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iio: imu: fxos8700: fix IMU data bits returned to user space

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commit a53f945879c0cb9de3a4c05a665f5157884b5208 upstream.

ACCEL output data registers contain the X-axis, Y-axis, and Z-axis
14-bit left-justified sample data and MAGN output data registers
contain the X-axis, Y-axis, and Z-axis 16-bit sample data. The ACCEL
raw register output data should be divided by 4 before sent to
userspace.

Apply a 2 bits signed right shift to the raw data from ACCEL output
data register but keep that from MAGN sensor as the origin.

Fixes: 84e5ddd5c46e ("iio: imu: Add support for the FXOS8700 IMU")
Signed-off-by: Carlos Song <carlos.song@nxp.com>
Link: https://lore.kernel.org/r/20221208071911.2405922-5-carlos.song@nxp.com
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Carlos Song 2022-12-08 15:19:08 +08:00 committed by Greg Kroah-Hartman
parent 6d43eddc56
commit 9545ce720a
1 changed files with 27 additions and 1 deletions
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28
drivers/iio/imu/fxos8700_core.c
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@ -418,6 +418,7 @@ static int fxos8700_get_data(struct fxos8700_data *data, int chan_type,
int axis, int *val)
{
u8 base, reg;
s16 tmp;
int ret;
enum fxos8700_sensor type = fxos8700_to_sensor(chan_type);
@ -432,8 +433,33 @@ static int fxos8700_get_data(struct fxos8700_data *data, int chan_type,
/* Convert axis to buffer index */
reg = axis - IIO_MOD_X;
/*
* Convert to native endianness. The accel data and magn data
* are signed, so a forced type conversion is needed.
*/
tmp = be16_to_cpu(data->buf[reg]);
/*
* ACCEL output data registers contain the X-axis, Y-axis, and Z-axis
* 14-bit left-justified sample data and MAGN output data registers
* contain the X-axis, Y-axis, and Z-axis 16-bit sample data. Apply
* a signed 2 bits right shift to the readback raw data from ACCEL
* output data register and keep that from MAGN sensor as the origin.
* Value should be extended to 32 bit.
*/
switch (chan_type) {
case IIO_ACCEL:
tmp = tmp >> 2;
break;
case IIO_MAGN:
/* Nothing to do */
break;
default:
return -EINVAL;
}
/* Convert to native endianness */
*val = sign_extend32(be16_to_cpu(data->buf[reg]), 15);
*val = sign_extend32(tmp, 15);
return 0;
}