[kbuild-all] [tobetter-linux:odroid-5.13.y 17/93] drivers/pwm/pwm-gpio.c:60:22: warning: no previous prototype for 'gpio_pwm_timer'

tree: https://github.com/tobetter/linux odroid-5.13.y head: ec41beb389cd0d7ab68345d550334d44842a2cb1 commit: 834c04942cc7aa318347e65dc3511510c68405e1 [17/93] ODROID-COMMON: pwm: gpio: Add a generic gpio based PWM driver config: arc-allyesconfig (attached as .config) compiler: arceb-elf-gcc (GCC) 9.3.0 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/tobetter/linux/commit/834c04942cc7aa318347e65dc3511510... git remote add tobetter-linux https://github.com/tobetter/linux git fetch --no-tags tobetter-linux odroid-5.13.y git checkout 834c04942cc7aa318347e65dc3511510c68405e1 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=arc 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 >>): 60 | enum hrtimer_restart gpio_pwm_timer(struct hrtimer *timer) | ^~~~~~~~~~~~~~ vim +/gpio_pwm_timer +60 drivers/pwm/pwm-gpio.c 59 61 { 62 struct gpio_pwm_data *gpio_data = container_of(timer, 63 struct gpio_pwm_data, 64 timer); 65 if (!gpio_data->run) { 66 gpio_pwm_off(gpio_data); 67 gpio_data->pin_on = false; 68 return HRTIMER_NORESTART; 69 } 70 71 if (!gpio_data->pin_on) { 72 hrtimer_forward_now(&gpio_data->timer, 73 ns_to_ktime(gpio_data->on_time)); 74 gpio_pwm_on(gpio_data); 75 gpio_data->pin_on = true; 76 } else { 77 hrtimer_forward_now(&gpio_data->timer, 78 ns_to_ktime(gpio_data->off_time)); 79 gpio_pwm_off(gpio_data); 80 gpio_data->pin_on = false; 81 } 82 83 return HRTIMER_RESTART; 84 } 85 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org