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 milli_kelvin_to_millicelsius(long t)44 static inline long milli_kelvin_to_millicelsius(long t) 45 { 46 return t + ABSOLUTE_ZERO_MILLICELSIUS; 47 } 48 millicelsius_to_milli_kelvin(long t)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 kelvin_to_millicelsius(long t)57 static inline long kelvin_to_millicelsius(long t) 58 { 59 return milli_kelvin_to_millicelsius(t * MILLIDEGREE_PER_DEGREE); 60 } 61 millicelsius_to_kelvin(long t)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 deci_kelvin_to_celsius(long t)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 celsius_to_deci_kelvin(long t)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 */ deci_kelvin_to_millicelsius_with_offset(long t,long offset)90 static inline long deci_kelvin_to_millicelsius_with_offset(long t, long offset) 91 { 92 return t * MILLIDEGREE_PER_DECIDEGREE - offset; 93 } 94 deci_kelvin_to_millicelsius(long t)95 static inline long deci_kelvin_to_millicelsius(long t) 96 { 97 return milli_kelvin_to_millicelsius(t * MILLIDEGREE_PER_DECIDEGREE); 98 } 99 millicelsius_to_deci_kelvin(long t)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 kelvin_to_celsius(long t)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 celsius_to_kelvin(long t)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