This is a note to let you know that I've just added the patch titled

iio: inkern: make a best effort on offset calculation

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-testing 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 be merged to the char-misc-next branch sometime soon, after it passes testing, and the merge window is open.

If you have any questions about this process, please let me know.

From ca85123354e1a65a22170286387b4791997fe864 Mon Sep 17 00:00:00 2001 From: Liam Beguin liambeguin@gmail.com Date: Sat, 8 Jan 2022 15:53:06 -0500 Subject: iio: inkern: make a best effort on offset calculation

iio_convert_raw_to_processed_unlocked() assumes the offset is an integer. Make a best effort to get a valid offset value for fractional cases without breaking implicit truncations.

Fixes: 48e44ce0f881 ("iio:inkern: Add function to read the processed value") Signed-off-by: Liam Beguin liambeguin@gmail.com Reviewed-by: Peter Rosin peda@axentia.se Reviewed-by: Andy Shevchenko andy.shevchenko@gmail.com Link: https://lore.kernel.org/r/20220108205319.2046348-4-liambeguin@gmail.com Cc: Stable@vger.kernel.org Signed-off-by: Jonathan Cameron Jonathan.Cameron@huawei.com --- drivers/iio/inkern.c | 32 +++++++++++++++++++++++++++----- 1 file changed, 27 insertions(+), 5 deletions(-)

diff --git a/drivers/iio/inkern.c b/drivers/iio/inkern.c index dbe13fad3cbb..df74765d33dc 100644 --- a/drivers/iio/inkern.c +++ b/drivers/iio/inkern.c @@ -595,13 +595,35 @@ EXPORT_SYMBOL_GPL(iio_read_channel_average_raw); static int iio_convert_raw_to_processed_unlocked(struct iio_channel *chan, int raw, int *processed, unsigned int scale) { - int scale_type, scale_val, scale_val2, offset; + int scale_type, scale_val, scale_val2; + int offset_type, offset_val, offset_val2; s64 raw64 = raw; - int ret;

- ret = iio_channel_read(chan, &offset, NULL, IIO_CHAN_INFO_OFFSET); - if (ret >= 0) - raw64 += offset; + offset_type = iio_channel_read(chan, &offset_val, &offset_val2, + IIO_CHAN_INFO_OFFSET); + if (offset_type >= 0) { + switch (offset_type) { + case IIO_VAL_INT: + break; + case IIO_VAL_INT_PLUS_MICRO: + case IIO_VAL_INT_PLUS_NANO: + /* + * Both IIO_VAL_INT_PLUS_MICRO and IIO_VAL_INT_PLUS_NANO + * implicitely truncate the offset to it's integer form. + */ + break; + case IIO_VAL_FRACTIONAL: + offset_val /= offset_val2; + break; + case IIO_VAL_FRACTIONAL_LOG2: + offset_val >>= offset_val2; + break; + default: + return -EINVAL; + } + + raw64 += offset_val; + }

scale_type = iio_channel_read(chan, &scale_val, &scale_val2, IIO_CHAN_INFO_SCALE);