1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Driver for the Asahi Kasei EMD Corporation AK8974
4 * and Aichi Steel AMI305 magnetometer chips.
5 * Based on a patch from Samu Onkalo and the AK8975 IIO driver.
6 *
7 * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
8 * Copyright (c) 2010 NVIDIA Corporation.
9 * Copyright (C) 2016 Linaro Ltd.
10 *
11 * Author: Samu Onkalo <samu.p.onkalo@nokia.com>
12 * Author: Linus Walleij <linus.walleij@linaro.org>
13 */
14#include <linux/module.h>
15#include <linux/mod_devicetable.h>
16#include <linux/kernel.h>
17#include <linux/i2c.h>
18#include <linux/interrupt.h>
19#include <linux/irq.h> /* For irq_get_irq_data() */
20#include <linux/completion.h>
21#include <linux/err.h>
22#include <linux/mutex.h>
23#include <linux/delay.h>
24#include <linux/bitops.h>
25#include <linux/random.h>
26#include <linux/regmap.h>
27#include <linux/regulator/consumer.h>
28#include <linux/pm_runtime.h>
29
30#include <linux/iio/iio.h>
31#include <linux/iio/sysfs.h>
32#include <linux/iio/buffer.h>
33#include <linux/iio/trigger.h>
34#include <linux/iio/trigger_consumer.h>
35#include <linux/iio/triggered_buffer.h>
36
37/*
38 * 16-bit registers are little-endian. LSB is at the address defined below
39 * and MSB is at the next higher address.
40 */
41
42/* These registers are common for AK8974 and AMI30x */
43#define AK8974_SELFTEST 0x0C
44#define AK8974_SELFTEST_IDLE 0x55
45#define AK8974_SELFTEST_OK 0xAA
46
47#define AK8974_INFO 0x0D
48
49#define AK8974_WHOAMI 0x0F
50#define AK8974_WHOAMI_VALUE_AMI306 0x46
51#define AK8974_WHOAMI_VALUE_AMI305 0x47
52#define AK8974_WHOAMI_VALUE_AK8974 0x48
53#define AK8974_WHOAMI_VALUE_HSCDTD008A 0x49
54
55#define AK8974_DATA_X 0x10
56#define AK8974_DATA_Y 0x12
57#define AK8974_DATA_Z 0x14
58#define AK8974_INT_SRC 0x16
59#define AK8974_STATUS 0x18
60#define AK8974_INT_CLEAR 0x1A
61#define AK8974_CTRL1 0x1B
62#define AK8974_CTRL2 0x1C
63#define AK8974_CTRL3 0x1D
64#define AK8974_INT_CTRL 0x1E
65#define AK8974_INT_THRES 0x26 /* Absolute any axis value threshold */
66#define AK8974_PRESET 0x30
67
68/* AK8974-specific offsets */
69#define AK8974_OFFSET_X 0x20
70#define AK8974_OFFSET_Y 0x22
71#define AK8974_OFFSET_Z 0x24
72/* AMI305-specific offsets */
73#define AMI305_OFFSET_X 0x6C
74#define AMI305_OFFSET_Y 0x72
75#define AMI305_OFFSET_Z 0x78
76
77/* Different temperature registers */
78#define AK8974_TEMP 0x31
79#define AMI305_TEMP 0x60
80
81/* AMI306-specific control register */
82#define AMI306_CTRL4 0x5C
83
84/* AMI306 factory calibration data */
85
86/* fine axis sensitivity */
87#define AMI306_FINEOUTPUT_X 0x90
88#define AMI306_FINEOUTPUT_Y 0x92
89#define AMI306_FINEOUTPUT_Z 0x94
90
91/* axis sensitivity */
92#define AMI306_SENS_X 0x96
93#define AMI306_SENS_Y 0x98
94#define AMI306_SENS_Z 0x9A
95
96/* axis cross-interference */
97#define AMI306_GAIN_PARA_XZ 0x9C
98#define AMI306_GAIN_PARA_XY 0x9D
99#define AMI306_GAIN_PARA_YZ 0x9E
100#define AMI306_GAIN_PARA_YX 0x9F
101#define AMI306_GAIN_PARA_ZY 0xA0
102#define AMI306_GAIN_PARA_ZX 0xA1
103
104/* offset at ZERO magnetic field */
105#define AMI306_OFFZERO_X 0xF8
106#define AMI306_OFFZERO_Y 0xFA
107#define AMI306_OFFZERO_Z 0xFC
108
109
110#define AK8974_INT_X_HIGH BIT(7) /* Axis over +threshold */
111#define AK8974_INT_Y_HIGH BIT(6)
112#define AK8974_INT_Z_HIGH BIT(5)
113#define AK8974_INT_X_LOW BIT(4) /* Axis below -threshold */
114#define AK8974_INT_Y_LOW BIT(3)
115#define AK8974_INT_Z_LOW BIT(2)
116#define AK8974_INT_RANGE BIT(1) /* Range overflow (any axis) */
117
118#define AK8974_STATUS_DRDY BIT(6) /* Data ready */
119#define AK8974_STATUS_OVERRUN BIT(5) /* Data overrun */
120#define AK8974_STATUS_INT BIT(4) /* Interrupt occurred */
