1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * MMC35240 - MEMSIC 3-axis Magnetic Sensor
4 *
5 * Copyright (c) 2015, Intel Corporation.
6 *
7 * IIO driver for MMC35240 (7-bit I2C slave address 0x30).
8 *
9 * TODO: offset, ACPI, continuous measurement mode, PM
10 */
11
12#include <linux/module.h>
13#include <linux/mod_devicetable.h>
14#include <linux/init.h>
15#include <linux/i2c.h>
16#include <linux/delay.h>
17#include <linux/regmap.h>
18#include <linux/pm.h>
19
20#include <linux/iio/iio.h>
21#include <linux/iio/sysfs.h>
22
23#define MMC35240_DRV_NAME "mmc35240"
24#define MMC35240_REGMAP_NAME "mmc35240_regmap"
25
26#define MMC35240_REG_XOUT_L 0x00
27#define MMC35240_REG_XOUT_H 0x01
28#define MMC35240_REG_YOUT_L 0x02
29#define MMC35240_REG_YOUT_H 0x03
30#define MMC35240_REG_ZOUT_L 0x04
31#define MMC35240_REG_ZOUT_H 0x05
32
33#define MMC35240_REG_STATUS 0x06
34#define MMC35240_REG_CTRL0 0x07
35#define MMC35240_REG_CTRL1 0x08
36
37#define MMC35240_REG_ID 0x20
38
39#define MMC35240_STATUS_MEAS_DONE_BIT BIT(0)
40
41#define MMC35240_CTRL0_REFILL_BIT BIT(7)
42#define MMC35240_CTRL0_RESET_BIT BIT(6)
43#define MMC35240_CTRL0_SET_BIT BIT(5)
44#define MMC35240_CTRL0_CMM_BIT BIT(1)
45#define MMC35240_CTRL0_TM_BIT BIT(0)
46
47/* output resolution bits */
48#define MMC35240_CTRL1_BW0_BIT BIT(0)
49#define MMC35240_CTRL1_BW1_BIT BIT(1)
50
51#define MMC35240_CTRL1_BW_MASK (MMC35240_CTRL1_BW0_BIT | \
52 MMC35240_CTRL1_BW1_BIT)
53#define MMC35240_CTRL1_BW_SHIFT 0
54
55#define MMC35240_WAIT_CHARGE_PUMP 50000 /* us */
56#define MMC35240_WAIT_SET_RESET 1000 /* us */
57
58/*
59 * Memsic OTP process code piece is put here for reference:
60 *
61 * #define OTP_CONVERT(REG) ((float)((REG) >=32 ? (32 - (REG)) : (REG)) * 0.006
62 * 1) For X axis, the COEFFICIENT is always 1.
63 * 2) For Y axis, the COEFFICIENT is as below:
64 * f_OTP_matrix[4] = OTP_CONVERT(((reg_data[1] & 0x03) << 4) |
65 * (reg_data[2] >> 4)) + 1.0;
66 * 3) For Z axis, the COEFFICIENT is as below:
67 * f_OTP_matrix[8] = (OTP_CONVERT(reg_data[3] & 0x3f) + 1) * 1.35;
68 * We implemented the OTP logic into driver.
