PWM_DUTY_WIDTH
c *= (1 << PWM_DUTY_WIDTH);
required_clk_rate = DIV_ROUND_UP_ULL((u64)NSEC_PER_SEC << PWM_DUTY_WIDTH,
(u64)NSEC_PER_SEC << PWM_DUTY_WIDTH);
(NSEC_PER_SEC / (pc->soc->max_frequency >> PWM_DUTY_WIDTH)) + 1;