1 | /* SPDX-License-Identifier: GPL-2.0 */ |
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2 | #ifndef _LINUX_UNITS_H |
3 | #define _LINUX_UNITS_H |
4 | |
5 | #include <linux/math.h> |
6 | |
7 | /* Metric prefixes in accordance with Système international (d'unités) */ |
8 | #define PETA 1000000000000000ULL |
9 | #define TERA 1000000000000ULL |
10 | #define GIGA 1000000000UL |
11 | #define MEGA 1000000UL |
12 | #define KILO 1000UL |
13 | #define HECTO 100UL |
14 | #define DECA 10UL |
15 | #define DECI 10UL |
16 | #define CENTI 100UL |
17 | #define MILLI 1000UL |
18 | #define MICRO 1000000UL |
19 | #define NANO 1000000000UL |
20 | #define PICO 1000000000000ULL |
21 | #define FEMTO 1000000000000000ULL |
22 | |
23 | #define NANOHZ_PER_HZ 1000000000UL |
24 | #define MICROHZ_PER_HZ 1000000UL |
25 | #define MILLIHZ_PER_HZ 1000UL |
26 | #define HZ_PER_KHZ 1000UL |
27 | #define KHZ_PER_MHZ 1000UL |
28 | #define HZ_PER_MHZ 1000000UL |
29 | |
30 | #define MILLIWATT_PER_WATT 1000UL |
31 | #define MICROWATT_PER_MILLIWATT 1000UL |
32 | #define MICROWATT_PER_WATT 1000000UL |
33 | |
34 | #define BYTES_PER_KBIT (KILO / BITS_PER_BYTE) |
35 | #define BYTES_PER_MBIT (MEGA / BITS_PER_BYTE) |
36 | #define BYTES_PER_GBIT (GIGA / BITS_PER_BYTE) |
37 | |
38 | #define ABSOLUTE_ZERO_MILLICELSIUS -273150 |
39 | |
40 | static inline long milli_kelvin_to_millicelsius(long t) |
41 | { |
42 | return t + ABSOLUTE_ZERO_MILLICELSIUS; |
43 | } |
44 | |
45 | static inline long millicelsius_to_milli_kelvin(long t) |
46 | { |
47 | return t - ABSOLUTE_ZERO_MILLICELSIUS; |
48 | } |
49 | |
50 | #define MILLIDEGREE_PER_DEGREE 1000 |
51 | #define MILLIDEGREE_PER_DECIDEGREE 100 |
52 | |
53 | static inline long kelvin_to_millicelsius(long t) |
54 | { |
55 | return milli_kelvin_to_millicelsius(t: t * MILLIDEGREE_PER_DEGREE); |
56 | } |
57 | |
58 | static inline long millicelsius_to_kelvin(long t) |
59 | { |
60 | t = millicelsius_to_milli_kelvin(t); |
61 | |
62 | return DIV_ROUND_CLOSEST(t, MILLIDEGREE_PER_DEGREE); |
63 | } |
64 | |
65 | static inline long deci_kelvin_to_celsius(long t) |
66 | { |
67 | t = milli_kelvin_to_millicelsius(t: t * MILLIDEGREE_PER_DECIDEGREE); |
68 | |
69 | return DIV_ROUND_CLOSEST(t, MILLIDEGREE_PER_DEGREE); |
70 | } |
71 | |
72 | static inline long celsius_to_deci_kelvin(long t) |
73 | { |
74 | t = millicelsius_to_milli_kelvin(t: t * MILLIDEGREE_PER_DEGREE); |
75 | |
76 | return DIV_ROUND_CLOSEST(t, MILLIDEGREE_PER_DECIDEGREE); |
77 | } |
78 | |
79 | /** |
80 | * deci_kelvin_to_millicelsius_with_offset - convert Kelvin to Celsius |
81 | * @t: temperature value in decidegrees Kelvin |
82 | * @offset: difference between Kelvin and Celsius in millidegrees |
83 | * |
84 | * Return: temperature value in millidegrees Celsius |
85 | */ |
86 | static inline long deci_kelvin_to_millicelsius_with_offset(long t, long offset) |
87 | { |
88 | return t * MILLIDEGREE_PER_DECIDEGREE - offset; |
89 | } |
90 | |
91 | static inline long deci_kelvin_to_millicelsius(long t) |
92 | { |
93 | return milli_kelvin_to_millicelsius(t: t * MILLIDEGREE_PER_DECIDEGREE); |
94 | } |
95 | |
96 | static inline long millicelsius_to_deci_kelvin(long t) |
97 | { |
98 | t = millicelsius_to_milli_kelvin(t); |
99 | |
100 | return DIV_ROUND_CLOSEST(t, MILLIDEGREE_PER_DECIDEGREE); |
101 | } |
102 | |
103 | static inline long kelvin_to_celsius(long t) |
104 | { |
105 | return t + DIV_ROUND_CLOSEST(ABSOLUTE_ZERO_MILLICELSIUS, |
106 | MILLIDEGREE_PER_DEGREE); |
107 | } |
108 | |
109 | static inline long celsius_to_kelvin(long t) |
110 | { |
111 | return t - DIV_ROUND_CLOSEST(ABSOLUTE_ZERO_MILLICELSIUS, |
112 | MILLIDEGREE_PER_DEGREE); |
113 | } |
114 | |
115 | #endif /* _LINUX_UNITS_H */ |
116 |