Hi! Sorry for the delay, and thank you Jonathan for the reminder. 2023-09-02 at 21:46, 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. > > When a user asks for IIO_CHAN_INFO_OFFSET in rescale_read_raw() > we now have to deal with the fact that OFFSET could be present > but SCALE missing. Add code to simply scale 1:1 in this case. > > 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> > --- > Changes in v2: > - Fix rescale_read_raw() handle channels with offset but no scale. > - Link to v1: https://lore.kernel.org/r/20230830-iio-rescale-only-offset-v1-1-40ab9f4436c7@xxxxxxxxxx > --- > drivers/iio/afe/iio-rescale.c | 19 +++++++++++++++---- > 1 file changed, 15 insertions(+), 4 deletions(-) > > diff --git a/drivers/iio/afe/iio-rescale.c b/drivers/iio/afe/iio-rescale.c > index 1f280c360701..56e5913ab82d 100644 > --- a/drivers/iio/afe/iio-rescale.c > +++ b/drivers/iio/afe/iio-rescale.c > @@ -214,8 +214,18 @@ static int rescale_read_raw(struct iio_dev *indio_dev, > return ret < 0 ? ret : -EOPNOTSUPP; > } > > - ret = iio_read_channel_scale(rescale->source, &scale, &scale2); > - return rescale_process_offset(rescale, ret, scale, scale2, > + if (iio_channel_has_info(rescale->source->channel, > + IIO_CHAN_INFO_SCALE)) { > + ret = iio_read_channel_scale(rescale->source, &scale, &scale2); > + return rescale_process_offset(rescale, ret, scale, scale2, > + schan_off, val, val2); > + } > + > + /* > + * If we get here we have no scale so scale 1:1 but apply > + * rescaler and offset, if any. > + */ > + return rescale_process_offset(rescale, IIO_VAL_FRACTIONAL, 1, 1, > schan_off, val, val2); > default: > return -EINVAL; > @@ -280,8 +290,9 @@ 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"); If the rules really are that when not provided scale is 1 and offset 0 (reasonable of course) then the above still looks suspect to me. Should this part not simply be if (iio_channel_has_info(schan, IIO_CHAN_INFO_RAW)) { dev_info(dev, "using raw source channel\n"); in that case? Or was "raw + processed" some kind of special case that we want to handle as processed? If that's the case then we need to have more complex logic. 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,
