286 строки
6.6 KiB
C
286 строки
6.6 KiB
C
/**
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* Freescale MMA7660FC 3-Axis Accelerometer
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*
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* Copyright (c) 2016, Intel Corporation.
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*
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* This file is subject to the terms and conditions of version 2 of
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* the GNU General Public License. See the file COPYING in the main
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* directory of this archive for more details.
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*
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* IIO driver for Freescale MMA7660FC; 7-bit I2C address: 0x4c.
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*/
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#include <linux/acpi.h>
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#include <linux/i2c.h>
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#include <linux/module.h>
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#include <linux/iio/iio.h>
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#include <linux/iio/sysfs.h>
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#define MMA7660_DRIVER_NAME "mma7660"
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#define MMA7660_REG_XOUT 0x00
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#define MMA7660_REG_YOUT 0x01
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#define MMA7660_REG_ZOUT 0x02
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#define MMA7660_REG_OUT_BIT_ALERT BIT(6)
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#define MMA7660_REG_MODE 0x07
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#define MMA7660_REG_MODE_BIT_MODE BIT(0)
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#define MMA7660_REG_MODE_BIT_TON BIT(2)
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#define MMA7660_I2C_READ_RETRIES 5
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/*
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* The accelerometer has one measurement range:
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*
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* -1.5g - +1.5g (6-bit, signed)
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*
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* scale = (1.5 + 1.5) * 9.81 / (2^6 - 1) = 0.467142857
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*/
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#define MMA7660_SCALE_AVAIL "0.467142857"
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static const int mma7660_nscale = 467142857;
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#define MMA7660_CHANNEL(reg, axis) { \
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.type = IIO_ACCEL, \
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.address = reg, \
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.modified = 1, \
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.channel2 = IIO_MOD_##axis, \
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.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
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.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
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}
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static const struct iio_chan_spec mma7660_channels[] = {
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MMA7660_CHANNEL(MMA7660_REG_XOUT, X),
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MMA7660_CHANNEL(MMA7660_REG_YOUT, Y),
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MMA7660_CHANNEL(MMA7660_REG_ZOUT, Z),
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};
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enum mma7660_mode {
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MMA7660_MODE_STANDBY,
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MMA7660_MODE_ACTIVE
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};
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struct mma7660_data {
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struct i2c_client *client;
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struct mutex lock;
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enum mma7660_mode mode;
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};
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static IIO_CONST_ATTR(in_accel_scale_available, MMA7660_SCALE_AVAIL);
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static struct attribute *mma7660_attributes[] = {
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&iio_const_attr_in_accel_scale_available.dev_attr.attr,
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NULL,
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};
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static const struct attribute_group mma7660_attribute_group = {
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.attrs = mma7660_attributes
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};
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static int mma7660_set_mode(struct mma7660_data *data,
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enum mma7660_mode mode)
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{
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int ret;
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struct i2c_client *client = data->client;
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if (mode == data->mode)
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return 0;
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ret = i2c_smbus_read_byte_data(client, MMA7660_REG_MODE);
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if (ret < 0) {
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dev_err(&client->dev, "failed to read sensor mode\n");
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return ret;
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}
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if (mode == MMA7660_MODE_ACTIVE) {
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ret &= ~MMA7660_REG_MODE_BIT_TON;
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ret |= MMA7660_REG_MODE_BIT_MODE;
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} else {
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ret &= ~MMA7660_REG_MODE_BIT_TON;
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ret &= ~MMA7660_REG_MODE_BIT_MODE;
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}
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ret = i2c_smbus_write_byte_data(client, MMA7660_REG_MODE, ret);
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if (ret < 0) {
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dev_err(&client->dev, "failed to change sensor mode\n");
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return ret;
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}
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data->mode = mode;
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return ret;
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}
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static int mma7660_read_accel(struct mma7660_data *data, u8 address)
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{
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int ret, retries = MMA7660_I2C_READ_RETRIES;
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struct i2c_client *client = data->client;
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/*
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* Read data. If the Alert bit is set, the register was read at
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* the same time as the device was attempting to update the content.
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* The solution is to read the register again. Do this only
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* MMA7660_I2C_READ_RETRIES times to avoid spending too much time
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* in the kernel.
