpi_match_device(dev->driver->acpi_match_table, dev);
805 	if (!id)
806 		return NULL;
807 	*chipset = (int)id->driver_data;
808 
809 	return dev_name(dev);
810 }
811 
812 static void ak8975_fill_buffer(struct iio_dev *indio_dev)
813 {
814 	struct ak8975_data *data = iio_priv(indio_dev);
815 	const struct i2c_client *client = data->client;
816 	const struct ak_def *def = data->def;
817 	int ret;
818 	s16 buff[8]; /* 3 x 16 bits axis values + 1 aligned 64 bits timestamp */
819 	__le16 fval[3];
820 
821 	mutex_lock(&data->lock);
822 
823 	ret = ak8975_start_read_axis(data, client);
824 	if (ret)
825 		goto unlock;
826 
827 	/*
828 	 * For each axis, read the flux value from the appropriate register
829 	 * (the register is specified in the iio device attributes).
830 	 */
831 	ret = i2c_smbus_read_i2c_block_data_or_emulated(client,
832 							def->data_regs[0],
833 							3 * sizeof(fval[0]),
834 							(u8 *)fval);
835 	if (ret < 0)
836 		goto unlock;
837 
838 	mutex_unlock(&data->lock);
839 
840 	/* Clamp to valid range. */
841 	buff[0] = clamp_t(s16, le16_to_cpu(fval[0]), -def->range, def->range);
842 	buff[1] = clamp_t(s16, le16_to_cpu(fval[1]), -def->range, def->range);
843 	buff[2] = clamp_t(s16, le16_to_cpu(fval[2]), -def->range, def->range);
844 
845 	iio_push_to_buffers_with_timestamp(indio_dev, buff,
846 					   iio_get_time_ns(indio_dev));
847 	return;
848 
849 unlock:
850 	mutex_unlock(&data->lock);
851 	dev_err(&client->dev, "Error in reading axes block\n");
852 }
853 
854 static irqreturn_t ak8975_handle_trigger(int irq, void *p)
855 {
856 	const struct iio_poll_func *pf = p;
857 	struct iio_dev *indio_dev = pf->indio_dev;
858 
859 	ak8975_fill_buffer(indio_dev);
860 	iio_trigger_notify_done(indio_dev->trig);
861 	return IRQ_HANDLED;
862 }
863 
864 static int ak8975_probe(struct i2c_client *client,
865 			const struct i2c_device_id *id)
866 {
867 	struct ak8975_data *data;
868 	struct iio_dev *indio_dev;
869 	int eoc_gpio;
870 	int err;
871 	const char *name = NULL;
872 	enum asahi_compass_chipset chipset = AK_MAX_TYPE;
873 	const struct ak8975_platform_data *pdata =
874 		dev_get_platdata(&client->dev);
875 
876 	/* Grab and set up the supplied GPIO. */
877 	if (pdata)
878 		eoc_gpio = pdata->eoc_gpio;
879 	else if (client->dev.of_node)
880 		eoc_gpio = of_get_gpio(client->dev.of_node, 0);
881 	else
882 		eoc_gpio = -1;
883 
884 	if (eoc_gpio == -EPROBE_DEFER)
885 		return -EPROBE_DEFER;
886 
887 	/* We may not have a GPIO based IRQ to scan, that is fine, we will
888 	   poll if so */
889 	if (gpio_is_valid(eoc_gpio)) {
890 		err = devm_gpio_request_one(&client->dev, eoc_gpio,
891 							GPIOF_IN, "ak_8975");
892 		if (err < 0) {
893 			dev_err(&client->dev,
894 				"failed to request GPIO %d, error %d\n",
895 							eoc_gpio, err);
896 			return err;
897 		}
898 	}
899 
