1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_UNITS_H
3 #define _LINUX_UNITS_H
4
5 #include <linux/bits.h>
6 #include <linux/math.h>
7
8 /* Metric prefixes in accordance with Système international (d'unités) */
9 #define PETA 1000000000000000ULL
10 #define TERA 1000000000000ULL
11 #define GIGA 1000000000UL
12 #define MEGA 1000000UL
13 #define KILO 1000UL
14 #define HECTO 100UL
15 #define DECA 10UL
16 #define DECI 10UL
17 #define CENTI 100UL
18 #define MILLI 1000UL
19 #define MICRO 1000000UL
20 #define NANO 1000000000UL
21 #define PICO 1000000000000ULL
22 #define FEMTO 1000000000000000ULL
23
24 #define NANOHZ_PER_HZ 1000000000UL
25 #define MICROHZ_PER_HZ 1000000UL
26 #define MILLIHZ_PER_HZ 1000UL
27
28 #define HZ_PER_KHZ 1000UL
29 #define HZ_PER_MHZ 1000000UL
30
31 #define KHZ_PER_MHZ 1000UL
32 #define KHZ_PER_GHZ 1000000UL
33
34 #define MILLIWATT_PER_WATT 1000UL
35 #define MICROWATT_PER_MILLIWATT 1000UL
36 #define MICROWATT_PER_WATT 1000000UL
37
38 #define BYTES_PER_KBIT (KILO / BITS_PER_BYTE)
39 #define BYTES_PER_MBIT (MEGA / BITS_PER_BYTE)
40 #define BYTES_PER_GBIT (GIGA / BITS_PER_BYTE)
41
42 #define ABSOLUTE_ZERO_MILLICELSIUS -273150
43
44 static inline long milli_kelvin_to_millicelsius(long t)
45 {
46 return t + ABSOLUTE_ZERO_MILLICELSIUS;
47 }
48
49 static inline long millicelsius_to_milli_kelvin(long t)
50 {
51 return t - ABSOLUTE_ZERO_MILLICELSIUS;
52 }
53
54 #define MILLIDEGREE_PER_DEGREE 1000
55 #define MILLIDEGREE_PER_DECIDEGREE 100
56
57 static inline long kelvin_to_millicelsius(long t)
58 {
59 return milli_kelvin_to_millicelsius(t * MILLIDEGREE_PER_DEGREE);
60 }
61
62 static inline long millicelsius_to_kelvin(long t)
63 {
64 t = millicelsius_to_milli_kelvin(t);
65
66 return DIV_ROUND_CLOSEST(t, MILLIDEGREE_PER_DEGREE);
67 }
68
69 static inline long deci_kelvin_to_celsius(long t)
70 {
71 t = milli_kelvin_to_millicelsius(t * MILLIDEGREE_PER_DECIDEGREE);
72
73 return DIV_ROUND_CLOSEST(t, MILLIDEGREE_PER_DEGREE);
74 }
75
76 static inline long celsius_to_deci_kelvin(long t)
77 {
78 t = millicelsius_to_milli_kelvin(t * MILLIDEGREE_PER_DEGREE);
79
80 return DIV_ROUND_CLOSEST(t, MILLIDEGREE_PER_DECIDEGREE);
81 }
82
83 /**
84 * deci_kelvin_to_millicelsius_with_offset - convert Kelvin to Celsius
85 * @t: temperature value in decidegrees Kelvin
86 * @offset: difference between Kelvin and Celsius in millidegrees
87 *
88 * Return: temperature value in millidegrees Celsius
89 */
90 static inline long deci_kelvin_to_millicelsius_with_offset(long t, long offset)
91 {
92 return t * MILLIDEGREE_PER_DECIDEGREE - offset;
93 }
94
95 static inline long deci_kelvin_to_millicelsius(long t)
96 {
97 return milli_kelvin_to_millicelsius(t * MILLIDEGREE_PER_DECIDEGREE);
98 }
99
100 static inline long millicelsius_to_deci_kelvin(long t)
101 {
102 t = millicelsius_to_milli_kelvin(t);
103
104 return DIV_ROUND_CLOSEST(t, MILLIDEGREE_PER_DECIDEGREE);
105 }
106
107 static inline long kelvin_to_celsius(long t)
108 {
109 return t + DIV_ROUND_CLOSEST(ABSOLUTE_ZERO_MILLICELSIUS,
110 MILLIDEGREE_PER_DEGREE);
111 }
112
113 static inline long celsius_to_kelvin(long t)
114 {
115 return t - DIV_ROUND_CLOSEST(ABSOLUTE_ZERO_MILLICELSIUS,
116 MILLIDEGREE_PER_DEGREE);
117 }
118
119 #endif /* _LINUX_UNITS_H */
120
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.