69 */
70
71/* scale = 1000 here for Y otp */
72#define MMC35240_OTP_CONVERT_Y(REG) (((REG) >= 32 ? (32 - (REG)) : (REG)) * 6)
73
74/* 0.6 * 1.35 = 0.81, scale 10000 for Z otp */
75#define MMC35240_OTP_CONVERT_Z(REG) (((REG) >= 32 ? (32 - (REG)) : (REG)) * 81)
76
77#define MMC35240_X_COEFF(x) (x)
78#define MMC35240_Y_COEFF(y) (y + 1000)
79#define MMC35240_Z_COEFF(z) (z + 13500)
80
81#define MMC35240_OTP_START_ADDR 0x1B
82
83enum mmc35240_resolution {
84 MMC35240_16_BITS_SLOW = 0, /* 7.92 ms */
85 MMC35240_16_BITS_FAST, /* 4.08 ms */
86 MMC35240_14_BITS, /* 2.16 ms */
87 MMC35240_12_BITS, /* 1.20 ms */
88};
89
90enum mmc35240_axis {
91 AXIS_X = 0,
92 AXIS_Y,
93 AXIS_Z,
94};
95
96static const struct {
97 int sens[3]; /* sensitivity per X, Y, Z axis */
98 int nfo; /* null field output */
99} mmc35240_props_table[] = {
100 /* 16 bits, 125Hz ODR */
101 {
102 {1024, 1024, 1024},
103 32768,
104 },
105 /* 16 bits, 250Hz ODR */
106 {
107 {1024, 1024, 770},
108 32768,
109 },
110 /* 14 bits, 450Hz ODR */
111 {
112 {256, 256, 193},
113 8192,
114 },
115 /* 12 bits, 800Hz ODR */
116 {
117 {64, 64, 48},
118 2048,
119 },
120};
121
122struct mmc35240_data {
123 struct i2c_client *client;
124 struct mutex mutex;
125 struct regmap *regmap;
126 enum mmc35240_resolution res;
127
128 /* OTP compensation */
129 int axis_coef[3];
130 int axis_scale[3];
131};
132
133static const struct {
134 int val;
135 int val2;
136} mmc35240_samp_freq[] = { {1, 500000},
137 {13, 0},
138 {25, 0},
139 {50, 0} };
140
141static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("1.5 13 25 50");
142
143#define MMC35240_CHANNEL(_axis) { \
144 .type = IIO_MAGN, \
145 .modified = 1, \
146 .channel2 = IIO_MOD_ ## _axis, \
147 .address = AXIS_ ## _axis, \
148 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
149 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ) | \
150 BIT(IIO_CHAN_INFO_SCALE), \
151}
152
153static const struct iio_chan_spec mmc35240_channels[] = {
154 MMC35240_CHANNEL(X),
155 MMC35240_CHANNEL(Y),
156 MMC35240_CHANNEL(Z),
157};
158
159static struct attribute *mmc35240_attributes[] = {
160 &iio_const_attr_sampling_frequency_available.dev_attr.attr,
161 NULL
162};
163
164static const struct attribute_group mmc35240_attribute_group = {
165 .attrs = mmc35240_attributes,
166};
167
168static int mmc35240_get_samp_freq_index(struct mmc35240_data *data,
169 int val, int val2)
170{
171 int i;
172
173 for (i = 0; i < ARRAY_SIZE(mmc35240_samp_freq); i++)
174 if (mmc35240_samp_freq[i].val == val &&
175 mmc35240_samp_freq[i].val2 == val2)
176 return i;
177 return -EINVAL;
178}
179
180static int mmc35240_hw_set(struct mmc35240_data *data, bool set)
181{
182 int ret;
183 u8 coil_bit;
184
185 /*
186 * Recharge the capacitor at VCAP pin, requested to be issued
187 * before a SET/RESET command.
188 */
189 ret = regmap_update_bits(map: data->regmap, MMC35240_REG_CTRL0,
190 MMC35240_CTRL0_REFILL_BIT,
191 MMC35240_CTRL0_REFILL_BIT);
192 if (ret < 0)
193 return ret;
194 usleep_range(MMC35240_WAIT_CHARGE_PUMP, MMC35240_WAIT_CHARGE_PUMP + 1);
195
196 if (set)
197 coil_bit = MMC35240_CTRL0_SET_BIT;
198 else
199 coil_bit = MMC35240_CTRL0_RESET_BIT;
200
201 return regmap_update_bits(map: data->regmap, MMC35240_REG_CTRL0,
202 mask: coil_bit, val: coil_bit);
203
204}
205
206static int mmc35240_init(struct mmc35240_data *data)
207{
208 int ret, y_convert, z_convert;
209 unsigned int reg_id;
210 u8 otp_data[6];
211
212 ret = regmap_read(map: data->regmap, MMC35240_REG_ID, val: &reg_id);
