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 
37 #include <linux/iio/iio.h>
38 #include <linux/iio/sysfs.h>
39 #include <linux/iio/buffer.h>
40 #include <linux/iio/trigger.h>
41 #include <linux/iio/trigger_consumer.h>
42 #include <linux/iio/triggered_buffer.h>
43 
44 #include <linux/iio/magnetometer/ak8975.h>
45 
46 /*
47  * Register definitions, as well as various shifts and masks to get at the
48  * individual fields of the registers.
49  */
50 #define AK8975_REG_WIA			0x00
51 #define AK8975_DEVICE_ID		0x48
52 
53 #define AK8975_REG_INFO			0x01
54 
55 #define AK8975_REG_ST1			0x02
56 #define AK8975_REG_ST1_DRDY_SHIFT	0
57 #define AK8975_REG_ST1_DRDY_MASK	(1 << AK8975_REG_ST1_DRDY_SHIFT)
58 
59 #define AK8975_REG_HXL			0x03
60 #define AK8975_REG_HXH			0x04
61 #define AK8975_REG_HYL			0x05
62 #define AK8975_REG_HYH			0x06
63 #define AK8975_REG_HZL			0x07
64 #define AK8975_REG_HZH			0x08
65 #define AK8975_REG_ST2			0x09
66 #define AK8975_REG_ST2_DERR_SHIFT	2
67 #define AK8975_REG_ST2_DERR_MASK	(1 << AK8975_REG_ST2_DERR_SHIFT)
68 
69 #define AK8975_REG_ST2_HOFL_SHIFT	3
70 #define AK8975_REG_ST2_HOFL_MASK	(1 << AK8975_REG_ST2_HOFL_SHIFT)
71 
72 #define AK8975_REG_CNTL			0x0A
73 #define AK8975_REG_CNTL_MODE_SHIFT	0
74 #define AK8975_REG_CNTL_MODE_MASK	(0xF << AK8975_REG_CNTL_MODE_SHIFT)
75 #define AK8975_REG_CNTL_MODE_POWER_DOWN	0x00
76 #define AK8975_REG_CNTL_MODE_ONCE	0x01
77 #define AK8975_REG_CNTL_MODE_SELF_TEST	0x08
78 #define AK8975_REG_CNTL_MODE_FUSE_ROM	0x0F
79 
80 #define AK8975_REG_RSVC			0x0B
81 #define AK8975_REG_ASTC			0x0C
82 #define AK8975_REG_TS1			0x0D
83 #define AK8975_REG_TS2			0x0E
84 #define AK8975_REG_I2CDIS		0x0F
85 #define AK8975_REG_ASAX			0x10
86 #define AK8975_REG_ASAY			0x11
87 #define AK8975_REG_ASAZ			0x12
88 
89 #define AK8975_MAX_REGS			AK8975_REG_ASAZ
90 
91 /*
92  * AK09912 Register definitions
93  */
94 #define AK09912_REG_WIA1		0x00
95 #define AK09912_REG_WIA2		0x01
96 #define AK09912_DEVICE_ID		0x04
97 #define AK09911_DEVICE_ID		0x05
98 
99 #define AK09911_REG_INFO1		0x02
100 #define AK09911_REG_INFO2		0x03
101 
102 #define AK09912_REG_ST1			0x10
103 
104 #define AK09912_REG_ST1_DRDY_SHIFT	0
105 #define AK09912_REG_ST1_DRDY_MASK	(1 << AK09912_REG_ST1_DRDY_SHIFT)
106 
107 #define AK09912_REG_HXL			0x11
108 #define AK09912_REG_HXH			0x12
109 #define AK09912_REG_HYL			0x13
110 #define AK09912_REG_HYH			0x14
111 #define AK09912_REG_HZL			0x15
112 #define AK09912_REG_HZH			0x16
113 #define AK09912_REG_TMPS		0x17
114 
115 #define AK09912_REG_ST2			0x18
116 #define AK09912_REG_ST2_HOFL_SHIFT	3
117 #define AK09912_REG_ST2_HOFL_MASK	(1 << AK09912_REG_ST2_HOFL_SHIFT)
118 
119 #define AK09912_REG_CNTL1		0x30
120 
121 #define AK09912_REG_CNTL2		0x31
122 #define AK09912_REG_CNTL_MODE_POWER_DOWN	0x00
123 #define AK09912_REG_CNTL_MODE_ONCE	0x01
124 #define AK09912_REG_CNTL_MODE_SELF_TEST	0x10
125 #define AK09912_REG_CNTL_MODE_FUSE_ROM	0x1F
126 #define AK09912_REG_CNTL2_MODE_SHIFT	0
127 #define AK09912_REG_CNTL2_MODE_MASK	(0x1F << AK09912_REG_CNTL2_MODE_SHIFT)
128 
129 #define AK09912_REG_CNTL3		0x32
130 
131 #define AK09912_REG_TS1			0x33
132 #define AK09912_REG_TS2			0x34
133 #define AK09912_REG_TS3			0x35
134 #define AK09912_REG_I2CDIS		0x36
135 #define AK09912_REG_TS4			0x37
136 
137 #define AK09912_REG_ASAX		0x60
138 #define AK09912_REG_ASAY		0x61
139 #define AK09912_REG_ASAZ		0x62
140 
141 #define AK09912_MAX_REGS		AK09912_REG_ASAZ
142 
143 /*
144  * Miscellaneous values.
