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/*
* MXC6255 - MEMSIC orientation sensing accelerometer
*
* 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 MXC6255 (7-bit I2C slave address 0x15).
*/
#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/init.h>
#include <linux/iio/iio.h>
#include <linux/delay.h>
#include <linux/acpi.h>
#include <linux/regmap.h>
#include <linux/iio/sysfs.h>
#define MXC6255_DRV_NAME "mxc6255"
#define MXC6255_REGMAP_NAME "mxc6255_regmap"
#define MXC6255_REG_XOUT 0x00
#define MXC6255_REG_YOUT 0x01
#define MXC6255_REG_CHIP_ID 0x08
#define MXC6255_CHIP_ID 0x05
/*
* MXC6255 has only one measurement range: +/- 2G.
* The acceleration output is an 8-bit value.
*
* Scale is calculated as follows:
* (2 + 2) * 9.80665 / (2^8 - 1) = 0.153829
*
* Scale value for +/- 2G measurement range
*/
#define MXC6255_SCALE 153829
enum mxc6255_axis {
AXIS_X,
AXIS_Y,
};
struct mxc6255_data {
struct i2c_client *client;
struct regmap *regmap;
};
static int mxc6255_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val, int *val2, long mask)
{
struct mxc6255_data *data = iio_priv(indio_dev);
unsigned int reg;
int ret;
switch (mask) {
case IIO_CHAN_INFO_RAW:
ret = regmap_read(data->regmap, chan->address, ®);
if (ret < 0) {
dev_err(&data->client->dev,
"Error reading reg %lu\n", chan->address);
return ret;
}
*val = sign_extend32(reg, 7);
return IIO_VAL_INT;
case IIO_CHAN_INFO_SCALE:
*val = 0;
*val2 = MXC6255_SCALE;
return IIO_VAL_INT_PLUS_MICRO;
default:
return -EINVAL;
}
}
static const struct iio_info mxc6255_info = {
.driver_module = THIS_MODULE,
.read_raw = mxc6255_read_raw,
};
#define MXC6255_CHANNEL(_axis, reg) { \
.type = IIO_ACCEL, \
.modified = 1, \
.channel2 = IIO_MOD_##_axis, \
.address = reg, \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
}
static const struct iio_chan_spec mxc6255_channels[] = {
MXC6255_CHANNEL(X, MXC6255_REG_XOUT),
MXC6255_CHANNEL(Y, MXC6255_REG_YOUT),
};
static bool mxc6255_is_readable_reg(struct device *dev, unsigned int reg)
{
switch (reg) {
case MXC6255_REG_XOUT:
case MXC6255_REG_YOUT:
case MXC6255_REG_CHIP_ID:
return true;
default:
return false;
}
}
static const struct regmap_config mxc6255_regmap_config = {
.name = MXC6255_REGMAP_NAME,
.reg_bits = 8,
.val_bits = 8,
.readable_reg = mxc6255_is_readable_reg,
};
static int mxc6255_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct mxc6255_data *data;
struct iio_dev *indio_dev;
struct regmap *regmap;
unsigned int chip_id;
int ret;
indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
if (!indio_dev)
return -ENOMEM;
regmap = devm_regmap_init_i2c(client, &mxc6255_regmap_config);
if (IS_ERR(regmap)) {
dev_err(&client->dev, "Error initializing regmap\n");
return PTR_ERR(regmap);
}
data = iio_priv(indio_dev);
i2c_set_clientdata(client, indio_dev);
data->client = client;
data->regmap = regmap;
indio_dev->name = MXC6255_DRV_NAME;
indio_dev->dev.parent = &client->dev;
indio_dev->channels = mxc6255_channels;
indio_dev->num_channels = ARRAY_SIZE(mxc6255_channels);
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->info = &mxc6255_info;
ret = regmap_read(data->regmap, MXC6255_REG_CHIP_ID, &chip_id);
if (ret < 0) {
dev_err(&client->dev, "Error reading chip id %d\n", ret);
return ret;
}
if (chip_id != MXC6255_CHIP_ID) {
dev_err(&client->dev, "Invalid chip id %x\n", chip_id);
return -ENODEV;
}
dev_dbg(&client->dev, "Chip id %x\n", chip_id);
ret = devm_iio_device_register(&client->dev, indio_dev);
if (ret < 0) {
dev_err(&client->dev, "Could not register IIO device\n");
return ret;
}
return 0;
}
static const struct acpi_device_id mxc6255_acpi_match[] = {
{"MXC6255", 0},
{ }
};
MODULE_DEVICE_TABLE(acpi, mxc6255_acpi_match);
static const struct i2c_device_id mxc6255_id[] = {
{"mxc6255", 0},
{ }
};
MODULE_DEVICE_TABLE(i2c, mxc6255_id);
static struct i2c_driver mxc6255_driver = {
.driver = {
.name = MXC6255_DRV_NAME,
.acpi_match_table = ACPI_PTR(mxc6255_acpi_match),
},
.probe = mxc6255_probe,
.id_table = mxc6255_id,
};
module_i2c_driver(mxc6255_driver);
MODULE_AUTHOR("Teodora Baluta <teodora.baluta@intel.com>");
MODULE_DESCRIPTION("MEMSIC MXC6255 orientation sensing accelerometer driver");
MODULE_LICENSE("GPL v2");
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