- 根目录:
- drivers
- iio
- accel
- mma8452.c
/*
* mma8452.c - Support for Freescale MMA8452Q 3-axis 12-bit accelerometer
*
* Copyright 2014 Peter Meerwald <pmeerw@pmeerw.net>
*
* 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.
*
* 7-bit I2C slave address 0x1c/0x1d (pin selectable)
*
* TODO: interrupt, thresholding, orientation / freefall events, autosleep
*/
#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/iio/trigger_consumer.h>
#include <linux/iio/buffer.h>
#include <linux/iio/triggered_buffer.h>
#include <linux/delay.h>
#define MMA8452_STATUS 0x00
#define MMA8452_OUT_X 0x01 /* MSB first, 12-bit */
#define MMA8452_OUT_Y 0x03
#define MMA8452_OUT_Z 0x05
#define MMA8452_WHO_AM_I 0x0d
#define MMA8452_DATA_CFG 0x0e
#define MMA8452_OFF_X 0x2f
#define MMA8452_OFF_Y 0x30
#define MMA8452_OFF_Z 0x31
#define MMA8452_CTRL_REG1 0x2a
#define MMA8452_CTRL_REG2 0x2b
#define MMA8452_STATUS_DRDY (BIT(2) | BIT(1) | BIT(0))
#define MMA8452_CTRL_DR_MASK (BIT(5) | BIT(4) | BIT(3))
#define MMA8452_CTRL_DR_SHIFT 3
#define MMA8452_CTRL_DR_DEFAULT 0x4 /* 50 Hz sample frequency */
#define MMA8452_CTRL_ACTIVE BIT(0)
#define MMA8452_DATA_CFG_FS_MASK (BIT(1) | BIT(0))
#define MMA8452_DATA_CFG_FS_2G 0
#define MMA8452_DATA_CFG_FS_4G 1
#define MMA8452_DATA_CFG_FS_8G 2
#define MMA8452_DEVICE_ID 0x2a
struct mma8452_data {
struct i2c_client *client;
struct mutex lock;
u8 ctrl_reg1;
u8 data_cfg;
};
static int mma8452_drdy(struct mma8452_data *data)
{
int tries = 150;
while (tries-- > 0) {
int ret = i2c_smbus_read_byte_data(data->client,
MMA8452_STATUS);
if (ret < 0)
return ret;
if ((ret & MMA8452_STATUS_DRDY) == MMA8452_STATUS_DRDY)
return 0;
msleep(20);
}
dev_err(&data->client->dev, "data not ready\n");
return -EIO;
}
static int mma8452_read(struct mma8452_data *data, __be16 buf[3])
{
int ret = mma8452_drdy(data);
if (ret < 0)
return ret;
return i2c_smbus_read_i2c_block_data(data->client,
MMA8452_OUT_X, 3 * sizeof(__be16), (u8 *) buf);
}
static ssize_t mma8452_show_int_plus_micros(char *buf,
const int (*vals)[2], int n)
{
size_t len = 0;
while (n-- > 0)
len += scnprintf(buf + len, PAGE_SIZE - len,
"%d.%06d ", vals[n][0], vals[n][1]);
/* replace trailing space by newline */
buf[len - 1] = '\n';
return len;
}
static int mma8452_get_int_plus_micros_index(const int (*vals)[2], int n,
int val, int val2)
{
while (n-- > 0)
if (val == vals[n][0] && val2 == vals[n][1])
return n;
return -EINVAL;
}
static const int mma8452_samp_freq[8][2] = {
{800, 0}, {400, 0}, {200, 0}, {100, 0}, {50, 0}, {12, 500000},
{6, 250000}, {1, 560000}
};
/*
* Hardware has fullscale of -2G, -4G, -8G corresponding to raw value -2048
* The userspace interface uses m/s^2 and we declare micro units
* So scale factor is given by:
* g * N * 1000000 / 2048 for N = 2, 4, 8 and g=9.80665
*/
static const int mma8452_scales[3][2] = {
{0, 9577}, {0, 19154}, {0, 38307}
};
static ssize_t mma8452_show_samp_freq_avail(struct device *dev,
struct device_attribute *attr, char *buf)
{
return mma8452_show_int_plus_micros(buf, mma8452_samp_freq,
ARRAY_SIZE(mma8452_samp_freq));
}
static ssize_t mma8452_show_scale_avail(struct device *dev,
struct device_attribute *attr, char *buf)
{
return mma8452_show_int_plus_micros(buf, mma8452_scales,
ARRAY_SIZE(mma8452_scales));
}
static IIO_DEV_ATTR_SAMP_FREQ_AVAIL(mma8452_show_samp_freq_avail);
static IIO_DEVICE_ATTR(in_accel_scale_available, S_IRUGO,
mma8452_show_scale_avail, NULL, 0);
static int mma8452_get_samp_freq_index(struct mma8452_data *data,
int val, int val2)
{
return mma8452_get_int_plus_micros_index(mma8452_samp_freq,
