root/i2c-tools/trunk/eeprom/ddcmon

#!/usr/bin/perl -w
#
# Copyright (C) 2004-2005  Jean Delvare <khali@linux-fr.org>
#
# Parts inspired from decode-edid.
# Copyright (C) 2003-2004  Jean Delvare <khali@linux-fr.org>
#
# Parts inspired from the ddcmon driver and sensors' print_ddcmon function.
# Copyright (C) 1998-2004  Mark D. Studebaker
#
# Parts inspired from the fbmon driver (Linux 2.6.10).
# Copyright (C) 2002  James Simmons <jsimmons@users.sf.net>
#
#    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., 51 Franklin Street, Fifth Floor, Boston,
#    MA 02110-1301 USA.
#
# Version 1.0  2005-01-04  Jean Delvare <khali@linux-fr.org>
#
# This script is a replacement for the now deprecated ddcmon kernel driver.
# Instead of having a dedicated driver, it is better to reuse the standard
# eeprom driver and implement the EDID-specific code in user-space.
#
# 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.
#
# Syntax: ddcmon [bus [address]]
# Address can be given in decimal or hexadecimal (with a 0x prefix).
# If no address is given, default is 0x50.
# Bus number must be given in decimal. If no bus number is given,
# try them all.

use strict;
use Fcntl qw(:DEFAULT :seek);
use vars qw(@standard_scales);

@standard_scales = ([1, 1], [3, 4], [4, 5], [16, 9]);

# Make sure the eeprom module is loaded.
# For non-modular kernels, we can't help.
if (-r '/proc/modules')
{
        my $found = 0;
        open(MODULES, '/proc/modules');
        while (!$found && defined ($_ = <MODULES>))
        {
                $found++ if m/^eeprom\s+/;
        }
        close(MODULES);

        unless ($found)
        {
                print STDERR
                        "This script requires the eeprom module to be loaded.\n";
                exit 1;
        }
}

# Only used for sysfs
sub rawread
{
        my $filename = shift;
        my $length = shift;
        my $offset = shift || 0;
        my $bytes = '';
        
        sysopen(FH, $filename, O_RDONLY)
                or die "Can't open $filename";
        if ($offset)
        {
                sysseek(FH, $offset, SEEK_SET)
                        or die "Can't seek in $filename";
        }

        $offset = 0;
        while ($length)
        {
                my $r = sysread(FH, $bytes, $length, $offset);
                die "Can't read $filename"
                        unless defined($r);
                die "Unexpected EOF in $filename"
                        unless $r;
                $offset += $r;
                $length -= $r;
        }
        close(FH);

        return $bytes;
}

sub get_edid_sysfs
{
        my ($bus, $addr) = @_;

        my @bytes = unpack("C*", rawread("/sys/bus/i2c/devices/$bus-00$addr/eeprom", 128));

        return \@bytes;
}

sub get_edid_procfs
{
        my ($bus, $addr) = @_;

        my @bytes;

        for (my $i = 0 ; $i < 0x80; $i += 0x10)
        {
                my $filename = sprintf("/proc/sys/dev/sensors/eeprom-i2c-\%s-\%s/\%02x",
                                       $bus, $addr, $i);
                open(EEDATA, $filename)
                        or die "Can't read $filename";
                push @bytes, split(/\s+/, <EEDATA>);
                close(EEDATA);
        }

        return \@bytes;
}

sub print_line
{
        my $label = shift;
        my $pattern = shift;

        printf("\%-24s$pattern\n", $label.':', @_);
}

sub extract_byte
{
        my ($bytes, $offset) = @_;
        
        return $bytes->[$offset];
}

sub extract_word
{
        my ($bytes, $offset) = @_;
        
        return ($bytes->[$offset]
              | ($bytes->[$offset+1] << 8));
}

sub extract_manufacturer
{
        my ($bytes, $offset) = @_;
        my $i = ($bytes->[$offset+1] | ($bytes->[$offset] << 8));

        return sprintf('%c%c%c',
                       (($i >> 10) & 0x1f) + ord('A') - 1,
                       (($i >> 5) & 0x1f) + ord('A') - 1,
                       ($i & 0x1f) + ord('A') - 1);
}

sub extract_sesquiword
{
        my ($bytes, $offset) = @_;
        
