[094/145] hwmon: (tmp421) Fix temperature conversions

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From: Greg KH
Date: Friday, March 12, 2010 - 5:27 pm

2.6.32-stable review patch.  If anyone has any objections, please let me know.

----------------
From: Jean Delvare <khali@linux-fr.org>

commit a44908d742a577fb5ccb9a8c082326d4cea234c2 upstream.

The low bits of temperature registers are status bits, they must be
masked out before converting the register values to temperatures.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Tested-by: Andre Prendel <andre.prendel@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
 drivers/hwmon/tmp421.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

--- a/drivers/hwmon/tmp421.c
+++ b/drivers/hwmon/tmp421.c
@@ -81,14 +81,16 @@ struct tmp421_data {
 
 static int temp_from_s16(s16 reg)
 {
-	int temp = reg;
+	/* Mask out status bits */
+	int temp = reg & ~0xf;
 
 	return (temp * 1000 + 128) / 256;
 }
 
 static int temp_from_u16(u16 reg)
 {
-	int temp = reg;
+	/* Mask out status bits */
+	int temp = reg & ~0xf;
 
 	/* Add offset for extended temperature range. */
 	temp -= 64 * 256;


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[094/145] hwmon: (tmp421) Fix temperature conversions, Greg KH, (Fri Mar 12, 5:27 pm)