CPM_BRG_EN
out_be32(bp, (((BRG_UART_CLK / rate) - 1) << 1) | CPM_BRG_EN);
CPM_BRG_EN | CPM_BRG_DIV16);
val = (((clk * 2 / rate) - 1) & ~1) | CPM_BRG_EN | src;