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/*
* IIO driver for the 3-axis accelerometer Domintech DMARD09.
*
* Copyright (c) 2016, Jelle van der Waa <jelle@vdwaa.nl>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*/
#include <asm/unaligned.h>
#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/iio/iio.h>
#define DMARD09_DRV_NAME "dmard09"
#define DMARD09_REG_CHIPID 0x18
#define DMARD09_REG_STAT 0x0A
#define DMARD09_REG_X 0x0C
#define DMARD09_REG_Y 0x0E
#define DMARD09_REG_Z 0x10
#define DMARD09_CHIPID 0x95
#define DMARD09_BUF_LEN 8
#define DMARD09_AXIS_X 0
#define DMARD09_AXIS_Y 1
#define DMARD09_AXIS_Z 2
#define DMARD09_AXIS_X_OFFSET ((DMARD09_AXIS_X + 1) * 2)
#define DMARD09_AXIS_Y_OFFSET ((DMARD09_AXIS_Y + 1 )* 2)
#define DMARD09_AXIS_Z_OFFSET ((DMARD09_AXIS_Z + 1) * 2)
struct dmard09_data {
struct i2c_client *client;
};
#define DMARD09_CHANNEL(_axis, offset) { \
.type = IIO_ACCEL, \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
.modified = 1, \
.address = offset, \
.channel2 = IIO_MOD_##_axis, \
}
static const struct iio_chan_spec dmard09_channels[] = {
DMARD09_CHANNEL(X, DMARD09_AXIS_X_OFFSET),
DMARD09_CHANNEL(Y, DMARD09_AXIS_Y_OFFSET),
DMARD09_CHANNEL(Z, DMARD09_AXIS_Z_OFFSET),
};
static int dmard09_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val, int *val2, long mask)
{
struct dmard09_data *data = iio_priv(indio_dev);
u8 buf[DMARD09_BUF_LEN];
int ret;
s16 accel;
switch (mask) {
case IIO_CHAN_INFO_RAW:
/*
* Read from the DMAR09_REG_STAT register, since the chip
* caches reads from the individual X, Y, Z registers.
*/
ret = i2c_smbus_read_i2c_block_data(data->client,
DMARD09_REG_STAT,
DMARD09_BUF_LEN, buf);
if (ret < 0) {
dev_err(&data->client->dev, "Error reading reg %d\n",
DMARD09_REG_STAT);
return ret;
}
accel = get_unaligned_le16(&buf[chan->address]);
/* Remove lower 3 bits and sign extend */
accel <<= 4;
accel >>= 7;
*val = accel;
return IIO_VAL_INT;
default:
return -EINVAL;
}
}
static const struct iio_info dmard09_info = {
.read_raw = dmard09_read_raw,
};
static int dmard09_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
int ret;
struct iio_dev *indio_dev;
struct dmard09_data *data;
indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
if (!indio_dev) {
dev_err(&client->dev, "iio allocation failed\n");
return -ENOMEM;
}
data = iio_priv(indio_dev);
data->client = client;
ret = i2c_smbus_read_byte_data(data->client, DMARD09_REG_CHIPID);
if (ret < 0) {
dev_err(&client->dev, "Error reading chip id %d\n", ret);
return ret;
}
if (ret != DMARD09_CHIPID) {
dev_err(&client->dev, "Invalid chip id %d\n", ret);
return -ENODEV;
}
i2c_set_clientdata(client, indio_dev);
indio_dev->dev.parent = &client->dev;
indio_dev->name = DMARD09_DRV_NAME;
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->channels = dmard09_channels;
indio_dev->num_channels = ARRAY_SIZE(dmard09_channels);
indio_dev->info = &dmard09_info;
return devm_iio_device_register(&client->dev, indio_dev);
}
static const struct i2c_device_id dmard09_id[] = {
{ "dmard09", 0},
{ },
};
MODULE_DEVICE_TABLE(i2c, dmard09_id);
static struct i2c_driver dmard09_driver = {
.driver = {
.name = DMARD09_DRV_NAME
},
.probe = dmard09_probe,
.id_table = dmard09_id,
};
module_i2c_driver(dmard09_driver);
MODULE_AUTHOR("Jelle van der Waa <jelle@vdwaa.nl>");
MODULE_DESCRIPTION("DMARD09 3-axis accelerometer driver");
MODULE_LICENSE("GPL");
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