Hi Sui, Thank you for the patch! Yet something to improve: [auto build test ERROR on drm/drm-next] [also build test ERROR on robh/for-next linus/master v5.17 next-20220401] [cannot apply to mripard/sunxi/for-next] [If your patch is applied to the wrong git tree, kindly drop us a note. And when submitting patch, we suggest to use '--base' as documented in https://git-scm.com/docs/git-format-patch] url: https://github.com/intel-lab-lkp/linux/commits/Sui-Jingfeng/drm-loongson-add-drm-driver-for-loongson-display-controller/20220402-003557 base: git://anongit.freedesktop.org/drm/drm drm-next config: sparc-randconfig-r012-20220402 (https://download.01.org/0day-ci/archive/20220402/202204021321.5sYDUPbx-lkp@xxxxxxxxx/config) compiler: sparc64-linux-gcc (GCC) 11.2.0 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 # https://github.com/intel-lab-lkp/linux/commit/b52cc469ed1a99a0803faef886f81607b1f7f5c0 git remote add linux-review https://github.com/intel-lab-lkp/linux git fetch --no-tags linux-review Sui-Jingfeng/drm-loongson-add-drm-driver-for-loongson-display-controller/20220402-003557 git checkout b52cc469ed1a99a0803faef886f81607b1f7f5c0 # save the config file to linux build tree mkdir build_dir COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross O=build_dir ARCH=sparc SHELL=/bin/bash drivers/gpu/drm/loongson/ If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp@xxxxxxxxx> All errors (new ones prefixed by >>): drivers/gpu/drm/loongson/lsdc_i2c.c: In function 'ls7a_gpio_i2c_set': >> drivers/gpu/drm/loongson/lsdc_i2c.c:37:23: error: implicit declaration of function 'readb' [-Werror=implicit-function-declaration] 37 | val = readb(li2c->dir_reg); | ^~~~~ >> drivers/gpu/drm/loongson/lsdc_i2c.c:39:17: error: implicit declaration of function 'writeb' [-Werror=implicit-function-declaration] 39 | writeb(val, li2c->dir_reg); | ^~~~~~ cc1: some warnings being treated as errors vim +/readb +37 drivers/gpu/drm/loongson/lsdc_i2c.c 19 20 /* 21 * ls7a_gpio_i2c_set - set the state of a gpio pin, either high or low. 22 * @mask: gpio pin mask indicate which pin to set 23 */ 24 static void ls7a_gpio_i2c_set(struct lsdc_i2c * const li2c, int mask, int state) 25 { 26 unsigned long flags; 27 u8 val; 28 29 spin_lock_irqsave(&li2c->reglock, flags); 30 31 if (state) { 32 /* 33 * The high state is achieved by setting the direction as 34 * input, because the GPIO is open drained with external 35 * pull up resistance. 36 */ > 37 val = readb(li2c->dir_reg); 38 val |= mask; > 39 writeb(val, li2c->dir_reg); 40 } else { 41 /* First, set this pin as output */ 42 val = readb(li2c->dir_reg); 43 val &= ~mask; 44 writeb(val, li2c->dir_reg); 45 46 /* Then, set the state to it */ 47 val = readb(li2c->dat_reg); 48 val &= ~mask; 49 writeb(val, li2c->dat_reg); 50 } 51 52 spin_unlock_irqrestore(&li2c->reglock, flags); 53 } 54 -- 0-DAY CI Kernel Test Service https://01.org/lkp