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*/
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do {
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ret = i2c_smbus_read_byte_data(client, address);
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if (ret < 0) {
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dev_err(&client->dev, "register read failed\n");
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return ret;
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}
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} while (retries-- > 0 && ret & MMA7660_REG_OUT_BIT_ALERT);
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if (ret & MMA7660_REG_OUT_BIT_ALERT) {
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dev_err(&client->dev, "all register read retries failed\n");
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return -ETIMEDOUT;
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}
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return ret;
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}
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static int mma7660_read_raw(struct iio_dev *indio_dev,
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struct iio_chan_spec const *chan,
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int *val, int *val2, long mask)
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{
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struct mma7660_data *data = iio_priv(indio_dev);
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int ret;
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switch (mask) {
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case IIO_CHAN_INFO_RAW:
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mutex_lock(&data->lock);
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ret = mma7660_read_accel(data, chan->address);
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mutex_unlock(&data->lock);
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if (ret < 0)
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return ret;
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*val = sign_extend32(ret, 5);
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return IIO_VAL_INT;
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case IIO_CHAN_INFO_SCALE:
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*val = 0;
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*val2 = mma7660_nscale;
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return IIO_VAL_INT_PLUS_NANO;
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default:
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return -EINVAL;
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}
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return -EINVAL;
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}
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static const struct iio_info mma7660_info = {
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.driver_module = THIS_MODULE,
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.read_raw = mma7660_read_raw,
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.attrs = &mma7660_attribute_group,
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};
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static int mma7660_probe(struct i2c_client *client,
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const struct i2c_device_id *id)
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{
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int ret;
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struct iio_dev *indio_dev;
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struct mma7660_data *data;
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indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
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if (!indio_dev) {
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dev_err(&client->dev, "iio allocation failed!\n");
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return -ENOMEM;
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}
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data = iio_priv(indio_dev);
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data->client = client;
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i2c_set_clientdata(client, indio_dev);
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mutex_init(&data->lock);
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data->mode = MMA7660_MODE_STANDBY;
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indio_dev->dev.parent = &client->dev;
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indio_dev->info = &mma7660_info;
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indio_dev->name = MMA7660_DRIVER_NAME;
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indio_dev->modes = INDIO_DIRECT_MODE;
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indio_dev->channels = mma7660_channels;
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indio_dev->num_channels = ARRAY_SIZE(mma7660_channels);
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ret = mma7660_set_mode(data, MMA7660_MODE_ACTIVE);
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if (ret < 0)
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return ret;
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ret = iio_device_register(indio_dev);
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if (ret < 0) {
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dev_err(&client->dev, "device_register failed\n");
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mma7660_set_mode(data, MMA7660_MODE_STANDBY);
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}
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return ret;
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}
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static int mma7660_remove(struct i2c_client *client)
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{
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struct iio_dev *indio_dev = i2c_get_clientdata(client);
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iio_device_unregister(indio_dev);
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return mma7660_set_mode(iio_priv(indio_dev), MMA7660_MODE_STANDBY);
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}
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#ifdef CONFIG_PM_SLEEP
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static int mma7660_suspend(struct device *dev)
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{
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struct mma7660_data *data;
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data = iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
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return mma7660_set_mode(data, MMA7660_MODE_STANDBY);
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}
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static int mma7660_resume(struct device *dev)
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{
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struct mma7660_data *data;
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data = iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
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return mma7660_set_mode(data, MMA7660_MODE_ACTIVE);
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}
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static SIMPLE_DEV_PM_OPS(mma7660_pm_ops, mma7660_suspend, mma7660_resume);
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#define MMA7660_PM_OPS (&mma7660_pm_ops)
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#else
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#define MMA7660_PM_OPS NULL
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#endif
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static const struct i2c_device_id mma7660_i2c_id[] = {
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{"mma7660", 0},
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{}
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};
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MODULE_DEVICE_TABLE(i2c, mma7660_i2c_id);
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static const struct of_device_id mma7660_of_match[] = {
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{ .compatible = "fsl,mma7660" },
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{ }
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};
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MODULE_DEVICE_TABLE(of, mma7660_of_match);
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static const struct acpi_device_id mma7660_acpi_id[] = {
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{"MMA7660", 0},
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{}
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};
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MODULE_DEVICE_TABLE(acpi, mma7660_acpi_id);
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static struct i2c_driver mma7660_driver = {
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.driver = {
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.name = "mma7660",
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.pm = MMA7660_PM_OPS,
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.of_match_table = mma7660_of_match,
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.acpi_match_table = ACPI_PTR(mma7660_acpi_id),
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},
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.probe = mma7660_probe,
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.remove = mma7660_remove,
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.id_table = mma7660_i2c_id,
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};
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module_i2c_driver(mma7660_driver);
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MODULE_AUTHOR("Constantin Musca <constantin.musca@intel.com>");
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MODULE_DESCRIPTION("Freescale MMA7660FC 3-Axis Accelerometer driver");
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MODULE_LICENSE("GPL v2");
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