1 /* SPDX-License-Identifier: GPL-2.0 */
5 #include <linux/math.h>
7 #define MILLIWATT_PER_WATT 1000L
8 #define MICROWATT_PER_MILLIWATT 1000L
9 #define MICROWATT_PER_WATT 1000000L
11 #define ABSOLUTE_ZERO_MILLICELSIUS -273150
13 static inline long milli_kelvin_to_millicelsius(long t
)
15 return t
+ ABSOLUTE_ZERO_MILLICELSIUS
;
18 static inline long millicelsius_to_milli_kelvin(long t
)
20 return t
- ABSOLUTE_ZERO_MILLICELSIUS
;
23 #define MILLIDEGREE_PER_DEGREE 1000
24 #define MILLIDEGREE_PER_DECIDEGREE 100
26 static inline long kelvin_to_millicelsius(long t
)
28 return milli_kelvin_to_millicelsius(t
* MILLIDEGREE_PER_DEGREE
);
31 static inline long millicelsius_to_kelvin(long t
)
33 t
= millicelsius_to_milli_kelvin(t
);
35 return DIV_ROUND_CLOSEST(t
, MILLIDEGREE_PER_DEGREE
);
38 static inline long deci_kelvin_to_celsius(long t
)
40 t
= milli_kelvin_to_millicelsius(t
* MILLIDEGREE_PER_DECIDEGREE
);
42 return DIV_ROUND_CLOSEST(t
, MILLIDEGREE_PER_DEGREE
);
45 static inline long celsius_to_deci_kelvin(long t
)
47 t
= millicelsius_to_milli_kelvin(t
* MILLIDEGREE_PER_DEGREE
);
49 return DIV_ROUND_CLOSEST(t
, MILLIDEGREE_PER_DECIDEGREE
);
53 * deci_kelvin_to_millicelsius_with_offset - convert Kelvin to Celsius
54 * @t: temperature value in decidegrees Kelvin
55 * @offset: difference between Kelvin and Celsius in millidegrees
57 * Return: temperature value in millidegrees Celsius
59 static inline long deci_kelvin_to_millicelsius_with_offset(long t
, long offset
)
61 return t
* MILLIDEGREE_PER_DECIDEGREE
- offset
;
64 static inline long deci_kelvin_to_millicelsius(long t
)
66 return milli_kelvin_to_millicelsius(t
* MILLIDEGREE_PER_DECIDEGREE
);
69 static inline long millicelsius_to_deci_kelvin(long t
)
71 t
= millicelsius_to_milli_kelvin(t
);
73 return DIV_ROUND_CLOSEST(t
, MILLIDEGREE_PER_DECIDEGREE
);
76 static inline long kelvin_to_celsius(long t
)
78 return t
+ DIV_ROUND_CLOSEST(ABSOLUTE_ZERO_MILLICELSIUS
,
79 MILLIDEGREE_PER_DEGREE
);
82 static inline long celsius_to_kelvin(long t
)
84 return t
- DIV_ROUND_CLOSEST(ABSOLUTE_ZERO_MILLICELSIUS
,
85 MILLIDEGREE_PER_DEGREE
);
88 #endif /* _LINUX_UNITS_H */