RWTCNT
u16 val = readw_relaxed(priv->base + RWTCNT);
rwdt_write(priv, 0xffff, RWTCNT);
if (reg == RWTCNT)
rwdt_write(priv, 65536 - MUL_BY_CLKS_PER_SEC(priv, wdev->timeout), RWTCNT);