121
122#define AK8974_CTRL1_POWER BIT(7) /* 0 = standby; 1 = active */
123#define AK8974_CTRL1_RATE BIT(4) /* 0 = 10 Hz; 1 = 20 Hz */
124#define AK8974_CTRL1_FORCE_EN BIT(1) /* 0 = normal; 1 = force */
125#define AK8974_CTRL1_MODE2 BIT(0) /* 0 */
126
127#define AK8974_CTRL2_INT_EN BIT(4) /* 1 = enable interrupts */
128#define AK8974_CTRL2_DRDY_EN BIT(3) /* 1 = enable data ready signal */
129#define AK8974_CTRL2_DRDY_POL BIT(2) /* 1 = data ready active high */
130#define AK8974_CTRL2_RESDEF (AK8974_CTRL2_DRDY_POL)
131
132#define AK8974_CTRL3_RESET BIT(7) /* Software reset */
133#define AK8974_CTRL3_FORCE BIT(6) /* Start forced measurement */
134#define AK8974_CTRL3_SELFTEST BIT(4) /* Set selftest register */
135#define AK8974_CTRL3_RESDEF 0x00
136
137#define AK8974_INT_CTRL_XEN BIT(7) /* Enable interrupt for this axis */
138#define AK8974_INT_CTRL_YEN BIT(6)
139#define AK8974_INT_CTRL_ZEN BIT(5)
140#define AK8974_INT_CTRL_XYZEN (BIT(7)|BIT(6)|BIT(5))
141#define AK8974_INT_CTRL_POL BIT(3) /* 0 = active low; 1 = active high */
142#define AK8974_INT_CTRL_PULSE BIT(1) /* 0 = latched; 1 = pulse (50 usec) */
143#define AK8974_INT_CTRL_RESDEF (AK8974_INT_CTRL_XYZEN | AK8974_INT_CTRL_POL)
144
145/* HSCDTD008A-specific control register */
146#define HSCDTD008A_CTRL4 0x1E
147#define HSCDTD008A_CTRL4_MMD BIT(7) /* must be set to 1 */
148#define HSCDTD008A_CTRL4_RANGE BIT(4) /* 0 = 14-bit output; 1 = 15-bit output */
149#define HSCDTD008A_CTRL4_RESDEF (HSCDTD008A_CTRL4_MMD | HSCDTD008A_CTRL4_RANGE)
150
151/* The AMI305 has elaborate FW version and serial number registers */
152#define AMI305_VER 0xE8
153#define AMI305_SN 0xEA
154
155#define AK8974_MAX_RANGE 2048
156
157#define AK8974_POWERON_DELAY 50
158#define AK8974_ACTIVATE_DELAY 1
159#define AK8974_SELFTEST_DELAY 1
160/*
161 * Set the autosuspend to two orders of magnitude larger than the poweron
162 * delay to make sane reasonable power tradeoff savings (5 seconds in
163 * this case).
164 */
165#define AK8974_AUTOSUSPEND_DELAY 5000
166
167#define AK8974_MEASTIME 3
168
169#define AK8974_PWR_ON 1
170#define AK8974_PWR_OFF 0
171
172/**
173 * struct ak8974 - state container for the AK8974 driver
174 * @i2c: parent I2C client
175 * @orientation: mounting matrix, flipped axis etc
176 * @map: regmap to access the AK8974 registers over I2C
177 * @regs: the avdd and dvdd power regulators
178 * @name: the name of the part
179 * @variant: the whoami ID value (for selecting code paths)
180 * @lock: locks the magnetometer for exclusive use during a measurement
181 * @drdy_irq: uses the DRDY IRQ line
182 * @drdy_complete: completion for DRDY
183 * @drdy_active_low: the DRDY IRQ is active low
184 * @scan: timestamps
185 */
186struct ak8974 {
187 struct i2c_client *i2c;
188 struct iio_mount_matrix orientation;
189 struct regmap *map;
190 struct regulator_bulk_data regs[2];
191 const char *name;
192 u8 variant;
193 struct mutex lock;
194 bool drdy_irq;
195 struct completion drdy_complete;
196 bool drdy_active_low;
197 /* Ensure timestamp is naturally aligned */
198 struct {
199 __le16 channels[3];
200 s64 ts __aligned(8);
201 } scan;
202};
203
204static const char ak8974_reg_avdd[] = "avdd";
205static const char ak8974_reg_dvdd[] = "dvdd";
206
207static int ak8974_get_u16_val(struct ak8974 *ak8974, u8 reg, u16 *val)
208{
209 int ret;
210 __le16 bulk;
211
212 ret = regmap_bulk_read(map: ak8974->map, reg, val: &bulk, val_count: 2);
213 if (ret)
214 return ret;
215 *val = le16_to_cpu(bulk);
216
217 return 0;
218}
219
220static int ak8974_set_u16_val(struct ak8974 *ak8974, u8 reg, u16 val)
221{
222 __le16 bulk = cpu_to_le16(val);
223
