From 8cc83cfee4b2a1733378cc3147a5a34b86f07e1c Mon Sep 17 00:00:00 2001
From: Jean Delvare <khali@linux-fr.org>
Date: Thu, 17 Jul 2003 17:26:04 +0000
Subject: [PATCH] EDID data decoder (interfaces our eeprom module with
 parse-edid         from the read-edid project).

git-svn-id: http://lm-sensors.org/svn/lm-sensors/trunk@1885 7894878c-1315-0410-8ee3-d5d059ff63e0
---
 prog/eeprom/decode-edid.pl | 143 +++++++++++++++++++++++++++++++++++++
 1 file changed, 143 insertions(+)
 create mode 100755 prog/eeprom/decode-edid.pl

diff --git a/prog/eeprom/decode-edid.pl b/prog/eeprom/decode-edid.pl
new file mode 100755
index 00000000..0f370c1a
--- /dev/null
+++ b/prog/eeprom/decode-edid.pl
@@ -0,0 +1,143 @@
+#!/usr/bin/perl -w
+#
+# Copyright 2003 Jean Delvare <khali@linux-fr.org>
+#
+#    This program is free software; you can redistribute it and/or modify
+#    it under the terms of the GNU General Public License as published by
+#    the Free Software Foundation; either version 2 of the License, or
+#    (at your option) any later version.
+#
+#    This program is distributed in the hope that it will be useful,
+#    but WITHOUT ANY WARRANTY; without even the implied warranty of
+#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#    GNU General Public License for more details.
+#
+#    You should have received a copy of the GNU General Public License
+#    along with this program; if not, write to the Free Software
+#    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+#
+# Version 0.1  2003-07-17  Jean Delvare <khali@linux-fr.org>
+#
+# EEPROM data decoding for EDID. EDID (Extended Display Identification
+# Data) is a VESA standard which allows storing (on manufacturer's side)
+# and retrieving (on user's side) of configuration information about
+# displays, such as manufacturer, serial number, physical dimensions and
+# allowed horizontal and vertical refresh rates.
+#
+# Using the LM Sensors modules and tools, you have two possibilities to
+# make use of these data:
+#  1* Use the ddcmon driver and run sensors.
+#  2* Use the eeprom driver and run this script.
+# Both solutions will return a different kind of information. The first
+# method will report user-interesting information, such as the model number
+# or the year of manufacturing. The second method will report video-card-
+# interesting information, such as video modes and refresh rates.
+#
+# Note that this script does almost nothing by itself. It simply converts
+# what it finds in /proc to binary data to feed the parse-edid script.
+# The parse-edid script was written by John Fremlin and is available at
+# the following address:
+#   http://john.fremlin.de/programs/linux/read-edid/
+
+use strict;
+
+use vars qw($bus $address);
+
+sub edid_valid
+{
+	my ($bus, $addr) = @_;
+
+	open EEDATA, "/proc/sys/dev/sensors/eeprom-i2c-$bus-$addr/00";
+	my $line = <EEDATA>;
+	close EEDATA;
+	return 1
+		if $line =~ m/^0 255 255 255 255 255 255 0 /;
+	return 0;
+}
+
+sub bus_detect
+{
+	my $max = shift;
+
+	for (my $i=0; $i<$max; $i++)
+	{
+		if ( -r "/proc/sys/dev/sensors/eeprom-i2c-$i-50/00" )
+		{
+			if (edid_valid ($i, '50'))
+			{
+				print STDERR
+					"decode-edid: using bus $i (autodetected)\n";
+				return $i;
+			}
+		}
+	}
+	
+	return; # default
+}
+
+sub edid_decode
+{
+	my ($bus, $addr) = @_;
+
+	# Make sure it is an EDID EEPROM.
+
+	unless (edid_valid ($bus, $addr))
+	{
+		print STDERR
+			"decode-edid: not an EDID EEPROM at $bus-$addr\n";
+		return;
+	}
+
+	$SIG{__WARN__} = sub { };
+	open PIPE, "| parse-edid"
+		or die "Can't open parse-edid. Please install read-edid.\n";
+	delete $SIG{__WARN__};
+	binmode PIPE;
+	
+	for (my $i=0; $i<=0xf0; $i+=0x10)
+	{
+		my $file = sprintf '%02x', $i;
+		my $output = '';
+		open EEDATA, "/proc/sys/dev/sensors/eeprom-i2c-$bus-$addr/$file"
+			or die "Can't read /proc/sys/dev/sensors/eeprom-i2c-$bus-$addr/$file";
+		while(<EEDATA>)
+		{
+			foreach my $item (split)
+			{
+				$output .= pack "C", $item;
+			}
+		}
+		close EEDATA;
+		syswrite PIPE, $output;
+	}
+
+	syswrite PIPE, "\n"; # keep the customer satifsied
+	close PIPE;
+}
+
+# Get the address. Default to 0x50 if not given.
+$address = $ARGV[1] || 0x50;
+# Convert to decimal, whatever the value.
+$address = oct $address if $address =~ m/^0/;
+# Convert to an hexadecimal string.
+$address = sprintf '%02x', $address;
+
+# Get the bus. Try to autodetect if not given.
+$bus = $ARGV[0] if defined $ARGV[0];
+$bus = bus_detect (8) unless defined $bus;
+
+if ( defined $bus
+  && -r "/proc/sys/dev/sensors/eeprom-i2c-$bus-$address" )
+{
+	print STDERR
+		"decode-edid: decode-edid version 0.1\n";
+	edid_decode ($bus, $address);
+}
+else
+{
+	print STDERR
+		"EDID EEPROM not found.  Please make sure that the eeprom module is loaded.\n";
+	print STDERR
+		"Maybe your EDID EEPROM is on another bus.  Try \"decode-edid ".($bus+1)."\".\n"
+		if defined $bus;
+}