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 */
186 struct 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
204 static const char ak8974_reg_avdd[] = "avdd";
205 static const char ak8974_reg_dvdd[] = "dvdd";
206
ak8974_get_u16_val(struct ak8974 * ak8974,u8 reg,u16 * val)207 static 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(ak8974->map, reg, &bulk, 2);
213 if (ret)
214 return ret;
215 *val = le16_to_cpu(bulk);
216
217 return 0;
218 }
219
ak8974_set_u16_val(struct ak8974 * ak8974,u8 reg,u16 val)220 static 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(ak8974->map, reg, &bulk, 2);
225 }
226
ak8974_set_power(struct ak8974 * ak8974,bool mode)227 static 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(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
ak8974_reset(struct ak8974 * ak8974)244 static 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(ak8974->map, AK8974_CTRL2, AK8974_CTRL2_RESDEF);
253 if (ret)
254 return ret;
255 ret = regmap_write(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(ak8974->map, AK8974_INT_CTRL,
260 AK8974_INT_CTRL_RESDEF);
261 if (ret)
262 return ret;
263 } else {
264 ret = regmap_write(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
ak8974_configure(struct ak8974 * ak8974)274 static int ak8974_configure(struct ak8974 *ak8974)
275 {
276 int ret;
277
278 ret = regmap_write(ak8974->map, AK8974_CTRL2, AK8974_CTRL2_DRDY_EN |
279 AK8974_CTRL2_INT_EN);
280 if (ret)
281 return ret;
282 ret = regmap_write(ak8974->map, AK8974_CTRL3, 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, 0xA07E);
288 if (ret)
289 return ret;
290 }
291 if (ak8974->variant == AK8974_WHOAMI_VALUE_HSCDTD008A)
292 return 0;
293 ret = regmap_write(ak8974->map, AK8974_INT_CTRL, AK8974_INT_CTRL_POL);
294 if (ret)
295 return ret;
296
297 return regmap_write(ak8974->map, AK8974_PRESET, 0);
298 }
299
ak8974_trigmeas(struct ak8974 * ak8974)300 static 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(ak8974->map, AK8974_INT_CLEAR, &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(&ak8974->drdy_complete);
323 ret = regmap_update_bits(ak8974->map, AK8974_CTRL2,
324 mask, val);
325 if (ret)
326 return ret;
327 }
328
329 /* Force a measurement */
330 return regmap_update_bits(ak8974->map,
331 AK8974_CTRL3,
332 AK8974_CTRL3_FORCE,
333 AK8974_CTRL3_FORCE);
334 }
335
ak8974_await_drdy(struct ak8974 * ak8974)336 static 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(&ak8974->drdy_complete,
344 1 + msecs_to_jiffies(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(ak8974->map, AK8974_STATUS, &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
ak8974_getresult(struct ak8974 * ak8974,__le16 * result)367 static 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(ak8974->map, AK8974_INT_SRC, &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(ak8974->map, AK8974_DATA_X, result, 6);
387 if (ret)
388 return ret;
389
390 return ret;
391 }
392
ak8974_drdy_irq(int irq,void * d)393 static 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
ak8974_drdy_irq_thread(int irq,void * d)404 static 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(ak8974->map, AK8974_STATUS, &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
ak8974_selftest(struct ak8974 * ak8974)426 static 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(ak8974->map, AK8974_SELFTEST, &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(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(ak8974->map, AK8974_SELFTEST, &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(ak8974->map, AK8974_SELFTEST, &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
