[PATCH v7 1/3] phy: mediatek: remove temporary variable @mask_

From: Chunfeng Yun <chunfeng.yun@mediatek.com>
To: Vinod Koul <vkoul@kernel.org>
Cc: Chunfeng Yun <chunfeng.yun@mediatek.com>,
	Kishon Vijay Abraham I <kishon@kernel.org>,
	Matthias Brugger <matthias.bgg@gmail.com>,
	Nathan Chancellor <nathan@kernel.org>,
	Nick Desaulniers <ndesaulniers@google.com>,
	Tom Rix <trix@redhat.com>,
	AngeloGioacchino Del Regno
	<angelogioacchino.delregno@collabora.com>,
	<linux-arm-kernel@lists.infradead.org>,
	<linux-mediatek@lists.infradead.org>,
	<linux-phy@lists.infradead.org>, <linux-kernel@vger.kernel.org>,
	<llvm@lists.linux.dev>, Eddie Hung <eddie.hung@mediatek.com>,
	kernel test robot <lkp@intel.com>
Subject: [PATCH v7 1/3] phy: mediatek: remove temporary variable @mask_
Date: Wed, 18 Jan 2023 16:43:41 +0800	[thread overview]
Message-ID: <20230118084343.26913-1-chunfeng.yun@mediatek.com> (raw)

Remove the temporary @mask_, this may cause build warning when use clang
compiler for powerpc, but can't reproduce it when compile for arm64.
the build warning is caused by:

"warning: result of comparison of constant 18446744073709551615 with
expression of type (aka 'unsigned long') is always false
[-Wtautological-constant-out-of-range-compare]"

More information provided in below lore link.

After removing @mask_, there is a "CHECK:MACRO_ARG_REUSE" when run
checkpatch.pl, but due to @mask is constant, no reuse problem will happen.

Link: https://lore.kernel.org/lkml/202212160357.jJuesD8n-lkp@intel.com/t/
Fixes: 84513eccd678 ("phy: mediatek: fix build warning of FIELD_PREP()")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
---
v7: modify title suggested by Vinod,
    modify commit message and add link tag suggested by Nick

v6: modify the title
v5: no changes
v4 new patch, I'm not sure it can fix build warning, due to I don't cross compile
    it for powerpc using clang in office.
---
 drivers/phy/mediatek/phy-mtk-io.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/phy/mediatek/phy-mtk-io.h b/drivers/phy/mediatek/phy-mtk-io.h
index d20ad5e5be81..58f06db822cb 100644
--- a/drivers/phy/mediatek/phy-mtk-io.h
+++ b/drivers/phy/mediatek/phy-mtk-io.h
@@ -39,8 +39,8 @@ static inline void mtk_phy_update_bits(void __iomem *reg, u32 mask, u32 val)
 /* field @mask shall be constant and continuous */
 #define mtk_phy_update_field(reg, mask, val) \
 ({ \
-	typeof(mask) mask_ = (mask);	\
-	mtk_phy_update_bits(reg, mask_, FIELD_PREP(mask_, val)); \
+	BUILD_BUG_ON_MSG(!__builtin_constant_p(mask), "mask is not constant"); \
+	mtk_phy_update_bits(reg, mask, FIELD_PREP(mask, val)); \
 })
 
 #endif
-- 
2.18.0

