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/**
* Sensortek STK8BA50 3-Axis 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.
*
* STK8BA50 7-bit I2C address: 0x18.
*/
#include <linux/acpi.h>
#include <linux/i2c.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#define STK8BA50_REG_XOUT 0x02
#define STK8BA50_REG_YOUT 0x04
#define STK8BA50_REG_ZOUT 0x06
#define STK8BA50_REG_RANGE 0x0F
#define STK8BA50_REG_POWMODE 0x11
#define STK8BA50_REG_SWRST 0x14
#define STK8BA50_MODE_NORMAL 0
#define STK8BA50_MODE_SUSPEND 1
#define STK8BA50_MODE_POWERBIT BIT(7)
#define STK8BA50_DATA_SHIFT 6
#define STK8BA50_RESET_CMD 0xB6
#define STK8BA50_DRIVER_NAME "stk8ba50"
#define STK8BA50_SCALE_AVAIL "0.0384 0.0767 0.1534 0.3069"
/*
* The accelerometer has four measurement ranges:
* +/-2g; +/-4g; +/-8g; +/-16g
*
* Acceleration values are 10-bit, 2's complement.
* Scales are calculated as following:
*
* scale1 = (2 + 2) * 9.81 / (2^10 - 1) = 0.0384
* scale2 = (4 + 4) * 9.81 / (2^10 - 1) = 0.0767
* etc.
*
* Scales are stored in this format:
* { <register value>, <scale value> }
*
* Locally, the range is stored as a table index.
*/
static const int stk8ba50_scale_table[][2] = {
{3, 38400}, {5, 76700}, {8, 153400}, {12, 306900}
};
struct stk8ba50_data {
struct i2c_client *client;
struct mutex lock;
int range;
};
#define STK8BA50_ACCEL_CHANNEL(reg, axis) { \
.type = IIO_ACCEL, \
.address = reg, \
.modified = 1, \
.channel2 = IIO_MOD_##axis, \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
}
static const struct iio_chan_spec stk8ba50_channels[] = {
STK8BA50_ACCEL_CHANNEL(STK8BA50_REG_XOUT, X),
STK8BA50_ACCEL_CHANNEL(STK8BA50_REG_YOUT, Y),
STK8BA50_ACCEL_CHANNEL(STK8BA50_REG_ZOUT, Z),
};
static IIO_CONST_ATTR(in_accel_scale_available, STK8BA50_SCALE_AVAIL);
static struct attribute *stk8ba50_attributes[] = {
&iio_const_attr_in_accel_scale_available.dev_attr.attr,
NULL,
};
static const struct attribute_group stk8ba50_attribute_group = {
.attrs = stk8ba50_attributes
};
static int stk8ba50_read_accel(struct stk8ba50_data *data, u8 reg)
{
int ret;
struct i2c_client *client = data->client;
ret = i2c_smbus_read_word_data(client, reg);
if (ret < 0) {
dev_err(&client->dev, "register read failed\n");
return ret;
}
return sign_extend32(ret >> STK8BA50_DATA_SHIFT, 9);
}
static int stk8ba50_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val, int *val2, long mask)
{
struct stk8ba50_data *data = iio_priv(indio_dev);
switch (mask) {
case IIO_CHAN_INFO_RAW:
mutex_lock(&data->lock);
*val = stk8ba50_read_accel(data, chan->address);
mutex_unlock(&data->lock);
return IIO_VAL_INT;
case IIO_CHAN_INFO_SCALE:
*val = 0;
*val2 = stk8ba50_scale_table[data->range][1];
return IIO_VAL_INT_PLUS_MICRO;
}
return -EINVAL;
}
static int stk8ba50_write_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int val, int val2, long mask)
{
int ret;
int i;
int index = -1;
struct stk8ba50_data *data = iio_priv(indio_dev);
switch (mask) {
case IIO_CHAN_INFO_SCALE:
if (val != 0)
return -EINVAL;
for (i = 0; i < ARRAY_SIZE(stk8ba50_scale_table); i++)
if (val2 == stk8ba50_scale_table[i][1]) {
index = i;
break;
}
if (index < 0)
return -EINVAL;
ret = i2c_smbus_write_byte_data(data->client,
STK8BA50_REG_RANGE,