224 return regmap_bulk_write(map: ak8974->map, reg, val: &bulk, val_count: 2);
225}
226
227static int ak8974_set_power(struct ak8974 *ak8974, bool mode)
228{
229 int ret;
230 u8 val;
231
232 val = mode ? AK8974_CTRL1_POWER : 0;
233 val |= AK8974_CTRL1_FORCE_EN;
234 ret = regmap_write(map: ak8974->map, AK8974_CTRL1, val);
235 if (ret < 0)
236 return ret;
237
238 if (mode)
239 msleep(AK8974_ACTIVATE_DELAY);
240
241 return 0;
242}
243
244static int ak8974_reset(struct ak8974 *ak8974)
245{
246 int ret;
247
248 /* Power on to get register access. Sets CTRL1 reg to reset state */
249 ret = ak8974_set_power(ak8974, AK8974_PWR_ON);
250 if (ret)
251 return ret;
252 ret = regmap_write(map: ak8974->map, AK8974_CTRL2, AK8974_CTRL2_RESDEF);
253 if (ret)
254 return ret;
255 ret = regmap_write(map: ak8974->map, AK8974_CTRL3, AK8974_CTRL3_RESDEF);
256 if (ret)
257 return ret;
258 if (ak8974->variant != AK8974_WHOAMI_VALUE_HSCDTD008A) {
259 ret = regmap_write(map: ak8974->map, AK8974_INT_CTRL,
260 AK8974_INT_CTRL_RESDEF);
261 if (ret)
262 return ret;
263 } else {
264 ret = regmap_write(map: ak8974->map, HSCDTD008A_CTRL4,
265 HSCDTD008A_CTRL4_RESDEF);
266 if (ret)
267 return ret;
268 }
269
270 /* After reset, power off is default state */
271 return ak8974_set_power(ak8974, AK8974_PWR_OFF);
272}
273
274static int ak8974_configure(struct ak8974 *ak8974)
275{
276 int ret;
277
278 ret = regmap_write(map: ak8974->map, AK8974_CTRL2, AK8974_CTRL2_DRDY_EN |
279 AK8974_CTRL2_INT_EN);
280 if (ret)
281 return ret;
282 ret = regmap_write(map: ak8974->map, AK8974_CTRL3, val: 0);
283 if (ret)
284 return ret;
285 if (ak8974->variant == AK8974_WHOAMI_VALUE_AMI306) {
286 /* magic from datasheet: set high-speed measurement mode */
287 ret = ak8974_set_u16_val(ak8974, AMI306_CTRL4, val: 0xA07E);
288 if (ret)
289 return ret;
290 }
291 if (ak8974->variant == AK8974_WHOAMI_VALUE_HSCDTD008A)
292 return 0;
293 ret = regmap_write(map: ak8974->map, AK8974_INT_CTRL, AK8974_INT_CTRL_POL);
294 if (ret)
295 return ret;
296
297 return regmap_write(map: ak8974->map, AK8974_PRESET, val: 0);
298}
299
300static int ak8974_trigmeas(struct ak8974 *ak8974)
301{
302 unsigned int clear;
303 u8 mask;
304 u8 val;
305 int ret;
306
307 /* Clear any previous measurement overflow status */
308 ret = regmap_read(map: ak8974->map, AK8974_INT_CLEAR, val: &clear);
309 if (ret)
310 return ret;
311
312 /* If we have a DRDY IRQ line, use it */
313 if (ak8974->drdy_irq) {
314 mask = AK8974_CTRL2_INT_EN |
315 AK8974_CTRL2_DRDY_EN |
316 AK8974_CTRL2_DRDY_POL;
317 val = AK8974_CTRL2_DRDY_EN;
318
319 if (!ak8974->drdy_active_low)
320 val |= AK8974_CTRL2_DRDY_POL;
321
322 init_completion(x: &ak8974->drdy_complete);
323 ret = regmap_update_bits(map: ak8974->map, AK8974_CTRL2,
324 mask, val);
325 if (ret)
326 return ret;
327 }
328
329 /* Force a measurement */
330 return regmap_update_bits(map: ak8974->map,
331 AK8974_CTRL3,
332 AK8974_CTRL3_FORCE,
333 AK8974_CTRL3_FORCE);
334}
335
336static int ak8974_await_drdy(struct ak8974 *ak8974)
337{
338 int timeout = 2;
339 unsigned int val;
340 int ret;
341
342 if (ak8974->drdy_irq) {
343 ret = wait_for_completion_timeout(x: &ak8974->drdy_complete,
344 timeout: 1 + msecs_to_jiffies(m: 1000));
345 if (!ret) {
346 dev_err(&ak8974->i2c->dev,
347 "timeout waiting for DRDY IRQ\n");
348 return -ETIMEDOUT;
349 }
350 return 0;
351 }
352
353 /* Default delay-based poll loop */
354 do {
355 msleep(AK8974_MEASTIME);
356 ret = regmap_read(map: ak8974->map, AK8974_STATUS, val: &val);
357 if (ret < 0)
358 return ret;
359 if (val & AK8974_STATUS_DRDY)
360 return 0;
361 } while (--timeout);
362
363 dev_err(&ak8974->i2c->dev, "timeout waiting for DRDY\n");
364 return -ETIMEDOUT;
365}
366
