- 根目录:
- drivers
- iio
- magnetometer
- mmc35240.c
/*
* MMC35240 - MEMSIC 3-axis Magnetic Sensor
*
* Copyright (c) 2015, Intel Corporation.
*
* This file is subject to the terms and conditions of version 2 of
* the GNU General Public License. See the file COPYING in the main
* directory of this archive for more details.
*
* IIO driver for MMC35240 (7-bit I2C slave address 0x30).
*
* TODO: offset, ACPI, continuous measurement mode, PM
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/i2c.h>
#include <linux/delay.h>
#include <linux/regmap.h>
#include <linux/acpi.h>
#include <linux/pm.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#define MMC35240_DRV_NAME "mmc35240"
#define MMC35240_REGMAP_NAME "mmc35240_regmap"
#define MMC35240_REG_XOUT_L 0x00
#define MMC35240_REG_XOUT_H 0x01
#define MMC35240_REG_YOUT_L 0x02
#define MMC35240_REG_YOUT_H 0x03
#define MMC35240_REG_ZOUT_L 0x04
#define MMC35240_REG_ZOUT_H 0x05
#define MMC35240_REG_STATUS 0x06
#define MMC35240_REG_CTRL0 0x07
#define MMC35240_REG_CTRL1 0x08
#define MMC35240_REG_ID 0x20
#define MMC35240_STATUS_MEAS_DONE_BIT BIT(0)
#define MMC35240_CTRL0_REFILL_BIT BIT(7)
#define MMC35240_CTRL0_RESET_BIT BIT(6)
#define MMC35240_CTRL0_SET_BIT BIT(5)
#define MMC35240_CTRL0_CMM_BIT BIT(1)
#define MMC35240_CTRL0_TM_BIT BIT(0)
/* output resolution bits */
#define MMC35240_CTRL1_BW0_BIT BIT(0)
#define MMC35240_CTRL1_BW1_BIT BIT(1)
#define MMC35240_CTRL1_BW_MASK (MMC35240_CTRL1_BW0_BIT | \
MMC35240_CTRL1_BW1_BIT)
#define MMC35240_CTRL1_BW_SHIFT 0
#define MMC35240_WAIT_CHARGE_PUMP 50000 /* us */
#define MMC53240_WAIT_SET_RESET 1000 /* us */
/*
* Memsic OTP process code piece is put here for reference:
*
* #define OTP_CONVERT(REG) ((float)((REG) >=32 ? (32 - (REG)) : (REG)) * 0.006
* 1) For X axis, the COEFFICIENT is always 1.
* 2) For Y axis, the COEFFICIENT is as below:
* f_OTP_matrix[4] = OTP_CONVERT(((reg_data[1] & 0x03) << 4) |
* (reg_data[2] >> 4)) + 1.0;
* 3) For Z axis, the COEFFICIENT is as below:
* f_OTP_matrix[8] = (OTP_CONVERT(reg_data[3] & 0x3f) + 1) * 1.35;
* We implemented the OTP logic into driver.
*/
/* scale = 1000 here for Y otp */
#define MMC35240_OTP_CONVERT_Y(REG) (((REG) >= 32 ? (32 - (REG)) : (REG)) * 6)
/* 0.6 * 1.35 = 0.81, scale 10000 for Z otp */
#define MMC35240_OTP_CONVERT_Z(REG) (((REG) >= 32 ? (32 - (REG)) : (REG)) * 81)
#define MMC35240_X_COEFF(x) (x)
#define MMC35240_Y_COEFF(y) (y + 1000)
#define MMC35240_Z_COEFF(z) (z + 13500)
#define MMC35240_OTP_START_ADDR 0x1B
enum mmc35240_resolution {
MMC35240_16_BITS_SLOW = 0, /* 7.92 ms */
MMC35240_16_BITS_FAST, /* 4.08 ms */
MMC35240_14_BITS, /* 2.16 ms */
MMC35240_12_BITS, /* 1.20 ms */
};
enum mmc35240_axis {
AXIS_X = 0,
AXIS_Y,
AXIS_Z,
};
static const struct {
int sens[3]; /* sensitivity per X, Y, Z axis */
int nfo; /* null field output */
} mmc35240_props_table[] = {
/* 16 bits, 125Hz ODR */
{
{1024, 1024, 1024},
32768,
},
/* 16 bits, 250Hz ODR */
{
{1024, 1024, 770},
32768,
},
/* 14 bits, 450Hz ODR */
{
{256, 256, 193},
8192,
},
/* 12 bits, 800Hz ODR */
{
{64, 64, 48},
2048,
},
};
struct mmc35240_data {
struct i2c_client *client;
struct mutex mutex;
struct regmap *regmap;
enum mmc35240_resolution res;
/* OTP compensation */
int axis_coef[3];
int axis_scale[3];
};
static const struct {
int val;
int val2;
} mmc35240_samp_freq[] = { {1, 500000},
{13, 0},
{25, 0},
{50, 0} };
static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("1.5 13 25 50");
#define MMC35240_CHANNEL(_axis) { \
.type = IIO_MAGN, \
.modified = 1, \
.channel2 = IIO_MOD_ ## _axis, \