213 if (ret < 0) {
214 dev_err(&data->client->dev, "Error reading product id\n");
215 return ret;
216 }
217
218 dev_dbg(&data->client->dev, "MMC35240 chip id %x\n", reg_id);
219
220 /*
221 * make sure we restore sensor characteristics, by doing
222 * a SET/RESET sequence, the axis polarity being naturally
223 * aligned after RESET
224 */
225 ret = mmc35240_hw_set(data, set: true);
226 if (ret < 0)
227 return ret;
228 usleep_range(MMC35240_WAIT_SET_RESET, MMC35240_WAIT_SET_RESET + 1);
229
230 ret = mmc35240_hw_set(data, set: false);
231 if (ret < 0)
232 return ret;
233
234 /* set default sampling frequency */
235 ret = regmap_update_bits(map: data->regmap, MMC35240_REG_CTRL1,
236 MMC35240_CTRL1_BW_MASK,
237 val: data->res << MMC35240_CTRL1_BW_SHIFT);
238 if (ret < 0)
239 return ret;
240
241 ret = regmap_bulk_read(map: data->regmap, MMC35240_OTP_START_ADDR,
242 val: otp_data, val_count: sizeof(otp_data));
243 if (ret < 0)
244 return ret;
245
246 y_convert = MMC35240_OTP_CONVERT_Y(((otp_data[1] & 0x03) << 4) |
247 (otp_data[2] >> 4));
248 z_convert = MMC35240_OTP_CONVERT_Z(otp_data[3] & 0x3f);
249
250 data->axis_coef[0] = MMC35240_X_COEFF(1);
251 data->axis_coef[1] = MMC35240_Y_COEFF(y_convert);
252 data->axis_coef[2] = MMC35240_Z_COEFF(z_convert);
253
254 data->axis_scale[0] = 1;
255 data->axis_scale[1] = 1000;
256 data->axis_scale[2] = 10000;
257
258 return 0;
259}
260
261static int mmc35240_take_measurement(struct mmc35240_data *data)
262{
263 int ret, tries = 100;
264 unsigned int reg_status;
265
266 ret = regmap_write(map: data->regmap, MMC35240_REG_CTRL0,
267 MMC35240_CTRL0_TM_BIT);
268 if (ret < 0)
269 return ret;
270
271 while (tries-- > 0) {
272 ret = regmap_read(map: data->regmap, MMC35240_REG_STATUS,
273 val: &reg_status);
274 if (ret < 0)
275 return ret;
276 if (reg_status & MMC35240_STATUS_MEAS_DONE_BIT)
277 break;
278 /* minimum wait time to complete measurement is 10 ms */
279 usleep_range(min: 10000, max: 11000);
280 }
281
282 if (tries < 0) {
283 dev_err(&data->client->dev, "data not ready\n");
284 return -EIO;
285 }
286
287 return 0;
288}
289
290static int mmc35240_read_measurement(struct mmc35240_data *data, __le16 buf[3])
291{
292 int ret;
293
294 ret = mmc35240_take_measurement(data);
295 if (ret < 0)
296 return ret;
297
298 return regmap_bulk_read(map: data->regmap, MMC35240_REG_XOUT_L, val: buf,
299 val_count: 3 * sizeof(__le16));
300}
301
302/**
303 * mmc35240_raw_to_mgauss - convert raw readings to milli gauss. Also apply
304 * compensation for output value.
305 *
306 * @data: device private data
307 * @index: axis index for which we want the conversion
308 * @buf: raw data to be converted, 2 bytes in little endian format
309 * @val: compensated output reading (unit is milli gauss)
310 *
311 * Returns: 0 in case of success, -EINVAL when @index is not valid
312 */
313static int mmc35240_raw_to_mgauss(struct mmc35240_data *data, int index,
314 __le16 buf[], int *val)
315{
316 int raw[3];
317 int sens[3];
318 int nfo;
319
320 raw[AXIS_X] = le16_to_cpu(buf[AXIS_X]);
321 raw[AXIS_Y] = le16_to_cpu(buf[AXIS_Y]);
322 raw[AXIS_Z] = le16_to_cpu(buf[AXIS_Z]);
323
324 sens[AXIS_X] = mmc35240_props_table[data->res].sens[AXIS_X];
325 sens[AXIS_Y] = mmc35240_props_table[data->res].sens[AXIS_Y];
326 sens[AXIS_Z] = mmc35240_props_table[data->res].sens[AXIS_Z];
327
328 nfo = mmc35240_props_table[data->res].nfo;
329
330 switch (index) {
331 case AXIS_X:
