[patch 063/123] hwmon: (tmp421) Fix temperature conversions

From: Greg KH
Date: Fri Mar 12 2010 - 20:22:56 EST


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

-----------------

From: Jean Delvare <khali@xxxxxxxxxxxx>

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@xxxxxxxxxxxx>
Tested-by: Andre Prendel <andre.prendel@xxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

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

--- a/drivers/hwmon/tmp421.c
+++ b/drivers/hwmon/tmp421.c
@@ -80,14 +80,16 @@ 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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