Hi Vinod, I love your patch! Perhaps something to improve: [auto build test WARNING on robh/for-next] [also build test WARNING on drm-intel/for-linux-next drm-tip/drm-tip linus/master v5.7-rc5 next-20200512] [if your patch is applied to the wrong git tree, please drop us a note to help improve the system. BTW, we also suggest to use '--base' option to specify the base tree in git format-patch, please see https://stackoverflow.com/a/37406982] url: https://github.com/0day-ci/linux/commits/Vinod-Koul/Add-LT9611-DSI-to-HDM... base: https://git.kernel.org/pub/scm/linux/kernel/git/robh/linux.git for-next config: nios2-allyesconfig (attached as .config) compiler: nios2-linux-gcc (GCC) 9.3.0 reproduce: wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day GCC_VERSION=9.3.0 make.cross ARCH=nios2 If you fix the issue, kindly add following tag as appropriate Reported-by: kbuild test robot <lkp(a)intel.com&gt; All warnings (new ones prefixed by >>): drivers/gpu/drm/bridge/lt9611.c: In function 'lt9611_reset': drivers/gpu/drm/bridge/lt9611.c:518:2: error: implicit declaration of function 'gpiod_set_value_cansleep' [-Werror=implicit-function-declaration] 518 | gpiod_set_value_cansleep(lt9611->reset_gpio, 1); | ^~~~~~~~~~~~~~~~~~~~~~~~ drivers/gpu/drm/bridge/lt9611.c: In function 'lt9611_gpio_init': drivers/gpu/drm/bridge/lt9611.c:963:23: error: implicit declaration of function 'devm_gpiod_get' [-Werror=implicit-function-declaration] 963 | lt9611->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH); | ^~~~~~~~~~~~~~ drivers/gpu/drm/bridge/lt9611.c:963:52: error: 'GPIOD_OUT_HIGH' undeclared (first use in this function) 963 | lt9611->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH); | ^~~~~~~~~~~~~~ drivers/gpu/drm/bridge/lt9611.c:963:52: note: each undeclared identifier is reported only once for each function it appears in drivers/gpu/drm/bridge/lt9611.c:969:24: error: implicit declaration of function 'devm_gpiod_get_optional'; did you mean 'devm_regulator_get_optional'? [-Werror=implicit-function-declaration] 969 | lt9611->enable_gpio = devm_gpiod_get_optional(dev, "enable", | ^~~~~~~~~~~~~~~~~~~~~~~ | devm_regulator_get_optional drivers/gpu/drm/bridge/lt9611.c:970:13: error: 'GPIOD_OUT_LOW' undeclared (first use in this function) 970 | GPIOD_OUT_LOW); | ^~~~~~~~~~~~~ drivers/gpu/drm/bridge/lt9611.c: At top level: drivers/gpu/drm/bridge/lt9611.c:1100:1: warning: data definition has no type or storage class 1100 | MODULE_DEVICE_TABLE(of, lt9611_match_table); | ^~~~~~~~~~~~~~~~~~~ drivers/gpu/drm/bridge/lt9611.c:1100:1: error: type defaults to 'int' in declaration of 'MODULE_DEVICE_TABLE' [-Werror=implicit-int] drivers/gpu/drm/bridge/lt9611.c:1100:1: warning: parameter names (without types) in function declaration In file included from include/linux/device.h:31, from include/linux/platform_device.h:13, from drivers/gpu/drm/bridge/lt9611.c:7: include/linux/device/driver.h:263:1: warning: data definition has no type or storage class 263 | module_init(__driver##_init); | ^~~~~~~~~~~ include/linux/i2c.h:923:2: note: in expansion of macro 'module_driver' 923 | module_driver(__i2c_driver, i2c_add_driver, | ^~~~~~~~~~~~~ drivers/gpu/drm/bridge/lt9611.c:1111:1: note: in expansion of macro 'module_i2c_driver' 1111 | module_i2c_driver(lt9611_driver); | ^~~~~~~~~~~~~~~~~ include/linux/device/driver.h:263:1: error: type defaults to 'int' in declaration of 'module_init' [-Werror=implicit-int] 263 | module_init(__driver##_init); | ^~~~~~~~~~~ include/linux/i2c.h:923:2: note: in expansion of macro 'module_driver' 923 | module_driver(__i2c_driver, i2c_add_driver, | ^~~~~~~~~~~~~ drivers/gpu/drm/bridge/lt9611.c:1111:1: note: in expansion of macro 'module_i2c_driver' 1111 | module_i2c_driver(lt9611_driver); | ^~~~~~~~~~~~~~~~~ In file included from include/linux/linkage.h:7, from include/linux/kernel.h:8, from include/asm-generic/bug.h:19, from ./arch/nios2/include/generated/asm/bug.h:1, from include/linux/bug.h:5, from include/linux/thread_info.h:12, from include/asm-generic/current.h:5, from ./arch/nios2/include/generated/asm/current.h:1, from include/linux/sched.h:12, from include/linux/ratelimit.h:6, from include/linux/dev_printk.h:16, from include/linux/device.h:15, from include/linux/platform_device.h:13, from drivers/gpu/drm/bridge/lt9611.c:7: 19 | #define THIS_MODULE ((struct module *)0) | ^~~~~~ include/linux/i2c.h:855:22: note: in expansion of macro 'THIS_MODULE' 855 | i2c_register_driver(THIS_MODULE, driver) | ^~~~~~~~~~~ include/linux/device/driver.h:261:9: note: in expansion of macro 'i2c_add_driver' 261 | return __register(&(__driver) , ##__VA_ARGS__); | ^~~~~~~~~~ include/linux/i2c.h:923:2: note: in expansion of macro 'module_driver' 923 | module_driver(__i2c_driver, i2c_add_driver, | ^~~~~~~~~~~~~ drivers/gpu/drm/bridge/lt9611.c:1111:1: note: in expansion of macro 'module_i2c_driver' 1111 | module_i2c_driver(lt9611_driver); | ^~~~~~~~~~~~~~~~~ In file included from include/linux/device.h:31, from include/linux/platform_device.h:13, from drivers/gpu/drm/bridge/lt9611.c:7: include/linux/device/driver.h:268:1: warning: data definition has no type or storage class 268 | module_exit(__driver##_exit); | ^~~~~~~~~~~ include/linux/i2c.h:923:2: note: in expansion of macro 'module_driver' 923 | module_driver(__i2c_driver, i2c_add_driver, | ^~~~~~~~~~~~~ drivers/gpu/drm/bridge/lt9611.c:1111:1: note: in expansion of macro 'module_i2c_driver' 1111 | module_i2c_driver(lt9611_driver); | ^~~~~~~~~~~~~~~~~ include/linux/device/driver.h:268:1: error: type defaults to 'int' in declaration of 'module_exit' [-Werror=implicit-int] 268 | module_exit(__driver##_exit); | ^~~~~~~~~~~ include/linux/i2c.h:923:2: note: in expansion of macro 'module_driver' 923 | module_driver(__i2c_driver, i2c_add_driver, | ^~~~~~~~~~~~~ drivers/gpu/drm/bridge/lt9611.c:1111:1: note: in expansion of macro 'module_i2c_driver' 1111 | module_i2c_driver(lt9611_driver); | ^~~~~~~~~~~~~~~~~ In file included from include/linux/linkage.h:7, from include/linux/kernel.h:8, from include/asm-generic/bug.h:19, from ./arch/nios2/include/generated/asm/bug.h:1, from include/linux/bug.h:5, from include/linux/thread_info.h:12, from include/asm-generic/current.h:5, from ./arch/nios2/include/generated/asm/current.h:1, from include/linux/sched.h:12, from include/linux/ratelimit.h:6, from