367static int ak8974_getresult(struct ak8974 *ak8974, __le16 *result)
368{
369 unsigned int src;
370 int ret;
371
372 ret = ak8974_await_drdy(ak8974);
373 if (ret)
374 return ret;
375 ret = regmap_read(map: ak8974->map, AK8974_INT_SRC, val: &src);
376 if (ret < 0)
377 return ret;
378
379 /* Out of range overflow! Strong magnet close? */
380 if (src & AK8974_INT_RANGE) {
381 dev_err(&ak8974->i2c->dev,
382 "range overflow in sensor\n");
383 return -ERANGE;
384 }
385
386 ret = regmap_bulk_read(map: ak8974->map, AK8974_DATA_X, val: result, val_count: 6);
387 if (ret)
388 return ret;
389
390 return ret;
391}
392
393static irqreturn_t ak8974_drdy_irq(int irq, void *d)
394{
395 struct ak8974 *ak8974 = d;
396
397 if (!ak8974->drdy_irq)
398 return IRQ_NONE;
399
400 /* TODO: timestamp here to get good measurement stamps */
401 return IRQ_WAKE_THREAD;
402}
403
404static irqreturn_t ak8974_drdy_irq_thread(int irq, void *d)
405{
406 struct ak8974 *ak8974 = d;
407 unsigned int val;
408 int ret;
409
410 /* Check if this was a DRDY from us */
411 ret = regmap_read(map: ak8974->map, AK8974_STATUS, val: &val);
412 if (ret < 0) {
413 dev_err(&ak8974->i2c->dev, "error reading DRDY status\n");
414 return IRQ_HANDLED;
415 }
416 if (val & AK8974_STATUS_DRDY) {
417 /* Yes this was our IRQ */
418 complete(&ak8974->drdy_complete);
419 return IRQ_HANDLED;
420 }
421
422 /* We may be on a shared IRQ, let the next client check */
423 return IRQ_NONE;
424}
425
426static int ak8974_selftest(struct ak8974 *ak8974)
427{
428 struct device *dev = &ak8974->i2c->dev;
429 unsigned int val;
430 int ret;
431
432 ret = regmap_read(map: ak8974->map, AK8974_SELFTEST, val: &val);
433 if (ret)
434 return ret;
435 if (val != AK8974_SELFTEST_IDLE) {
436 dev_err(dev, "selftest not idle before test\n");
437 return -EIO;
438 }
439
440 /* Trigger self-test */
441 ret = regmap_update_bits(map: ak8974->map,
442 AK8974_CTRL3,
443 AK8974_CTRL3_SELFTEST,
444 AK8974_CTRL3_SELFTEST);
445 if (ret) {
446 dev_err(dev, "could not write CTRL3\n");
447 return ret;
448 }
449
450 msleep(AK8974_SELFTEST_DELAY);
451
452 ret = regmap_read(map: ak8974->map, AK8974_SELFTEST, val: &val);
453 if (ret)
454 return ret;
455 if (val != AK8974_SELFTEST_OK) {
456 dev_err(dev, "selftest result NOT OK (%02x)\n", val);
457 return -EIO;
458 }
459
460 ret = regmap_read(map: ak8974->map, AK8974_SELFTEST, val: &val);
461 if (ret)
462 return ret;
463 if (val != AK8974_SELFTEST_IDLE) {
464 dev_err(dev, "selftest not idle after test (%02x)\n", val);
465 return -EIO;
466 }
467 dev_dbg(dev, "passed self-test\n");
468
469 return 0;
470}
471
472static void ak8974_read_calib_data(struct ak8974 *ak8974, unsigned int reg,
473 __le16 *tab, size_t tab_size)
474{
475 int ret = regmap_bulk_read(map: ak8974->map, reg, val: tab, val_count: tab_size);
476 if (ret) {
477 memset(tab, 0xFF, tab_size);
478 dev_warn(&ak8974->i2c->dev,
479 "can't read calibration data (regs %u..%zu): %d\n",
480 reg, reg + tab_size - 1, ret);
481 } else {
482 add_device_randomness(buf: tab, len: tab_size);
483 }
484}
485
486static int ak8974_detect(struct ak8974 *ak8974)
487{
488 unsigned int whoami;
489 const char *name;
490 int ret;
491 unsigned int fw;
492 u16 sn;
493
494 ret = regmap_read(map: ak8974->map, AK8974_WHOAMI, val: &whoami);
495 if (ret)
496 return ret;
497
498 name = "ami305";
499
500 switch (whoami) {
501 case AK8974_WHOAMI_VALUE_AMI306:
502 name = "ami306";
503 fallthrough;
504 case AK8974_WHOAMI_VALUE_AMI305:
505 ret = regmap_read(map: ak8974->map, AMI305_VER, val: &fw);
506 if (ret)
507 return ret;
508 fw &= 0x7f; /* only bits 0 thru 6 valid */
509 ret = ak8974_get_u16_val(ak8974, AMI305_SN, val: &sn);
510 if (ret)
511 return ret;
