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iio: magnetometer: Add support for MEMSIC MMC35240 sensor 

Minimal implementation for MMC35240 3-axis magnetometer
sensor. It provides processed readings and possiblity to change
the sampling frequency.

Signed-off-by: Daniel Baluta <daniel.baluta@intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
This commit is contained in:
Daniel Baluta 2015-04-24 18:58:30 +03:00 committed by Jonathan Cameron
parent 5990dc9703
commit abeb6b1e7b
3 changed files with 481 additions and 0 deletions
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11
drivers/iio/magnetometer/Kconfig
View File

@ -47,6 +47,17 @@ config HID_SENSOR_MAGNETOMETER_3D
Say yes here to build support for the HID SENSOR
Magnetometer 3D.
config MMC35240
tristate "MEMSIC MMC35240 3-axis magnetic sensor"
select REGMAP_I2C
depends on I2C
help
Say yes here to build support for the MEMSIC MMC35240 3-axis
magnetic sensor.
To compile this driver as a module, choose M here: the module
will be called mmc35240.
config IIO_ST_MAGN_3AXIS
tristate "STMicroelectronics magnetometers 3-Axis Driver"
depends on (I2C || SPI_MASTER) && SYSFS

1
drivers/iio/magnetometer/Makefile
View File

@ -6,6 +6,7 @@
obj-$(CONFIG_AK8975) += ak8975.o
obj-$(CONFIG_MAG3110) += mag3110.o
obj-$(CONFIG_HID_SENSOR_MAGNETOMETER_3D) += hid-sensor-magn-3d.o
obj-$(CONFIG_MMC35240) += mmc35240.o
obj-$(CONFIG_IIO_ST_MAGN_3AXIS) += st_magn.o
st_magn-y := st_magn_core.o

469
drivers/iio/magnetometer/mmc35240.c Normal file
View File

@ -0,0 +1,469 @@
/*
* 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/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 */
enum mmc35240_resolution {
MMC35240_16_BITS_SLOW = 0, /* 100 Hz */
MMC35240_16_BITS_FAST, /* 200 Hz */
MMC35240_14_BITS, /* 333 Hz */
MMC35240_12_BITS, /* 666 Hz */
};
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, 100Hz ODR */
{
{1024, 1024, 770},
32768,
},
/* 16 bits, 200Hz ODR */
{
{1024, 1024, 770},
32768,
},
/* 14 bits, 333Hz ODR */
{
{256, 256, 193},
8192,
},
/* 12 bits, 666Hz ODR */
{
{64, 64, 48},
2048,
},
};
struct mmc35240_data {
struct i2c_client *client;
struct mutex mutex;
struct regmap *regmap;
enum mmc35240_resolution res;
};
static const int mmc35240_samp_freq[] = {100, 200, 333, 666};
static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("100 200 333 666");
#define MMC35240_CHANNEL(_axis) { \
.type = IIO_MAGN, \
.modified = 1, \
.channel2 = IIO_MOD_ ## _axis, \
.address = AXIS_ ## _axis, \
.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED), \
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ), \
}
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,
};
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)
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,
MMC35240_CTRL0_REFILL_BIT,
coil_bit);
}
static int mmc35240_init(struct mmc35240_data *data)
{
int ret;
unsigned int reg_id;
ret = regmap_read(data->regmap, MMC35240_REG_ID, &reg_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 RESET/SET sequence
*/
ret = mmc35240_hw_set(data, false);
if (ret < 0)
return ret;
usleep_range(MMC53240_WAIT_SET_RESET, MMC53240_WAIT_SET_RESET + 1);
ret = mmc35240_hw_set(data, true);
if (ret < 0)
return ret;
/* set default sampling frequency */
return regmap_update_bits(data->regmap, MMC35240_REG_CTRL1,
MMC35240_CTRL1_BW_MASK,
data->res << MMC35240_CTRL1_BW_SHIFT);
}
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,
&reg_status);
if (ret < 0)
return ret;
if (reg_status & MMC35240_STATUS_MEAS_DONE_BIT)
break;
msleep(20);
}
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));
}
static int mmc35240_raw_to_gauss(struct mmc35240_data *data, int index,
__le16 buf[],
int *val, int *val2)
{
int raw_x, raw_y, raw_z;
int sens_x, sens_y, sens_z;
int nfo;
raw_x = le16_to_cpu(buf[AXIS_X]);
raw_y = le16_to_cpu(buf[AXIS_Y]);
raw_z = le16_to_cpu(buf[AXIS_Z]);
sens_x = mmc35240_props_table[data->res].sens[AXIS_X];
sens_y = mmc35240_props_table[data->res].sens[AXIS_Y];
sens_z = mmc35240_props_table[data->res].sens[AXIS_Z];
nfo = mmc35240_props_table[data->res].nfo;
switch (index) {
case AXIS_X:
*val = (raw_x - nfo) / sens_x;
*val2 = ((raw_x - nfo) % sens_x) * 1000000;
break;
case AXIS_Y:
*val = (raw_y - nfo) / sens_y - (raw_z - nfo) / sens_z;
*val2 = (((raw_y - nfo) % sens_y - (raw_z - nfo) % sens_z))
* 1000000;
break;
case AXIS_Z:
*val = (raw_y - nfo) / sens_y + (raw_z - nfo) / sens_z;
*val2 = (((raw_y - nfo) % sens_y + (raw_z - nfo) % sens_z))
* 1000000;
break;
default:
return -EINVAL;
}
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_PROCESSED:
mutex_lock(&data->mutex);
ret = mmc35240_read_measurement(data, buf);
mutex_unlock(&data->mutex);
if (ret < 0)
return ret;
ret = mmc35240_raw_to_gauss(data, chan->address,
buf, val, val2);
if (ret < 0)
return ret;
return IIO_VAL_INT_PLUS_MICRO;
case IIO_CHAN_INFO_SAMP_FREQ:
mutex_lock(&data->mutex);
ret = regmap_read(data->regmap, MMC35240_REG_CTRL1, &reg);
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];
*val2 = 0;
return IIO_VAL_INT;
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);
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);
}
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,
},
.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");