ak8974_read_calib_data(struct ak8974 * ak8974,unsigned int reg,__le16 * tab,size_t tab_size)472 static 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(ak8974->map, reg, tab, 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(tab, tab_size);
483 }
484 }
485
ak8974_detect(struct ak8974 * ak8974)486 static 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(ak8974->map, AK8974_WHOAMI, &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(ak8974->map, AMI305_VER, &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, &sn);
510 if (ret)
511 return ret;
512 add_device_randomness(&sn, 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 fab_data1, sizeof(fab_data1));
540 ak8974_read_calib_data(ak8974, AMI306_OFFZERO_X,
541 fab_data2, 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
ak8974_measure_channel(struct ak8974 * ak8974,unsigned long address,int * val)564 static 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(&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, 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]);
590 out_unlock:
591 mutex_unlock(&ak8974->lock);
592 pm_runtime_mark_last_busy(&ak8974->i2c->dev);
593 pm_runtime_put_autosuspend(&ak8974->i2c->dev);
594
595 return ret;
596 }
597
ak8974_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)598 static 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, 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
ak8974_fill_buffer(struct iio_dev * indio_dev)663 static 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(&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, 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, &ak8974->scan,
683 iio_get_time_ns(indio_dev));
684
685 out_unlock:
686 mutex_unlock(&ak8974->lock);
687 pm_runtime_mark_last_busy(&ak8974->i2c->dev);
688 pm_runtime_put_autosuspend(&ak8974->i2c->dev);
689 }
690
ak8974_handle_trigger(int irq,void * p)691 static 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(indio_dev->trig);
698
699 return IRQ_HANDLED;
700 }
701
702 static const struct iio_mount_matrix *
ak8974_get_mount_matrix(const struct iio_dev * indio_dev,const struct iio_chan_spec * chan)703 ak8974_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
711 static 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 */
739 static 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 */
750 static 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
757 static const unsigned long ak8974_scan_masks[] = { 0x7, 0 };
758
759 static const struct iio_info ak8974_info = {
760 .read_raw = &ak8974_read_raw,
761 };
762
ak8974_writeable_reg(struct device * dev,unsigned int reg)763 static 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(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
ak8974_precious_reg(struct device * dev,unsigned int reg)804 static bool ak8974_precious_reg(struct device *dev, unsigned int reg)
805 {
806 return reg == AK8974_INT_CLEAR;
807 }
808
809 static 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
ak8974_probe(struct i2c_client * i2c,const struct i2c_device_id * id)817 static int ak8974_probe(struct i2c_client *i2c,
818 const struct i2c_device_id *id)
819 {
820 struct iio_dev *indio_dev;
821 struct ak8974 *ak8974;