512 add_device_randomness(buf: &sn, len: sizeof(sn));
513 dev_info(&ak8974->i2c->dev,
514 "detected %s, FW ver %02x, S/N: %04x\n",
515 name, fw, sn);
516 break;
517 case AK8974_WHOAMI_VALUE_AK8974:
518 name = "ak8974";
519 dev_info(&ak8974->i2c->dev, "detected AK8974\n");
520 break;
521 case AK8974_WHOAMI_VALUE_HSCDTD008A:
522 name = "hscdtd008a";
523 dev_info(&ak8974->i2c->dev, "detected hscdtd008a\n");
524 break;
525 default:
526 dev_err(&ak8974->i2c->dev, "unsupported device (%02x) ",
527 whoami);
528 return -ENODEV;
529 }
530
531 ak8974->name = name;
532 ak8974->variant = whoami;
533
534 if (whoami == AK8974_WHOAMI_VALUE_AMI306) {
535 __le16 fab_data1[9], fab_data2[3];
536 int i;
537
538 ak8974_read_calib_data(ak8974, AMI306_FINEOUTPUT_X,
539 tab: fab_data1, tab_size: sizeof(fab_data1));
540 ak8974_read_calib_data(ak8974, AMI306_OFFZERO_X,
541 tab: fab_data2, tab_size: sizeof(fab_data2));
542
543 for (i = 0; i < 3; ++i) {
544 static const char axis[3] = "XYZ";
545 static const char pgaxis[6] = "ZYZXYX";
546 unsigned offz = le16_to_cpu(fab_data2[i]) & 0x7F;
547 unsigned fine = le16_to_cpu(fab_data1[i]);
548 unsigned sens = le16_to_cpu(fab_data1[i + 3]);
549 unsigned pgain1 = le16_to_cpu(fab_data1[i + 6]);
550 unsigned pgain2 = pgain1 >> 8;
551
552 pgain1 &= 0xFF;
553
554 dev_info(&ak8974->i2c->dev,
555 "factory calibration for axis %c: offz=%u sens=%u fine=%u pga%c=%u pga%c=%u\n",
556 axis[i], offz, sens, fine, pgaxis[i * 2],
557 pgain1, pgaxis[i * 2 + 1], pgain2);
558 }
559 }
560
561 return 0;
562}
563
564static int ak8974_measure_channel(struct ak8974 *ak8974, unsigned long address,
565 int *val)
566{
567 __le16 hw_values[3];
568 int ret;
569
570 pm_runtime_get_sync(dev: &ak8974->i2c->dev);
571 mutex_lock(&ak8974->lock);
572
573 /*
574 * We read all axes and discard all but one, for optimized
575 * reading, use the triggered buffer.
576 */
577 ret = ak8974_trigmeas(ak8974);
578 if (ret)
579 goto out_unlock;
580 ret = ak8974_getresult(ak8974, result: hw_values);
581 if (ret)
582 goto out_unlock;
583 /*
584 * This explicit cast to (s16) is necessary as the measurement
585 * is done in 2's complement with positive and negative values.
586 * The follwing assignment to *val will then convert the signed
587 * s16 value to a signed int value.
588 */
589 *val = (s16)le16_to_cpu(hw_values[address]);
590out_unlock:
591 mutex_unlock(lock: &ak8974->lock);
592 pm_runtime_mark_last_busy(dev: &ak8974->i2c->dev);
593 pm_runtime_put_autosuspend(dev: &ak8974->i2c->dev);
594
595 return ret;
596}
597
598static int ak8974_read_raw(struct iio_dev *indio_dev,
599 struct iio_chan_spec const *chan,
600 int *val, int *val2,
601 long mask)
602{
603 struct ak8974 *ak8974 = iio_priv(indio_dev);
604 int ret;
605
606 switch (mask) {
607 case IIO_CHAN_INFO_RAW:
608 if (chan->address > 2) {
609 dev_err(&ak8974->i2c->dev, "faulty channel address\n");
610 return -EIO;
611 }
612 ret = ak8974_measure_channel(ak8974, address: chan->address, val);
613 if (ret)
614 return ret;
615 return IIO_VAL_INT;
616 case IIO_CHAN_INFO_SCALE:
617 switch (ak8974->variant) {
618 case AK8974_WHOAMI_VALUE_AMI306:
619 case AK8974_WHOAMI_VALUE_AMI305:
620 /*
621 * The datasheet for AMI305 and AMI306, page 6
622 * specifies the range of the sensor to be
623 * +/- 12 Gauss.
624 */
625 *val = 12;
626 /*
627 * 12 bits are used, +/- 2^11
628 * [ -2048 .. 2047 ] (manual page 20)
629 * [ 0xf800 .. 0x07ff ]
630 */
631 *val2 = 11;
632 return IIO_VAL_FRACTIONAL_LOG2;
633 case AK8974_WHOAMI_VALUE_HSCDTD008A:
634 /*
635 * The datasheet for HSCDTF008A, page 3 specifies the
636 * range of the sensor as +/- 2.4 mT per axis, which
637 * corresponds to +/- 2400 uT = +/- 24 Gauss.
