serial: ns16550: Add reset ctrl to driver

Add code to reset all reset signals as in serial DT node. A reset
property is an optional feature, so do not fail if a reset property is
not present.

If a reset property is discovered, then use it to deassert, thus
bringing the IP out of reset.

Signed-off-by: Ley Foon Tan <ley.foon.tan@intel.com>
Reviewed-by: Marek Vasut <marex@denx.de>
Reviewed-by: Simon Glass <sjg@chromium.org>

drivers/serial/ns16550.c

@@ -9,6 +9,7 @@
 #include <dm.h>
 #include <errno.h>
 #include <ns16550.h>
+#include <reset.h>
 #include <serial.h>
 #include <watchdog.h>
 #include <linux/types.h>
@@ -177,6 +178,7 @@ void NS16550_init(NS16550_t com_port, int baud_divisor)
 #if defined(CONFIG_ARCH_OMAP2PLUS)
 	serial_out(0x7, &com_port->mdr1);	/* mode select reset TL16C750*/
 #endif
+
 	serial_out(UART_MCRVAL, &com_port->mcr);
 	serial_out(ns16550_getfcr(com_port), &com_port->fcr);
 	if (baud_divisor != -1)
@@ -370,6 +372,12 @@ static int ns16550_serial_setbrg(struct udevice *dev, int baudrate)
 int ns16550_serial_probe(struct udevice *dev)
 {
 	struct NS16550 *const com_port = dev_get_priv(dev);
+	struct reset_ctl_bulk reset_bulk;
+	int ret;
+
+	ret = reset_get_bulk(dev, &reset_bulk);
+	if (!ret)
+		reset_deassert_bulk(&reset_bulk);
 
 	com_port->plat = dev_get_platdata(dev);
 	NS16550_init(com_port, -1);