2 * MMC35240 - MEMSIC 3-axis Magnetic Sensor
4 * Copyright (c) 2015, Intel Corporation.
6 * This file is subject to the terms and conditions of version 2 of
7 * the GNU General Public License. See the file COPYING in the main
8 * directory of this archive for more details.
10 * IIO driver for MMC35240 (7-bit I2C slave address 0x30).
12 * TODO: offset, ACPI, continuous measurement mode, PM
15 #include <linux/module.h>
16 #include <linux/init.h>
17 #include <linux/i2c.h>
18 #include <linux/delay.h>
19 #include <linux/regmap.h>
20 #include <linux/acpi.h>
23 #include <linux/iio/iio.h>
24 #include <linux/iio/sysfs.h>
26 #define MMC35240_DRV_NAME "mmc35240"
27 #define MMC35240_REGMAP_NAME "mmc35240_regmap"
29 #define MMC35240_REG_XOUT_L 0x00
30 #define MMC35240_REG_XOUT_H 0x01
31 #define MMC35240_REG_YOUT_L 0x02
32 #define MMC35240_REG_YOUT_H 0x03
33 #define MMC35240_REG_ZOUT_L 0x04
34 #define MMC35240_REG_ZOUT_H 0x05
36 #define MMC35240_REG_STATUS 0x06
37 #define MMC35240_REG_CTRL0 0x07
38 #define MMC35240_REG_CTRL1 0x08
40 #define MMC35240_REG_ID 0x20
42 #define MMC35240_STATUS_MEAS_DONE_BIT BIT(0)
44 #define MMC35240_CTRL0_REFILL_BIT BIT(7)
45 #define MMC35240_CTRL0_RESET_BIT BIT(6)
46 #define MMC35240_CTRL0_SET_BIT BIT(5)
47 #define MMC35240_CTRL0_CMM_BIT BIT(1)
48 #define MMC35240_CTRL0_TM_BIT BIT(0)
50 /* output resolution bits */
51 #define MMC35240_CTRL1_BW0_BIT BIT(0)
52 #define MMC35240_CTRL1_BW1_BIT BIT(1)
54 #define MMC35240_CTRL1_BW_MASK (MMC35240_CTRL1_BW0_BIT | \
55 MMC35240_CTRL1_BW1_BIT)
56 #define MMC35240_CTRL1_BW_SHIFT 0
58 #define MMC35240_WAIT_CHARGE_PUMP 50000 /* us */
59 #define MMC53240_WAIT_SET_RESET 1000 /* us */
62 * Memsic OTP process code piece is put here for reference:
64 * #define OTP_CONVERT(REG) ((float)((REG) >=32 ? (32 - (REG)) : (REG)) * 0.006
65 * 1) For X axis, the COEFFICIENT is always 1.
66 * 2) For Y axis, the COEFFICIENT is as below:
67 * f_OTP_matrix[4] = OTP_CONVERT(((reg_data[1] & 0x03) << 4) |
68 * (reg_data[2] >> 4)) + 1.0;
69 * 3) For Z axis, the COEFFICIENT is as below:
70 * f_OTP_matrix[8] = (OTP_CONVERT(reg_data[3] & 0x3f) + 1) * 1.35;
71 * We implemented the OTP logic into driver.