145  */
146 #define AK8975_MAX_CONVERSION_TIMEOUT	500
147 #define AK8975_CONVERSION_DONE_POLL_TIME 10
148 #define AK8975_DATA_READY_TIMEOUT	((100*HZ)/1000)
149 
150 /*
151  * Precalculate scale factor (in Gauss units) for each axis and
152  * store in the device data.
153  *
154  * This scale factor is axis-dependent, and is derived from 3 calibration
155  * factors ASA(x), ASA(y), and ASA(z).
156  *
157  * These ASA values are read from the sensor device at start of day, and
158  * cached in the device context struct.
159  *
160  * Adjusting the flux value with the sensitivity adjustment value should be
161  * done via the following formula:
162  *
163  * Hadj = H * ( ( ( (ASA-128)*0.5 ) / 128 ) + 1 )
164  * where H is the raw value, ASA is the sensitivity adjustment, and Hadj
165  * is the resultant adjusted value.
166  *
167  * We reduce the formula to:
168  *
169  * Hadj = H * (ASA + 128) / 256
170  *
171  * H is in the range of -4096 to 4095.  The magnetometer has a range of
172  * +-1229uT.  To go from the raw value to uT is:
173  *
174  * HuT = H * 1229/4096, or roughly, 3/10.
175  *
176  * Since 1uT = 0.01 gauss, our final scale factor becomes:
177  *
178  * Hadj = H * ((ASA + 128) / 256) * 3/10 * 1/100
179  * Hadj = H * ((ASA + 128) * 0.003) / 256
180  *
181  * Since ASA doesn't change, we cache the resultant scale factor into the
182  * device context in ak8975_setup().
183  *
184  * Given we use IIO_VAL_INT_PLUS_MICRO bit when displaying the scale, we
185  * multiply the stored scale value by 1e6.
186  */
187 static long ak8975_raw_to_gauss(u16 data)
188 {
189 	return (((long)data + 128) * 3000) / 256;
190 }
191 
192 /*
193  * For AK8963 and AK09911, same calculation, but the device is less sensitive:
194  *
195  * H is in the range of +-8190.  The magnetometer has a range of
196  * +-4912uT.  To go from the raw value to uT is:
197  *
198  * HuT = H * 4912/8190, or roughly, 6/10, instead of 3/10.
199  */
200 
201 static long ak8963_09911_raw_to_gauss(u16 data)
202 {
203 	return (((long)data + 128) * 6000) / 256;
204 }
205 
206 /*
207  * For AK09912, same calculation, except the device is more sensitive:
208  *
209  * H is in the range of -32752 to 32752.  The magnetometer has a range of
210  * +-4912uT.  To go from the raw value to uT is:
211  *
212  * HuT = H * 4912/32752, or roughly, 3/20, instead of 3/10.