822 unsigned long irq_trig;
823 int irq = i2c->irq;
824 int ret;
825
826 /* Register with IIO */
827 indio_dev = devm_iio_device_alloc(&i2c->dev, sizeof(*ak8974));
828 if (indio_dev == NULL)
829 return -ENOMEM;
830
831 ak8974 = iio_priv(indio_dev);
832 i2c_set_clientdata(i2c, indio_dev);
833 ak8974->i2c = i2c;
834 mutex_init(&ak8974->lock);
835
836 ret = iio_read_mount_matrix(&i2c->dev, &ak8974->orientation);
837 if (ret)
838 return ret;
839
840 ak8974->regs[0].supply = ak8974_reg_avdd;
841 ak8974->regs[1].supply = ak8974_reg_dvdd;
842
843 ret = devm_regulator_bulk_get(&i2c->dev,
844 ARRAY_SIZE(ak8974->regs),
845 ak8974->regs);
846 if (ret < 0)
847 return dev_err_probe(&i2c->dev, ret, "cannot get regulators\n");
848
849 ret = regulator_bulk_enable(ARRAY_SIZE(ak8974->regs), ak8974->regs);
850 if (ret < 0) {
851 dev_err(&i2c->dev, "cannot enable regulators\n");
852 return ret;
853 }
854
855 /* Take runtime PM online */
856 pm_runtime_get_noresume(&i2c->dev);
857 pm_runtime_set_active(&i2c->dev);
858 pm_runtime_enable(&i2c->dev);
859
860 ak8974->map = devm_regmap_init_i2c(i2c, &ak8974_regmap_config);
861 if (IS_ERR(ak8974->map)) {
862 dev_err(&i2c->dev, "failed to allocate register map\n");
863 pm_runtime_put_noidle(&i2c->dev);
864 pm_runtime_disable(&i2c->dev);
865 return PTR_ERR(ak8974->map);
866 }
867
868 ret = ak8974_set_power(ak8974, AK8974_PWR_ON);
869 if (ret) {
870 dev_err(&i2c->dev, "could not power on\n");
871 goto disable_pm;
872 }
873
874 ret = ak8974_detect(ak8974);
875 if (ret) {
876 dev_err(&i2c->dev, "neither AK8974 nor AMI30x found\n");
877 goto disable_pm;
878 }
879
880 ret = ak8974_selftest(ak8974);
881 if (ret)
882 dev_err(&i2c->dev, "selftest failed (continuing anyway)\n");
883
884 ret = ak8974_reset(ak8974);
885 if (ret) {
886 dev_err(&i2c->dev, "AK8974 reset failed\n");
887 goto disable_pm;
888 }
889
890 switch (ak8974->variant) {
891 case AK8974_WHOAMI_VALUE_AMI306:
892 case AK8974_WHOAMI_VALUE_AMI305:
893 indio_dev->channels = ak8974_12_bits_channels;
894 indio_dev->num_channels = ARRAY_SIZE(ak8974_12_bits_channels);
895 break;
896 case AK8974_WHOAMI_VALUE_HSCDTD008A:
897 indio_dev->channels = ak8974_15_bits_channels;
898 indio_dev->num_channels = ARRAY_SIZE(ak8974_15_bits_channels);
899 break;
900 default:
901 indio_dev->channels = ak8974_12_bits_channels;
902 indio_dev->num_channels = ARRAY_SIZE(ak8974_12_bits_channels);
903 break;
904 }
905 indio_dev->info = &ak8974_info;
906 indio_dev->available_scan_masks = ak8974_scan_masks;
907 indio_dev->modes = INDIO_DIRECT_MODE;
908 indio_dev->name = ak8974->name;
909
910 ret = iio_triggered_buffer_setup(indio_dev, NULL,
911 ak8974_handle_trigger,
912 NULL);
913 if (ret) {
914 dev_err(&i2c->dev, "triggered buffer setup failed\n");
915 goto disable_pm;
916 }
917
918 /* If we have a valid DRDY IRQ, make use of it */
919 if (irq > 0) {
920 irq_trig = irqd_get_trigger_type(irq_get_irq_data(irq));
921 if (irq_trig == IRQF_TRIGGER_RISING) {
922 dev_info(&i2c->dev, "enable rising edge DRDY IRQ\n");
923 } else if (irq_trig == IRQF_TRIGGER_FALLING) {
924 ak8974->drdy_active_low = true;
925 dev_info(&i2c->dev, "enable falling edge DRDY IRQ\n");
926 } else {
927 irq_trig = IRQF_TRIGGER_RISING;
928 }
929 irq_trig |= IRQF_ONESHOT;
930 irq_trig |= IRQF_SHARED;
931
932 ret = devm_request_threaded_irq(&i2c->dev,
933 irq,
934 ak8974_drdy_irq,
935 ak8974_drdy_irq_thread,
936 irq_trig,
937 ak8974->name,
938 ak8974);
939 if (ret) {