74 /* scale = 1000 here for Y otp */
75 #define MMC35240_OTP_CONVERT_Y(REG) (((REG) >= 32 ? (32 - (REG)) : (REG)) * 6)
77 /* 0.6 * 1.35 = 0.81, scale 10000 for Z otp */
78 #define MMC35240_OTP_CONVERT_Z(REG) (((REG) >= 32 ? (32 - (REG)) : (REG)) * 81)
80 #define MMC35240_X_COEFF(x) (x)
81 #define MMC35240_Y_COEFF(y) (y + 1000)
82 #define MMC35240_Z_COEFF(z) (z + 13500)
84 #define MMC35240_OTP_START_ADDR 0x1B
86 enum mmc35240_resolution {
87 MMC35240_16_BITS_SLOW = 0, /* 7.92 ms */
88 MMC35240_16_BITS_FAST, /* 4.08 ms */
89 MMC35240_14_BITS, /* 2.16 ms */
90 MMC35240_12_BITS, /* 1.20 ms */
100 int sens[3]; /* sensitivity per X, Y, Z axis */
101 int nfo; /* null field output */
102 } mmc35240_props_table[] = {
103 /* 16 bits, 125Hz ODR */
108 /* 16 bits, 250Hz ODR */
113 /* 14 bits, 450Hz ODR */
118 /* 12 bits, 800Hz ODR */
125 struct mmc35240_data {
126 struct i2c_client *client;
128 struct regmap *regmap;
129 enum mmc35240_resolution res;
131 /* OTP compensation */
136 static const struct {
139 } mmc35240_samp_freq[] = { {1, 500000},
144 static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("1.5 13 25 50");
146 #define MMC35240_CHANNEL(_axis) { \
149 .channel2 = IIO_MOD_ ## _axis, \
150 .address = AXIS_ ## _axis, \
151 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
152 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ) | \
153 BIT(IIO_CHAN_INFO_SCALE), \
156 static const struct iio_chan_spec mmc35240_channels[] = {
162 static struct attribute *mmc35240_attributes[] = {
163 &iio_const_attr_sampling_frequency_available.dev_attr.attr,
167 static const struct attribute_group mmc35240_attribute_group = {
168 .attrs = mmc35240_attributes,
171 static int mmc35240_get_samp_freq_index(struct mmc35240_data *data,
176 for (i = 0; i < ARRAY_SIZE(mmc35240_samp_freq); i++)
177 if (mmc35240_samp_freq[i].val == val &&
178 mmc35240_samp_freq[i].val2 == val2)
183 static int mmc35240_hw_set(struct mmc35240_data *data, bool set)
189 * Recharge the capacitor at VCAP pin, requested to be issued
190 * before a SET/RESET command.
192 ret = regmap_update_bits(data->regmap, MMC35240_REG_CTRL0,
193 MMC35240_CTRL0_REFILL_BIT,
194 MMC35240_CTRL0_REFILL_BIT);
197 usleep_range(MMC35240_WAIT_CHARGE_PUMP, MMC35240_WAIT_CHARGE_PUMP + 1);
200 coil_bit = MMC35240_CTRL0_SET_BIT;
202 coil_bit = MMC35240_CTRL0_RESET_BIT;
204 return regmap_update_bits(data->regmap, MMC35240_REG_CTRL0,
205 MMC35240_CTRL0_REFILL_BIT,
209 static int mmc35240_init(struct mmc35240_data *data)
211 int ret, y_convert, z_convert;
215 ret = regmap_read(data->regmap, MMC35240_REG_ID, ®_id);
217 dev_err(&data->client->dev, "Error reading product id\n");
221 dev_dbg(&data->client->dev, "MMC35240 chip id %x\n", reg_id);
224 * make sure we restore sensor characteristics, by doing
225 * a RESET/SET sequence
227 ret = mmc35240_hw_set(data, false);
230 usleep_range(MMC53240_WAIT_SET_RESET, MMC53240_WAIT_SET_RESET + 1);
232 ret = mmc35240_hw_set(data, true);
236 /* set default sampling frequency */
237 ret = regmap_update_bits(data->regmap, MMC35240_REG_CTRL1,
238 MMC35240_CTRL1_BW_MASK,
239 data->res << MMC35240_CTRL1_BW_SHIFT);
243 ret = regmap_bulk_read(data->regmap, MMC35240_OTP_START_ADDR,
244 (u8 *)otp_data, sizeof(otp_data));
248 y_convert = MMC35240_OTP_CONVERT_Y(((otp_data[1] & 0x03) << 4) |
250 z_convert = MMC35240_OTP_CONVERT_Z(otp_data[3] & 0x3f);
252 data->axis_coef[0] = MMC35240_X_COEFF(1);
253 data->axis_coef[1] = MMC35240_Y_COEFF(y_convert);
254 data->axis_coef[2] = MMC35240_Z_COEFF(z_convert);
256 data->axis_scale[0] = 1;
257 data->axis_scale[1] = 1000;
258 data->axis_scale[2] = 10000;
263 static int mmc35240_take_measurement(struct mmc35240_data *data)
265 int ret, tries = 100;
266 unsigned int reg_status;
268 ret = regmap_write(data->regmap, MMC35240_REG_CTRL0,
269 MMC35240_CTRL0_TM_BIT);
273 while (tries-- > 0) {
274 ret = regmap_read(data->regmap, MMC35240_REG_STATUS,
278 if (reg_status & MMC35240_STATUS_MEAS_DONE_BIT)
280 /* minimum wait time to complete measurement is 10 ms */
281 usleep_range(10000, 11000);
285 dev_err(&data->client->dev, "data not ready\n");
292 static int mmc35240_read_measurement(struct mmc35240_data *data, __le16 buf[3])
296 ret = mmc35240_take_measurement(data);
300 return regmap_bulk_read(data->regmap, MMC35240_REG_XOUT_L, (u8 *)buf,
305 * mmc35240_raw_to_mgauss - convert raw readings to milli gauss. Also apply
306 compensation for output value.
