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1 | /* SPDX-License-Identifier: GPL-2.0 */ |
2 | #ifndef _LINUX_UNITS_H | |
3 | #define _LINUX_UNITS_H | |
4 | ||
aa6159ab | 5 | #include <linux/math.h> |
23331e48 AM |
6 | |
7 | #define ABSOLUTE_ZERO_MILLICELSIUS -273150 | |
8 | ||
9 | static inline long milli_kelvin_to_millicelsius(long t) | |
10 | { | |
11 | return t + ABSOLUTE_ZERO_MILLICELSIUS; | |
12 | } | |
13 | ||
14 | static inline long millicelsius_to_milli_kelvin(long t) | |
15 | { | |
16 | return t - ABSOLUTE_ZERO_MILLICELSIUS; | |
17 | } | |
18 | ||
19 | #define MILLIDEGREE_PER_DEGREE 1000 | |
20 | #define MILLIDEGREE_PER_DECIDEGREE 100 | |
21 | ||
22 | static inline long kelvin_to_millicelsius(long t) | |
23 | { | |
24 | return milli_kelvin_to_millicelsius(t * MILLIDEGREE_PER_DEGREE); | |
25 | } | |
26 | ||
27 | static inline long millicelsius_to_kelvin(long t) | |
28 | { | |
29 | t = millicelsius_to_milli_kelvin(t); | |
30 | ||
31 | return DIV_ROUND_CLOSEST(t, MILLIDEGREE_PER_DEGREE); | |
32 | } | |
33 | ||
34 | static inline long deci_kelvin_to_celsius(long t) | |
35 | { | |
36 | t = milli_kelvin_to_millicelsius(t * MILLIDEGREE_PER_DECIDEGREE); | |
37 | ||
38 | return DIV_ROUND_CLOSEST(t, MILLIDEGREE_PER_DEGREE); | |
39 | } | |
40 | ||
41 | static inline long celsius_to_deci_kelvin(long t) | |
42 | { | |
43 | t = millicelsius_to_milli_kelvin(t * MILLIDEGREE_PER_DEGREE); | |
44 | ||
45 | return DIV_ROUND_CLOSEST(t, MILLIDEGREE_PER_DECIDEGREE); | |
46 | } | |
47 | ||
48 | /** | |
49 | * deci_kelvin_to_millicelsius_with_offset - convert Kelvin to Celsius | |
50 | * @t: temperature value in decidegrees Kelvin | |
51 | * @offset: difference between Kelvin and Celsius in millidegrees | |
52 | * | |
53 | * Return: temperature value in millidegrees Celsius | |
54 | */ | |
55 | static inline long deci_kelvin_to_millicelsius_with_offset(long t, long offset) | |
56 | { | |
57 | return t * MILLIDEGREE_PER_DECIDEGREE - offset; | |
58 | } | |
59 | ||
60 | static inline long deci_kelvin_to_millicelsius(long t) | |
61 | { | |
62 | return milli_kelvin_to_millicelsius(t * MILLIDEGREE_PER_DECIDEGREE); | |
63 | } | |
64 | ||
65 | static inline long millicelsius_to_deci_kelvin(long t) | |
66 | { | |
67 | t = millicelsius_to_milli_kelvin(t); | |
68 | ||
69 | return DIV_ROUND_CLOSEST(t, MILLIDEGREE_PER_DECIDEGREE); | |
70 | } | |
71 | ||
72 | static inline long kelvin_to_celsius(long t) | |
73 | { | |
74 | return t + DIV_ROUND_CLOSEST(ABSOLUTE_ZERO_MILLICELSIUS, | |
75 | MILLIDEGREE_PER_DEGREE); | |
76 | } | |
77 | ||
78 | static inline long celsius_to_kelvin(long t) | |
79 | { | |
80 | return t - DIV_ROUND_CLOSEST(ABSOLUTE_ZERO_MILLICELSIUS, | |
81 | MILLIDEGREE_PER_DEGREE); | |
82 | } | |
83 | ||
84 | #endif /* _LINUX_UNITS_H */ |