        return ($bytes->[$offset]
              | ($bytes->[$offset+1] << 8)
              | ($bytes->[$offset+2] << 16));
}

sub extract_dword
{
        my ($bytes, $offset) = @_;
        
        return ($bytes->[$offset]
              | ($bytes->[$offset+1] << 8)
              | ($bytes->[$offset+2] << 16)
              | ($bytes->[$offset+3] << 24));
}

sub extract_display_input
{
        my ($bytes, $offset) = @_;

        my @voltage = ('0.700V/0.300V', '0.714V/0.286V',
                       '1.000V/0.400V', '0.700V/0.000V');

        return 'Digital'
                if ($bytes->[$offset] & 0x80);

        return 'Analog ('.$voltage[($bytes->[$offset] & 0x60) >> 5].')';
}

sub extract_dpms
{
        my ($bytes, $offset) = @_;

        my @supported;

        push @supported, 'Active Off' if ($bytes->[$offset] & 0x20);
        push @supported, 'Suspend' if ($bytes->[$offset] & 0x40);
        push @supported, 'Standby' if ($bytes->[$offset] & 0x80);

        return join(', ', @supported)
                if (@supported);

        return 'None supported';
}

sub extract_color_mode
{
        my ($bytes, $offset) = @_;

        my @mode = ('Monochrome', 'RGB Multicolor', 'Non-RGB Multicolor');

        return $mode[($bytes->[$offset] >> 3) & 0x03];
}
  
sub good_signature
{
        my $bytes = shift;
        
        return $bytes->[0] == 0x00
            && $bytes->[1] == 0xff
            && $bytes->[2] == 0xff
            && $bytes->[3] == 0xff
            && $bytes->[4] == 0xff
            && $bytes->[5] == 0xff
            && $bytes->[6] == 0xff
            && $bytes->[7] == 0x00;
}

sub verify_checksum
{
        my $bytes = shift;
        my $cs;

        for (my $i = 0, $cs = 0; $i < 0x80; $i++)
        {
                $cs += $bytes->[$i];
        }
        
        return (($cs & 0xff) == 0 ? 'OK' : 'Not OK');
}

sub add_timing
{
        my ($timings, $new) = @_;

        my $mode = sprintf('%ux%u@%u%s', $new->[0], $new->[1],
                        $new->[2], defined ($new->[3]) &&
                        $new->[3] eq 'interlaced' ? 'i' : '');

        $timings->{$mode} = $new;
}

sub add_standard_timing
{
        my ($timings, $byte0, $byte1) = @_;

        # Unused slot
        return if ($byte0 == $byte1)
               && ($byte0 == 0x01 || $byte0 == 0x00 || $byte0 == 0x20);

        my $width = ($byte0 + 31) * 8;
        my $height = $width * $standard_scales[$byte1 >> 6]->[0]
                            / $standard_scales[$byte1 >> 6]->[1];
        my $refresh = 60 + ($byte1 & 0x3f);

        add_timing($timings, [$width, $height, $refresh]);
}

sub sort_timings
{
        # First order by width
        return -1 if  $a->[0] < $b->[0];
        return 1 if  $a->[0] > $b->[0];

        # Second by height
        return -1 if  $a->[1] < $b->[1];
        return 1 if  $a->[1] > $b->[1];

        # Third by frequency
        # Interlaced modes count for half their frequency
        my $freq_a = $a->[2];
        my $freq_b = $b->[2];
        $freq_a /= 2 if defined $a->[3] && $a->[3] eq 'interlaced';
        $freq_b /= 2 if defined $b->[3] && $b->[3] eq 'interlaced';
        return -1 if $freq_a < $freq_b;
        return 1 if $freq_a > $freq_b;

        return 0;
}

sub print_timings
{
        my ($bytes, $timings) = @_;

        # Established Timings
        my @established =
        (
                [720, 400, 70],
                [720, 400, 88],
                [640, 480, 60],
                [640, 480, 67],
                [640, 480, 72],
                [640, 480, 75],
                [800, 600, 56],
                [800, 600, 60],
                [800, 600, 72],
                [800, 600, 75],
                [832, 624, 75],
                [1024, 768, 87, 'interlaced'],
                [1024, 768, 60],
                [1024, 768, 70],
                [1024, 768, 75],
                [1280, 1024, 75],
                undef, undef, undef,
                [1152, 870, 75],
        );
        my $temp = extract_sesquiword($bytes, 0x23);
        for (my $i = 0; $i < 24; $i++)
        {
                next unless defined($established[$i]);
                add_timing($timings, $established[$i])
                        if ($temp & (1 << $i));
        }

