1 // SPDX-License-Identifier: GPL-2.0-only
3 * MMC35240 - MEMSIC 3-axis Magnetic Sensor
5 * Copyright (c) 2015, Intel Corporation.
7 * IIO driver for MMC35240 (7-bit I2C slave address 0x30).
9 * TODO: offset, ACPI, continuous measurement mode, PM
12 #include <linux/module.h>
13 #include <linux/init.h>
14 #include <linux/i2c.h>
15 #include <linux/delay.h>
16 #include <linux/regmap.h>
17 #include <linux/acpi.h>
20 #include <linux/iio/iio.h>
21 #include <linux/iio/sysfs.h>
23 #define MMC35240_DRV_NAME "mmc35240"
24 #define MMC35240_REGMAP_NAME "mmc35240_regmap"
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
33 #define MMC35240_REG_STATUS 0x06
34 #define MMC35240_REG_CTRL0 0x07
35 #define MMC35240_REG_CTRL1 0x08
37 #define MMC35240_REG_ID 0x20
39 #define MMC35240_STATUS_MEAS_DONE_BIT BIT(0)
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)
47 /* output resolution bits */
48 #define MMC35240_CTRL1_BW0_BIT BIT(0)
49 #define MMC35240_CTRL1_BW1_BIT BIT(1)
51 #define MMC35240_CTRL1_BW_MASK (MMC35240_CTRL1_BW0_BIT | \
52 MMC35240_CTRL1_BW1_BIT)
53 #define MMC35240_CTRL1_BW_SHIFT 0
55 #define MMC35240_WAIT_CHARGE_PUMP 50000 /* us */
56 #define MMC35240_WAIT_SET_RESET 1000 /* us */
59 * Memsic OTP process code piece is put here for reference:
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.
71 /* scale = 1000 here for Y otp */
72 #define MMC35240_OTP_CONVERT_Y(REG) (((REG) >= 32 ? (32 - (REG)) : (REG)) * 6)
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)
77 #define MMC35240_X_COEFF(x) (x)
78 #define MMC35240_Y_COEFF(y) (y + 1000)
79 #define MMC35240_Z_COEFF(z) (z + 13500)
81 #define MMC35240_OTP_START_ADDR 0x1B
83 enum 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 */
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 */
105 /* 16 bits, 250Hz ODR */
110 /* 14 bits, 450Hz ODR */
115 /* 12 bits, 800Hz ODR */
122 struct mmc35240_data {
123 struct i2c_client *client;
125 struct regmap *regmap;
126 enum mmc35240_resolution res;
128 /* OTP compensation */
133 static const struct {
136 } mmc35240_samp_freq[] = { {1, 500000},
141 static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("1.5 13 25 50");
143 #define MMC35240_CHANNEL(_axis) { \
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), \
153 static const struct iio_chan_spec mmc35240_channels[] = {
159 static struct attribute *mmc35240_attributes[] = {
160 &iio_const_attr_sampling_frequency_available.dev_attr.attr,
164 static const struct attribute_group mmc35240_attribute_group = {
165 .attrs = mmc35240_attributes,
168 static int mmc35240_get_samp_freq_index(struct mmc35240_data *data,
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)
180 static int mmc35240_hw_set(struct mmc35240_data *data, bool set)
186 * Recharge the capacitor at VCAP pin, requested to be issued
187 * before a SET/RESET command.