stk8ba50_scale_table[index][0]);
if (ret < 0)
dev_err(&data->client->dev,
"failed to set measurement range\n");
else
data->range = index;
return ret;
}
return -EINVAL;
}
static const struct iio_info stk8ba50_info = {
.driver_module = THIS_MODULE,
.read_raw = stk8ba50_read_raw,
.write_raw = stk8ba50_write_raw,
.attrs = &stk8ba50_attribute_group,
};
static int stk8ba50_set_power(struct stk8ba50_data *data, bool mode)
{
int ret;
u8 masked_reg;
struct i2c_client *client = data->client;
ret = i2c_smbus_read_byte_data(client, STK8BA50_REG_POWMODE);
if (ret < 0)
goto exit_err;
if (mode)
masked_reg = ret | STK8BA50_MODE_POWERBIT;
else
masked_reg = ret & (~STK8BA50_MODE_POWERBIT);
ret = i2c_smbus_write_byte_data(client, STK8BA50_REG_POWMODE,
masked_reg);
if (ret < 0)
goto exit_err;
return ret;
exit_err:
dev_err(&client->dev, "failed to change sensor mode\n");
return ret;
}
static int stk8ba50_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
int ret;
struct iio_dev *indio_dev;
struct stk8ba50_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;
i2c_set_clientdata(client, indio_dev);
mutex_init(&data->lock);
indio_dev->dev.parent = &client->dev;
indio_dev->info = &stk8ba50_info;
indio_dev->name = STK8BA50_DRIVER_NAME;
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->channels = stk8ba50_channels;
indio_dev->num_channels = ARRAY_SIZE(stk8ba50_channels);
/* Reset all registers on startup */
ret = i2c_smbus_write_byte_data(client,
STK8BA50_REG_SWRST, STK8BA50_RESET_CMD);
if (ret < 0) {
dev_err(&client->dev, "failed to reset sensor\n");
return ret;
}
/* The default range is +/-2g */
data->range = 0;
ret = iio_device_register(indio_dev);
if (ret < 0) {
dev_err(&client->dev, "device_register failed\n");
stk8ba50_set_power(data, STK8BA50_MODE_SUSPEND);
}
return ret;
}
static int stk8ba50_remove(struct i2c_client *client)
{
struct iio_dev *indio_dev = i2c_get_clientdata(client);
iio_device_unregister(indio_dev);
return stk8ba50_set_power(iio_priv(indio_dev), STK8BA50_MODE_SUSPEND);
}
#ifdef CONFIG_PM_SLEEP
static int stk8ba50_suspend(struct device *dev)
{
struct stk8ba50_data *data;
data = iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
return stk8ba50_set_power(data, STK8BA50_MODE_SUSPEND);
}
static int stk8ba50_resume(struct device *dev)
{
struct stk8ba50_data *data;
data = iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
return stk8ba50_set_power(data, STK8BA50_MODE_NORMAL);
}
static SIMPLE_DEV_PM_OPS(stk8ba50_pm_ops, stk8ba50_suspend, stk8ba50_resume);
#define STK8BA50_PM_OPS (&stk8ba50_pm_ops)
#else
#define STK8BA50_PM_OPS NULL
#endif
static const struct i2c_device_id stk8ba50_i2c_id[] = {
{"stk8ba50", 0},
{}
};
static const struct acpi_device_id stk8ba50_acpi_id[] = {
{"STK8BA50", 0},
{}
};
MODULE_DEVICE_TABLE(acpi, stk8ba50_acpi_id);
static struct i2c_driver stk8ba50_driver = {
.driver = {
.name = "stk8ba50",
.pm = STK8BA50_PM_OPS,
.acpi_match_table = ACPI_PTR(stk8ba50_acpi_id),
},
.probe = stk8ba50_probe,
.remove = stk8ba50_remove,
.id_table = stk8ba50_i2c_id,
};
module_i2c_driver(stk8ba50_driver);
MODULE_AUTHOR("Tiberiu Breana <tiberiu.a.breana@intel.com>");
MODULE_DESCRIPTION("STK8BA50 3-Axis Accelerometer driver");
MODULE_LICENSE("GPL v2");