213  */
214 static long ak09912_raw_to_gauss(u16 data)
215 {
216 	return (((long)data + 128) * 1500) / 256;
217 }
218 
219 /* Compatible Asahi Kasei Compass parts */
220 enum asahi_compass_chipset {
221 	AK8975,
222 	AK8963,
223 	AK09911,
224 	AK09912,
225 	AK_MAX_TYPE
226 };
227 
228 enum ak_ctrl_reg_addr {
229 	ST1,
230 	ST2,
231 	CNTL,
232 	ASA_BASE,
233 	MAX_REGS,
234 	REGS_END,
235 };
236 
237 enum ak_ctrl_reg_mask {
238 	ST1_DRDY,
239 	ST2_HOFL,
240 	ST2_DERR,
241 	CNTL_MODE,
242 	MASK_END,
243 };
244 
245 enum ak_ctrl_mode {
246 	POWER_DOWN,
247 	MODE_ONCE,
248 	SELF_TEST,
249 	FUSE_ROM,
250 	MODE_END,
251 };
252 
253 struct ak_def {
254 	enum asahi_compass_chipset type;
255 	long (*raw_to_gauss)(u16 data);
256 	u16 range;
257 	u8 ctrl_regs[REGS_END];
258 	u8 ctrl_masks[MASK_END];
259 	u8 ctrl_modes[MODE_END];
260 	u8 data_regs[3];
261 };
262 
263 static const struct ak_def ak_def_array[AK_MAX_TYPE] = {
264 	{
265 		.type = AK8975,
266 		.raw_to_gauss = ak8975_raw_to_gauss,
267 		.range = 4096,
268 		.ctrl_regs = {
269 			AK8975_REG_ST1,
270 			AK8975_REG_ST2,
271 			AK8975_REG_CNTL,
272 			AK8975_REG_ASAX,
273 			AK8975_MAX_REGS},
274 		.ctrl_masks = {
275 			AK8975_REG_ST1_DRDY_MASK,
276 			AK8975_REG_ST2_HOFL_MASK,
277 			AK8975_REG_ST2_DERR_MASK,
278 			AK8975_REG_CNTL_MODE_MASK},
279 		.ctrl_modes = {
280 			AK8975_REG_CNTL_MODE_POWER_DOWN,
281 			AK8975_REG_CNTL_MODE_ONCE,
282 			AK8975_REG_CNTL_MODE_SELF_TEST,
283 			AK8975_REG_CNTL_MODE_FUSE_ROM},
284 		.data_regs = {
285 			AK8975_REG_HXL,
286 			AK8975_REG_HYL,
287 			AK8975_REG_HZL},
288 	},
289 	{
290 		.type = AK8963,
291 		.raw_to_gauss = ak8963_09911_raw_to_gauss,
292 		.range = 8190,
293 		.ctrl_regs = {
294 			AK8975_REG_ST1,
295 			AK8975_REG_ST2,
296 			AK8975_REG_CNTL,
297 			AK8975_REG_ASAX,
298 			AK8975_MAX_REGS},
299 		.ctrl_masks = {
300 			AK8975_REG_ST1_DRDY_MASK,
301 			AK8975_REG_ST2_HOFL_MASK,
302 			0,
303 			AK8975_REG_CNTL_MODE_MASK},
304 		.ctrl_modes = {
305 			AK8975_REG_CNTL_MODE_POWER_DOWN,
306 			AK8975_REG_CNTL_MODE_ONCE,
307 			AK8975_REG_CNTL_MODE_SELF_TEST,
308 			AK8975_REG_CNTL_MODE_FUSE_ROM},
309 		.data_regs = {
310 			AK8975_REG_HXL,
311 			AK8975_REG_HYL,
312 			AK8975_REG_HZL},
313 	},
314 	{
315 		.type = AK09911,
316 		.raw_to_gauss = ak8963_09911_raw_to_gauss,
317 		.range = 8192,
318 		.ctrl_regs = {
319 			AK09912_REG_ST1,
320 			AK09912_REG_ST2,
321 			AK09912_REG_CNTL2,
322 			AK09912_REG_ASAX,
323 			AK09912_MAX_REGS},
324 		.ctrl_masks = {
325 			AK09912_REG_ST1_DRDY_MASK,
326 			AK09912_REG_ST2_HOFL_MASK,
327 			0,
328 			AK09912_REG_CNTL2_MODE_MASK},
329 		.ctrl_modes = {
330 			AK09912_REG_CNTL_MODE_POWER_DOWN,
331 			AK09912_REG_CNTL_MODE_ONCE,
