Fix sysmon POST problem: check I2C error codes

This fixes a problem of displaying bogus voltages when the voltages
are so low that the I2C devices start failing while the rest of the
system keeps running.

CHANGELOG

@@ -2,6 +2,11 @@
 Changes for U-Boot 1.1.3:
 ======================================================================
 
+* Fix sysmon POST problem: check I2C error codes
+  This fixes a problem of displaying bogus voltages when the voltages
+  are so low that the I2C devices start failing while the rest of the
+  system keeps running.
+
 * Patch by Cedric Vincent, 6 Jul 2005:
   Fix CFG_CMD_SETGETDCR handling in "common/cmd_dcr.c"
 

post/sysmon.c

@@ -185,6 +185,10 @@ static char *sysmon_unit_value (sysmon_table_t *s, uint val)
 	char *p, sign;
 	int dec, frac;
 
+	if (val == -1) {
+		return "I/O ERROR";
+	}
+
 	if (unit_val < 0) {
 		sign = '-';
 		unit_val = -unit_val;
@@ -297,8 +301,13 @@ int sysmon_post_test (int flags)
 		}
 
 		val = t->sysmon->read(t->sysmon, t->addr);
-		t->val_valid = val >= t->val_min && val <= t->val_max;
-		t->val_valid_alt = val >= t->val_min_alt && val <= t->val_max_alt;
+		if (val != -1) {
+			t->val_valid = val >= t->val_min && val <= t->val_max;
+			t->val_valid_alt = val >= t->val_min_alt && val <= t->val_max_alt;
+		} else {
+			t->val_valid = 0;
+			t->val_valid_alt = 0;
+		}
 
 		if (t->exec_after) {
 			t->exec_after(t);