Re: [PATCH] iio: adc: ad7476: fix clang -Wpointer-bool-conversion warning

From: Nick Desaulniers <ndesaulniers@google.com>
To: Arnd Bergmann <arnd@arndb.de>
Cc: Lars-Peter Clausen <lars@metafoo.de>,
	Michael Hennerich <Michael.Hennerich@analog.com>,
	Jonathan Cameron <jic23@kernel.org>,
	Dragos Bogdan <dragos.bogdan@analog.com>,
	Beniamin Bia <beniamin.bia@analog.com>,
	Jonathan Cameron <Jonathan.Cameron@huawei.com>,
	Hartmut Knaack <knaack.h@gmx.de>,
	Peter Meerwald-Stadler <pmeerw@pmeerw.net>,
	linux-iio@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>,
	clang-built-linux <clang-built-linux@googlegroups.com>
Subject: Re: [PATCH] iio: adc: ad7476: fix clang -Wpointer-bool-conversion warning
Date: Fri, 8 May 2020 11:20:56 -0700	[thread overview]
Message-ID: <CAKwvOdmQ8pzxGdNEJ=eG+rRFK1J4Xg6738dYvdZSqf0u0gtscw@mail.gmail.com> (raw)
In-Reply-To: <20200505142408.1113763-1-arnd@arndb.de>

On Tue, May 5, 2020 at 7:24 AM Arnd Bergmann <arnd@arndb.de> wrote:
>
> Checking the pointer value of st->chip_info->convst_channel is pointless
> since this this an array inside of a struct: even if st->chip_info is NULL,
> the pointer is non-zero. Clang warns about this:
>
> drivers/iio/adc/ad7476.c:312:40: warning: address of array 'st->chip_info->convst_channel' will always evaluate to 'true' [-Wpointer-bool-conversion]
>         if (st->convst_gpio && st->chip_info->convst_channel)
>                             ~~ ~~~~~~~~~~~~~~~^~~~~~~~~~~~~~
>
> I could not come up with a sane way to check whether the entry
> is valid, so just remove the check and keep the behavior as it
> is today but without the warning.

Me too. Thanks for the patch.
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>

>
> Fixes: 3a6af93dd66e ("iio: adc: ad7476: Add IIO_CHAN_INFO_RAW for AD7091R")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
>  drivers/iio/adc/ad7476.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/iio/adc/ad7476.c b/drivers/iio/adc/ad7476.c
> index e9984a38fc4c..4e816d714ad2 100644
> --- a/drivers/iio/adc/ad7476.c
> +++ b/drivers/iio/adc/ad7476.c
> @@ -309,7 +309,7 @@ static int ad7476_probe(struct spi_device *spi)
>         indio_dev->num_channels = 2;
>         indio_dev->info = &ad7476_info;
>
> -       if (st->convst_gpio && st->chip_info->convst_channel)
> +       if (st->convst_gpio)
>                 indio_dev->channels = st->chip_info->convst_channel;
>         /* Setup default message */
>
> --
> 2.26.0
>
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-- 
Thanks,
~Nick Desaulniers