[U-Boot] [PATCH v2] Create configuration option for restricted ns16550 functions

[Ron Madrid]

This patch will create a configuration option for a minimum configuration for
the ns16550 serial driver at drivers/serial/ns16550.c which will exclude all
functions with exception of NS16550_putc and NS16550_init.  This will be used
primarily to save space and remove unused code from builds in which space is
limited.

Signed-off-by: Ron Madrid <ron_madrid at sbcglobal.net>
---
 README                   |    7 +++++++
 drivers/serial/ns16550.c |    4 ++++
 2 files changed, 11 insertions(+), 0 deletions(-)

diff --git a/README b/README
index 132650e..afea6a6 100644
--- a/README
+++ b/README
@@ -2434,6 +2434,13 @@ use the "saveenv" command to store a valid environment.
 - CONFIG_SYS_64BIT_STRTOUL:
 		Adds simple_strtoull that returns a 64bit value
 
+- CONFIG_NS16550_MIN_FUNCTIONS:
+		Define this if you desire to only have use of the NS16550_init
+		and NS16550_putc functions for the serial driver located at
+		drivers/serial/ns16550.c.  This option is useful for saving
+		space for already greatly restricted images, including but not
+		limited to NAND_SPL configurations.
+
 Low Level (hardware related) configuration options:
 ---------------------------------------------------
 
diff --git a/drivers/serial/ns16550.c b/drivers/serial/ns16550.c
index 93c2243..1b347e9 100644
--- a/drivers/serial/ns16550.c
+++ b/drivers/serial/ns16550.c
@@ -39,6 +39,7 @@ void NS16550_init (NS16550_t com_port, int baud_divisor)
 #endif
 }
 
+#ifndef CONFIG_NS16550_MIN_FUNCTIONS
 void NS16550_reinit (NS16550_t com_port, int baud_divisor)
 {
 	com_port->ier = 0x00;
@@ -53,6 +54,7 @@ void NS16550_reinit (NS16550_t com_port, int baud_divisor)
 	com_port->dlm = (baud_divisor >> 8) & 0xff;
 	com_port->lcr = LCRVAL;
 }
+#endif /* CONFIG_NS16550_MIN_FUNCTIONS */
 
 void NS16550_putc (NS16550_t com_port, char c)
 {
@@ -60,6 +62,7 @@ void NS16550_putc (NS16550_t com_port, char c)
 	com_port->thr = c;
 }
 
+#ifndef CONFIG_NS16550_MIN_FUNCTIONS
 char NS16550_getc (NS16550_t com_port)
 {
 	while ((com_port->lsr & LSR_DR) == 0) {
@@ -76,4 +79,5 @@ int NS16550_tstc (NS16550_t com_port)
 	return ((com_port->lsr & LSR_DR) != 0);
 }
 
+#endif /* CONFIG_NS16550_MIN_FUNCTIONS */
 #endif
-- 
1.5.5.1