mirror of
git://projects.qi-hardware.com/openwrt-xburst.git
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fb189822fc
git-svn-id: svn://svn.openwrt.org/openwrt/trunk@15918 3c298f89-4303-0410-b956-a3cf2f4a3e73
175 lines
4.3 KiB
C
175 lines
4.3 KiB
C
/*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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* Copyright (c) 2008,2009
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* Andy Green <andy@openmoko.com>
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* Nelson Castillo <arhuaco@freaks-unidos.net>
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*
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* Simple mean filter.
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*
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*/
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#include <linux/errno.h>
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#include <linux/kernel.h>
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#include <linux/slab.h>
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#include <linux/touchscreen/ts_filter_mean.h>
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struct ts_filter_mean {
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/* Copy of the private filter configuration. */
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struct ts_filter_mean_configuration *config;
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/* Filter API. */
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struct ts_filter tsf;
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/* Index on a circular buffer. */
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int curr;
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/* Useful to tell if the circular buffer is full(read:ready). */
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int count;
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/* Sumation used to compute the mean. */
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int sum[MAX_TS_FILTER_COORDS];
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/* Keep point values and decrement them from the sum on time. */
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int *fifo[MAX_TS_FILTER_COORDS];
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/* Store the output of this filter. */
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int ready;
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};
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#define ts_filter_to_filter_mean(f) container_of(f, struct ts_filter_mean, tsf)
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static void ts_filter_mean_clear(struct ts_filter *tsf);
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static struct ts_filter *ts_filter_mean_create(
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struct platform_device *pdev,
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const struct ts_filter_configuration *conf,
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int count_coords)
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{
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struct ts_filter_mean *priv;
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int *v;
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int n;
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priv = kzalloc(sizeof(struct ts_filter_mean), GFP_KERNEL);
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if (!priv)
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return NULL;
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priv->tsf.count_coords = count_coords;
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priv->config = container_of(conf,
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struct ts_filter_mean_configuration,
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config);
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BUG_ON(priv->config->length <= 0);
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v = kmalloc(priv->config->length * sizeof(int) * count_coords,
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GFP_KERNEL);
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if (!v)
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return NULL;
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for (n = 0; n < count_coords; n++) {
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priv->fifo[n] = v;
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v += priv->config->length;
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}
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ts_filter_mean_clear(&priv->tsf);
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dev_info(&pdev->dev, "Created Mean filter len:%d coords:%d\n",
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priv->config->length, count_coords);
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return &priv->tsf;
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}
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static void ts_filter_mean_destroy(struct ts_filter *tsf)
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{
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struct ts_filter_mean *priv = ts_filter_to_filter_mean(tsf);
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kfree(priv->fifo[0]); /* first guy has pointer from kmalloc */
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kfree(tsf);
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}
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static void ts_filter_mean_clear(struct ts_filter *tsf)
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{
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struct ts_filter_mean *priv = ts_filter_to_filter_mean(tsf);
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priv->count = 0;
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priv->curr = 0;
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priv->ready = 0;
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memset(priv->sum, 0, tsf->count_coords * sizeof(int));
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}
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static int ts_filter_mean_process(struct ts_filter *tsf, int *coords)
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{
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struct ts_filter_mean *priv = ts_filter_to_filter_mean(tsf);
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int n;
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BUG_ON(priv->ready);
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for (n = 0; n < tsf->count_coords; n++) {
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priv->sum[n] += coords[n];
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priv->fifo[n][priv->curr] = coords[n];
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}
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if (priv->count + 1 == priv->config->length)
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priv->ready = 1;
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else
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priv->count++;
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priv->curr = (priv->curr + 1) % priv->config->length;
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return 0; /* No error. */
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}
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static int ts_filter_mean_haspoint(struct ts_filter *tsf)
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{
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struct ts_filter_mean *priv = ts_filter_to_filter_mean(tsf);
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return priv->ready;
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}
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static void ts_filter_mean_getpoint(struct ts_filter *tsf, int *point)
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{
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struct ts_filter_mean *priv = ts_filter_to_filter_mean(tsf);
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int n;
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BUG_ON(!priv->ready);
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for (n = 0; n < tsf->count_coords; n++) {
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point[n] = priv->sum[n];
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priv->sum[n] -= priv->fifo[n][priv->curr];
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}
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priv->ready = 0;
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}
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static void ts_filter_mean_scale(struct ts_filter *tsf, int *coords)
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{
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int n;
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struct ts_filter_mean *priv = ts_filter_to_filter_mean(tsf);
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for (n = 0; n < tsf->count_coords; n++) {
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coords[n] += priv->config->length >> 1; /* Rounding. */
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coords[n] /= priv->config->length;
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}
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}
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const struct ts_filter_api ts_filter_mean_api = {
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.create = ts_filter_mean_create,
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.destroy = ts_filter_mean_destroy,
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.clear = ts_filter_mean_clear,
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.process = ts_filter_mean_process,
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.scale = ts_filter_mean_scale,
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.haspoint = ts_filter_mean_haspoint,
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.getpoint = ts_filter_mean_getpoint,
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};
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EXPORT_SYMBOL_GPL(ts_filter_mean_api);
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