308 * @data: device private data
309 * @index: axis index for which we want the conversion
310 * @buf: raw data to be converted, 2 bytes in little endian format
311 * @val: compensated output reading (unit is milli gauss)
313 * Returns: 0 in case of success, -EINVAL when @index is not valid
315 static int mmc35240_raw_to_mgauss(struct mmc35240_data *data, int index,
316 __le16 buf[], int *val)
318 int raw_x, raw_y, raw_z;
319 int sens_x, sens_y, sens_z;
322 raw_x = le16_to_cpu(buf[AXIS_X]);
323 raw_y = le16_to_cpu(buf[AXIS_Y]);
324 raw_z = le16_to_cpu(buf[AXIS_Z]);
326 sens_x = mmc35240_props_table[data->res].sens[AXIS_X];
327 sens_y = mmc35240_props_table[data->res].sens[AXIS_Y];
328 sens_z = mmc35240_props_table[data->res].sens[AXIS_Z];
330 nfo = mmc35240_props_table[data->res].nfo;
334 *val = (raw_x - nfo) * 1000 / sens_x;
337 *val = (raw_y - nfo) * 1000 / sens_y -
338 (raw_z - nfo) * 1000 / sens_z;
341 *val = (raw_y - nfo) * 1000 / sens_y +
342 (raw_z - nfo) * 1000 / sens_z;
347 /* apply OTP compensation */
348 *val = (*val) * data->axis_coef[index] / data->axis_scale[index];
353 static int mmc35240_read_raw(struct iio_dev *indio_dev,
354 struct iio_chan_spec const *chan, int *val,
355 int *val2, long mask)
357 struct mmc35240_data *data = iio_priv(indio_dev);
363 case IIO_CHAN_INFO_RAW:
364 mutex_lock(&data->mutex);
365 ret = mmc35240_read_measurement(data, buf);
366 mutex_unlock(&data->mutex);
369 ret = mmc35240_raw_to_mgauss(data, chan->address, buf, val);
373 case IIO_CHAN_INFO_SCALE:
376 return IIO_VAL_INT_PLUS_MICRO;
377 case IIO_CHAN_INFO_SAMP_FREQ:
378 mutex_lock(&data->mutex);
379 ret = regmap_read(data->regmap, MMC35240_REG_CTRL1, ®);
380 mutex_unlock(&data->mutex);
384 i = (reg & MMC35240_CTRL1_BW_MASK) >> MMC35240_CTRL1_BW_SHIFT;
385 if (i < 0 || i >= ARRAY_SIZE(mmc35240_samp_freq))
388 *val = mmc35240_samp_freq[i].val;
389 *val2 = mmc35240_samp_freq[i].val2;
390 return IIO_VAL_INT_PLUS_MICRO;
396 static int mmc35240_write_raw(struct iio_dev *indio_dev,
397 struct iio_chan_spec const *chan, int val,
400 struct mmc35240_data *data = iio_priv(indio_dev);
404 case IIO_CHAN_INFO_SAMP_FREQ:
405 i = mmc35240_get_samp_freq_index(data, val, val2);
408 mutex_lock(&data->mutex);
409 ret = regmap_update_bits(data->regmap, MMC35240_REG_CTRL1,
410 MMC35240_CTRL1_BW_MASK,
411 i << MMC35240_CTRL1_BW_SHIFT);
412 mutex_unlock(&data->mutex);
419 static const struct iio_info mmc35240_info = {
420 .driver_module = THIS_MODULE,
421 .read_raw = mmc35240_read_raw,
422 .write_raw = mmc35240_write_raw,
423 .attrs = &mmc35240_attribute_group,
426 static bool mmc35240_is_writeable_reg(struct device *dev, unsigned int reg)
429 case MMC35240_REG_CTRL0:
430 case MMC35240_REG_CTRL1:
437 static bool mmc35240_is_readable_reg(struct device *dev, unsigned int reg)
440 case MMC35240_REG_XOUT_L:
441 case MMC35240_REG_XOUT_H:
442 case MMC35240_REG_YOUT_L:
443 case MMC35240_REG_YOUT_H:
444 case MMC35240_REG_ZOUT_L:
445 case MMC35240_REG_ZOUT_H:
446 case MMC35240_REG_STATUS:
447 case MMC35240_REG_ID:
