Changeset 5248

Timestamp:

05/11/08 19:16:27 (6 months ago)

Author:

khali

Message:

Rework all device detection routines which use SMBus read word
transactions in address range 0x40-0x48. Some devices don't like word
transactions, so we now try to do as much of the detection as possible
using byte transactions, and only use word transactions when there is
a good chance that the detection will succeed.

Files:

• lm-sensors/trunk/CHANGES (modified) (1 diff)
• lm-sensors/trunk/prog/detect/sensors-detect (modified) (8 diffs)

lm-sensors/trunk/CHANGES

@@ -20 +20 @@
-                          Fix the parsing of I2C addresses not to scan
-                          Detect and skip 1-register-only I2C devices
+                          Avoid SMBus word transactions where possible
-
-2.10.6 "Welcome Home Lina" (20080306)

lm-sensors/trunk/prog/detect/sensors-detect

@@ -2725 +2725 @@
-# $_[1]: Command byte (usually register number)
-# Returns: -1 on failure, the read word on success.
+# Use this function with care, some devices don't like word reads,
+# so you should do as much of the detection as possible using byte reads,
+# and only start using word reads when there is a good chance that
+# the detection will succeed.
-# Note: some devices use the wrong endiannes; use swap_bytes to correct for 
-# this.
@@ -3588 +3592 @@
-# all register addresses from 0x04 to 0x0f behave like 0x04-0x07 do for
-# the LM75.
+# Not all devices enjoy SMBus read word transactions, so we use read byte
+# transactions even for the 16-bit registers. The low bits aren't very
+# useful for detection anyway.
-sub lm75_detect
-{
-  my $i;
-  my ($chip, $file, $addr) = @_;
-word_data($file,
+byte_data($file, 
-  my $conf = i2c_smbus_read_byte_data($file,0x01);
-
-word_data($file,
+byte_data($file, 
-  my $maxreg = $chip == 1 ? 0x0f : 0x07;
-  for $i (0x04 .. $maxreg) {
-word
-
-
-word_data($file,
+byte
+
+
+byte_data($file, 
-  for $i (0x04 .. $maxreg) {
-word
+byte
-  }
-
@@ -3609 +3616 @@
-    for ($i = 8; $i <= 248; $i += 40) {
-      return if i2c_smbus_read_byte_data($file, $i + 0x01) != $conf
-word
-word
+byte
+byte
-    }
-  }
-
-  # All registers hold the same value, obviously a misdetection
-
-
-
-
-
-
+
+
-  # Unused bits
-  return if $chip == 0 and ($conf & 0xe0);
-  return if $chip == 1 and ($conf & 0x80);
-
-  $cur = $cur >> 8;
-  $hyst = $hyst >> 8;
-  $os = $os >> 8;
-  # Most probable value ranges
-  return 6 if $cur <= 100 and ($hyst >= 10 && $hyst <= 125)
@@ -3646 +3646 @@
-#   0x04: Low limit
-#   0x05: High limit
-4
+6
-# The first detection step is based on the fact that the LM77 has only
-# six registers, and cycles addresses over 8-byte boundaries. We use the
@@ -3653 +3653 @@
-# documented.
-# Note that register 0x00 may change, so we can't use the modulo trick on it.
+# Not all devices enjoy SMBus read word transactions, so we use read byte
+# transactions even for the 16-bit registers at first. We only use read word
+# transactions in the end when we are already almost certain that we have an
+# LM77 chip.
-sub lm77_detect
-{
-  my $i;
-  my ($file,$addr) = @_;
-word_data($file,
+byte_data($file, 
-  my $conf = i2c_smbus_read_byte_data($file,0x01);
-word_data($file,
