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| author | Ian Dall <ian@beware.dropbear.id.au> | 2010-04-23 13:17:53 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2010-05-12 15:02:32 -0700 |
| commit | 73791763dbad4d68a1d36b7f2ded26d0214bf09c (patch) | |
| tree | dac7f4aaca02012a5419bdc1e7b6d24b02a0c977 /drivers/w1 | |
| parent | 5555d67fab1f38f51faf870a445d329dc0ba3388 (diff) | |
| download | lwn-73791763dbad4d68a1d36b7f2ded26d0214bf09c.tar.gz lwn-73791763dbad4d68a1d36b7f2ded26d0214bf09c.zip | |
w1: w1 temp: fix negative termperature calculation
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>
Diffstat (limited to 'drivers/w1')
| -rw-r--r-- | drivers/w1/slaves/w1_therm.c | 5 |
1 files changed, 2 insertions, 3 deletions
diff --git a/drivers/w1/slaves/w1_therm.c b/drivers/w1/slaves/w1_therm.c index 1ed3d554e372..17726a05a0a6 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]) |