[U-Boot] [PATCH V3 4/6] sf command: allow default chip select through CONFIG_SPI_FLASH_CS

[Eric Nelson]

This patch allows a board configuration file to provide a default 
chip-select for serial flash so that first argument to the 'sf' command
is optional.

On boards that use the mxc_spi driver and a GPIO for chip select, this allows 
a much simpler command line:
	U-Boot> sf probe
instead of
	U-Boot> sf probe 0x5300

Signed-off-by: Eric Nelson <eric.nelson at boundarydevices.com>
Acked-by: Dirk Behme <dirk.behme at de.bosch.com> 
Acked-by: Stefano Babic <sbabic at denx.de>
---
 common/cmd_sf.c |   34 +++++++++++++++++++++++-----------
 1 files changed, 23 insertions(+), 11 deletions(-)

diff --git a/common/cmd_sf.c b/common/cmd_sf.c
index 7225656..4b32171 100644
--- a/common/cmd_sf.c
+++ b/common/cmd_sf.c
@@ -70,20 +70,28 @@ static int do_spi_flash_probe(int argc, char * const argv[])
 	char *endp;
 	struct spi_flash *new;
 
-	if (argc < 2)
-		return -1;
-
-	cs = simple_strtoul(argv[1], &endp, 0);
-	if (*argv[1] == 0 || (*endp != 0 && *endp != ':'))
+#ifndef CONFIG_SPI_FLASH_CS
+	if (argc < 2) {
+		printf("%s: missing arguments\n", __func__);
 		return -1;
-	if (*endp == ':') {
-		if (endp[1] == 0)
-			return -1;
+	}
+#else
+	cs = CONFIG_SPI_FLASH_CS ;
+#endif
 
-		bus = cs;
-		cs = simple_strtoul(endp + 1, &endp, 0);
-		if (*endp != 0)
+	if (argc >= 2) {
+		cs = simple_strtoul(argv[1], &endp, 0);
+		if (*argv[1] == 0 || (*endp != 0 && *endp != ':'))
 			return -1;
+		if (*endp == ':') {
+			if (endp[1] == 0)
+				return -1;
+
+			bus = cs;
+			cs = simple_strtoul(endp + 1, &endp, 0);
+			if (*endp != 0)
+				return -1;
+		}
 	}
 
 	if (argc >= 3) {
@@ -299,7 +307,11 @@ usage:
 U_BOOT_CMD(
 	sf,	5,	1,	do_spi_flash,
 	"SPI flash sub-system",
+#ifndef CONFIG_SPI_FLASH_CS
 	"probe [bus:]cs [hz] [mode]	- init flash device on given SPI bus\n"
+#else
+	"probe [[bus:]cs] [hz] [mode]	- init flash device on given SPI bus\n"
+#endif
 	"				  and chip select\n"
 	"sf read addr offset len 	- read `len' bytes starting at\n"
 	"				  `offset' to memory at `addr'\n"
-- 
1.7.1