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Date:   Mon, 11 Jul 2022 15:16:11 -0700
From:   Jakub Kicinski <kubakici@wp.pl>
To:     Justin Stitt <justinstitt@google.com>
Cc:     Kalle Valo <kvalo@kernel.org>,
        "David S . Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Paolo Abeni <pabeni@redhat.com>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        Nathan Chancellor <nathan@kernel.org>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Tom Rix <trix@redhat.com>, linux-wireless@vger.kernel.org,
        netdev@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-mediatek@lists.infradead.org, linux-kernel@vger.kernel.org,
        llvm@lists.linux.dev
Subject: Re: [PATCH] mediatek: mt7601u: fix clang -Wformat warning
Message-ID: <20220711151611.573190f5@kicinski-fedora-PC1C0HJN>
In-Reply-To: <20220711212932.1501592-1-justinstitt@google.com>
References: <20220711212932.1501592-1-justinstitt@google.com>
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On Mon, 11 Jul 2022 14:29:32 -0700 Justin Stitt wrote:
> When building with Clang we encounter this warning:
> | drivers/net/wireless/mediatek/mt7601u/debugfs.c:92:6: error: format
> | specifies type 'unsigned char' but the argument has type 'int'
> | [-Werror,-Wformat] dev->ee->reg.start + dev->ee->reg.num - 1);
> 
> The format specifier used is `%hhu` which describes a u8. Both
> `dev->ee->reg.start` and `.num` are u8 as well. However, the expression
> as a whole is promoted to an int as you cannot get smaller-than-int from
> addition. Therefore, to fix the warning, use the promoted-to-type's
> format specifier -- in this case `%d`.

Acked-by: Jakub Kicinski <kubakici@wp.pl>