900 	/* Register with IIO */
901 	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
902 	if (indio_dev == NULL)
903 		return -ENOMEM;
904 
905 	data = iio_priv(indio_dev);
906 	i2c_set_clientdata(client, indio_dev);
907 
908 	data->client = client;
909 	data->eoc_gpio = eoc_gpio;
910 	data->eoc_irq = 0;
911 
912 	if (!pdata) {
913 		err = of_iio_read_mount_matrix(&client->dev,
914 					       "mount-matrix",
915 					       &data->orientation);
916 		if (err)
917 			return err;
918 	} else
919 		data->orientation = pdata->orientation;
920 
921 	/* id will be NULL when enumerated via ACPI */
922 	if (id) {
923 		chipset = (enum asahi_compass_chipset)(id->driver_data);
924 		name = id->name;
925 	} else if (ACPI_HANDLE(&client->dev)) {
926 		name = ak8975_match_acpi_device(&client->dev, &chipset);
927 		if (!name)
928 			return -ENODEV;
929 	} else
930 		return -ENOSYS;
931 
932 	if (chipset >= AK_MAX_TYPE) {
933 		dev_err(&client->dev, "AKM device type unsupported: %d\n",
934 			chipset);
935 		return -ENODEV;
936 	}
937 
938 	data->def = &ak_def_array[chipset];
939 
940 	/* Fetch the regulators */
941 	data->vdd = devm_regulator_get(&client->dev, "vdd");
942 	if (IS_ERR(data->vdd))
943 		return PTR_ERR(data->vdd);
944 	data->vid = devm_regulator_get(&client->dev, "vid");
945 	if (IS_ERR(data->vid))
946 		return PTR_ERR(data->vid);
947 
948 	err = ak8975_power_on(data);
949 	if (err)
950 		return err;
951 
952 	err = ak8975_who_i_am(client, data->def->type);
953 	if (err < 0) {
954 		dev_err(&client->dev, "Unexpected device\n");
955 		goto power_off;
956 	}
957 	dev_dbg(&client->dev, "Asahi compass chip %s\n", name);
958 
959 	/* Perform some basic start-of-day setup of the device. */
960 	err = ak8975_setup(client);
961 	if (err < 0) {
962 		dev_err(&client->dev, "%s initialization fails\n", name);
963 		goto power_off;
964 	}
965 
966 	mutex_init(&data->lock);
967 	indio_dev->dev.parent = &client->dev;
968 	indio_dev->channels = ak8975_channels;
969 	indio_dev->num_channels = ARRAY_SIZE(ak8975_channels);
970 	indio_dev->info = &ak8975_info;
971 	indio_dev->available_scan_masks = ak8975_scan_masks;
972 	indio_dev->modes = INDIO_DIRECT_MODE;
973 	indio_dev->name = name;
974 
975 	err = iio_triggered_buffer_setup(indio_dev, NULL, ak8975_handle_trigger,
976 					 NULL);
977 	if (err) {
978 		dev_err(&client->dev, "triggered buffer setup failed\n");
979 		goto power_off;
980 	}
981 
982 	err = iio_device_register(indio_dev);
983 	if (err) {
984 		dev_err(&client->dev, "device register failed\n");
985 		goto cleanup_buffer;
986 	}
987 
988 	/* Enable runtime PM */
989 	pm_runtime_get_noresume(&client->dev);
990 	pm_runtime_set_active(&client->dev);
991 	pm_runtime_enable(&client->dev);
992 	/*
993 	 * The device comes online in 500us, so add two orders of magnitude
994 	 * of delay before autosuspending: 50 ms.
