serial: 16550: Add getfcr accessor

Add function which allows fetching the default FCR register setting
from platform data for DM , while retaining old behavior for non-DM
by returning UART_FCRVAL.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Tom Rini <trini@konsulko.com>
Cc: Simon Glass <sjg@chromium.org>
Reviewed-by: Simon Glass <sjg@chromium.org>

drivers/serial/ns16550.c

@@ -121,6 +121,13 @@ static int ns16550_readb(NS16550_t port, int offset)
 	return serial_in_shift(addr + plat->reg_offset, plat->reg_shift);
 }
 
+static u32 ns16550_getfcr(NS16550_t port)
+{
+	struct ns16550_platdata *plat = port->plat;
+
+	return plat->fcr;
+}
+
 /* We can clean these up once everything is moved to driver model */
 #define serial_out(value, addr)	\
 	ns16550_writeb(com_port, \
@@ -128,6 +135,11 @@ static int ns16550_readb(NS16550_t port, int offset)
 #define serial_in(addr) \
 	ns16550_readb(com_port, \
 		(unsigned char *)addr - (unsigned char *)com_port)
+#else
+static u32 ns16550_getfcr(NS16550_t port)
+{
+	return UART_FCRVAL;
+}
 #endif
 
 int ns16550_calc_divisor(NS16550_t port, int clock, int baudrate)
@@ -171,7 +183,7 @@ void NS16550_init(NS16550_t com_port, int baud_divisor)
 	serial_out(0x7, &com_port->mdr1);	/* mode select reset TL16C750*/
 #endif
 	serial_out(UART_MCRVAL, &com_port->mcr);
-	serial_out(UART_FCRVAL, &com_port->fcr);
+	serial_out(ns16550_getfcr(com_port), &com_port->fcr);
 	if (baud_divisor != -1)
 		NS16550_setbrg(com_port, baud_divisor);
 #if defined(CONFIG_OMAP) || \
@@ -192,7 +204,7 @@ void NS16550_reinit(NS16550_t com_port, int baud_divisor)
 	serial_out(CONFIG_SYS_NS16550_IER, &com_port->ier);
 	NS16550_setbrg(com_port, 0);
 	serial_out(UART_MCRVAL, &com_port->mcr);
-	serial_out(UART_FCRVAL, &com_port->fcr);
+	serial_out(ns16550_getfcr(com_port), &com_port->fcr);
 	NS16550_setbrg(com_port, baud_divisor);
 }
 #endif /* CONFIG_NS16550_MIN_FUNCTIONS */
@@ -420,6 +432,8 @@ int ns16550_serial_ofdata_to_platdata(struct udevice *dev)
 		return -EINVAL;
 	}
 
+	plat->fcr = UART_FCRVAL;
+
 	return 0;
 }
 #endif

include/ns16550.h

@@ -57,6 +57,7 @@ struct ns16550_platdata {
 	int reg_shift;
 	int clock;
 	int reg_offset;
+	u32 fcr;
 };
 
 struct udevice;