[PATCH] iio: afe: rescale: Accept only offset channels

[Linus Walleij]

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");
 	} 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,
-- 
Linus Walleij <linus.walleij@xxxxxxxxxx>