W1: w1_therm.c ds18b20 decode freezing temperatures correctly

commit c4ad974f3acef11e538e825ca0cb73be6faf2461

Author: David Fries <[email protected]>
Date:   Sun Nov 4 18:14:21 2007 -0600

Corrected the decoding of negative C temperatures. The code did a binary OR of two bytes to make a 16 bit value, but assignd it to an integer. This caused the value to not be sign extended and to loose that it was a negative number in the assignment.
Before the patch (in my freezer),
w1_slave
ed fe 4b 46 7f ff 03 10 e4 : crc=e4 YES
ed fe 4b 46 7f ff 03 10 e4 t=4078
With the patch,
e3 fe 4b 46 7f ff 0d 10 81 : crc=81 YES
e3 fe 4b 46 7f ff 0d 10 81 t=-17

index 4318935..feed89e 100644
@@ -112,7 +112,7 @@ static struct w1_therm_family_converter w1_therm_families[] = {
 
 static inline int w1_DS18B20_convert_temp(u8 rom[9])
 {
-	int t = (rom[1] << 8) | rom[0];
+	s16 t = (rom[1] << 8) | rom[0];
 	t /= 16;
 	return t;
 }

David Fries <[email protected]>
http://fries.net/~david/ (PGP encryption key available)

Hi David.

Both patches looks ok, thanks a lot.
Andrew, please apply.

	Evgeniy Polyakov