SPRD_PWM_ENABLE
sprd_pwm_write(spc, pwm->hwpwm, SPRD_PWM_ENABLE, 1);
sprd_pwm_write(spc, pwm->hwpwm, SPRD_PWM_ENABLE, 0);
val = sprd_pwm_read(spc, pwm->hwpwm, SPRD_PWM_ENABLE);