From 941ed3b53086697eac7449f3ab5d2c5ab3259de2 Mon Sep 17 00:00:00 2001 From: David Fries Date: Tue, 22 Jan 2008 03:31:37 -0800 Subject: W1: w1_therm.c ds18b20 decode freezing temperatures correctly Correct 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 Signed-off-by: David Fries Acked-by: Evgeniy Polyakov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/w1/slaves/w1_therm.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/w1/slaves/w1_therm.c') diff --git a/drivers/w1/slaves/w1_therm.c b/drivers/w1/slaves/w1_therm.c index 4318935678c5..feed89e733e4 100644 --- a/drivers/w1/slaves/w1_therm.c +++ b/drivers/w1/slaves/w1_therm.c @@ -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; } -- cgit v1.2.3