ARRAY_SIZE(mma8452_samp_freq), val, val2);
}
static int mma8452_get_scale_index(struct mma8452_data *data,
int val, int val2)
{
return mma8452_get_int_plus_micros_index(mma8452_scales,
ARRAY_SIZE(mma8452_scales), val, val2);
}
static int mma8452_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val, int *val2, long mask)
{
struct mma8452_data *data = iio_priv(indio_dev);
__be16 buffer[3];
int i, ret;
switch (mask) {
case IIO_CHAN_INFO_RAW:
if (iio_buffer_enabled(indio_dev))
return -EBUSY;
mutex_lock(&data->lock);
ret = mma8452_read(data, buffer);
mutex_unlock(&data->lock);
if (ret < 0)
return ret;
*val = sign_extend32(
be16_to_cpu(buffer[chan->scan_index]) >> 4, 11);
return IIO_VAL_INT;
case IIO_CHAN_INFO_SCALE:
i = data->data_cfg & MMA8452_DATA_CFG_FS_MASK;
*val = mma8452_scales[i][0];
*val2 = mma8452_scales[i][1];
return IIO_VAL_INT_PLUS_MICRO;
case IIO_CHAN_INFO_SAMP_FREQ:
i = (data->ctrl_reg1 & MMA8452_CTRL_DR_MASK) >>
MMA8452_CTRL_DR_SHIFT;
*val = mma8452_samp_freq[i][0];
*val2 = mma8452_samp_freq[i][1];
return IIO_VAL_INT_PLUS_MICRO;
case IIO_CHAN_INFO_CALIBBIAS:
ret = i2c_smbus_read_byte_data(data->client, MMA8452_OFF_X +
chan->scan_index);
if (ret < 0)
return ret;
*val = sign_extend32(ret, 7);
return IIO_VAL_INT;
}
return -EINVAL;
}
static int mma8452_standby(struct mma8452_data *data)
{
return i2c_smbus_write_byte_data(data->client, MMA8452_CTRL_REG1,
data->ctrl_reg1 & ~MMA8452_CTRL_ACTIVE);
}
static int mma8452_active(struct mma8452_data *data)
{
return i2c_smbus_write_byte_data(data->client, MMA8452_CTRL_REG1,
data->ctrl_reg1);
}
static int mma8452_change_config(struct mma8452_data *data, u8 reg, u8 val)
{
int ret;
mutex_lock(&data->lock);
/* config can only be changed when in standby */
ret = mma8452_standby(data);
if (ret < 0)
goto fail;
ret = i2c_smbus_write_byte_data(data->client, reg, val);
if (ret < 0)
goto fail;
ret = mma8452_active(data);
if (ret < 0)
goto fail;
ret = 0;
fail:
mutex_unlock(&data->lock);
return ret;
}
static int mma8452_write_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int val, int val2, long mask)
{
struct mma8452_data *data = iio_priv(indio_dev);
int i;
if (iio_buffer_enabled(indio_dev))
return -EBUSY;
switch (mask) {
case IIO_CHAN_INFO_SAMP_FREQ:
i = mma8452_get_samp_freq_index(data, val, val2);
if (i < 0)
return -EINVAL;
data->ctrl_reg1 &= ~MMA8452_CTRL_DR_MASK;
data->ctrl_reg1 |= i << MMA8452_CTRL_DR_SHIFT;
return mma8452_change_config(data, MMA8452_CTRL_REG1,
data->ctrl_reg1);
case IIO_CHAN_INFO_SCALE:
i = mma8452_get_scale_index(data, val, val2);
if (i < 0)
return -EINVAL;
data->data_cfg &= ~MMA8452_DATA_CFG_FS_MASK;
data->data_cfg |= i;
return mma8452_change_config(data, MMA8452_DATA_CFG,
data->data_cfg);
case IIO_CHAN_INFO_CALIBBIAS:
if (val < -128 || val > 127)
return -EINVAL;
return mma8452_change_config(data, MMA8452_OFF_X +
chan->scan_index, val);
default:
return -EINVAL;
}
}
static irqreturn_t mma8452_trigger_handler(int irq, void *p)
{
struct iio_poll_func *pf = p;
struct iio_dev *indio_dev = pf->indio_dev;
struct mma8452_data *data = iio_priv(indio_dev);
u8 buffer[16]; /* 3 16-bit channels + padding + ts */
int ret;
ret = mma8452_read(data, (__be16 *) buffer);
if (ret < 0)
goto done;
iio_push_to_buffers_with_timestamp(indio_dev, buffer,
iio_get_time_ns());
done:
iio_trigger_notify_done(indio_dev->trig);
return IRQ_HANDLED;
}
#define MMA8452_CHANNEL(axis, idx) { \
.type = IIO_ACCEL, \
.modified = 1, \
.channel2 = IIO_MOD_##axis, \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
