This is a note to let you know that I've just added the patch titled
iio: imu: fxos8700: fix IMU data bits returned to user space
to my char-misc git tree which can be found at git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git in the char-misc-linus branch.
The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)
The patch will hopefully also be merged in Linus's tree for the next -rc kernel release.
If you have any questions about this process, please let me know.
From a53f945879c0cb9de3a4c05a665f5157884b5208 Mon Sep 17 00:00:00 2001 From: Carlos Song carlos.song@nxp.com Date: Thu, 8 Dec 2022 15:19:08 +0800 Subject: iio: imu: fxos8700: fix IMU data bits returned to user space
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 --- drivers/iio/imu/fxos8700_core.c | 28 +++++++++++++++++++++++++++- 1 file changed, 27 insertions(+), 1 deletion(-)
diff --git a/drivers/iio/imu/fxos8700_core.c b/drivers/iio/imu/fxos8700_core.c index b62bc92bbacc..06948a8cc315 100644 --- a/drivers/iio/imu/fxos8700_core.c +++ b/drivers/iio/imu/fxos8700_core.c @@ -394,6 +394,7 @@ static int fxos8700_get_data(struct fxos8700_data *data, int chan_type, int axis, int *val) { u8 base, reg; + s16 tmp; int ret;
/* @@ -421,8 +422,33 @@ 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; }