From ab116c9658f2de210d84976b2667cb94ee41cd99 Mon Sep 17 00:00:00 2001
From: Guenter Roeck <linux@roeck-us.net>
Date: Wed, 1 Jun 2011 16:20:05 +0000
Subject: [PATCH] Add detection of MAX6642

git-svn-id: http://lm-sensors.org/svn/lm-sensors/trunk@5978 7894878c-1315-0410-8ee3-d5d059ff63e0
---
 CHANGES                    |  1 +
 prog/detect/sensors-detect | 39 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 40 insertions(+)

diff --git a/CHANGES b/CHANGES
index 1edb744d..d1bd5c11 100644
--- a/CHANGES
+++ b/CHANGES
@@ -13,6 +13,7 @@ SVN HEAD
                   Add detection of SMSC EMC6W201
                   Drop unreliable detection of Maxim MAX6650
                   Add detection of SMSC EMC2300
+                  Add detection of MAX6642
 
 3.3.0 (2011-03-28)
   Makefile: Check for bison and flex
diff --git a/prog/detect/sensors-detect b/prog/detect/sensors-detect
index 734e36c1..7757fb0a 100755
--- a/prog/detect/sensors-detect
+++ b/prog/detect/sensors-detect
@@ -847,6 +847,11 @@ use vars qw(@i2c_adapter_names);
 		driver => "max6639",
 		i2c_addrs => [0x2c, 0x2e, 0x2f],
 		i2c_detect => sub { max6639_detect(@_); },
+	}, {
+		name => "Maxim MAX6642",
+		driver => "max6642",
+		i2c_addrs => [0x48..0x4f],
+		i2c_detect => sub { max6642_detect(@_); },
 	}, {
 		name => "Maxim MAX6655/MAX6656",
 		driver => "max6655",
@@ -5789,6 +5794,40 @@ sub max6639_detect
 	return 6;
 }
 
+# Chip to detect: MAX6642
+# Registers used:
+#   0x02: Status register
+#   0x03: Configuration register
+#   0xfe: Manufacturer ID
+#   0x04, 0x06, 0xff: No registers
+# We use the 0x04, 0x06 and 0xff addresses (unused) to improve reliability.
+# These are not real registers and will always return the last returned value.
+# This isn't documented.
+sub max6642_detect
+{
+	my ($file, $addr) = @_;
+	my ($man_id, $conf, $status);
+
+	$man_id = i2c_smbus_read_byte_data($file, 0xfe);
+	return unless $man_id == 0x4d;	# Maxim
+	return if i2c_smbus_read_byte_data($file, 0x04, NO_CACHE) != $man_id;
+	return if i2c_smbus_read_byte_data($file, 0x06, NO_CACHE) != $man_id;
+	return if i2c_smbus_read_byte_data($file, 0xff, NO_CACHE) != $man_id;
+
+	$status = i2c_smbus_read_byte_data($file, 0x02);
+	# Bit 5, 3, 1 and 0 should be zero
+	return unless ($status & 0x2b) == 0x00;
+	return if i2c_smbus_read_byte_data($file, 0x04, NO_CACHE) != $status;
+	return if i2c_smbus_read_byte_data($file, 0x06, NO_CACHE) != $status;
+	return if i2c_smbus_read_byte_data($file, 0xff, NO_CACHE) != $status;
+
+	$conf = i2c_smbus_read_byte_data($file, 0x03);
+	# The 4 lower bits should be zero
+	return unless ($conf & 0x0f) == 0x00;
+
+	return 5;
+}
+
 sub max6655_detect
 {
 	my ($file, $addr) = @_;