Hi Bartosz, I love your patch! Perhaps something to improve: [auto build test WARNING on robh/for-next] [also build test WARNING on linus/master v5.8-rc2] [cannot apply to arm/for-next next-20200622] [If your patch is applied to the wrong git tree, kindly drop us a note. And when submitting patch, we suggest to use as documented in https://git-scm.com/docs/git-format-patch] url: https://github.com/0day-ci/linux/commits/Bartosz-Golaszewski/net-phy-corr... base: https://git.kernel.org/pub/scm/linux/kernel/git/robh/linux.git for-next config: x86_64-allyesconfig (attached as .config) compiler: clang version 11.0.0 (https://github.com/llvm/llvm-project 1d4c87335d5236ea1f35937e1014980ba961ae34) reproduce (this is a W=1 build): wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # install x86_64 cross compiling tool for clang build # apt-get install binutils-x86-64-linux-gnu # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=x86_64 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All warnings (new ones prefixed by >>, old ones prefixed by <<): if (!is_c45) { ^~~~~~~ drivers/of/of_mdio.c:129:38: note: uninitialized use occurs here phy = phy_device_create(mdio, addr, phy_id, is_c45); ^~~~~~ drivers/of/of_mdio.c:123:2: note: remove the 'if' if its condition is always true if (!is_c45) { ^~~~~~~~~~~~~ drivers/of/of_mdio.c:114:12: note: initialize the variable 'phy_id' to silence this warning u32 phy_id; ^ = 0 1 warning generated. vim +123 drivers/of/of_mdio.c 106 107 static int of_mdiobus_register_phy(struct mii_bus *mdio, 108 struct device_node *child, u32 addr) 109 { 110 struct mii_timestamper *mii_ts; 111 struct phy_device *phy; 112 bool is_c45; 113 int rc; 114 u32 phy_id; 115 116 mii_ts = of_find_mii_timestamper(child); 117 if (IS_ERR(mii_ts)) 118 return PTR_ERR(mii_ts); 119 120 is_c45 = of_device_is_compatible(child, 121 "ethernet-phy-ieee802.3-c45"); 122 124 rc = of_get_phy_id(child, &phy_id); 125 if (rc) 126 phy_id = PHY_ID_NONE; 127 } 128 129 phy = phy_device_create(mdio, addr, phy_id, is_c45); 130 if (IS_ERR(phy)) { 131 if (mii_ts) 132 unregister_mii_timestamper(mii_ts); 133 return PTR_ERR(phy); 134 } 135 136 rc = of_mdiobus_phy_device_register(mdio, phy, child, addr); 137 if (rc) { 138 if (mii_ts) 139 unregister_mii_timestamper(mii_ts); 140 phy_device_free(phy); 141 return rc; 142 } 143 144 /* phy->mii_ts may already be defined by the PHY driver. A 145 * mii_timestamper probed via the device tree will still have 146 * precedence. 147 */ 148 if (mii_ts) 149 phy->mii_ts = mii_ts; 150 151 return 0; 152 } 153 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org