332 *val = (raw[AXIS_X] - nfo) * 1000 / sens[AXIS_X];
333 break;
334 case AXIS_Y:
335 *val = (raw[AXIS_Y] - nfo) * 1000 / sens[AXIS_Y] -
336 (raw[AXIS_Z] - nfo) * 1000 / sens[AXIS_Z];
337 break;
338 case AXIS_Z:
339 *val = (raw[AXIS_Y] - nfo) * 1000 / sens[AXIS_Y] +
340 (raw[AXIS_Z] - nfo) * 1000 / sens[AXIS_Z];
341 break;
342 default:
343 return -EINVAL;
344 }
345 /* apply OTP compensation */
346 *val = (*val) * data->axis_coef[index] / data->axis_scale[index];
347
348 return 0;
349}
350
351static int mmc35240_read_raw(struct iio_dev *indio_dev,
352 struct iio_chan_spec const *chan, int *val,
353 int *val2, long mask)
354{
355 struct mmc35240_data *data = iio_priv(indio_dev);
356 int ret, i;
357 unsigned int reg;
358 __le16 buf[3];
359
360 switch (mask) {
361 case IIO_CHAN_INFO_RAW:
362 mutex_lock(&data->mutex);
363 ret = mmc35240_read_measurement(data, buf);
364 mutex_unlock(lock: &data->mutex);
365 if (ret < 0)
366 return ret;
367 ret = mmc35240_raw_to_mgauss(data, index: chan->address, buf, val);
368 if (ret < 0)
369 return ret;
370 return IIO_VAL_INT;
371 case IIO_CHAN_INFO_SCALE:
372 *val = 0;
373 *val2 = 1000;
374 return IIO_VAL_INT_PLUS_MICRO;
375 case IIO_CHAN_INFO_SAMP_FREQ:
376 mutex_lock(&data->mutex);
377 ret = regmap_read(map: data->regmap, MMC35240_REG_CTRL1, val: &reg);
378 mutex_unlock(lock: &data->mutex);
379 if (ret < 0)
380 return ret;
381
382 i = (reg & MMC35240_CTRL1_BW_MASK) >> MMC35240_CTRL1_BW_SHIFT;
383 if (i < 0 || i >= ARRAY_SIZE(mmc35240_samp_freq))
384 return -EINVAL;
385
386 *val = mmc35240_samp_freq[i].val;
387 *val2 = mmc35240_samp_freq[i].val2;
388 return IIO_VAL_INT_PLUS_MICRO;
389 default:
390 return -EINVAL;
391 }
392}
393
394static int mmc35240_write_raw(struct iio_dev *indio_dev,
395 struct iio_chan_spec const *chan, int val,
396 int val2, long mask)
397{
398 struct mmc35240_data *data = iio_priv(indio_dev);
399 int i, ret;
400
401 switch (mask) {
402 case IIO_CHAN_INFO_SAMP_FREQ:
403 i = mmc35240_get_samp_freq_index(data, val, val2);
404 if (i < 0)
405 return -EINVAL;
406 mutex_lock(&data->mutex);
407 ret = regmap_update_bits(map: data->regmap, MMC35240_REG_CTRL1,
408 MMC35240_CTRL1_BW_MASK,
409 val: i << MMC35240_CTRL1_BW_SHIFT);
410 mutex_unlock(lock: &data->mutex);
411 return ret;
412 default:
413 return -EINVAL;
414 }
415}
416
417static const struct iio_info mmc35240_info = {
418 .read_raw = mmc35240_read_raw,
419 .write_raw = mmc35240_write_raw,
420 .attrs = &mmc35240_attribute_group,
421};
422
423static bool mmc35240_is_writeable_reg(struct device *dev, unsigned int reg)
424{
425 switch (reg) {
426 case MMC35240_REG_CTRL0:
427 case MMC35240_REG_CTRL1:
428 return true;
429 default:
430 return false;
431 }
432}
433
434static bool mmc35240_is_readable_reg(struct device *dev, unsigned int reg)
435{
436 switch (reg) {
437 case MMC35240_REG_XOUT_L:
438 case MMC35240_REG_XOUT_H:
439 case MMC35240_REG_YOUT_L:
440 case MMC35240_REG_YOUT_H:
441 case MMC35240_REG_ZOUT_L:
442 case MMC35240_REG_ZOUT_H:
443 case MMC35240_REG_STATUS:
444 case MMC35240_REG_ID:
445 return true;
446 default:
447 return false;
448 }
449}
450
451static bool mmc35240_is_volatile_reg(struct device *dev, unsigned int reg)
452{
453 switch (reg) {
454 case MMC35240_REG_CTRL0:
455 case MMC35240_REG_CTRL1:
456 return false;
457 default:
458 return true;
459 }
460}
461
462static const struct reg_default mmc35240_reg_defaults[] = {
463 { MMC35240_REG_CTRL0, 0x00 },
464 { MMC35240_REG_CTRL1, 0x00 },
465};
466