189 ret = regmap_update_bits(data->regmap, MMC35240_REG_CTRL0,
190 MMC35240_CTRL0_REFILL_BIT,
191 MMC35240_CTRL0_REFILL_BIT);
194 usleep_range(MMC35240_WAIT_CHARGE_PUMP, MMC35240_WAIT_CHARGE_PUMP + 1);
197 coil_bit = MMC35240_CTRL0_SET_BIT;
199 coil_bit = MMC35240_CTRL0_RESET_BIT;
201 return regmap_update_bits(data->regmap, MMC35240_REG_CTRL0,
206 static int mmc35240_init(struct mmc35240_data *data)
208 int ret, y_convert, z_convert;
212 ret = regmap_read(data->regmap, MMC35240_REG_ID, ®_id);
214 dev_err(&data->client->dev, "Error reading product id\n");
218 dev_dbg(&data->client->dev, "MMC35240 chip id %x\n", reg_id);
221 * make sure we restore sensor characteristics, by doing
222 * a SET/RESET sequence, the axis polarity being naturally
223 * aligned after RESET
225 ret = mmc35240_hw_set(data, true);
228 usleep_range(MMC35240_WAIT_SET_RESET, MMC35240_WAIT_SET_RESET + 1);
230 ret = mmc35240_hw_set(data, false);
234 /* set default sampling frequency */
235 ret = regmap_update_bits(data->regmap, MMC35240_REG_CTRL1,
236 MMC35240_CTRL1_BW_MASK,
237 data->res << MMC35240_CTRL1_BW_SHIFT);
241 ret = regmap_bulk_read(data->regmap, MMC35240_OTP_START_ADDR,
242 (u8 *)otp_data, sizeof(otp_data));
246 y_convert = MMC35240_OTP_CONVERT_Y(((otp_data[1] & 0x03) << 4) |
248 z_convert = MMC35240_OTP_CONVERT_Z(otp_data[3] & 0x3f);
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);
254 data->axis_scale[0] = 1;
255 data->axis_scale[1] = 1000;
256 data->axis_scale[2] = 10000;
261 static int mmc35240_take_measurement(struct mmc35240_data *data)
263 int ret, tries = 100;
264 unsigned int reg_status;
266 ret = regmap_write(data->regmap, MMC35240_REG_CTRL0,
267 MMC35240_CTRL0_TM_BIT);
271 while (tries-- > 0) {
272 ret = regmap_read(data->regmap, MMC35240_REG_STATUS,
276 if (reg_status & MMC35240_STATUS_MEAS_DONE_BIT)
278 /* minimum wait time to complete measurement is 10 ms */
279 usleep_range(10000, 11000);
283 dev_err(&data->client->dev, "data not ready\n");
290 static int mmc35240_read_measurement(struct mmc35240_data *data, __le16 buf[3])
294 ret = mmc35240_take_measurement(data);
298 return regmap_bulk_read(data->regmap, MMC35240_REG_XOUT_L, (u8 *)buf,
303 * mmc35240_raw_to_mgauss - convert raw readings to milli gauss. Also apply
304 compensation for output value.
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)
311 * Returns: 0 in case of success, -EINVAL when @index is not valid
313 static int mmc35240_raw_to_mgauss(struct mmc35240_data *data, int index,
314 __le16 buf[], int *val)
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]);
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];
328 nfo = mmc35240_props_table[data->res].nfo;
332 *val = (raw[AXIS_X] - nfo) * 1000 / sens[AXIS_X];
335 *val = (raw[AXIS_Y] - nfo) * 1000 / sens[AXIS_Y] -
336 (raw[AXIS_Z] - nfo) * 1000 / sens[AXIS_Z];
339 *val = (raw[AXIS_Y] - nfo) * 1000 / sens[AXIS_Y] +
340 (raw[AXIS_Z] - nfo) * 1000 / sens[AXIS_Z];
345 /* apply OTP compensation */
346 *val = (*val) * data->axis_coef[index] / data->axis_scale[index];
351 static int mmc35240_read_raw(struct iio_dev *indio_dev,
352 struct iio_chan_spec const *chan, int *val,
353 int *val2, long mask)
355 struct mmc35240_data *data = iio_priv(indio_dev);
361 case IIO_CHAN_INFO_RAW:
362 mutex_lock(&data->mutex);
363 ret = mmc35240_read_measurement(data, buf);
364 mutex_unlock(&data->mutex);
367 ret = mmc35240_raw_to_mgauss(data, chan->address, buf, val);
371 case IIO_CHAN_INFO_SCALE:
374 return IIO_VAL_INT_PLUS_MICRO;
375 case IIO_CHAN_INFO_SAMP_FREQ:
376 mutex_lock(&data->mutex);
377 ret = regmap_read(data->regmap, MMC35240_REG_CTRL1, ®);
378 mutex_unlock(&data->mutex);
382 i = (reg & MMC35240_CTRL1_BW_MASK) >> MMC35240_CTRL1_BW_SHIFT;
383 if (i < 0 || i >= ARRAY_SIZE(mmc35240_samp_freq))
386 *val = mmc35240_samp_freq[i].val;
387 *val2 = mmc35240_samp_freq[i].val2;
388 return IIO_VAL_INT_PLUS_MICRO;
394 static int mmc35240_write_raw(struct iio_dev *indio_dev,
395 struct iio_chan_spec const *chan, int val,