-word_data($file,
-
-word_data($file,
-word_data($file,
-word_data($file,
-
-word_data($file,
-word_data($file,
-word_data($file,
+byte_data($file, 
+byte_data($file, 
+
+byte_data($file, 
+byte_data($file, 
+byte_data($file, 
+
+byte_data($file, 
+byte_data($file, 
+byte_data($file, 
-
-  for ($i = 8; $i <= 248; $i += 40) {
-    return if i2c_smbus_read_byte_data($file, $i + 0x01) != $conf;
-word
-word
-word
-word
+byte
+byte
+byte
+byte
-  }
-
-  # All registers hold the same value, obviously a misdetection
-($cur & 0xff)
+$cur
-    and $cur == $os and $cur == $low and $cur == $high;
-
-  $cur = swap_bytes($cur);
-  $os = swap_bytes($os);
-  $hyst = swap_bytes($hyst);
-  $low = swap_bytes($low);
-  $high = swap_bytes($high);
-  # Unused bits
-  return if ($conf & 0xe0)
-
-
-
-
-
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
-
-  $cur /= 16;
@@ -3721 +3732 @@
-# limited number of registers, which cycle modulo 16 address values.
-# Note that register 0x00 may change, so we can't use the modulo trick on it.
+# Not all devices enjoy SMBus read word transactions, so we use read byte
+# transactions even for the 16-bit registers at first. We only use read
+# word transactions in the end when we are already almost certain that we
+# have an LM92 chip or compatible.
-sub lm92_detect
-{
@@ -3726 +3741 @@
-
-  my $conf = i2c_smbus_read_byte_data($file, 0x01);
-word
-word
-word
-word
+byte
+byte
+byte
+byte
-
-  return if $conf == 0 and $hyst == 0 and $crit == 0
-        and $low == 0 and $high == 0;
-
+  # Unused bits
+  return if ($chip == 0 || $chip == 1)
+        and ($conf & 0xE0);
+
+  for (my $i = 0; $i <= 240; $i += 16) {
+    return if i2c_smbus_read_byte_data($file, $i + 0x01) != $conf;
+    return if i2c_smbus_read_byte_data($file, $i + 0x02) != $hyst;
+    return if i2c_smbus_read_byte_data($file, $i + 0x03) != $crit;
+    return if i2c_smbus_read_byte_data($file, $i + 0x04) != $low;
+    return if i2c_smbus_read_byte_data($file, $i + 0x05) != $high;
+  }
+  
-  return if $chip == 0
-        and i2c_smbus_read_word_data($file, 0x07) != 0x0180;
-
-
-
-
-
-
-
-
-
-
-
-
+
+
+
+
+
+
+
+
+
+
+
-  foreach my $temp ($hyst, $crit, $low, $high) {
-    return if $chip == 2 and ($temp & 0x7F00);
@@ -3764 +3790 @@
-#   0xA1: High limit
-#   0xA2: Low limit
+#   0xA8: Counter
+#   0xA9: Slope
-#   0xAC: Configuration
-# Detection is weak. We check if bit 4 (NVB) is clear, because it is
-# unlikely to be set (would mean that EEPROM is currently being accessed).
-
-
+
+
+
+
+
+
-sub ds1621_detect
-{
-  my $i;
-  my ($file,$addr) = @_;
+
+  my $conf = i2c_smbus_read_byte_data($file, 0xAC);
+  return if ($conf & 0x10);
+
+  my $counter = i2c_smbus_read_byte_data($file, 0xA8);
+  my $slope = i2c_smbus_read_byte_data($file, 0xA9);
+  return if ($slope != 0x10 || $counter > $slope);
+
-  my $temp = i2c_smbus_read_word_data($file,0xAA);
+  return if $temp < 0 || ($temp & 0x7f00);
-  my $high = i2c_smbus_read_word_data($file,0xA1);
+  return if $high < 0 || ($high & 0x7f00);
-  my $low = i2c_smbus_read_word_data($file,0xA2);
-($temp | $high | $low) & 0x7F00
-
+$low < 0 || ($low & 0x7f00)
+
-  return if ($temp == 0 && $high == 0 && $low == 0 && $conf == 0);
-
-
+
+ 3
-}
-