332 			AK09912_REG_CNTL_MODE_SELF_TEST,
333 			AK09912_REG_CNTL_MODE_FUSE_ROM},
334 		.data_regs = {
335 			AK09912_REG_HXL,
336 			AK09912_REG_HYL,
337 			AK09912_REG_HZL},
338 	},
339 	{
340 		.type = AK09912,
341 		.raw_to_gauss = ak09912_raw_to_gauss,
342 		.range = 32752,
343 		.ctrl_regs = {
344 			AK09912_REG_ST1,
345 			AK09912_REG_ST2,
346 			AK09912_REG_CNTL2,
347 			AK09912_REG_ASAX,
348 			AK09912_MAX_REGS},
349 		.ctrl_masks = {
350 			AK09912_REG_ST1_DRDY_MASK,
351 			AK09912_REG_ST2_HOFL_MASK,
352 			0,
353 			AK09912_REG_CNTL2_MODE_MASK},
354 		.ctrl_modes = {
355 			AK09912_REG_CNTL_MODE_POWER_DOWN,
356 			AK09912_REG_CNTL_MODE_ONCE,
357 			AK09912_REG_CNTL_MODE_SELF_TEST,
358 			AK09912_REG_CNTL_MODE_FUSE_ROM},
359 		.data_regs = {
360 			AK09912_REG_HXL,
361 			AK09912_REG_HYL,
362 			AK09912_REG_HZL},
363 	}
364 };
365 
366 /*
367  * Per-instance context data for the device.
368  */
369 struct ak8975_data {
370 	struct i2c_client	*client;
371 	const struct ak_def	*def;
372 	struct mutex		lock;
373 	u8			asa[3];
374 	long			raw_to_gauss[3];
375 	int			eoc_gpio;
376 	int			eoc_irq;
377 	wait_queue_head_t	data_ready_queue;
378 	unsigned long		flags;
379 	u8			cntl_cache;
380 	struct iio_mount_matrix orientation;
381 	struct regulator	*vdd;
382 };
383 
384 /* Enable attached power regulator if any. */
385 static int ak8975_power_on(struct i2c_client *client)
386 {
387 	const struct iio_dev *indio_dev = i2c_get_clientdata(client);
388 	struct ak8975_data *data = iio_priv(indio_dev);
389 	int ret;
390 
391 	data->vdd = devm_regulator_get(&client->dev, "vdd");
392 	if (IS_ERR_OR_NULL(data->vdd)) {
393 		ret = PTR_ERR(data->vdd);
394 		if (ret == -ENODEV)
395 			ret = 0;
396 	} else {
397 		ret = regulator_enable(data->vdd);
398 	}
399 
400 	if (ret)
401 		dev_err(&client->dev, "failed to enable Vdd supply: %d\n", ret);
402 	return ret;
403 }
404 
405 /* Disable attached power regulator if any. */
406 static void ak8975_power_off(const struct i2c_client *client)
407 {
408 	const struct iio_dev *indio_dev = i2c_get_clientdata(client);
409 	const struct ak8975_data *data = iio_priv(indio_dev);
410 
411 	if (!IS_ERR_OR_NULL(data->vdd))
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(client, AK09912_REG_WIA1,
434 					    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 = gpio_to_irq(data->eoc_gpio);
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,
517 			"irq %d request failed, (gpio %d): %d\n",
518 			irq, data->eoc_gpio, rc);
519 		return rc;
520 	}
521 
522 	data->eoc_irq = irq;
523 
524 	return rc;
525 }
526 
527 
528 /*
529  * Perform some start-of-day setup, including reading the asa calibration
530  * values and caching them.