include/linux/dev_printk.h:16, from include/linux/device.h:15, from include/linux/platform_device.h:13, from drivers/gpu/drm/bridge/lt9611.c:7: 19 | #define THIS_MODULE ((struct module *)0) | ^~~~~~ include/linux/i2c.h:855:22: note: in expansion of macro 'THIS_MODULE' 855 | i2c_register_driver(THIS_MODULE, driver) | ^~~~~~~~~~~ include/linux/device/driver.h:261:9: note: in expansion of macro 'i2c_add_driver' 261 | return __register(&(__driver) , ##__VA_ARGS__); | ^~~~~~~~~~ include/linux/i2c.h:923:2: note: in expansion of macro 'module_driver' 923 | module_driver(__i2c_driver, i2c_add_driver, | ^~~~~~~~~~~~~ drivers/gpu/drm/bridge/lt9611.c:1111:1: note: in expansion of macro 'module_i2c_driver' 1111 | module_i2c_driver(lt9611_driver); | ^~~~~~~~~~~~~~~~~ drivers/gpu/drm/bridge/lt9611.c:1113:16: error: expected declaration specifiers or '...' before string constant 1113 | MODULE_LICENSE("GPL v2"); | ^~~~~~~~ In file included from include/linux/device.h:31, from include/linux/platform_device.h:13, from drivers/gpu/drm/bridge/lt9611.c:7: drivers/gpu/drm/bridge/lt9611.c:1111:19: warning: 'lt9611_driver_init' defined but not used [-Wunused-function] 1111 | module_i2c_driver(lt9611_driver); | ^~~~~~~~~~~~~ include/linux/device/driver.h:259:19: note: in definition of macro 'module_driver' 259 | static int __init __driver##_init(void) | ^~~~~~~~ drivers/gpu/drm/bridge/lt9611.c:1111:1: note: in expansion of macro 'module_i2c_driver' 1111 | module_i2c_driver(lt9611_driver); | ^~~~~~~~~~~~~~~~~ cc1: some warnings being treated as errors vim +19 include/linux/export.h b67067f1176df6 Nicholas Piggin 2016-08-24 4 f50169324df4ad Paul Gortmaker 2011-05-23 5 /* f50169324df4ad Paul Gortmaker 2011-05-23 6 * Export symbols from the kernel to modules. Forked from module.h f50169324df4ad Paul Gortmaker 2011-05-23 7 * to reduce the amount of pointless cruft we feed to gcc when only f50169324df4ad Paul Gortmaker 2011-05-23 8 * exporting a simple symbol or two. f50169324df4ad Paul Gortmaker 2011-05-23 9 * b92021b09df70c Rusty Russell 2013-03-15 10 * Try not to add #includes here. It slows compilation and makes kernel b92021b09df70c Rusty Russell 2013-03-15 11 * hackers place grumpy comments in header files. f50169324df4ad Paul Gortmaker 2011-05-23 12 */ f50169324df4ad Paul Gortmaker 2011-05-23 13 b92021b09df70c Rusty Russell 2013-03-15 14 #ifndef __ASSEMBLY__ f50169324df4ad Paul Gortmaker 2011-05-23 15 #ifdef MODULE f50169324df4ad Paul Gortmaker 2011-05-23 16 extern struct module __this_module; f50169324df4ad Paul Gortmaker 2011-05-23 17 #define THIS_MODULE (&__this_module) f50169324df4ad Paul Gortmaker 2011-05-23 18 #else f50169324df4ad Paul Gortmaker 2011-05-23 @19 #define THIS_MODULE ((struct module *)0) f50169324df4ad Paul Gortmaker 2011-05-23 20 #endif f50169324df4ad Paul Gortmaker 2011-05-23 21 :::::: The code at line 19 was first introduced by commit :::::: f50169324df4ad942e544386d136216c8617636a module.h: split out the EXPORT_SYMBOL into export.h :::::: TO: Paul Gortmaker <paul.gortmaker(a)windriver.com&gt; :::::: CC: Paul Gortmaker <paul.gortmaker(a)windriver.com&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org