| From 9a6a1ecd9e9b5d046a236da2f7eb6b6812f04229 Mon Sep 17 00:00:00 2001 |
| From: Ian Dall <ian@beware.dropbear.id.au> |
| Date: Fri, 23 Apr 2010 13:17:53 -0400 |
| Subject: w1: w1 temp: fix negative termperature calculation |
| |
| From: Ian Dall <ian@beware.dropbear.id.au> |
| |
| commit 9a6a1ecd9e9b5d046a236da2f7eb6b6812f04229 upstream. |
| |
| 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 <ian@beware.dropbear.id.au> |
| Cc: Evgeniy Polyakov <johnpol@2ka.mipt.ru> |
| Tested-by: Karsten Elfenbein <kelfe@gmx.de> |
| Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
| Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> |
| |
| --- |
| drivers/w1/slaves/w1_therm.c | 5 ++--- |
| 1 file changed, 2 insertions(+), 3 deletions(-) |
| |
| --- a/drivers/w1/slaves/w1_therm.c |
| +++ b/drivers/w1/slaves/w1_therm.c |
| @@ -115,9 +115,8 @@ static struct w1_therm_family_converter |
| |
| 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]) |
