/*
+	 * Mediatek UARTs use an extra highspeed register (UART_MTK_HIGHS)
+	 *
+	 * We need to recalcualte the quot register, as the claculation depends
+	 * on the vaule in the highspeed register.
+	 *
+	 * Some baudrates are not supported by the chip, so we use the next
+	 * lower rate supported.
+	 *
+	 * If highspeed register is set to 3, we need to specify sample count
+	 * and sample point to increase accuracy. If not, we reset the
+	 * registers to their default values.
+	 */

Don't put stuff in the core driver core for your chip specific weirdness,
wrap the termios method with your own in your driver code as a fair
number of other 8250ish drivers do.

If you do that then you don't need to waste a UART CAPS flag and you
don't need to put anything in the core driver code.

Alan