PWM_IMX_TPM_SC_PS
if ((!FIELD_FIT(PWM_IMX_TPM_SC_PS, prescale)))
prescale = FIELD_GET(PWM_IMX_TPM_SC_PS, val);
cur_prescale = FIELD_GET(PWM_IMX_TPM_SC_PS, val);
val &= ~PWM_IMX_TPM_SC_PS;
val |= FIELD_PREP(PWM_IMX_TPM_SC_PS, p->prescale);