__pwm_round_waveform_tohw
ret_tohw = __pwm_round_waveform_tohw(chip, pwm, wf, wfhw);
ret_tohw = __pwm_round_waveform_tohw(chip, pwm, wf, &wfhw);
err = __pwm_round_waveform_tohw(chip, pwm, &wf, &wfhw);