aboutsummaryrefslogtreecommitdiff
path: root/include/linux/units.h
blob: 5c115c809507f3c3d12d0fabf053ca3fcca79dfc (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_UNITS_H
#define _LINUX_UNITS_H

#include <linux/math.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 */