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hwmon: (adc128d818) Do proper sign extension 

data->temp[index] has type s16. Because of C's promotion rules,
(data->temp[index] << 7) >> 7 is exactly the same as
data->temp[index]. The intention was to use bit 8 as a sign bit, so do
that using the existing API.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
This commit is contained in:
Rasmus Villemoes 2015-01-22 23:44:14 +01:00 committed by Guenter Roeck
parent 984faa1fb9
commit 2c3b1189fd
1 changed files with 2 additions and 1 deletions
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3
drivers/hwmon/adc128d818.c
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@ -27,6 +27,7 @@
#include <linux/err.h>
#include <linux/regulator/consumer.h>
#include <linux/mutex.h>
#include <linux/bitops.h>
/* Addresses to scan
* The chip also supports addresses 0x35..0x37. Don't scan those addresses
@ -189,7 +190,7 @@ static ssize_t adc128_show_temp(struct device *dev,
if (IS_ERR(data))
return PTR_ERR(data);
temp = (data->temp[index] << 7) >> 7; /* sign extend */
temp = sign_extend32(data->temp[index], 8);
return sprintf(buf, "%d\n", temp * 500);/* 0.5 degrees C resolution */
}