units.h
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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_UNITS_H
#define _LINUX_UNITS_H
#include <linux/kernel.h>
#define ABSOLUTE_ZERO_MILLICELSIUS -273150
static inline long milli_kelvin_to_millicelsius(long t)
{
return t + ABSOLUTE_ZERO_MILLICELSIUS;
}
static inline long millicelsius_to_milli_kelvin(long t)
{
return t - ABSOLUTE_ZERO_MILLICELSIUS;
}
#define MILLIDEGREE_PER_DEGREE 1000
#define MILLIDEGREE_PER_DECIDEGREE 100
static inline long kelvin_to_millicelsius(long t)
{
return milli_kelvin_to_millicelsius(t * MILLIDEGREE_PER_DEGREE);
}
static inline long millicelsius_to_kelvin(long t)
{
t = millicelsius_to_milli_kelvin(t);
return DIV_ROUND_CLOSEST(t, MILLIDEGREE_PER_DEGREE);
}
static inline long deci_kelvin_to_celsius(long t)
{
t = milli_kelvin_to_millicelsius(t * MILLIDEGREE_PER_DECIDEGREE);
return DIV_ROUND_CLOSEST(t, MILLIDEGREE_PER_DEGREE);
}
static inline long celsius_to_deci_kelvin(long t)
{
t = millicelsius_to_milli_kelvin(t * MILLIDEGREE_PER_DEGREE);
return DIV_ROUND_CLOSEST(t, MILLIDEGREE_PER_DECIDEGREE);
}
/**
* deci_kelvin_to_millicelsius_with_offset - convert Kelvin to Celsius
* @t: temperature value in decidegrees Kelvin
* @offset: difference between Kelvin and Celsius in millidegrees
*
* Return: temperature value in millidegrees Celsius
*/
static inline long deci_kelvin_to_millicelsius_with_offset(long t, long offset)
{
return t * MILLIDEGREE_PER_DECIDEGREE - offset;
}
static inline long deci_kelvin_to_millicelsius(long t)
{
return milli_kelvin_to_millicelsius(t * MILLIDEGREE_PER_DECIDEGREE);
}
static inline long millicelsius_to_deci_kelvin(long t)
{
t = millicelsius_to_milli_kelvin(t);
return DIV_ROUND_CLOSEST(t, MILLIDEGREE_PER_DECIDEGREE);
}
static inline long kelvin_to_celsius(long t)
{
return t + DIV_ROUND_CLOSEST(ABSOLUTE_ZERO_MILLICELSIUS,
MILLIDEGREE_PER_DEGREE);
}
static inline long celsius_to_kelvin(long t)
{
return t - DIV_ROUND_CLOSEST(ABSOLUTE_ZERO_MILLICELSIUS,
MILLIDEGREE_PER_DEGREE);
}
#endif /* _LINUX_UNITS_H */