BIT(IIO_CHAN_INFO_CALIBBIAS), \
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ) | \
BIT(IIO_CHAN_INFO_SCALE), \
.scan_index = idx, \
.scan_type = { \
.sign = 's', \
.realbits = 12, \
.storagebits = 16, \
.shift = 4, \
.endianness = IIO_BE, \
}, \
}
static const struct iio_chan_spec mma8452_channels[] = {
MMA8452_CHANNEL(X, 0),
MMA8452_CHANNEL(Y, 1),
MMA8452_CHANNEL(Z, 2),
IIO_CHAN_SOFT_TIMESTAMP(3),
};
static struct attribute *mma8452_attributes[] = {
&iio_dev_attr_sampling_frequency_available.dev_attr.attr,
&iio_dev_attr_in_accel_scale_available.dev_attr.attr,
NULL
};
static const struct attribute_group mma8452_group = {
.attrs = mma8452_attributes,
};
static const struct iio_info mma8452_info = {
.attrs = &mma8452_group,
.read_raw = &mma8452_read_raw,
.write_raw = &mma8452_write_raw,
.driver_module = THIS_MODULE,
};
static const unsigned long mma8452_scan_masks[] = {0x7, 0};
static int mma8452_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct mma8452_data *data;
struct iio_dev *indio_dev;
int ret;
ret = i2c_smbus_read_byte_data(client, MMA8452_WHO_AM_I);
if (ret < 0)
return ret;
if (ret != MMA8452_DEVICE_ID)
return -ENODEV;
indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
if (!indio_dev)
return -ENOMEM;
data = iio_priv(indio_dev);
data->client = client;
mutex_init(&data->lock);
i2c_set_clientdata(client, indio_dev);
indio_dev->info = &mma8452_info;
indio_dev->name = id->name;
indio_dev->dev.parent = &client->dev;
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->channels = mma8452_channels;
indio_dev->num_channels = ARRAY_SIZE(mma8452_channels);
indio_dev->available_scan_masks = mma8452_scan_masks;
data->ctrl_reg1 = MMA8452_CTRL_ACTIVE |
(MMA8452_CTRL_DR_DEFAULT << MMA8452_CTRL_DR_SHIFT);
ret = i2c_smbus_write_byte_data(client, MMA8452_CTRL_REG1,
data->ctrl_reg1);
if (ret < 0)
return ret;
data->data_cfg = MMA8452_DATA_CFG_FS_2G;
ret = i2c_smbus_write_byte_data(client, MMA8452_DATA_CFG,
data->data_cfg);
if (ret < 0)
return ret;
ret = iio_triggered_buffer_setup(indio_dev, NULL,
mma8452_trigger_handler, NULL);
if (ret < 0)
return ret;
ret = iio_device_register(indio_dev);
if (ret < 0)
goto buffer_cleanup;
return 0;
buffer_cleanup:
iio_triggered_buffer_cleanup(indio_dev);
return ret;
}
static int mma8452_remove(struct i2c_client *client)
{
struct iio_dev *indio_dev = i2c_get_clientdata(client);
iio_device_unregister(indio_dev);
iio_triggered_buffer_cleanup(indio_dev);
mma8452_standby(iio_priv(indio_dev));
return 0;
}
#ifdef CONFIG_PM_SLEEP
static int mma8452_suspend(struct device *dev)
{
return mma8452_standby(iio_priv(i2c_get_clientdata(
to_i2c_client(dev))));
}
static int mma8452_resume(struct device *dev)
{
return mma8452_active(iio_priv(i2c_get_clientdata(
to_i2c_client(dev))));
}
static SIMPLE_DEV_PM_OPS(mma8452_pm_ops, mma8452_suspend, mma8452_resume);
#define MMA8452_PM_OPS (&mma8452_pm_ops)
#else
#define MMA8452_PM_OPS NULL
#endif
static const struct i2c_device_id mma8452_id[] = {
{ "mma8452", 0 },
{ }
};
MODULE_DEVICE_TABLE(i2c, mma8452_id);
static const struct of_device_id mma8452_dt_ids[] = {
{ .compatible = "fsl,mma8452" },
{ }
};
static struct i2c_driver mma8452_driver = {
.driver = {
.name = "mma8452",
.of_match_table = of_match_ptr(mma8452_dt_ids),
.pm = MMA8452_PM_OPS,
},
.probe = mma8452_probe,
.remove = mma8452_remove,
.id_table = mma8452_id,
};
module_i2c_driver(mma8452_driver);
MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
MODULE_DESCRIPTION("Freescale MMA8452 accelerometer driver");
MODULE_LICENSE("GPL");