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-rw-r--r-- | include/linux/units.h | 84 |
1 files changed, 84 insertions, 0 deletions
diff --git a/include/linux/units.h b/include/linux/units.h new file mode 100644 index 000000000000..aaf716364ec3 --- /dev/null +++ b/include/linux/units.h @@ -0,0 +1,84 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _LINUX_UNITS_H +#define _LINUX_UNITS_H + +#include <linux/kernel.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 */ |