Behave properly when i2c-stub is already loaded.

git-svn-id: http://lm-sensors.org/svn/i2c-tools/trunk@5292 7894878c-1315-0410-8ee3-d5d059ff63e0

CHANGES

@@ -22,6 +22,7 @@ SVN
           Better error message on missing adapter functionality
   i2c-stub-from-dump: Add support for partial dumps
                       Report if only garbage is found in dump file
+                      Behave properly when i2c-stub is already loaded
 
 3.0.1 (2008-04-04)
   Drop the trailing .pl from all perl script names

stub/i2c-stub-from-dump

@@ -58,6 +58,45 @@ sub get_i2c_stub_bus_number
 	}
 	close(FH);
 
+	return $nr;
+}
+
+# Load the required kernel drivers if needed
+sub load_kernel_drivers
+{
+	local $_;
+	my $addr = oct shift;
+	my $nr;
+
+	# Maybe everything is already loaded
+	$nr = get_i2c_stub_bus_number();
+	if (defined $nr) {
+		if (kernel_version_at_least(2, 6, 19)) {
+			# Check if the chip address we need is there
+			open(CHIP_ADDR, "/sys/module/i2c_stub/parameters/chip_addr");
+			$_ = <CHIP_ADDR>;
+			chomp;
+			my @stub_addr = split ',';
+			close(CHIP_ADDR);
+
+			foreach (@stub_addr) {
+				return $nr if $addr == $_;
+			}
+			printf STDERR "i2c-stub already loaded without support for address 0x%02x\n", $addr;
+			exit 2;
+		}
+		return $nr;
+	}
+
+	system("/sbin/modprobe", "i2c-dev") == 0 || exit 1;
+	if (kernel_version_at_least(2, 6, 19)) {
+		system("/sbin/modprobe", "i2c-stub", "chip_addr=$addr") == 0 || exit 1;
+	} else {
+		system("/sbin/modprobe", "i2c-stub") == 0 || exit 1;
+	}
+	sleep(1); # udev may take some time to create the device node
+
+	$nr = get_i2c_stub_bus_number();
 	if (!defined($nr)) {
 		print STDERR "Please load i2c-stub first\n";
 		exit 2;
@@ -123,16 +162,7 @@ if ($addr !~ m/^0x[0-7][0-9a-f]$/i) {
 
 initialize_kernel_version();
 
-# Load the required kernel drivers if needed
-system("/sbin/modprobe", "i2c-dev") == 0 || exit 1;
-if (kernel_version_at_least(2, 6, 19)) {
-	system("/sbin/modprobe", "i2c-stub", "chip_addr=$addr") == 0 || exit 1;
-} else {
-	system("/sbin/modprobe", "i2c-stub") == 0 || exit 1;
-}
-sleep(1); # udev may take some time to create the device node
-
-$bus_nr = get_i2c_stub_bus_number();
+$bus_nr = load_kernel_drivers($addr);
 $bytes = $words = 0;
 
 # We don't want to see the output of 256 i2cset