638 */
639 *val = 24;
640 /*
641 * 15 bits are used (set up in CTRL4), +/- 2^14
642 * [ -16384 .. 16383 ] (manual page 24)
643 * [ 0xc000 .. 0x3fff ]
644 */
645 *val2 = 14;
646 return IIO_VAL_FRACTIONAL_LOG2;
647 default:
648 /* GUESSING +/- 12 Gauss */
649 *val = 12;
650 /* GUESSING 12 bits ADC +/- 2^11 */
651 *val2 = 11;
652 return IIO_VAL_FRACTIONAL_LOG2;
653 }
654 break;
655 default:
656 /* Unknown request */
657 break;
658 }
659
660 return -EINVAL;
661}
662
663static void ak8974_fill_buffer(struct iio_dev *indio_dev)
664{
665 struct ak8974 *ak8974 = iio_priv(indio_dev);
666 int ret;
667
668 pm_runtime_get_sync(dev: &ak8974->i2c->dev);
669 mutex_lock(&ak8974->lock);
670
671 ret = ak8974_trigmeas(ak8974);
672 if (ret) {
673 dev_err(&ak8974->i2c->dev, "error triggering measure\n");
674 goto out_unlock;
675 }
676 ret = ak8974_getresult(ak8974, result: ak8974->scan.channels);
677 if (ret) {
678 dev_err(&ak8974->i2c->dev, "error getting measures\n");
679 goto out_unlock;
680 }
681
682 iio_push_to_buffers_with_timestamp(indio_dev, data: &ak8974->scan,
683 timestamp: iio_get_time_ns(indio_dev));
684
685 out_unlock:
686 mutex_unlock(lock: &ak8974->lock);
687 pm_runtime_mark_last_busy(dev: &ak8974->i2c->dev);
688 pm_runtime_put_autosuspend(dev: &ak8974->i2c->dev);
689}
690
691static irqreturn_t ak8974_handle_trigger(int irq, void *p)
692{
693 const struct iio_poll_func *pf = p;
694 struct iio_dev *indio_dev = pf->indio_dev;
695
696 ak8974_fill_buffer(indio_dev);
697 iio_trigger_notify_done(trig: indio_dev->trig);
698
699 return IRQ_HANDLED;
700}
701
702static const struct iio_mount_matrix *
703ak8974_get_mount_matrix(const struct iio_dev *indio_dev,
704 const struct iio_chan_spec *chan)
705{
706 struct ak8974 *ak8974 = iio_priv(indio_dev);
707
708 return &ak8974->orientation;
709}
710
711static const struct iio_chan_spec_ext_info ak8974_ext_info[] = {
712 IIO_MOUNT_MATRIX(IIO_SHARED_BY_DIR, ak8974_get_mount_matrix),
713 { },
714};
715
716#define AK8974_AXIS_CHANNEL(axis, index, bits) \
717 { \
718 .type = IIO_MAGN, \
719 .modified = 1, \
720 .channel2 = IIO_MOD_##axis, \
721 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
722 BIT(IIO_CHAN_INFO_SCALE), \
723 .ext_info = ak8974_ext_info, \
724 .address = index, \
725 .scan_index = index, \
726 .scan_type = { \
727 .sign = 's', \
728 .realbits = bits, \
729 .storagebits = 16, \
730 .endianness = IIO_LE \
731 }, \
732 }
733
734/*
735 * We have no datasheet for the AK8974 but we guess that its
736 * ADC is 12 bits. The AMI305 and AMI306 certainly has 12bit
737 * ADC.
738 */
739static const struct iio_chan_spec ak8974_12_bits_channels[] = {
740 AK8974_AXIS_CHANNEL(X, 0, 12),
741 AK8974_AXIS_CHANNEL(Y, 1, 12),
742 AK8974_AXIS_CHANNEL(Z, 2, 12),
743 IIO_CHAN_SOFT_TIMESTAMP(3),
744};
745
746/*
747 * The HSCDTD008A has 15 bits resolution the way we set it up
748 * in CTRL4.
749 */
750static const struct iio_chan_spec ak8974_15_bits_channels[] = {
751 AK8974_AXIS_CHANNEL(X, 0, 15),
752 AK8974_AXIS_CHANNEL(Y, 1, 15),
753 AK8974_AXIS_CHANNEL(Z, 2, 15),
754 IIO_CHAN_SOFT_TIMESTAMP(3),
755};
756
757static const unsigned long ak8974_scan_masks[] = { 0x7, 0 };
758
759static const struct iio_info ak8974_info = {
760 .read_raw = &ak8974_read_raw,
761};
762
763static bool ak8974_writeable_reg(struct device *dev, unsigned int reg)
764{
765 struct i2c_client *i2c = to_i2c_client(dev);
766 struct iio_dev *indio_dev = i2c_get_clientdata(client: i2c);
767 struct ak8974 *ak8974 = iio_priv(indio_dev);
768
769 switch (reg) {
770 case AK8974_CTRL1:
771 case AK8974_CTRL2:
772 case AK8974_CTRL3:
773 case AK8974_INT_CTRL:
774 case AK8974_INT_THRES:
775 case AK8974_INT_THRES + 1:
776 return true;
777 case AK8974_PRESET:
778 case AK8974_PRESET + 1:
779 return ak8974->variant != AK8974_WHOAMI_VALUE_HSCDTD008A;
780 case AK8974_OFFSET_X:
781 case AK8974_OFFSET_X + 1:
782 case AK8974_OFFSET_Y:
783 case AK8974_OFFSET_Y + 1:
784 case AK8974_OFFSET_Z:
785 case AK8974_OFFSET_Z + 1:
786 return ak8974->variant == AK8974_WHOAMI_VALUE_AK8974 ||
