1 files changed, 144 insertions, 0 deletions
diff --git a/include/linux/units.h b/include/linux/units.h
new file mode 100644
index 000000000..c6d789886
--- /dev/null
+++ b/include/linux/units.h
@@ -0,0 +1,144 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_UNITS_H
+#define _LINUX_UNITS_H
+
+#include <linux/bits.h>
+#include <linux/math.h>
+
+/* Metric prefixes in accordance with Système international (d'unités) */
+#define PETA	1000000000000000ULL
+#define TERA	1000000000000ULL
+#define GIGA	1000000000UL
+#define MEGA	1000000UL
+#define KILO	1000UL
+#define HECTO	100UL
+#define DECA	10UL
+#define DECI	10UL
+#define CENTI	100UL
+#define MILLI	1000UL
+#define MICRO	1000000UL
+#define NANO	1000000000UL
+#define PICO	1000000000000ULL
+#define FEMTO	1000000000000000ULL
+
+/*
+ * Percentage and related scaling units
+ *
+ * These macros define scaling factors used to convert between ratio and
+ * percentage-based representations with different decimal resolutions.
+ * They are used for precise fractional calculations in engineering, finance,
+ * and measurement applications.
+ *
+ * Examples:
+ *   1%     = 0.01    = 1 / PERCENT
+ *   0.1%   = 0.001   = 1 / PERMILLE
+ *   0.01%  = 0.0001  = 1 / PERMYRIAD (1 basis point)
+ *   0.001% = 0.00001 = 1 / PERCENTMILLE
+ */
+#define PERCENT		100
+#define PERMILLE	1000
+#define PERMYRIAD	10000
+#define PERCENTMILLE	100000
+
+#define NANOHZ_PER_HZ		1000000000UL
+#define MICROHZ_PER_HZ		1000000UL
+#define MILLIHZ_PER_HZ		1000UL
+
+/* Hz based multipliers */
+#define HZ_PER_KHZ		1000UL
+#define HZ_PER_MHZ		1000000UL
+#define HZ_PER_GHZ		1000000000UL
+
+/* kHz based multipliers */
+#define KHZ_PER_MHZ		1000UL
+#define KHZ_PER_GHZ		1000000UL
+
+#define MILLIWATT_PER_WATT	1000UL
+#define MICROWATT_PER_MILLIWATT	1000UL
+#define MICROWATT_PER_WATT	1000000UL
+
+#define MICROJOULE_PER_JOULE	1000000UL
+#define NANOJOULE_PER_JOULE	1000000000UL
+
+#define BYTES_PER_KBIT		(KILO / BITS_PER_BYTE)
+#define BYTES_PER_MBIT		(MEGA / BITS_PER_BYTE)
+#define BYTES_PER_GBIT		(GIGA / BITS_PER_BYTE)
+
+#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 */