.address = AXIS_ ## _axis, \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ) | \
BIT(IIO_CHAN_INFO_SCALE), \
}
static const struct iio_chan_spec mmc35240_channels[] = {
MMC35240_CHANNEL(X),
MMC35240_CHANNEL(Y),
MMC35240_CHANNEL(Z),
};
static struct attribute *mmc35240_attributes[] = {
&iio_const_attr_sampling_frequency_available.dev_attr.attr,
NULL
};
static const struct attribute_group mmc35240_attribute_group = {
.attrs = mmc35240_attributes,
};
static int mmc35240_get_samp_freq_index(struct mmc35240_data *data,
int val, int val2)
{
int i;
for (i = 0; i < ARRAY_SIZE(mmc35240_samp_freq); i++)
if (mmc35240_samp_freq[i].val == val &&
mmc35240_samp_freq[i].val2 == val2)
return i;
return -EINVAL;
}
static int mmc35240_hw_set(struct mmc35240_data *data, bool set)
{
int ret;
u8 coil_bit;
/*
* Recharge the capacitor at VCAP pin, requested to be issued
* before a SET/RESET command.
*/
ret = regmap_update_bits(data->regmap, MMC35240_REG_CTRL0,
MMC35240_CTRL0_REFILL_BIT,
MMC35240_CTRL0_REFILL_BIT);
if (ret < 0)
return ret;
usleep_range(MMC35240_WAIT_CHARGE_PUMP, MMC35240_WAIT_CHARGE_PUMP + 1);
if (set)
coil_bit = MMC35240_CTRL0_SET_BIT;
else
coil_bit = MMC35240_CTRL0_RESET_BIT;
return regmap_update_bits(data->regmap, MMC35240_REG_CTRL0,
coil_bit, coil_bit);
}
static int mmc35240_init(struct mmc35240_data *data)
{
int ret, y_convert, z_convert;
unsigned int reg_id;
u8 otp_data[6];
ret = regmap_read(data->regmap, MMC35240_REG_ID, ®_id);
if (ret < 0) {
dev_err(&data->client->dev, "Error reading product id\n");
return ret;
}
dev_dbg(&data->client->dev, "MMC35240 chip id %x\n", reg_id);
/*
* make sure we restore sensor characteristics, by doing
* a SET/RESET sequence, the axis polarity being naturally
* aligned after RESET
*/
ret = mmc35240_hw_set(data, true);
if (ret < 0)
return ret;
usleep_range(MMC53240_WAIT_SET_RESET, MMC53240_WAIT_SET_RESET + 1);
ret = mmc35240_hw_set(data, false);
if (ret < 0)
return ret;
/* set default sampling frequency */
ret = regmap_update_bits(data->regmap, MMC35240_REG_CTRL1,
MMC35240_CTRL1_BW_MASK,
data->res << MMC35240_CTRL1_BW_SHIFT);
if (ret < 0)
return ret;
ret = regmap_bulk_read(data->regmap, MMC35240_OTP_START_ADDR,
(u8 *)otp_data, sizeof(otp_data));
if (ret < 0)
return ret;
y_convert = MMC35240_OTP_CONVERT_Y(((otp_data[1] & 0x03) << 4) |
(otp_data[2] >> 4));
z_convert = MMC35240_OTP_CONVERT_Z(otp_data[3] & 0x3f);
data->axis_coef[0] = MMC35240_X_COEFF(1);
data->axis_coef[1] = MMC35240_Y_COEFF(y_convert);
data->axis_coef[2] = MMC35240_Z_COEFF(z_convert);
data->axis_scale[0] = 1;
data->axis_scale[1] = 1000;
data->axis_scale[2] = 10000;
return 0;
}
static int mmc35240_take_measurement(struct mmc35240_data *data)
{
int ret, tries = 100;
unsigned int reg_status;
ret = regmap_write(data->regmap, MMC35240_REG_CTRL0,
MMC35240_CTRL0_TM_BIT);
if (ret < 0)
return ret;
while (tries-- > 0) {
ret = regmap_read(data->regmap, MMC35240_REG_STATUS,
®_status);
if (ret < 0)
return ret;
if (reg_status & MMC35240_STATUS_MEAS_DONE_BIT)
break;
/* minimum wait time to complete measurement is 10 ms */
usleep_range(10000, 11000);
}
if (tries < 0) {
dev_err(&data->client->dev, "data not ready\n");
return -EIO;
}
return 0;
}
static int mmc35240_read_measurement(struct mmc35240_data *data, __le16 buf[3])
{
int ret;
ret = mmc35240_take_measurement(data);
if (ret < 0)
return ret;
return regmap_bulk_read(data->regmap, MMC35240_REG_XOUT_L, (u8 *)buf,
3 * sizeof(__le16));
}
/**
* mmc35240_raw_to_mgauss - convert raw readings to milli gauss. Also apply
compensation for output value.