398 struct mmc35240_data *data = iio_priv(indio_dev);
402 case IIO_CHAN_INFO_SAMP_FREQ:
403 i = mmc35240_get_samp_freq_index(data, val, val2);
406 mutex_lock(&data->mutex);
407 ret = regmap_update_bits(data->regmap, MMC35240_REG_CTRL1,
408 MMC35240_CTRL1_BW_MASK,
409 i << MMC35240_CTRL1_BW_SHIFT);
410 mutex_unlock(&data->mutex);
417 static const struct iio_info mmc35240_info = {
418 .read_raw = mmc35240_read_raw,
419 .write_raw = mmc35240_write_raw,
420 .attrs = &mmc35240_attribute_group,
423 static bool mmc35240_is_writeable_reg(struct device *dev, unsigned int reg)
426 case MMC35240_REG_CTRL0:
427 case MMC35240_REG_CTRL1:
434 static bool mmc35240_is_readable_reg(struct device *dev, unsigned int 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:
451 static bool mmc35240_is_volatile_reg(struct device *dev, unsigned int reg)
454 case MMC35240_REG_CTRL0:
455 case MMC35240_REG_CTRL1:
462 static struct reg_default mmc35240_reg_defaults[] = {
463 { MMC35240_REG_CTRL0, 0x00 },
464 { MMC35240_REG_CTRL1, 0x00 },
467 static const struct regmap_config mmc35240_regmap_config = {
468 .name = MMC35240_REGMAP_NAME,
473 .max_register = MMC35240_REG_ID,
474 .cache_type = REGCACHE_FLAT,
476 .writeable_reg = mmc35240_is_writeable_reg,
477 .readable_reg = mmc35240_is_readable_reg,
478 .volatile_reg = mmc35240_is_volatile_reg,
480 .reg_defaults = mmc35240_reg_defaults,
481 .num_reg_defaults = ARRAY_SIZE(mmc35240_reg_defaults),
484 static int mmc35240_probe(struct i2c_client *client,
485 const struct i2c_device_id *id)
487 struct mmc35240_data *data;
488 struct iio_dev *indio_dev;
489 struct regmap *regmap;
492 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
496 regmap = devm_regmap_init_i2c(client, &mmc35240_regmap_config);
497 if (IS_ERR(regmap)) {
498 dev_err(&client->dev, "regmap initialization failed\n");
499 return PTR_ERR(regmap);
502 data = iio_priv(indio_dev);
503 i2c_set_clientdata(client, indio_dev);
504 data->client = client;
505 data->regmap = regmap;
506 data->res = MMC35240_16_BITS_SLOW;
508 mutex_init(&data->mutex);
510 indio_dev->dev.parent = &client->dev;
511 indio_dev->info = &mmc35240_info;
512 indio_dev->name = MMC35240_DRV_NAME;
513 indio_dev->channels = mmc35240_channels;
514 indio_dev->num_channels = ARRAY_SIZE(mmc35240_channels);
515 indio_dev->modes = INDIO_DIRECT_MODE;
517 ret = mmc35240_init(data);
519 dev_err(&client->dev, "mmc35240 chip init failed\n");
522 return devm_iio_device_register(&client->dev, indio_dev);
525 #ifdef CONFIG_PM_SLEEP
526 static int mmc35240_suspend(struct device *dev)
528 struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
529 struct mmc35240_data *data = iio_priv(indio_dev);
531 regcache_cache_only(data->regmap, true);
536 static int mmc35240_resume(struct device *dev)
538 struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
539 struct mmc35240_data *data = iio_priv(indio_dev);
542 regcache_mark_dirty(data->regmap);
543 ret = regcache_sync_region(data->regmap, MMC35240_REG_CTRL0,
546 dev_err(dev, "Failed to restore control registers\n");
548 regcache_cache_only(data->regmap, false);
554 static const struct dev_pm_ops mmc35240_pm_ops = {
555 SET_SYSTEM_SLEEP_PM_OPS(mmc35240_suspend, mmc35240_resume)
558 static const struct of_device_id mmc35240_of_match[] = {
559 { .compatible = "memsic,mmc35240", },
562 MODULE_DEVICE_TABLE(of, mmc35240_of_match);
564 static const struct acpi_device_id mmc35240_acpi_match[] = {
568 MODULE_DEVICE_TABLE(acpi, mmc35240_acpi_match);
570 static const struct i2c_device_id mmc35240_id[] = {
574 MODULE_DEVICE_TABLE(i2c, mmc35240_id);
576 static struct i2c_driver mmc35240_driver = {
578 .name = MMC35240_DRV_NAME,
579 .of_match_table = mmc35240_of_match,
580 .pm = &mmc35240_pm_ops,
581 .acpi_match_table = ACPI_PTR(mmc35240_acpi_match),
583 .probe = mmc35240_probe,
584 .id_table = mmc35240_id,
587 module_i2c_driver(mmc35240_driver);
589 MODULE_AUTHOR("Daniel Baluta <daniel.baluta@intel.com>");
590 MODULE_DESCRIPTION("MEMSIC MMC35240 magnetic sensor driver");
591 MODULE_LICENSE("GPL v2");