Re: [PATCH] iio: afe: rescale: Fix logic bug

[Jonathan Cameron <jic23@kernel.org>]

On Wed, 25 May 2022 21:29:27 -0400
Liam Beguin <liambeguin@gmail.com> wrote:

> On Tue, May 24, 2022 at 09:54:48AM +0200, Linus Walleij wrote:
> > 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.  
> 
> Maybe `iio: afe: rescale: Fix boolean logic bug` if you're resending,
> otherwise,

Makes sense - I tweaked that whilst applying.

Applied to the fixes-togreg branch of iio.git.

Thanks,

Jonathan

> 
> Reviewed-by: Liam Beguin <liambeguin@gmail.com>
> 
> Thanks,
> Liam
> 
> > 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>
> > ---
> >  drivers/iio/afe/iio-rescale.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/drivers/iio/afe/iio-rescale.c b/drivers/iio/afe/iio-rescale.c
> > index 7e511293d6d1..dc426e1484f0 100644
> > --- a/drivers/iio/afe/iio-rescale.c
> > +++ b/drivers/iio/afe/iio-rescale.c
> > @@ -278,7 +278,7 @@ static int rescale_configure_channel(struct device *dev,
> >  	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)) {
> > -- 
> > 2.35.3
> >