6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Matti Vaittinen mazziesaccount@gmail.com
commit b7d2bc99b3bdc03fff9b416dd830632346d83530 upstream.
The KX022A provides the accelerometer data in two subsequent registers. The registers are laid out so that the value obtained via bulk-read of these registers can be interpreted as signed 16-bit little endian value. The read value is converted to cpu_endianes and stored into 32bit integer. The le16_to_cpu() casts value to unsigned 16-bit value, and when this is assigned to 32-bit integer the resulting value will always be positive.
This has not been a problem to users (at least not all users) of the sysfs interface, who know the data format based on the scan info and who have converted the read value back to 16-bit signed value. This isn't compliant with the ABI however.
This, however, will be a problem for those who use the in-kernel interfaces, especially the iio_read_channel_processed_scale().
The iio_read_channel_processed_scale() performs multiplications to the returned (always positive) raw value, which will cause strange results when the data from the sensor has been negative.
Fix the read_raw format by casting the result of the le_to_cpu() to signed 16-bit value before assigning it to the integer. This will make the negative readings to be correctly reported as negative.
This fix will be visible to users by changing values returned via sysfs to appear in correct (negative) format.
Reported-by: Kalle Niemi kaleposti@gmail.com Fixes: 7c1d1677b322 ("iio: accel: Support Kionix/ROHM KX022A accelerometer") Signed-off-by: Matti Vaittinen mazziesaccount@gmail.com Tested-by: Kalle Niemi kaleposti@gmail.com Cc: Stable@vger.kernel.org Link: https://patch.msgid.link/ZyIxm_zamZfIGrnB@mva-rohm Signed-off-by: Jonathan Cameron Jonathan.Cameron@huawei.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/iio/accel/kionix-kx022a.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/iio/accel/kionix-kx022a.c +++ b/drivers/iio/accel/kionix-kx022a.c @@ -475,7 +475,7 @@ static int kx022a_get_axis(struct kx022a if (ret) return ret;
- *val = le16_to_cpu(data->buffer[0]); + *val = (s16)le16_to_cpu(data->buffer[0]);
return IIO_VAL_INT; }