531  */
532 static int ak8975_setup(struct i2c_client *client)
533 {
534 	struct iio_dev *indio_dev = i2c_get_clientdata(client);
535 	struct ak8975_data *data = iio_priv(indio_dev);
536 	int ret;
537 
538 	/* Write the fused rom access mode. */
539 	ret = ak8975_set_mode(data, FUSE_ROM);
540 	if (ret < 0) {
541 		dev_err(&client->dev, "Error in setting fuse access mode\n");
542 		return ret;
543 	}
544 
545 	/* Get asa data and store in the device data. */
546 	ret = i2c_smbus_read_i2c_block_data(client,
547 					    data->def->ctrl_regs[ASA_BASE],
548 					    3, data->asa);
549 	if (ret < 0) {
550 		dev_err(&client->dev, "Not able to read asa data\n");
551 		return ret;
552 	}
553 
554 	/* After reading fuse ROM data set power-down mode */
555 	ret = ak8975_set_mode(data, POWER_DOWN);
556 	if (ret < 0) {
557 		dev_err(&client->dev, "Error in setting power-down mode\n");
558 		return ret;
559 	}
560 
561 	if (data->eoc_gpio > 0 || client->irq > 0) {
562 		ret = ak8975_setup_irq(data);
563 		if (ret < 0) {
564 			dev_err(&client->dev,
565 				"Error setting data ready interrupt\n");
566 			return ret;
567 		}
568 	}
569 
570 	data->raw_to_gauss[0] = data->def->raw_to_gauss(data->asa[0]);
571 	data->raw_to_gauss[1] = data->def->raw_to_gauss(data->asa[1]);
572 	data->raw_to_gauss[2] = data->def->raw_to_gauss(data->asa[2]);
573 
574 	return 0;
575 }
576 
577 static int wait_conversion_complete_gpio(struct ak8975_data *data)
578 {
579 	struct i2c_client *client = data->client;
580 	u32 timeout_ms = AK8975_MAX_CONVERSION_TIMEOUT;
581 	int ret;
582 
583 	/* Wait for the conversion to complete. */
584 	while (timeout_ms) {
585 		msleep(AK8975_CONVERSION_DONE_POLL_TIME);
586 		if (gpio_get_value(data->eoc_gpio))
587 			break;
588 		timeout_ms -= AK8975_CONVERSION_DONE_POLL_TIME;
589 	}
590 	if (!timeout_ms) {
591 		dev_err(&client->dev, "Conversion timeout happened\n");
592 		return -EINVAL;
593 	}
594 
595 	ret = i2c_smbus_read_byte_data(client, data->def->ctrl_regs[ST1]);
596 	if (ret < 0)
597 		dev_err(&client->dev, "Error in reading ST1\n");
598 
599 	return ret;
600 }
601 
602 static int wait_conversion_complete_polled(struct ak8975_data *data)
603 {
604 	struct i2c_client *client = data->client;
605 	u8 read_status;
606 	u32 timeout_ms = AK8975_MAX_CONVERSION_TIMEOUT;
607 	int ret;
608 
609 	/* Wait for the conversion to complete. */
610 	while (timeout_ms) {
611 		msleep(AK8975_CONVERSION_DONE_POLL_TIME);
612 		ret = i2c_smbus_read_byte_data(client,
613 					       data->def->ctrl_regs[ST1]);
614 		if (ret < 0) {
615 			dev_err(&client->dev, "Error in reading ST1\n");
616 			return ret;
617 		}
618 		read_status = ret;
619 		if (read_status)
620 			break;
621 		timeout_ms -= AK8975_CONVERSION_DONE_POLL_TIME;
622 	}
623 	if (!timeout_ms) {
624 		dev_err(&client->dev, "Conversion timeout happened\n");
625 		return -EINVAL;
626 	}
627 
628 	return read_status;
629 }
630 
631 /* Returns 0 if the end of conversion interrupt occured or -ETIME otherwise */
632 static int wait_conversion_complete_interrupt(struct ak8975_data *data)
633 {
634 	int ret;
635 
636 	ret = wait_event_timeout(data->data_ready_queue,
637 				 test_bit(0, &data->flags),
638 				 AK8975_DATA_READY_TIMEOUT);
639 	clear_bit(0, &data->flags);
640 
641 	return ret > 0 ? 0 : -ETIME;
642 }
643 
644 static int ak8975_start_read_axis(struct ak8975_data *data,
645 				  const struct i2c_client *client)
646 {
