[PATCH 5.15 105/135] iio: afe: rescale: Fix boolean logic bug

Greg Kroah-Hartman
2022-06-27T11:43:40Z

From: Linus Walleij <linus.walleij@linaro.org>

commit 9decacd8b3a432316d61c4366f302e63384cb08d upstream.

When introducing support for processed channels I needed
to invert the expression:

if (!iio_channel_has_info(schan, IIO_CHAN_INFO_RAW) ||
!iio_channel_has_info(schan, IIO_CHAN_INFO_SCALE))
dev_err(dev, "source channel does not support raw/scale\n");

To the inverse, meaning detect when we can usse raw+scale
rather than when we can not. This was the result:

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");

Ooops. Spot the error. Yep old George Boole came up and bit me.
That should be an &&.

The current code "mostly works" because we have not run into
systems supporting only raw but not scale or only scale but not
raw, and I doubt there are few using the rescaler on anything
such, but let's fix the logic.

Cc: Liam Beguin <liambeguin@gmail.com>
Cc: stable@vger.kernel.org
Fixes: 53ebee949980 ("iio: afe: iio-rescale: Support processed channels")
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Liam Beguin <liambeguin@gmail.com>
Acked-by: Peter Rosin <peda@axentia.se>
Link: https://lore.kernel.org/r/20220524075448.140238-1-linus.walleij@linaro.org
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/iio/afe/iio-rescale.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/iio/afe/iio-rescale.c
+++ b/drivers/iio/afe/iio-rescale.c
@@ -148,7 +148,7 @@ static int rescale_configure_channel(str
chan->ext_info = rescale->ext_info;
chan->type = rescale->cfg->type;

- if (iio_channel_has_info(schan, IIO_CHAN_INFO_RAW) ||
+ 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");
} else if (iio_channel_has_info(schan, IIO_CHAN_INFO_PROCESSED)) {