linux-stable/include/linux/units.h
Andy Shevchenko aa6159ab99 kernel.h: split out mathematical helpers
kernel.h is being used as a dump for all kinds of stuff for a long time.
Here is the attempt to start cleaning it up by splitting out
mathematical helpers.

At the same time convert users in header and lib folder to use new
header.  Though for time being include new header back to kernel.h to
avoid twisted indirected includes for existing users.

[sfr@canb.auug.org.au: fix powerpc build]
  Link: https://lkml.kernel.org/r/20201029150809.13059608@canb.auug.org.au

Link: https://lkml.kernel.org/r/20201028173212.41768-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-12-15 22:46:15 -08:00

84 lines
2 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_UNITS_H
#define _LINUX_UNITS_H
#include <linux/math.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 */