467static const struct regmap_config mmc35240_regmap_config = {
468 .name = MMC35240_REGMAP_NAME,
469
470 .reg_bits = 8,
471 .val_bits = 8,
472
473 .max_register = MMC35240_REG_ID,
474 .cache_type = REGCACHE_FLAT,
475
476 .writeable_reg = mmc35240_is_writeable_reg,
477 .readable_reg = mmc35240_is_readable_reg,
478 .volatile_reg = mmc35240_is_volatile_reg,
479
480 .reg_defaults = mmc35240_reg_defaults,
481 .num_reg_defaults = ARRAY_SIZE(mmc35240_reg_defaults),
482};
483
484static int mmc35240_probe(struct i2c_client *client)
485{
486 struct mmc35240_data *data;
487 struct iio_dev *indio_dev;
488 struct regmap *regmap;
489 int ret;
490
491 indio_dev = devm_iio_device_alloc(parent: &client->dev, sizeof_priv: sizeof(*data));
492 if (!indio_dev)
493 return -ENOMEM;
494
495 regmap = devm_regmap_init_i2c(client, &mmc35240_regmap_config);
496 if (IS_ERR(ptr: regmap)) {
497 dev_err(&client->dev, "regmap initialization failed\n");
498 return PTR_ERR(ptr: regmap);
499 }
500
501 data = iio_priv(indio_dev);
502 i2c_set_clientdata(client, data: indio_dev);
503 data->client = client;
504 data->regmap = regmap;
505 data->res = MMC35240_16_BITS_SLOW;
506
507 mutex_init(&data->mutex);
508
509 indio_dev->info = &mmc35240_info;
510 indio_dev->name = MMC35240_DRV_NAME;
511 indio_dev->channels = mmc35240_channels;
512 indio_dev->num_channels = ARRAY_SIZE(mmc35240_channels);
513 indio_dev->modes = INDIO_DIRECT_MODE;
514
515 ret = mmc35240_init(data);
516 if (ret < 0) {
517 dev_err(&client->dev, "mmc35240 chip init failed\n");
518 return ret;
519 }
520 return devm_iio_device_register(&client->dev, indio_dev);
521}
522
523static int mmc35240_suspend(struct device *dev)
524{
525 struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
526 struct mmc35240_data *data = iio_priv(indio_dev);
527
528 regcache_cache_only(map: data->regmap, enable: true);
529
530 return 0;
531}
532
533static int mmc35240_resume(struct device *dev)
534{
535 struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
536 struct mmc35240_data *data = iio_priv(indio_dev);
537 int ret;
538
539 regcache_mark_dirty(map: data->regmap);
540 ret = regcache_sync_region(map: data->regmap, MMC35240_REG_CTRL0,
541 MMC35240_REG_CTRL1);
542 if (ret < 0)
543 dev_err(dev, "Failed to restore control registers\n");
544
545 regcache_cache_only(map: data->regmap, enable: false);
546
547 return 0;
548}
549
550static DEFINE_SIMPLE_DEV_PM_OPS(mmc35240_pm_ops, mmc35240_suspend,
551 mmc35240_resume);
552
553static const struct of_device_id mmc35240_of_match[] = {
554 { .compatible = "memsic,mmc35240", },
555 { }
556};
557MODULE_DEVICE_TABLE(of, mmc35240_of_match);
558
559static const struct acpi_device_id mmc35240_acpi_match[] = {
560 {"MMC35240", 0},
561 { },
562};
563MODULE_DEVICE_TABLE(acpi, mmc35240_acpi_match);
564
565static const struct i2c_device_id mmc35240_id[] = {
566 {"mmc35240", 0},
567 {}
568};
569MODULE_DEVICE_TABLE(i2c, mmc35240_id);
570
571static struct i2c_driver mmc35240_driver = {
572 .driver = {
573 .name = MMC35240_DRV_NAME,
574 .of_match_table = mmc35240_of_match,
575 .pm = pm_sleep_ptr(&mmc35240_pm_ops),
576 .acpi_match_table = mmc35240_acpi_match,
577 },
578 .probe = mmc35240_probe,
579 .id_table = mmc35240_id,
580};
581
582module_i2c_driver(mmc35240_driver);
583
584MODULE_AUTHOR("Daniel Baluta <daniel.baluta@intel.com>");
585MODULE_DESCRIPTION("MEMSIC MMC35240 magnetic sensor driver");
586MODULE_LICENSE("GPL v2");
587

source code of linux/drivers/iio/magnetometer/mmc35240.c