        # Standard Timings
        for (my $i = 0x26; $i < 0x36; $i += 2)
        {
                add_standard_timing($timings, $bytes->[$i], $bytes->[$i+1]);
        }

        foreach my $v (sort sort_timings values(%{$timings}))
        {
                print_line("Timing", '%ux%u @ %u Hz%s',
                           $v->[0], $v->[1], $v->[2],
                           defined($v->[3]) ? ' ('.$v->[3].')' : '');
        }
}

sub extract_string
{
        my ($bytes, $offset) = @_;
        my $string = '';

        for (my $i = 5; $i < 18; $i++)
        {
                last if $bytes->[$offset+$i] == 0x0a
                     || $bytes->[$offset+$i] == 0x00;
                $string .= chr($bytes->[$offset+$i])
                        if ($bytes->[$offset+$i] >= 32
                        && $bytes->[$offset+$i] < 127);
        }
        $string =~ s/\s+$//;

        return $string;
}

# Some blocks contain different information:
#   0x00, 0x00, 0x00, 0xfa: Additional standard timings block
#   0x00, 0x00, 0x00, 0xfc: Monitor block
#   0x00, 0x00, 0x00, 0xfd: Limits block
#   0x00, 0x00, 0x00, 0xfe: Ascii block
#   0x00, 0x00, 0x00, 0xff: Serial block
# Return a reference to a hash containing all information.
sub extract_detailed_timings
{
        my ($bytes) = @_;

        my %info = ('timings' => {});

        for (my $offset = 0x36; $offset < 0x7e; $offset += 18)
        {
                if ($bytes->[$offset] == 0x00
                 && $bytes->[$offset+1] == 0x00
                 && $bytes->[$offset+2] == 0x00
                 && $bytes->[$offset+4] == 0x00)
                {
                        if ($bytes->[$offset+3] == 0xfa)
                        {
                                for (my $i = $offset + 5; $i < $offset + 17; $i += 2)
                                {
                                        add_standard_timing($info{'timings'},
                                                            $bytes->[$i],
                                                            $bytes->[$i+1]);
                                }
                        }

                        elsif ($bytes->[$offset+3] == 0xfc)
                        {
                                $info{'monitor'} .= extract_string($bytes, $offset);
                        }

                        elsif ($bytes->[$offset+3] == 0xfd)
                        {
                                $info{'limits'}{'vsync_min'} = $bytes->[$offset+5];
                                $info{'limits'}{'vsync_max'} = $bytes->[$offset+6];
                                $info{'limits'}{'hsync_min'} = $bytes->[$offset+7];
                                $info{'limits'}{'hsync_max'} = $bytes->[$offset+8];
                                $info{'limits'}{'clock_max'} = $bytes->[$offset+9];
                        }

                        elsif ($bytes->[$offset+3] == 0xfe)
                        {
                                $info{'ascii'} .= extract_string($bytes, $offset);
                        }

                        elsif ($bytes->[$offset+3] == 0xff)
                        {
                                $info{'serial'} .= extract_string($bytes, $offset);
                        }

                        next;
                }

                # Detailed Timing
                my $width = $bytes->[$offset+2] + (($bytes->[$offset+4] & 0xf0) << 4);
                my $height = $bytes->[$offset+5] + (($bytes->[$offset+7] & 0xf0) << 4);
                my $clock = extract_word($bytes, $offset) * 10000;
                my $hblank = $bytes->[$offset+3] + (($bytes->[$offset+4] & 0x0f) << 8);
                my $vblank = $bytes->[$offset+6] + (($bytes->[$offset+7] & 0x0f) << 8);
                my $area = ($width + $hblank) * ($height + $vblank);
                next unless $area; # Should not happen, but...
                my $refresh = ($clock + $area / 2) / $area; # Proper rounding
                add_timing($info{'timings'}, [$width, $height, $refresh]);
        }