940 dev_err(&i2c->dev, "unable to request DRDY IRQ "
941 "- proceeding without IRQ\n");
942 goto no_irq;
943 }
944 ak8974->drdy_irq = true;
945 }
946
947 no_irq:
948 ret = iio_device_register(indio_dev);
949 if (ret) {
950 dev_err(&i2c->dev, "device register failed\n");
951 goto cleanup_buffer;
952 }
953
954 pm_runtime_set_autosuspend_delay(&i2c->dev,
955 AK8974_AUTOSUSPEND_DELAY);
956 pm_runtime_use_autosuspend(&i2c->dev);
957 pm_runtime_put(&i2c->dev);
958
959 return 0;
960
961 cleanup_buffer:
962 iio_triggered_buffer_cleanup(indio_dev);
963 disable_pm:
964 pm_runtime_put_noidle(&i2c->dev);
965 pm_runtime_disable(&i2c->dev);
966 ak8974_set_power(ak8974, AK8974_PWR_OFF);
967 regulator_bulk_disable(ARRAY_SIZE(ak8974->regs), ak8974->regs);
968
969 return ret;
970 }
971
ak8974_remove(struct i2c_client * i2c)972 static void ak8974_remove(struct i2c_client *i2c)
973 {
974 struct iio_dev *indio_dev = i2c_get_clientdata(i2c);
975 struct ak8974 *ak8974 = iio_priv(indio_dev);
976
977 iio_device_unregister(indio_dev);
978 iio_triggered_buffer_cleanup(indio_dev);
979 pm_runtime_get_sync(&i2c->dev);
980 pm_runtime_put_noidle(&i2c->dev);
981 pm_runtime_disable(&i2c->dev);
982 ak8974_set_power(ak8974, AK8974_PWR_OFF);
983 regulator_bulk_disable(ARRAY_SIZE(ak8974->regs), ak8974->regs);
984 }
985
ak8974_runtime_suspend(struct device * dev)986 static int ak8974_runtime_suspend(struct device *dev)
987 {
988 struct ak8974 *ak8974 =
989 iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
990
991 ak8974_set_power(ak8974, AK8974_PWR_OFF);
992 regulator_bulk_disable(ARRAY_SIZE(ak8974->regs), ak8974->regs);
993
994 return 0;
995 }
996
ak8974_runtime_resume(struct device * dev)997 static int ak8974_runtime_resume(struct device *dev)
998 {
999 struct ak8974 *ak8974 =
1000 iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
1001 int ret;
1002
1003 ret = regulator_bulk_enable(ARRAY_SIZE(ak8974->regs), ak8974->regs);
1004 if (ret)
1005 return ret;
1006 msleep(AK8974_POWERON_DELAY);
1007 ret = ak8974_set_power(ak8974, AK8974_PWR_ON);
1008 if (ret)
1009 goto out_regulator_disable;
1010
1011 ret = ak8974_configure(ak8974);
1012 if (ret)
1013 goto out_disable_power;
1014
1015 return 0;
1016
1017 out_disable_power:
1018 ak8974_set_power(ak8974, AK8974_PWR_OFF);
1019 out_regulator_disable:
1020 regulator_bulk_disable(ARRAY_SIZE(ak8974->regs), ak8974->regs);
1021
1022 return ret;
1023 }
1024
1025 static DEFINE_RUNTIME_DEV_PM_OPS(ak8974_dev_pm_ops, ak8974_runtime_suspend,
1026 ak8974_runtime_resume, NULL);
1027
1028 static const struct i2c_device_id ak8974_id[] = {
1029 {"ami305", 0 },
1030 {"ami306", 0 },
1031 {"ak8974", 0 },
1032 {"hscdtd008a", 0 },
1033 {}
1034 };
1035 MODULE_DEVICE_TABLE(i2c, ak8974_id);
1036
1037 static const struct of_device_id ak8974_of_match[] = {
1038 { .compatible = "asahi-kasei,ak8974", },
1039 { .compatible = "alps,hscdtd008a", },
1040 {}
1041 };
1042 MODULE_DEVICE_TABLE(of, ak8974_of_match);
1043
1044 static struct i2c_driver ak8974_driver = {
1045 .driver = {
1046 .name = "ak8974",
1047 .pm = pm_ptr(&ak8974_dev_pm_ops),
1048 .of_match_table = ak8974_of_match,
1049 },
1050 .probe = ak8974_probe,
1051 .remove = ak8974_remove,
1052 .id_table = ak8974_id,
1053 };
1054 module_i2c_driver(ak8974_driver);
1055
1056 MODULE_DESCRIPTION("AK8974 and AMI30x 3-axis magnetometer driver");
1057 MODULE_AUTHOR("Samu Onkalo");
1058 MODULE_AUTHOR("Linus Walleij");
1059 MODULE_LICENSE("GPL v2");
1060