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@xxxxxxx>
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@xxxxxxx>
Link: https://lore.kernel.org/r/20221208071911.2405922-5-carlos.song@xxxxxxx
Cc: <Stable@xxxxxxxxxxxxxxx>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
---
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;
}
--
2.39.1
