pwm_get_relative_duty_cycle
level = pwm_get_relative_duty_cycle(&panel->backlight.pwm_state,
return pwm_get_relative_duty_cycle(&state, 100);
voltage = pwm_get_relative_duty_cycle(&pstate, duty_unit);
dutycycle = pwm_get_relative_duty_cycle(&pwm_state, 100);
duty = pwm_get_relative_duty_cycle(state, PWM_BL_MASK);