diff options
Diffstat (limited to 'drivers/input/touchscreen/ts_filter_variance.c')
| -rw-r--r-- | drivers/input/touchscreen/ts_filter_variance.c | 205 |
1 files changed, 0 insertions, 205 deletions
diff --git a/drivers/input/touchscreen/ts_filter_variance.c b/drivers/input/touchscreen/ts_filter_variance.c deleted file mode 100644 index c3352105c9f..00000000000 --- a/drivers/input/touchscreen/ts_filter_variance.c +++ /dev/null @@ -1,205 +0,0 @@ -/* - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License as published by - * the Free Software Foundation; either version 2 of the License, or - * (at your option) any later version. - * - * This program is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - * GNU General Public License for more details. - * - * You should have received a copy of the GNU General Public License - * along with this program; if not, write to the Free Software - * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA - * - * Copyright (C) 2008 by Openmoko, Inc. - * Author: Nelson Castillo <arhuaco@freaks-unidos.net> - * All rights reserved. - * - * This filter is useful to reject clicks that are not reliable. We - * only care about what happens when we receive DOWN events for the fist time. - * If this filter does not reject the first samples then it will change - * its internal state to "passed" and the remaining samples - * will be passed to the next filter in the chain. - * - * First we collect N samples, then then we sort them. We discard the borders - * (with a window) and then compute the variance of the remaining set. - * If the computed variance is bigger than a threshold, we reject the click. - * - */ - -#include <linux/kernel.h> -#include <linux/slab.h> -#include <linux/sort.h> -#include <linux/ts_filter_variance.h> - -static void ts_filter_variance_clear_internal(struct ts_filter_variance *tsfv, - int attempts) -{ - tsfv->N = 0; - tsfv->passed = 0; - tsfv->tries_left = attempts; -} - -static void ts_filter_variance_clear(struct ts_filter *tsf) -{ - struct ts_filter_variance *tsfv = (struct ts_filter_variance *)tsf; - - ts_filter_variance_clear_internal(tsfv, tsfv->config->attempts); - - if (tsf->next) /* chain */ - (tsf->next->api->clear)(tsf->next); -} - -static struct ts_filter *ts_filter_variance_create(void *conf, int count_coords) -{ - struct ts_filter_variance *tsfv; - int i; - - BUG_ON((count_coords < 1) || (count_coords > MAX_TS_FILTER_COORDS)); - - tsfv = kzalloc(sizeof(struct ts_filter_variance), GFP_KERNEL); - if (!tsfv) - return NULL; - - tsfv->config = (struct ts_filter_variance_configuration *)conf; - tsfv->tsf.count_coords = count_coords; - - BUG_ON(tsfv->config->attempts <= 0); - - tsfv->samples[0] = kmalloc(count_coords * sizeof(int) * - tsfv->config->extent, GFP_KERNEL); - if (!tsfv->samples[0]) { - kfree(tsfv); - return NULL; - } - for (i = 1; i < count_coords; ++i) - tsfv->samples[i] = tsfv->samples[0] + i * tsfv->config->extent; - - ts_filter_variance_clear_internal(tsfv, tsfv->config->attempts); - - printk(KERN_INFO" Created Variance ts filter len %d depth %d window" - " %d thresh %d\n", tsfv->config->extent, - count_coords, tsfv->config->window, - tsfv->config->threshold); - - /* scale the threshold to avoid divisions later */ - tsfv->config->threshold *= tsfv->config->extent - - (tsfv->config->window << 1); - - return &tsfv->tsf; -} - -static void ts_filter_variance_destroy(struct ts_filter *tsf) -{ - struct ts_filter_variance *tsfv = (struct ts_filter_variance *)tsf; - - kfree(tsfv->samples[0]); /* first guy has pointer from kmalloc */ - kfree(tsf); -} - -static void ts_filter_variance_scale(struct ts_filter *tsf, int *coords) -{ - struct ts_filter_variance *tsfv = (struct ts_filter_variance *)tsf; - - if (!tsfv->passed) - return; - - if (tsf->next) { - (tsf->next->api->scale)(tsf->next, coords); - } else { - int n; - for (n = 0; n < tsf->count_coords; n++) { - int c = tsfv->samples[n][tsfv->N / 2] + - tsfv->samples[n][tsfv->N / 2 + 1] + - tsfv->samples[n][tsfv->N / 2 - 1]; - coords[n] = (c + 2) / 3; - } - } -} - -static int int_cmp(const void *_a, const void *_b) -{ - const int *a = _a; - const int *b = _b; - - if (*a > *b) - return 1; - if (*a < *b) - return -1; - return 0; -} - -/* give us the raw sample data coords, and if we return 1 then you can - * get a filtered coordinate from coords: if we return 0 you didn't - * fill all the filters with samples yet. - */ - -static int ts_filter_variance_process(struct ts_filter *tsf, int *coords) -{ - struct ts_filter_variance *tsfv = (struct ts_filter_variance *)tsf; - int n; - - if (tsfv->passed) { /* chain */ - if (tsf->next) - return (tsf->next->api->process)(tsf->next, coords); - return 1; - } - - for (n = 0; n < tsf->count_coords; n++) - tsfv->samples[n][tsfv->N] = coords[n]; - - if (++tsfv->N < tsfv->config->extent) - return 0; /* we meed more samples */ - - tsfv->passed = 1; - - for (n = 0; n < tsfv->tsf.count_coords; n++) { - int i; - int avg = 0; - int variance = 0; - - sort(tsfv->samples[n], tsfv->config->extent, sizeof(int), - int_cmp, NULL); - - for (i = tsfv->config->window; i < tsfv->config->extent - - tsfv->config->window; ++i) - avg += tsfv->samples[n][i]; - - avg /= tsfv->config->extent - (tsfv->config->window << 1); - - for (i = tsfv->config->window; i < tsfv->config->extent - - tsfv->config->window; ++i) { - int s = tsfv->samples[n][i] - avg; - variance += s * s; - } - - if (variance > tsfv->config->threshold) { - tsfv->passed = 0; - break; - } - } - - if (tsfv->passed) /* Let's reuse the last sample */ - return ts_filter_variance_process(tsf, coords); - - if (--tsfv->tries_left) { - ts_filter_variance_clear_internal(tsfv, tsfv->tries_left); - return 0; /* ask for more samples */ - } - - /* avoid overflow if we are called again without clearing the filter */ - ts_filter_variance_clear_internal(tsfv, tsfv->config->attempts); - - return -1; -} - -struct ts_filter_api ts_filter_variance_api = { - .create = ts_filter_variance_create, - .destroy = ts_filter_variance_destroy, - .clear = ts_filter_variance_clear, - .process = ts_filter_variance_process, - .scale = ts_filter_variance_scale, -}; - |