https://github.com/torvalds/linux
Revision 5885b9b3f030f9b430f6b1c7fa396c885033f2f8 authored by Linus Torvalds on 16 December 2011, 19:14:42 UTC, committed by Linus Torvalds on 16 December 2011, 19:14:42 UTC
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound: ALSA: HDA: Use LPIB Position fix for Intel SCH Poulsbo ALSA: hda: fix mute led polarity for HP laptops with buggy BIOS ALSA: HDA: Set position fix to LPIB for an Atom/Poulsbo based device ASoC: Fix hx4700 error handling to free gpios if snd_soc_register_card fails ASoC: WM8958: correctly show firmware magic on mismatch ASoC: mxs: Add appropriate MODULE_ALIAS() ASoC: mxs: Add missing MODULE_LICENSE("GPL") ASoC: Fix WM8996 24.576MHz clock operation ASoC: Include linux/module.h for smdk2443_wm9710 ASoC: Fix a typo in jive_wm8750 ASoC: Fix build dependency for SND_SOC_JZ4740_CODEC ASoC: Include linux/io.h for jz4740 codec
Tip revision: 5885b9b3f030f9b430f6b1c7fa396c885033f2f8 authored by Linus Torvalds on 16 December 2011, 19:14:42 UTC
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound
Tip revision: 5885b9b
average.c
/*
* lib/average.c
*
* This source code is licensed under the GNU General Public License,
* Version 2. See the file COPYING for more details.
*/
#include <linux/module.h>
#include <linux/average.h>
#include <linux/bug.h>
#include <linux/log2.h>
/**
* DOC: Exponentially Weighted Moving Average (EWMA)
*
* These are generic functions for calculating Exponentially Weighted Moving
* Averages (EWMA). We keep a structure with the EWMA parameters and a scaled
* up internal representation of the average value to prevent rounding errors.
* The factor for scaling up and the exponential weight (or decay rate) have to
* be specified thru the init fuction. The structure should not be accessed
* directly but only thru the helper functions.
*/
/**
* ewma_init() - Initialize EWMA parameters
* @avg: Average structure
* @factor: Factor to use for the scaled up internal value. The maximum value
* of averages can be ULONG_MAX/(factor*weight). For performance reasons
* factor has to be a power of 2.
* @weight: Exponential weight, or decay rate. This defines how fast the
* influence of older values decreases. For performance reasons weight has
* to be a power of 2.
*
* Initialize the EWMA parameters for a given struct ewma @avg.
*/
void ewma_init(struct ewma *avg, unsigned long factor, unsigned long weight)
{
WARN_ON(!is_power_of_2(weight) || !is_power_of_2(factor));
avg->weight = ilog2(weight);
avg->factor = ilog2(factor);
avg->internal = 0;
}
EXPORT_SYMBOL(ewma_init);
/**
* ewma_add() - Exponentially weighted moving average (EWMA)
* @avg: Average structure
* @val: Current value
*
* Add a sample to the average.
*/
struct ewma *ewma_add(struct ewma *avg, unsigned long val)
{
avg->internal = avg->internal ?
(((avg->internal << avg->weight) - avg->internal) +
(val << avg->factor)) >> avg->weight :
(val << avg->factor);
return avg;
}
EXPORT_SYMBOL(ewma_add);
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