        return \%info;
}

sub print_edid
{
        my ($bus, $address) = @_;
        my $bytes;

        if (-r "/sys/bus/i2c/devices/$bus-00$address/eeprom")
        {
                $bytes = get_edid_sysfs($bus, $address);
        }
        elsif (-r "/proc/sys/dev/sensors/eeprom-i2c-$bus-$address/00")
        {
                $bytes = get_edid_procfs($bus, $address);
        }

        return 1 unless defined $bytes;
        return 2 unless good_signature($bytes);

        print_line('Checksum', '%s', verify_checksum($bytes));
        my $edid_version = extract_byte($bytes, 0x12);
        my $edid_revision = extract_byte($bytes, 0x13);
        print_line('EDID Version', '%u.%u', $edid_version,
                   $edid_revision);
        if ($edid_version > 1 || $edid_revision > 2)
        {
                $standard_scales[0][0] = 16;
                $standard_scales[0][1] = 10;
        }
        else
        {
                $standard_scales[0][0] = 1;
                $standard_scales[0][1] = 1;
        }

        my $info = extract_detailed_timings($bytes);

        print_line('Manufacturer ID', '%s', extract_manufacturer($bytes, 0x08));
        print_line('Model Number', '0x%04X', extract_word($bytes, 0x0A));
        print_line('Model Name', '%s', $info->{'monitor'})
                if defined $info->{'monitor'};

        if ($info->{'serial'})
        {
                print_line('Serial Number', '%s', $info->{'serial'})
        }
        elsif ((my $temp = extract_dword($bytes, 0x0C)))
        {
                print_line('Serial Number', '%u', $temp)
        }

        print_line('Manufacture Time', '%u-W%02u',
                   1990 + extract_byte($bytes, 0x11),
                   extract_byte($bytes, 0x10));
        print_line('Display Input', '%s', extract_display_input($bytes, 0x14));
        print_line('Monitor Size (cm)', '%ux%u', extract_byte($bytes, 0x15),
                   extract_byte($bytes, 0x16));
        print_line('Gamma Factor', '%.2f',
                   1 + extract_byte($bytes, 0x17) / 100.0);
        print_line('DPMS Modes', '%s', extract_dpms($bytes, 0x18));
        print_line('Color Mode', '%s', extract_color_mode($bytes, 0x18))
                if (($bytes->[0x18] & 0x18) != 0x18);
        print_line('Additional Info', '%s', $info->{'ascii'})
                if $info->{'ascii'};

        if (defined($info->{'limits'}))
        {
                print_line('Vertical Sync (Hz)', '%u-%u',
                           $info->{'limits'}{'vsync_min'},
                           $info->{'limits'}{'vsync_max'});
                print_line('Horizontal Sync (kHz)', '%u-%u',
                           $info->{'limits'}{'hsync_min'},
                           $info->{'limits'}{'hsync_max'});
                print_line('Max Pixel Clock (MHz)', '%u',
                           $info->{'limits'}{'clock_max'} * 10)
                        unless $info->{'limits'}{'clock_max'} == 0xff;
        }

        print_timings($bytes, $info->{'timings'});
        print("\n");
        return 0;
}

# Get the address. Default to 0x50 if not given.
my $address;
if (defined($ARGV[1]))
{
        $address = $ARGV[1];
        # Convert to decimal, whatever the value.
        $address = oct $address if $address =~ m/^0/;
        # Convert to an hexadecimal string.
        $address = sprintf '%02x', $address;
}
else
{
        $address = '50';
}

if (defined($ARGV[0]))
{
        my $error = print_edid($ARGV[0], $address);
        
        if ($error == 1)
        {
                print STDERR
                        "No EEPROM found at 0x$address on bus $ARGV[0].\n";
                exit 1;
        }
        elsif ($error == 2)
        {
                print STDERR
                        "EEPROM found at 0x$address on bus $ARGV[0], but is not an EDID EEPROM.\n";
                exit 1;
        }
}
# If no bus is given, try them all.
else
{
        my $total = 0;

        for (my $i = 0; $i < 16; $i++)
        {
                $total++ unless print_edid($i, $address);
        }

        unless ($total)
        {
                print STDERR
                        "No EDID EEPROM found.\n";
                exit 1;
        }
}