647 	/* Set up the device for taking a sample. */
648 	int ret = ak8975_set_mode(data, MODE_ONCE);
649 
650 	if (ret < 0) {
651 		dev_err(&client->dev, "Error in setting operating mode\n");
652 		return ret;
653 	}
654 
655 	/* Wait for the conversion to complete. */
656 	if (data->eoc_irq)
657 		ret = wait_conversion_complete_interrupt(data);
658 	else if (gpio_is_valid(data->eoc_gpio))
659 		ret = wait_conversion_complete_gpio(data);
660 	else
661 		ret = wait_conversion_complete_polled(data);
662 	if (ret < 0)
663 		return ret;
664 
665 	/* This will be executed only for non-interrupt based waiting case */
666 	if (ret & data->def->ctrl_masks[ST1_DRDY]) {
667 		ret = i2c_smbus_read_byte_data(client,
668 					       data->def->ctrl_regs[ST2]);
669 		if (ret < 0) {
670 			dev_err(&client->dev, "Error in reading ST2\n");
671 			return ret;
672 		}
673 		if (ret & (data->def->ctrl_masks[ST2_DERR] |
674 			   data->def->ctrl_masks[ST2_HOFL])) {
675 			dev_err(&client->dev, "ST2 status error 0x%x\n", ret);
676 			return -EINVAL;
677 		}
678 	}
679 
680 	return 0;
681 }
682 
683 /* Retrieve raw flux value for one of the x, y, or z axis.  */
684 static int ak8975_read_axis(struct iio_dev *indio_dev, int index, int *val)
685 {
686 	struct ak8975_data *data = iio_priv(indio_dev);
687 	const struct i2c_client *client = data->client;
688 	const struct ak_def *def = data->def;
689 	int ret;
690 
691 	mutex_lock(&data->lock);
692 
693 	ret = ak8975_start_read_axis(data, client);
694 	if (ret)
695 		goto exit;
696 
697 	ret = i2c_smbus_read_word_data(client, def->data_regs[index]);
698 	if (ret < 0)
699 		goto exit;
700 
701 	mutex_unlock(&data->lock);
702 
703 	/* Clamp to valid range. */
704 	*val = clamp_t(s16, ret, -def->range, def->range);
705 	return IIO_VAL_INT;
706 
707 exit:
708 	mutex_unlock(&data->lock);
709 	dev_err(&client->dev, "Error in reading axis\n");
710 	return ret;
711 }
712 
713 static int ak8975_read_raw(struct iio_dev *indio_dev,
714 			   struct iio_chan_spec const *chan,
715 			   int *val, int *val2,
716 			   long mask)
717 {
718 	struct ak8975_data *data = iio_priv(indio_dev);
719 
720 	switch (mask) {
721 	case IIO_CHAN_INFO_RAW:
722 		return ak8975_read_axis(indio_dev, chan->address, val);
723 	case IIO_CHAN_INFO_SCALE:
724 		*val = 0;
725 		*val2 = data->raw_to_gauss[chan->address];
726 		return IIO_VAL_INT_PLUS_MICRO;
727 	}
728 	return -EINVAL;
729 }
730 
731 static const struct iio_mount_matrix *
732 ak8975_get_mount_matrix(const struct iio_dev *indio_dev,
733 			const struct iio_chan_spec *chan)
734 {
735 	return &((struct ak8975_data *)iio_priv(indio_dev))->orientation;
736 }
737 
738 static const struct iio_chan_spec_ext_info ak8975_ext_info[] = {
739 	IIO_MOUNT_MATRIX(IIO_SHARED_BY_DIR, ak8975_get_mount_matrix),
740 	{ },
741 };
742 
743 #define AK8975_CHANNEL(axis, index)					\
744 	{								\
745 		.type = IIO_MAGN,					\
746 		.modified = 1,						\
747 		.channel2 = IIO_MOD_##axis,				\
748 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |		\
749 			     BIT(IIO_CHAN_INFO_SCALE),			\
750 		.address = index,					\
751 		.scan_index = index,					\
752 		.scan_type = {						\
753 			.sign = 's',					\
754 			.realbits = 16,					\
755 			.storagebits = 16,				\
756 			.endianness = IIO_CPU				\
757 		},							\
758 		.ext_info = ak8975_ext_info,				\
759 	}
760 
761 static const struct iio_chan_spec ak8975_channels[] = {
762 	AK8975_CHANNEL(X, 0), AK8975_CHANNEL(Y, 1), AK8975_CHANNEL(Z, 2),
