Hi! 2023-08-30 at 10:52, Linus Walleij wrote: > As noted by Jonathan Cameron: it is perfectly legal for a channel > to have an offset but no scale in addition to the raw interface. > The conversion will imply that scale is 1:1. > > Make rescale_configure_channel() accept just scale, or just offset > to process a channel. > > The code to handle channels with just offset is already there. > > Link: https://lore.kernel.org/linux-iio/CACRpkdZXBjHU4t-GVOCFxRO-AHGxKnxMeHD2s4Y4PuC29gBq6g@xxxxxxxxxxxxxx/ > Fixes: 53ebee949980 ("iio: afe: iio-rescale: Support processed channels") > Fixes: 9decacd8b3a4 ("iio: afe: rescale: Fix boolean logic bug") > Reported-by: Jonathan Cameron <jic23@xxxxxxxxxx> > Signed-off-by: Linus Walleij <linus.walleij@xxxxxxxxxx> > --- > drivers/iio/afe/iio-rescale.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/drivers/iio/afe/iio-rescale.c b/drivers/iio/afe/iio-rescale.c > index 1f280c360701..18aafb4bdda0 100644 > --- a/drivers/iio/afe/iio-rescale.c > +++ b/drivers/iio/afe/iio-rescale.c > @@ -280,8 +280,9 @@ static int rescale_configure_channel(struct device *dev, > chan->type = rescale->cfg->type; > > if (iio_channel_has_info(schan, IIO_CHAN_INFO_RAW) && > - iio_channel_has_info(schan, IIO_CHAN_INFO_SCALE)) { > - dev_info(dev, "using raw+scale source channel\n"); > + (iio_channel_has_info(schan, IIO_CHAN_INFO_SCALE) || > + iio_channel_has_info(schan, IIO_CHAN_INFO_OFFSET))) { > + dev_info(dev, "using raw+scale/offset source channel\n"); I do not think it's that simple. The rescale_read_raw function, when asked for IIO_CHAN_INFO_OFFSET, must know the scale of the source channel in order to rescale the offset. After this patch, trying to get the rescaled scale/offset when the source channel has an offset but lacks a scale will simply return -EOPNOTSUPP. Which is not what you intended, I think? Cheers, Peter > } else if (iio_channel_has_info(schan, IIO_CHAN_INFO_PROCESSED)) { > dev_info(dev, "using processed channel\n"); > rescale->chan_processed = true; > > --- > base-commit: 2dde18cd1d8fac735875f2e4987f11817cc0bc2c > change-id: 20230830-iio-rescale-only-offset-f28e05bd2deb > > Best regards,