*
* @data: device private data
* @index: axis index for which we want the conversion
* @buf: raw data to be converted, 2 bytes in little endian format
* @val: compensated output reading (unit is milli gauss)
*
* Returns: 0 in case of success, -EINVAL when @index is not valid
*/
static int mmc35240_raw_to_mgauss(struct mmc35240_data *data, int index,
__le16 buf[], int *val)
{
int raw[3];
int sens[3];
int nfo;
raw[AXIS_X] = le16_to_cpu(buf[AXIS_X]);
raw[AXIS_Y] = le16_to_cpu(buf[AXIS_Y]);
raw[AXIS_Z] = le16_to_cpu(buf[AXIS_Z]);
sens[AXIS_X] = mmc35240_props_table[data->res].sens[AXIS_X];
sens[AXIS_Y] = mmc35240_props_table[data->res].sens[AXIS_Y];
sens[AXIS_Z] = mmc35240_props_table[data->res].sens[AXIS_Z];
nfo = mmc35240_props_table[data->res].nfo;
switch (index) {
case AXIS_X:
*val = (raw[AXIS_X] - nfo) * 1000 / sens[AXIS_X];
break;
case AXIS_Y:
*val = (raw[AXIS_Y] - nfo) * 1000 / sens[AXIS_Y] -
(raw[AXIS_Z] - nfo) * 1000 / sens[AXIS_Z];
break;
case AXIS_Z:
*val = (raw[AXIS_Y] - nfo) * 1000 / sens[AXIS_Y] +
(raw[AXIS_Z] - nfo) * 1000 / sens[AXIS_Z];
break;
default:
return -EINVAL;
}
/* apply OTP compensation */
*val = (*val) * data->axis_coef[index] / data->axis_scale[index];
return 0;
}
static int mmc35240_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan, int *val,
int *val2, long mask)
{
struct mmc35240_data *data = iio_priv(indio_dev);
int ret, i;
unsigned int reg;
__le16 buf[3];
switch (mask) {
case IIO_CHAN_INFO_RAW:
mutex_lock(&data->mutex);
ret = mmc35240_read_measurement(data, buf);
mutex_unlock(&data->mutex);
if (ret < 0)
return ret;
ret = mmc35240_raw_to_mgauss(data, chan->address, buf, val);
if (ret < 0)
return ret;
return IIO_VAL_INT;
case IIO_CHAN_INFO_SCALE:
*val = 0;
*val2 = 1000;
return IIO_VAL_INT_PLUS_MICRO;
case IIO_CHAN_INFO_SAMP_FREQ:
mutex_lock(&data->mutex);
ret = regmap_read(data->regmap, MMC35240_REG_CTRL1, ®);
mutex_unlock(&data->mutex);
if (ret < 0)
return ret;
i = (reg & MMC35240_CTRL1_BW_MASK) >> MMC35240_CTRL1_BW_SHIFT;
if (i < 0 || i >= ARRAY_SIZE(mmc35240_samp_freq))
return -EINVAL;
*val = mmc35240_samp_freq[i].val;
*val2 = mmc35240_samp_freq[i].val2;
return IIO_VAL_INT_PLUS_MICRO;
default:
return -EINVAL;
}
}
static int mmc35240_write_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan, int val,
int val2, long mask)
{
struct mmc35240_data *data = iio_priv(indio_dev);
int i, ret;
switch (mask) {
case IIO_CHAN_INFO_SAMP_FREQ:
i = mmc35240_get_samp_freq_index(data, val, val2);
if (i < 0)
return -EINVAL;
mutex_lock(&data->mutex);
ret = regmap_update_bits(data->regmap, MMC35240_REG_CTRL1,
MMC35240_CTRL1_BW_MASK,
i << MMC35240_CTRL1_BW_SHIFT);
mutex_unlock(&data->mutex);
return ret;
default:
return -EINVAL;
}
}
static const struct iio_info mmc35240_info = {
.driver_module = THIS_MODULE,
.read_raw = mmc35240_read_raw,
.write_raw = mmc35240_write_raw,
.attrs = &mmc35240_attribute_group,
};
static bool mmc35240_is_writeable_reg(struct device *dev, unsigned int reg)
{
switch (reg) {
case MMC35240_REG_CTRL0:
case MMC35240_REG_CTRL1:
return true;
default:
return false;
}
}
static bool mmc35240_is_readable_reg(struct device *dev, unsigned int reg)
{
switch (reg) {
case MMC35240_REG_XOUT_L:
case MMC35240_REG_XOUT_H:
case MMC35240_REG_YOUT_L:
case MMC35240_REG_YOUT_H:
case MMC35240_REG_ZOUT_L:
case MMC35240_REG_ZOUT_H:
case MMC35240_REG_STATUS:
case MMC35240_REG_ID:
return true;
default:
return false;
}
}
static bool mmc35240_is_volatile_reg(struct device *dev, unsigned int reg)
{
switch (reg) {
case MMC35240_REG_CTRL0:
case MMC35240_REG_CTRL1:
return false;
default:
return true;
}
}
static struct reg_default mmc35240_reg_defaults[] = {
{ MMC35240_REG_CTRL0, 0x00 },
{ MMC35240_REG_CTRL1, 0x00 },
};
static const struct regmap_config mmc35240_regmap_config = {
.name = MMC35240_REGMAP_NAME,
.reg_bits = 8,
.val_bits = 8,
.max_register = MMC35240_REG_ID,
.cache_type = REGCACHE_FLAT,
.writeable_reg = mmc35240_is_writeable_reg,
.readable_reg = mmc35240_is_readable_reg,
.volatile_reg = mmc35240_is_volatile_reg,
.reg_defaults = mmc35240_reg_defaults,
.num_reg_defaults = ARRAY_SIZE(mmc35240_reg_defaults),
};
static int mmc35240_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct mmc35240_data *data;
struct iio_dev *indio_dev;
struct regmap *regmap;
int ret;
indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
if (!indio_dev)
return -ENOMEM;
regmap = devm_regmap_init_i2c(client, &mmc35240_regmap_config);
if (IS_ERR(regmap)) {
dev_err(&client->dev, "regmap initialization failed\n");
return PTR_ERR(regmap);
}
data = iio_priv(indio_dev);
i2c_set_clientdata(client, indio_dev);
data->client = client;
data->regmap = regmap;
data->res = MMC35240_16_BITS_SLOW;
mutex_init(&data->mutex);
indio_dev->dev.parent = &client->dev;
indio_dev->info = &mmc35240_info;
indio_dev->name = MMC35240_DRV_NAME;
indio_dev->channels = mmc35240_channels;
indio_dev->num_channels = ARRAY_SIZE(mmc35240_channels);
indio_dev->modes = INDIO_DIRECT_MODE;
ret = mmc35240_init(data);
if (ret < 0) {
dev_err(&client->dev, "mmc35240 chip init failed\n");
return ret;
}
return devm_iio_device_register(&client->dev, indio_dev);
}
#ifdef CONFIG_PM_SLEEP
static int mmc35240_suspend(struct device *dev)
{
struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
struct mmc35240_data *data = iio_priv(indio_dev);
regcache_cache_only(data->regmap, true);
return 0;
}
static int mmc35240_resume(struct device *dev)
{
struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
struct mmc35240_data *data = iio_priv(indio_dev);
int ret;
regcache_mark_dirty(data->regmap);
ret = regcache_sync_region(data->regmap, MMC35240_REG_CTRL0,
MMC35240_REG_CTRL1);
if (ret < 0)
dev_err(dev, "Failed to restore control registers\n");
regcache_cache_only(data->regmap, false);
return 0;
}
#endif
static const struct dev_pm_ops mmc35240_pm_ops = {
SET_SYSTEM_SLEEP_PM_OPS(mmc35240_suspend, mmc35240_resume)
};
static const struct of_device_id mmc35240_of_match[] = {
{ .compatible = "memsic,mmc35240", },
{ }
};
MODULE_DEVICE_TABLE(of, mmc35240_of_match);
static const struct acpi_device_id mmc35240_acpi_match[] = {
{"MMC35240", 0},
{ },
};
MODULE_DEVICE_TABLE(acpi, mmc35240_acpi_match);
static const struct i2c_device_id mmc35240_id[] = {
{"mmc35240", 0},
{}
};
MODULE_DEVICE_TABLE(i2c, mmc35240_id);
static struct i2c_driver mmc35240_driver = {
.driver = {
.name = MMC35240_DRV_NAME,
.of_match_table = mmc35240_of_match,
.pm = &mmc35240_pm_ops,
.acpi_match_table = ACPI_PTR(mmc35240_acpi_match),
},
.probe = mmc35240_probe,
.id_table = mmc35240_id,
};
module_i2c_driver(mmc35240_driver);
MODULE_AUTHOR("Daniel Baluta <daniel.baluta@intel.com>");
MODULE_DESCRIPTION("MEMSIC MMC35240 magnetic sensor driver");
MODULE_LICENSE("GPL v2");