763 	IIO_CHAN_SOFT_TIMESTAMP(3),
764 };
765 
766 static const unsigned long ak8975_scan_masks[] = { 0x7, 0 };
767 
768 static const struct iio_info ak8975_info = {
769 	.read_raw = &ak8975_read_raw,
770 	.driver_module = THIS_MODULE,
771 };
772 
773 static const struct acpi_device_id ak_acpi_match[] = {
774 	{"AK8975", AK8975},
775 	{"AK8963", AK8963},
776 	{"INVN6500", AK8963},
777 	{"AK09911", AK09911},
778 	{"AK09912", AK09912},
779 	{ },
780 };
781 MODULE_DEVICE_TABLE(acpi, ak_acpi_match);
782 
783 static const char *ak8975_match_acpi_device(struct device *dev,
784 					    enum asahi_compass_chipset *chipset)
785 {
786 	const struct acpi_device_id *id;
787 
788 	id = acpi_match_device(dev->driver->acpi_match_table, dev);
789 	if (!id)
790 		return NULL;
791 	*chipset = (int)id->driver_data;
792 
793 	return dev_name(dev);
794 }
795 
796 static void ak8975_fill_buffer(struct iio_dev *indio_dev)
797 {
798 	struct ak8975_data *data = iio_priv(indio_dev);
799 	const struct i2c_client *client = data->client;
800 	const struct ak_def *def = data->def;
801 	int ret;
802 	s16 buff[8]; /* 3 x 16 bits axis values + 1 aligned 64 bits timestamp */
803 
804 	mutex_lock(&data->lock);
805 
806 	ret = ak8975_start_read_axis(data, client);
807 	if (ret)
808 		goto unlock;
809 
810 	/*
811 	 * For each axis, read the flux value from the appropriate register
812 	 * (the register is specified in the iio device attributes).
813 	 */
814 	ret = i2c_smbus_read_i2c_block_data_or_emulated(client,
815 							def->data_regs[0],
816 							3 * sizeof(buff[0]),
817 							(u8 *)buff);
818 	if (ret < 0)
819 		goto unlock;
820 
821 	mutex_unlock(&data->lock);
822 
823 	/* Clamp to valid range. */
824 	buff[0] = clamp_t(s16, le16_to_cpu(buff[0]), -def->range, def->range);
825 	buff[1] = clamp_t(s16, le16_to_cpu(buff[1]), -def->range, def->range);
826 	buff[2] = clamp_t(s16, le16_to_cpu(buff[2]), -def->range, def->range);
827 
828 	iio_push_to_buffers_with_timestamp(indio_dev, buff, iio_get_time_ns());
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 	int eoc_gpio;
852 	int err;
853 	const char *name = NULL;
854 	enum asahi_compass_chipset chipset = AK_MAX_TYPE;
855 	const struct ak8975_platform_data *pdata =
856 		dev_get_platdata(&client->dev);
857 
858 	/* Grab and set up the supplied GPIO. */
859 	if (pdata)
860 		eoc_gpio = pdata->eoc_gpio;
861 	else if (client->dev.of_node)
862 		eoc_gpio = of_get_gpio(client->dev.of_node, 0);
863 	else
864 		eoc_gpio = -1;
865 
866 	if (eoc_gpio == -EPROBE_DEFER)
867 		return -EPROBE_DEFER;
868 
869 	/* We may not have a GPIO based IRQ to scan, that is fine, we will
870 	   poll if so */
871 	if (gpio_is_valid(eoc_gpio)) {
872 		err = devm_gpio_request_one(&client->dev, eoc_gpio,
873 							GPIOF_IN, "ak_8975");
874 		if (err < 0) {
875 			dev_err(&client->dev,
876 				"failed to request GPIO %d, error %d\n",
877 							eoc_gpio, err);
878 			return err;
879 		}
880 	}
881 
882 	/* Register with IIO */
883 	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
884 	if (indio_dev == NULL)
885 		return -ENOMEM;
886 
887 	data = iio_priv(indio_dev);
888 	i2c_set_clientdata(client, indio_dev);
889 
890 	data->client = client;
891 	data->eoc_gpio = eoc_gpio;
892 	data->eoc_irq = 0;
893 
894 	if (!pdata) {
895 		err = of_iio_read_mount_matrix(&client->dev,
896 					       "mount-matrix",
897 					       &data->orientation);
898 		if (err)
899 			return err;
900 	} else