787 ak8974->variant == AK8974_WHOAMI_VALUE_HSCDTD008A;
788 case AMI305_OFFSET_X:
789 case AMI305_OFFSET_X + 1:
790 case AMI305_OFFSET_Y:
791 case AMI305_OFFSET_Y + 1:
792 case AMI305_OFFSET_Z:
793 case AMI305_OFFSET_Z + 1:
794 return ak8974->variant == AK8974_WHOAMI_VALUE_AMI305 ||
795 ak8974->variant == AK8974_WHOAMI_VALUE_AMI306;
796 case AMI306_CTRL4:
797 case AMI306_CTRL4 + 1:
798 return ak8974->variant == AK8974_WHOAMI_VALUE_AMI306;
799 default:
800 return false;
801 }
802}
803
804static bool ak8974_precious_reg(struct device *dev, unsigned int reg)
805{
806 return reg == AK8974_INT_CLEAR;
807}
808
809static const struct regmap_config ak8974_regmap_config = {
810 .reg_bits = 8,
811 .val_bits = 8,
812 .max_register = 0xff,
813 .writeable_reg = ak8974_writeable_reg,
814 .precious_reg = ak8974_precious_reg,
815};
816
817static int ak8974_probe(struct i2c_client *i2c)
818{
819 struct iio_dev *indio_dev;
820 struct ak8974 *ak8974;
821 unsigned long irq_trig;
822 int irq = i2c->irq;
823 int ret;
824
825 /* Register with IIO */
826 indio_dev = devm_iio_device_alloc(parent: &i2c->dev, sizeof_priv: sizeof(*ak8974));
827 if (indio_dev == NULL)
828 return -ENOMEM;
829
830 ak8974 = iio_priv(indio_dev);
831 i2c_set_clientdata(client: i2c, data: indio_dev);
832 ak8974->i2c = i2c;
833 mutex_init(&ak8974->lock);
834
835 ret = iio_read_mount_matrix(dev: &i2c->dev, matrix: &ak8974->orientation);
836 if (ret)
837 return ret;
838
839 ak8974->regs[0].supply = ak8974_reg_avdd;
840 ak8974->regs[1].supply = ak8974_reg_dvdd;
841
842 ret = devm_regulator_bulk_get(dev: &i2c->dev,
843 ARRAY_SIZE(ak8974->regs),
844 consumers: ak8974->regs);
845 if (ret < 0)
846 return dev_err_probe(dev: &i2c->dev, err: ret, fmt: "cannot get regulators\n");
847
848 ret = regulator_bulk_enable(ARRAY_SIZE(ak8974->regs), consumers: ak8974->regs);
849 if (ret < 0) {
850 dev_err(&i2c->dev, "cannot enable regulators\n");
851 return ret;
852 }
853
854 /* Take runtime PM online */
855 pm_runtime_get_noresume(dev: &i2c->dev);
856 pm_runtime_set_active(dev: &i2c->dev);
857 pm_runtime_enable(dev: &i2c->dev);
858
859 ak8974->map = devm_regmap_init_i2c(i2c, &ak8974_regmap_config);
860 if (IS_ERR(ptr: ak8974->map)) {
861 dev_err(&i2c->dev, "failed to allocate register map\n");
862 pm_runtime_put_noidle(dev: &i2c->dev);
863 pm_runtime_disable(dev: &i2c->dev);
864 return PTR_ERR(ptr: ak8974->map);
865 }
866
867 ret = ak8974_set_power(ak8974, AK8974_PWR_ON);
868 if (ret) {
869 dev_err(&i2c->dev, "could not power on\n");
870 goto disable_pm;
871 }
872
873 ret = ak8974_detect(ak8974);
874 if (ret) {
875 dev_err(&i2c->dev, "neither AK8974 nor AMI30x found\n");
876 goto disable_pm;
877 }
878
879 ret = ak8974_selftest(ak8974);
880 if (ret)
881 dev_err(&i2c->dev, "selftest failed (continuing anyway)\n");
882
883 ret = ak8974_reset(ak8974);
884 if (ret) {
885 dev_err(&i2c->dev, "AK8974 reset failed\n");
886 goto disable_pm;
887 }
888
889 switch (ak8974->variant) {
890 case AK8974_WHOAMI_VALUE_AMI306:
891 case AK8974_WHOAMI_VALUE_AMI305:
892 indio_dev->channels = ak8974_12_bits_channels;
893 indio_dev->num_channels = ARRAY_SIZE(ak8974_12_bits_channels);
894 break;
895 case AK8974_WHOAMI_VALUE_HSCDTD008A:
896 indio_dev->channels = ak8974_15_bits_channels;
897 indio_dev->num_channels = ARRAY_SIZE(ak8974_15_bits_channels);
898 break;
899 default:
900 indio_dev->channels = ak8974_12_bits_channels;
901 indio_dev->num_channels = ARRAY_SIZE(ak8974_12_bits_channels);
902 break;
903 }
904 indio_dev->info = &ak8974_info;
905 indio_dev->available_scan_masks = ak8974_scan_masks;
906 indio_dev->modes = INDIO_DIRECT_MODE;
907 indio_dev->name = ak8974->name;
908
909 ret = iio_triggered_buffer_setup(indio_dev, NULL,
910 ak8974_handle_trigger,
911 NULL);
912 if (ret) {
913 dev_err(&i2c->dev, "triggered buffer setup failed\n");
914 goto disable_pm;
915 }
916
917 /* If we have a valid DRDY IRQ, make use of it */
918 if (irq > 0) {
919 irq_trig = irqd_get_trigger_type(d: irq_get_irq_data(irq));
920 if (irq_trig == IRQF_TRIGGER_RISING) {
