The patch titled
Subject: lib/math: move int_pow() from pwm_bl.c for wider use
has been added to the -mm tree. Its filename is
lib-math-move-int_pow-from-pwm_blc-for-wider-use.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/lib-math-move-int_pow-from-pwm_blc-for-wider-use.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/lib-math-move-int_pow-from-pwm_blc-for-wider-use.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Subject: lib/math: move int_pow() from pwm_bl.c for wider use
The integer exponentiation is used in few places and might be used in the
future by other call sites. Move it to wider use.
Link: http://lkml.kernel.org/r/20190323172531.80025-2-andriy.shevchenko@xxxxxxxxxxxxxxx
Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Cc: Daniel Thompson <daniel.thompson@xxxxxxxxxx>
Cc: Lee Jones <lee.jones@xxxxxxxxxx>
Cc: Ray Jui <rjui@xxxxxxxxxxxx>
Cc: Thierry Reding <thierry.reding@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/video/backlight/pwm_bl.c | 15 -------------
include/linux/kernel.h | 1
lib/math/Makefile | 2 -
lib/math/int_pow.c | 32 +++++++++++++++++++++++++++++
4 files changed, 34 insertions(+), 16 deletions(-)
--- a/drivers/video/backlight/pwm_bl.c~lib-math-move-int_pow-from-pwm_blc-for-wider-use
+++ a/drivers/video/backlight/pwm_bl.c
@@ -155,21 +155,6 @@ static const struct backlight_ops pwm_ba
#ifdef CONFIG_OF
#define PWM_LUMINANCE_SCALE 10000 /* luminance scale */
-/* An integer based power function */
-static u64 int_pow(u64 base, int exp)
-{
- u64 result = 1;
-
- while (exp) {
- if (exp & 1)
- result *= base;
- exp >>= 1;
- base *= base;
- }
-
- return result;
-}
-
/*
* CIE lightness to PWM conversion.
*
--- a/include/linux/kernel.h~lib-math-move-int_pow-from-pwm_blc-for-wider-use
+++ a/include/linux/kernel.h
@@ -494,6 +494,7 @@ extern int __kernel_text_address(unsigne
extern int kernel_text_address(unsigned long addr);
extern int func_ptr_is_kernel_text(void *ptr);
+u64 int_pow(u64 base, unsigned int exp);
unsigned long int_sqrt(unsigned long);
#if BITS_PER_LONG < 64
--- /dev/null
+++ a/lib/math/int_pow.c
@@ -0,0 +1,32 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * An integer based power function
+ *
+ * Derived from drivers/video/backlight/pwm_bl.c
+ */
+
+#include <linux/export.h>
+#include <linux/kernel.h>
+#include <linux/types.h>
+
+/**
+ * int_pow - computes the exponentiation of the given base and exponent
+ * @base: base which will be raised to the given power
+ * @exp: power to be raised to
+ *
+ * Computes: pow(base, exp), i.e. @base raised to the @exp power
+ */
+u64 int_pow(u64 base, unsigned int exp)
+{
+ u64 result = 1;
+
+ while (exp) {
+ if (exp & 1)
+ result *= base;
+ exp >>= 1;
+ base *= base;
+ }
+
+ return result;
+}
+EXPORT_SYMBOL_GPL(int_pow);
--- a/lib/math/Makefile~lib-math-move-int_pow-from-pwm_blc-for-wider-use
+++ a/lib/math/Makefile
@@ -1,4 +1,4 @@
-obj-y += div64.o gcd.o lcm.o int_sqrt.o reciprocal_div.o
+obj-y += div64.o gcd.o lcm.o int_pow.o int_sqrt.o reciprocal_div.o
obj-$(CONFIG_CORDIC) += cordic.o
obj-$(CONFIG_PRIME_NUMBERS) += prime_numbers.o
_
Patches currently in -mm which might be from andriy.shevchenko@xxxxxxxxxxxxxxx are
lib-move-mathematic-helpers-to-separate-folder.patch
lib-math-move-int_pow-from-pwm_blc-for-wider-use.patch