901 		data->orientation = pdata->orientation;
902 
903 	/* id will be NULL when enumerated via ACPI */
904 	if (id) {
905 		chipset = (enum asahi_compass_chipset)(id->driver_data);
906 		name = id->name;
907 	} else if (ACPI_HANDLE(&client->dev)) {
908 		name = ak8975_match_acpi_device(&client->dev, &chipset);
909 		if (!name)
910 			return -ENODEV;
911 	} else
912 		return -ENOSYS;
913 
914 	if (chipset >= AK_MAX_TYPE) {
915 		dev_err(&client->dev, "AKM device type unsupported: %d\n",
916 			chipset);
917 		return -ENODEV;
918 	}
919 
920 	data->def = &ak_def_array[chipset];
921 
922 	err = ak8975_power_on(client);
923 	if (err)
924 		return err;
925 
926 	err = ak8975_who_i_am(client, data->def->type);
927 	if (err < 0) {
928 		dev_err(&client->dev, "Unexpected device\n");
929 		goto power_off;
930 	}
931 	dev_dbg(&client->dev, "Asahi compass chip %s\n", name);
932 
933 	/* Perform some basic start-of-day setup of the device. */
934 	err = ak8975_setup(client);
935 	if (err < 0) {
936 		dev_err(&client->dev, "%s initialization fails\n", name);
937 		goto power_off;
938 	}
939 
940 	mutex_init(&data->lock);
941 	indio_dev->dev.parent = &client->dev;
942 	indio_dev->channels = ak8975_channels;
943 	indio_dev->num_channels = ARRAY_SIZE(ak8975_channels);
944 	indio_dev->info = &ak8975_info;
945 	indio_dev->available_scan_masks = ak8975_scan_masks;
946 	indio_dev->modes = INDIO_DIRECT_MODE;
947 	indio_dev->name = name;
948 
949 	err = iio_triggered_buffer_setup(indio_dev, NULL, ak8975_handle_trigger,
950 					 NULL);
951 	if (err) {
952 		dev_err(&client->dev, "triggered buffer setup failed\n");
953 		goto power_off;
954 	}
955 
956 	err = iio_device_register(indio_dev);
957 	if (err) {
958 		dev_err(&client->dev, "device register failed\n");
959 		goto cleanup_buffer;
960 	}
961 
962 	return 0;
963 
964 cleanup_buffer:
965 	iio_triggered_buffer_cleanup(indio_dev);
966 power_off:
967 	ak8975_power_off(client);
968 	return err;
969 }
970 
971 static int ak8975_remove(struct i2c_client *client)
972 {
973 	struct iio_dev *indio_dev = i2c_get_clientdata(client);
974 
975 	iio_device_unregister(indio_dev);
976 	iio_triggered_buffer_cleanup(indio_dev);
977 	ak8975_power_off(client);
978 
979 	return 0;
980 }
981 
982 static const struct i2c_device_id ak8975_id[] = {
983 	{"ak8975", AK8975},
984 	{"ak8963", AK8963},
985 	{"AK8963", AK8963},
986 	{"ak09911", AK09911},
987 	{"ak09912", AK09912},
988 	{}
989 };
990 
991 MODULE_DEVICE_TABLE(i2c, ak8975_id);
992 
993 static const struct of_device_id ak8975_of_match[] = {
994 	{ .compatible = "asahi-kasei,ak8975", },
995 	{ .compatible = "ak8975", },
996 	{ .compatible = "asahi-kasei,ak8963", },
997 	{ .compatible = "ak8963", },
998 	{ .compatible = "asahi-kasei,ak09911", },
999 	{ .compatible = "ak09911", },
1000 	{ .compatible = "asahi-kasei,ak09912", },
1001 	{ .compatible = "ak09912", },
1002 	{}
1003 };
1004 MODULE_DEVICE_TABLE(of, ak8975_of_match);
1005 
1006 static struct i2c_driver ak8975_driver = {
1007 	.driver = {
1008 		.name	= "ak8975",
1009 		.of_match_table = of_match_ptr(ak8975_of_match),
1010 		.acpi_match_table = ACPI_PTR(ak_acpi_match),
1011 	},
1012 	.probe		= ak8975_probe,
1013 	.remove		= ak8975_remove,
1014 	.id_table	= ak8975_id,
1015 };
1016 module_i2c_driver(ak8975_driver);
1017 
1018 MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
1019 MODULE_DESCRIPTION("AK8975 magnetometer driver");
1020 MODULE_LICENSE("GPL");
1021