921 dev_info(&i2c->dev, "enable rising edge DRDY IRQ\n");
922 } else if (irq_trig == IRQF_TRIGGER_FALLING) {
923 ak8974->drdy_active_low = true;
924 dev_info(&i2c->dev, "enable falling edge DRDY IRQ\n");
925 } else {
926 irq_trig = IRQF_TRIGGER_RISING;
927 }
928 irq_trig |= IRQF_ONESHOT;
929 irq_trig |= IRQF_SHARED;
930
931 ret = devm_request_threaded_irq(dev: &i2c->dev,
932 irq,
933 handler: ak8974_drdy_irq,
934 thread_fn: ak8974_drdy_irq_thread,
935 irqflags: irq_trig,
936 devname: ak8974->name,
937 dev_id: ak8974);
938 if (ret) {
939 dev_err(&i2c->dev, "unable to request DRDY IRQ "
940 "- proceeding without IRQ\n");
941 goto no_irq;
942 }
943 ak8974->drdy_irq = true;
944 }
945
946no_irq:
947 ret = iio_device_register(indio_dev);
948 if (ret) {
949 dev_err(&i2c->dev, "device register failed\n");
950 goto cleanup_buffer;
951 }
952
953 pm_runtime_set_autosuspend_delay(dev: &i2c->dev,
954 AK8974_AUTOSUSPEND_DELAY);
955 pm_runtime_use_autosuspend(dev: &i2c->dev);
956 pm_runtime_put(dev: &i2c->dev);
957
958 return 0;
959
960cleanup_buffer:
961 iio_triggered_buffer_cleanup(indio_dev);
962disable_pm:
963 pm_runtime_put_noidle(dev: &i2c->dev);
964 pm_runtime_disable(dev: &i2c->dev);
965 ak8974_set_power(ak8974, AK8974_PWR_OFF);
966 regulator_bulk_disable(ARRAY_SIZE(ak8974->regs), consumers: ak8974->regs);
967
968 return ret;
969}
970
971static void ak8974_remove(struct i2c_client *i2c)
972{
973 struct iio_dev *indio_dev = i2c_get_clientdata(client: i2c);
974 struct ak8974 *ak8974 = iio_priv(indio_dev);
975
976 iio_device_unregister(indio_dev);
977 iio_triggered_buffer_cleanup(indio_dev);
978 pm_runtime_get_sync(dev: &i2c->dev);
979 pm_runtime_put_noidle(dev: &i2c->dev);
980 pm_runtime_disable(dev: &i2c->dev);
981 ak8974_set_power(ak8974, AK8974_PWR_OFF);
982 regulator_bulk_disable(ARRAY_SIZE(ak8974->regs), consumers: ak8974->regs);
983}
984
985static int ak8974_runtime_suspend(struct device *dev)
986{
987 struct ak8974 *ak8974 =
988 iio_priv(indio_dev: i2c_get_clientdata(to_i2c_client(dev)));
989
990 ak8974_set_power(ak8974, AK8974_PWR_OFF);
991 regulator_bulk_disable(ARRAY_SIZE(ak8974->regs), consumers: ak8974->regs);
992
993 return 0;
994}
995
996static int ak8974_runtime_resume(struct device *dev)
997{
998 struct ak8974 *ak8974 =
999 iio_priv(indio_dev: i2c_get_clientdata(to_i2c_client(dev)));
1000 int ret;
1001
1002 ret = regulator_bulk_enable(ARRAY_SIZE(ak8974->regs), consumers: ak8974->regs);
1003 if (ret)
1004 return ret;
1005 msleep(AK8974_POWERON_DELAY);
1006 ret = ak8974_set_power(ak8974, AK8974_PWR_ON);
1007 if (ret)
1008 goto out_regulator_disable;
1009
1010 ret = ak8974_configure(ak8974);
1011 if (ret)
1012 goto out_disable_power;
1013
1014 return 0;
1015
1016out_disable_power:
1017 ak8974_set_power(ak8974, AK8974_PWR_OFF);
1018out_regulator_disable:
1019 regulator_bulk_disable(ARRAY_SIZE(ak8974->regs), consumers: ak8974->regs);
1020
1021 return ret;
1022}
1023
1024static DEFINE_RUNTIME_DEV_PM_OPS(ak8974_dev_pm_ops, ak8974_runtime_suspend,
1025 ak8974_runtime_resume, NULL);
1026
1027static const struct i2c_device_id ak8974_id[] = {
1028 {"ami305", 0 },
1029 {"ami306", 0 },
1030 {"ak8974", 0 },
1031 {"hscdtd008a", 0 },
1032 {}
1033};
1034MODULE_DEVICE_TABLE(i2c, ak8974_id);
1035
1036static const struct of_device_id ak8974_of_match[] = {
1037 { .compatible = "asahi-kasei,ak8974", },
1038 { .compatible = "alps,hscdtd008a", },
1039 {}
1040};
1041MODULE_DEVICE_TABLE(of, ak8974_of_match);
1042
1043static struct i2c_driver ak8974_driver = {
1044 .driver = {
1045 .name = "ak8974",
1046 .pm = pm_ptr(&ak8974_dev_pm_ops),
1047 .of_match_table = ak8974_of_match,
1048 },
1049 .probe = ak8974_probe,
1050 .remove = ak8974_remove,
1051 .id_table = ak8974_id,
1052};
1053module_i2c_driver(ak8974_driver);
1054
1055MODULE_DESCRIPTION("AK8974 and AMI30x 3-axis magnetometer driver");
1056MODULE_AUTHOR("Samu Onkalo");
1057MODULE_AUTHOR("Linus Walleij");
1058MODULE_LICENSE("GPL v2");
1059

source code of linux/drivers/iio/magnetometer/ak8974.c