454 static bool mmc35240_is_volatile_reg(struct device *dev, unsigned int reg)
457 case MMC35240_REG_CTRL0:
458 case MMC35240_REG_CTRL1:
465 static struct reg_default mmc35240_reg_defaults[] = {
466 { MMC35240_REG_CTRL0, 0x00 },
467 { MMC35240_REG_CTRL1, 0x00 },
470 static const struct regmap_config mmc35240_regmap_config = {
471 .name = MMC35240_REGMAP_NAME,
476 .max_register = MMC35240_REG_ID,
477 .cache_type = REGCACHE_FLAT,
479 .writeable_reg = mmc35240_is_writeable_reg,
480 .readable_reg = mmc35240_is_readable_reg,
481 .volatile_reg = mmc35240_is_volatile_reg,
483 .reg_defaults = mmc35240_reg_defaults,
484 .num_reg_defaults = ARRAY_SIZE(mmc35240_reg_defaults),
487 static int mmc35240_probe(struct i2c_client *client,
488 const struct i2c_device_id *id)
490 struct mmc35240_data *data;
491 struct iio_dev *indio_dev;
492 struct regmap *regmap;
495 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
499 regmap = devm_regmap_init_i2c(client, &mmc35240_regmap_config);
500 if (IS_ERR(regmap)) {
501 dev_err(&client->dev, "regmap initialization failed\n");
502 return PTR_ERR(regmap);
505 data = iio_priv(indio_dev);
506 data->client = client;
507 data->regmap = regmap;
508 data->res = MMC35240_16_BITS_SLOW;
510 mutex_init(&data->mutex);
512 indio_dev->dev.parent = &client->dev;
513 indio_dev->info = &mmc35240_info;
514 indio_dev->name = MMC35240_DRV_NAME;
515 indio_dev->channels = mmc35240_channels;
516 indio_dev->num_channels = ARRAY_SIZE(mmc35240_channels);
517 indio_dev->modes = INDIO_DIRECT_MODE;
519 ret = mmc35240_init(data);
521 dev_err(&client->dev, "mmc35240 chip init failed\n");
524 return devm_iio_device_register(&client->dev, indio_dev);
527 #ifdef CONFIG_PM_SLEEP
528 static int mmc35240_suspend(struct device *dev)
530 struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
531 struct mmc35240_data *data = iio_priv(indio_dev);
533 regcache_cache_only(data->regmap, true);
538 static int mmc35240_resume(struct device *dev)
540 struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
541 struct mmc35240_data *data = iio_priv(indio_dev);
544 regcache_mark_dirty(data->regmap);
545 ret = regcache_sync_region(data->regmap, MMC35240_REG_CTRL0,
548 dev_err(dev, "Failed to restore control registers\n");
550 regcache_cache_only(data->regmap, false);
556 static const struct dev_pm_ops mmc35240_pm_ops = {
557 SET_SYSTEM_SLEEP_PM_OPS(mmc35240_suspend, mmc35240_resume)
560 static const struct acpi_device_id mmc35240_acpi_match[] = {
564 MODULE_DEVICE_TABLE(acpi, mmc35240_acpi_match);
566 static const struct i2c_device_id mmc35240_id[] = {
570 MODULE_DEVICE_TABLE(i2c, mmc35240_id);
572 static struct i2c_driver mmc35240_driver = {
574 .name = MMC35240_DRV_NAME,
575 .pm = &mmc35240_pm_ops,
576 .acpi_match_table = ACPI_PTR(mmc35240_acpi_match),
578 .probe = mmc35240_probe,
579 .id_table = mmc35240_id,
582 module_i2c_driver(mmc35240_driver);
584 MODULE_AUTHOR("Daniel Baluta <daniel.baluta@intel.com>");
585 MODULE_DESCRIPTION("MEMSIC MMC35240 magnetic sensor driver");
586 MODULE_LICENSE("GPL v2");