1 /* SPDX-License-Identifier: GPL-2.0 */
5 #include <linux/bits.h>
6 #include <linux/math.h>
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
19 #define MICRO 1000000UL
20 #define NANO 1000000000UL
21 #define PICO 1000000000000ULL
22 #define FEMTO 1000000000000000ULL
24 #define NANOHZ_PER_HZ 1000000000UL
25 #define MICROHZ_PER_HZ 1000000UL
26 #define MILLIHZ_PER_HZ 1000UL
27 #define HZ_PER_KHZ 1000UL
28 #define KHZ_PER_MHZ 1000UL
29 #define HZ_PER_MHZ 1000000UL
31 #define MILLIWATT_PER_WATT 1000UL
32 #define MICROWATT_PER_MILLIWATT 1000UL
33 #define MICROWATT_PER_WATT 1000000UL
35 #define BYTES_PER_KBIT (KILO / BITS_PER_BYTE)
36 #define BYTES_PER_MBIT (MEGA / BITS_PER_BYTE)
37 #define BYTES_PER_GBIT (GIGA / BITS_PER_BYTE)
39 #define ABSOLUTE_ZERO_MILLICELSIUS -273150
41 static inline long milli_kelvin_to_millicelsius(long t)
43 return t + ABSOLUTE_ZERO_MILLICELSIUS;
46 static inline long millicelsius_to_milli_kelvin(long t)
48 return t - ABSOLUTE_ZERO_MILLICELSIUS;
51 #define MILLIDEGREE_PER_DEGREE 1000
52 #define MILLIDEGREE_PER_DECIDEGREE 100
54 static inline long kelvin_to_millicelsius(long t)
56 return milli_kelvin_to_millicelsius(t * MILLIDEGREE_PER_DEGREE);
59 static inline long millicelsius_to_kelvin(long t)
61 t = millicelsius_to_milli_kelvin(t);
63 return DIV_ROUND_CLOSEST(t, MILLIDEGREE_PER_DEGREE);
66 static inline long deci_kelvin_to_celsius(long t)
68 t = milli_kelvin_to_millicelsius(t * MILLIDEGREE_PER_DECIDEGREE);
70 return DIV_ROUND_CLOSEST(t, MILLIDEGREE_PER_DEGREE);
73 static inline long celsius_to_deci_kelvin(long t)
75 t = millicelsius_to_milli_kelvin(t * MILLIDEGREE_PER_DEGREE);
77 return DIV_ROUND_CLOSEST(t, MILLIDEGREE_PER_DECIDEGREE);
81 * deci_kelvin_to_millicelsius_with_offset - convert Kelvin to Celsius
82 * @t: temperature value in decidegrees Kelvin
83 * @offset: difference between Kelvin and Celsius in millidegrees
85 * Return: temperature value in millidegrees Celsius
87 static inline long deci_kelvin_to_millicelsius_with_offset(long t, long offset)
89 return t * MILLIDEGREE_PER_DECIDEGREE - offset;
92 static inline long deci_kelvin_to_millicelsius(long t)
94 return milli_kelvin_to_millicelsius(t * MILLIDEGREE_PER_DECIDEGREE);
97 static inline long millicelsius_to_deci_kelvin(long t)
99 t = millicelsius_to_milli_kelvin(t);
101 return DIV_ROUND_CLOSEST(t, MILLIDEGREE_PER_DECIDEGREE);
104 static inline long kelvin_to_celsius(long t)
106 return t + DIV_ROUND_CLOSEST(ABSOLUTE_ZERO_MILLICELSIUS,
107 MILLIDEGREE_PER_DEGREE);
110 static inline long celsius_to_kelvin(long t)
112 return t - DIV_ROUND_CLOSEST(ABSOLUTE_ZERO_MILLICELSIUS,
113 MILLIDEGREE_PER_DEGREE);
116 #endif /* _LINUX_UNITS_H */