Patch series "add header file for kelvin to/from Celsius conversion helpers", v4. There are several helper macros to convert kelvin to/from Celsius in <linux/thermal.h> for thermal drivers. These are useful for any other drivers or subsystems, but it's odd to include <linux/thermal.h> just for the helpers. This adds a new <linux/units.h> that provides the equivalent inline functions for any drivers or subsystems, and switches all the users of conversion helpers in <linux/thermal.h> to use <linux/units.h> helpers. This patch (of 12): There are several helper macros to convert kelvin to/from Celsius in <linux/thermal.h> for thermal drivers. These are useful for any other drivers or subsystems, but it's odd to include <linux/thermal.h> just for the helpers. This adds a new <linux/units.h> that provides the equivalent inline functions for any drivers or subsystems. It is intended to replace the helpers in <linux/thermal.h>.
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| 1 | /* SPDX-License-Identifier: GPL-2.0 */ | ||
| 2 | #ifndef _LINUX_UNITS_H | ||
| 3 | #define _LINUX_UNITS_H | ||
| 4 | |||
| 5 | #include <linux/kernel.h> | ||
| 6 | |||
| 7 | #define ABSOLUTE_ZERO_MILLICELSIUS -273150 | ||
| 8 | |||
| 9 | static inline long milli_kelvin_to_millicelsius(long t) | ||
| 10 | { | ||
| 11 | return t + ABSOLUTE_ZERO_MILLICELSIUS; | ||
| 12 | } | ||
| 13 | |||
| 14 | static inline long millicelsius_to_milli_kelvin(long t) | ||
| 15 | { | ||
| 16 | return t - ABSOLUTE_ZERO_MILLICELSIUS; | ||
| 17 | } | ||
| 18 | |||
| 19 | #define MILLIDEGREE_PER_DEGREE 1000 | ||
| 20 | #define MILLIDEGREE_PER_DECIDEGREE 100 | ||
| 21 | |||
| 22 | static inline long kelvin_to_millicelsius(long t) | ||
| 23 | { | ||
| 24 | return milli_kelvin_to_millicelsius(t * MILLIDEGREE_PER_DEGREE); | ||
| 25 | } | ||
| 26 | |||
| 27 | static inline long millicelsius_to_kelvin(long t) | ||
| 28 | { | ||
| 29 | t = millicelsius_to_milli_kelvin(t); | ||
| 30 | |||
| 31 | return DIV_ROUND_CLOSEST(t, MILLIDEGREE_PER_DEGREE); | ||
| 32 | } | ||
| 33 | |||
| 34 | static inline long deci_kelvin_to_celsius(long t) | ||
| 35 | { | ||
| 36 | t = milli_kelvin_to_millicelsius(t * MILLIDEGREE_PER_DECIDEGREE); | ||
| 37 | |||
| 38 | return DIV_ROUND_CLOSEST(t, MILLIDEGREE_PER_DEGREE); | ||
| 39 | } | ||
| 40 | |||
| 41 | static inline long celsius_to_deci_kelvin(long t) | ||
| 42 | { | ||
| 43 | t = millicelsius_to_milli_kelvin(t * MILLIDEGREE_PER_DEGREE); | ||
| 44 | |||
| 45 | return DIV_ROUND_CLOSEST(t, MILLIDEGREE_PER_DECIDEGREE); | ||
| 46 | } | ||
| 47 | |||
| 48 | /** | ||
| 49 | * deci_kelvin_to_millicelsius_with_offset - convert Kelvin to Celsius | ||
| 50 | * @t: temperature value in decidegrees Kelvin | ||
| 51 | * @offset: difference between Kelvin and Celsius in millidegrees | ||
| 52 | * | ||
| 53 | * Return: temperature value in millidegrees Celsius | ||
| 54 | */ | ||
| 55 | static inline long deci_kelvin_to_millicelsius_with_offset(long t, long offset) | ||
| 56 | { | ||
| 57 | return t * MILLIDEGREE_PER_DECIDEGREE - offset; | ||
| 58 | } | ||
| 59 | |||
| 60 | static inline long deci_kelvin_to_millicelsius(long t) | ||
| 61 | { | ||
| 62 | return milli_kelvin_to_millicelsius(t * MILLIDEGREE_PER_DECIDEGREE); | ||
| 63 | } | ||
| 64 | |||
| 65 | static inline long millicelsius_to_deci_kelvin(long t) | ||
| 66 | { | ||
| 67 | t = millicelsius_to_milli_kelvin(t); | ||
| 68 | |||
| 69 | return DIV_ROUND_CLOSEST(t, MILLIDEGREE_PER_DECIDEGREE); | ||
| 70 | } | ||
| 71 | |||
| 72 | static inline long kelvin_to_celsius(long t) | ||
| 73 | { | ||
| 74 | return t + DIV_ROUND_CLOSEST(ABSOLUTE_ZERO_MILLICELSIUS, | ||
| 75 | MILLIDEGREE_PER_DEGREE); | ||
| 76 | } | ||
| 77 | |||
| 78 | static inline long celsius_to_kelvin(long t) | ||
| 79 | { | ||
| 80 | return t - DIV_ROUND_CLOSEST(ABSOLUTE_ZERO_MILLICELSIUS, | ||
| 81 | MILLIDEGREE_PER_DEGREE); | ||
| 82 | } | ||
| 83 | |||
| 84 | #endif /* _LINUX_UNITS_H */ | ||