995 	 */
996 	pm_runtime_set_autosuspend_delay(&client->dev, 50);
997 	pm_runtime_use_autosuspend(&client->dev);
998 	pm_runtime_put(&client->dev);
999 
1000 	return 0;
1001 
1002 cleanup_buffer:
1003 	iio_triggered_buffer_cleanup(indio_dev);
1004 power_off:
1005 	ak8975_power_off(data);
1006 	return err;
1007 }
1008 
1009 static int ak8975_remove(struct i2c_client *client)
1010 {
1011 	struct iio_dev *indio_dev = i2c_get_clientdata(client);
1012 	struct ak8975_data *data = iio_priv(indio_dev);
1013 
1014 	pm_runtime_get_sync(&client->dev);
1015 	pm_runtime_put_noidle(&client->dev);
1016 	pm_runtime_disable(&client->dev);
1017 	iio_device_unregister(indio_dev);
1018 	iio_triggered_buffer_cleanup(indio_dev);
1019 	ak8975_set_mode(data, POWER_DOWN);
1020 	ak8975_power_off(data);
1021 
1022 	return 0;
1023 }
1024 
1025 #ifdef CONFIG_PM
1026 static int ak8975_runtime_suspend(struct device *dev)
1027 {
1028 	struct i2c_client *client = to_i2c_client(dev);
1029 	struct iio_dev *indio_dev = i2c_get_clientdata(client);
1030 	struct ak8975_data *data = iio_priv(indio_dev);
1031 	int ret;
1032 
1033 	/* Set the device in power down if it wasn't already */
1034 	ret = ak8975_set_mode(data, POWER_DOWN);
1035 	if (ret < 0) {
1036 		dev_err(&client->dev, "Error in setting power-down mode\n");
1037 		return ret;
1038 	}
1039 	/* Next cut the regulators */
1040 	ak8975_power_off(data);
1041 
1042 	return 0;
1043 }
1044 
1045 static int ak8975_runtime_resume(struct device *dev)
1046 {
1047 	struct i2c_client *client = to_i2c_client(dev);
1048 	struct iio_dev *indio_dev = i2c_get_clientdata(client);
1049 	struct ak8975_data *data = iio_priv(indio_dev);
1050 	int ret;
1051 
1052 	/* Take up the regulators */
1053 	ak8975_power_on(data);
1054 	/*
1055 	 * We come up in powered down mode, the reading routines will
1056 	 * put us in the mode to read values later.
1057 	 */
1058 	ret = ak8975_set_mode(data, POWER_DOWN);
1059 	if (ret < 0) {
1060 		dev_err(&client->dev, "Error in setting power-down mode\n");
1061 		return ret;
1062 	}
1063 
1064 	return 0;
1065 }
1066 #endif /* CONFIG_PM */
1067 
1068 static const struct dev_pm_ops ak8975_dev_pm_ops = {
1069 	SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
1070 				pm_runtime_force_resume)
1071 	SET_RUNTIME_PM_OPS(ak8975_runtime_suspend,
1072 			   ak8975_runtime_resume, NULL)
1073 };
1074 
1075 static const struct i2c_device_id ak8975_id[] = {
1076 	{"ak8975", AK8975},
1077 	{"ak8963", AK8963},
1078 	{"AK8963", AK8963},
1079 	{"ak09911", AK09911},
1080 	{"ak09912", AK09912},
1081 	{}
1082 };
1083 
1084 MODULE_DEVICE_TABLE(i2c, ak8975_id);
1085 
1086 static const struct of_device_id ak8975_of_match[] = {
1087 	{ .compatible = "asahi-kasei,ak8975", },
1088 	{ .compatible = "ak8975", },
1089 	{ .compatible = "asahi-kasei,ak8963", },
1090 	{ .compatible = "ak8963", },
1091 	{ .compatible = "asahi-kasei,ak09911", },
1092 	{ .compatible = "ak09911", },
1093 	{ .compatible = "asahi-kasei,ak09912", },
1094 	{ .compatible = "ak09912", },
1095 	{}
1096 };
1097 MODULE_DEVICE_TABLE(of, ak8975_of_match);
1098 
1099 static struct i2c_driver ak8975_driver = {
1100 	.driver = {
1101 		.name	= "ak8975",
1102 		.pm = &ak8975_dev_pm_ops,
1103 		.of_match_table = of_match_ptr(ak8975_of_match),
1104 		.acpi_match_table = ACPI_PTR(ak_acpi_match),
1105 	},
1106 	.probe		= ak8975_probe,
1107 	.remove		= ak8975_remove,
1108 	.id_table	= ak8975_id,
1109 };
1110 module_i2c_driver(ak8975_driver);
1111 
1112 MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
1113 MODULE_DESCRIPTION("AK8975 magnetometer driver");
1114 MODULE_LICENSE("GPL");
1115