1 /* SPDX-License-Identifier: GPL-2.0 */ 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 ABSOLUTE_ZERO_MILLICELSIUS -273150 35 milli_kelvin_to_millicelsius(long t)36 static inline long milli_kelvin_to_millicelsius(long t) 37 { 38 return t + ABSOLUTE_ZERO_MILLICELSIUS; 39 } 40 millicelsius_to_milli_kelvin(long t)41 static inline long millicelsius_to_milli_kelvin(long t) 42 { 43 return t - ABSOLUTE_ZERO_MILLICELSIUS; 44 } 45 46 #define MILLIDEGREE_PER_DEGREE 1000 47 #define MILLIDEGREE_PER_DECIDEGREE 100 48 kelvin_to_millicelsius(long t)49 static inline long kelvin_to_millicelsius(long t) 50 { 51 return milli_kelvin_to_millicelsius(t * MILLIDEGREE_PER_DEGREE); 52 } 53 millicelsius_to_kelvin(long t)54 static inline long millicelsius_to_kelvin(long t) 55 { 56 t = millicelsius_to_milli_kelvin(t); 57 58 return DIV_ROUND_CLOSEST(t, MILLIDEGREE_PER_DEGREE); 59 } 60 deci_kelvin_to_celsius(long t)61 static inline long deci_kelvin_to_celsius(long t) 62 { 63 t = milli_kelvin_to_millicelsius(t * MILLIDEGREE_PER_DECIDEGREE); 64 65 return DIV_ROUND_CLOSEST(t, MILLIDEGREE_PER_DEGREE); 66 } 67 celsius_to_deci_kelvin(long t)68 static inline long celsius_to_deci_kelvin(long t) 69 { 70 t = millicelsius_to_milli_kelvin(t * MILLIDEGREE_PER_DEGREE); 71 72 return DIV_ROUND_CLOSEST(t, MILLIDEGREE_PER_DECIDEGREE); 73 } 74 75 /** 76 * deci_kelvin_to_millicelsius_with_offset - convert Kelvin to Celsius 77 * @t: temperature value in decidegrees Kelvin 78 * @offset: difference between Kelvin and Celsius in millidegrees 79 * 80 * Return: temperature value in millidegrees Celsius 81 */ deci_kelvin_to_millicelsius_with_offset(long t,long offset)82 static inline long deci_kelvin_to_millicelsius_with_offset(long t, long offset) 83 { 84 return t * MILLIDEGREE_PER_DECIDEGREE - offset; 85 } 86 deci_kelvin_to_millicelsius(long t)87 static inline long deci_kelvin_to_millicelsius(long t) 88 { 89 return milli_kelvin_to_millicelsius(t * MILLIDEGREE_PER_DECIDEGREE); 90 } 91 millicelsius_to_deci_kelvin(long t)92 static inline long millicelsius_to_deci_kelvin(long t) 93 { 94 t = millicelsius_to_milli_kelvin(t); 95 96 return DIV_ROUND_CLOSEST(t, MILLIDEGREE_PER_DECIDEGREE); 97 } 98 kelvin_to_celsius(long t)99 static inline long kelvin_to_celsius(long t) 100 { 101 return t + DIV_ROUND_CLOSEST(ABSOLUTE_ZERO_MILLICELSIUS, 102 MILLIDEGREE_PER_DEGREE); 103 } 104 celsius_to_kelvin(long t)105 static inline long celsius_to_kelvin(long t) 106 { 107 return t - DIV_ROUND_CLOSEST(ABSOLUTE_ZERO_MILLICELSIUS, 108 MILLIDEGREE_PER_DEGREE); 109 } 110 111 #endif /* _LINUX_UNITS_H */ 112