[PATCH] I2C: Add support for multiple I2C busses for RTC & DTT

This patch switches to the desired I2C bus when the date/dtt
commands are called. This can be configured using the
CFG_RTC_BUS_NUM and/or CFG_DTT_BUS_NUM defines.

Signed-off-by: Stefan Roese <sr@denx.de>
diff --git a/common/cmd_dtt.c b/common/cmd_dtt.c
index 9db64e9..4f7b049 100644
--- a/common/cmd_dtt.c
+++ b/common/cmd_dtt.c
@@ -28,19 +28,27 @@
 #if (CONFIG_COMMANDS & CFG_CMD_DTT)
 
 #include <dtt.h>
+#include <i2c.h>
 
 int do_dtt (cmd_tbl_t * cmdtp, int flag, int argc, char *argv[])
 {
 	int i;
 	unsigned char sensors[] = CONFIG_DTT_SENSORS;
+	int old_bus;
+
+	/* switch to correct I2C bus */
+	old_bus = I2C_GET_BUS();
+	I2C_SET_BUS(CFG_DTT_BUS_NUM);
 
 	/*
 	 * Loop through sensors, read
 	 * temperature, and output it.
 	 */
-	for (i = 0; i < sizeof (sensors); i++) {
+	for (i = 0; i < sizeof (sensors); i++)
 		printf ("DTT%d: %i C\n", i + 1, dtt_get_temp (sensors[i]));
-	}
+
+	/* switch back to original I2C bus */
+	I2C_SET_BUS(old_bus);
 
 	return 0;
 }	/* do_dtt() */