From 9a6a1ecd9e9b5d046a236da2f7eb6b6812f04229 Mon Sep 17 00:00:00 2001 From: Ian Dall Date: Fri, 23 Apr 2010 13:17:53 -0400 Subject: [PATCH] w1: w1 temp: fix negative termperature calculation Fix regression caused by commit 507e2fbaaacb6f164b4125b87c5002f95143174b ("w1: w1 temp calculation overflow fix") whereby negative temperatures for the DS18B20 are not converted properly. When the temperature exceeds 32767 milli-degrees the temperature overflows to -32768 millidegrees. These are both well within the -55 - +125 degree range for the sensor. Addresses https://bugzilla.kernel.org/show_bug.cgi?id=12646 Signed-of-by: Ian Dall Cc: Evgeniy Polyakov Tested-by: Karsten Elfenbein Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/w1/slaves/w1_therm.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/drivers/w1/slaves/w1_therm.c b/drivers/w1/slaves/w1_therm.c index 1ed3d55..17726a0 100644 --- a/drivers/w1/slaves/w1_therm.c +++ b/drivers/w1/slaves/w1_therm.c @@ -115,9 +115,8 @@ static struct w1_therm_family_converter w1_therm_families[] = { static inline int w1_DS18B20_convert_temp(u8 rom[9]) { - int t = ((s16)rom[1] << 8) | rom[0]; - t = t*1000/16; - return t; + s16 t = le16_to_cpup((__le16 *)rom); + return t*1000/16; } static inline int w1_DS18S20_convert_temp(u8 rom[9]) -- 2.7.4