diff options
| -rw-r--r-- | drivers/input/touchscreen/Kconfig | 44 | ||||
| -rw-r--r-- | drivers/input/touchscreen/Makefile | 5 | ||||
| -rw-r--r-- | drivers/input/touchscreen/ts_filter.h | 74 | ||||
| -rw-r--r-- | drivers/input/touchscreen/ts_filter_chain.c | 183 | ||||
| -rw-r--r-- | drivers/input/touchscreen/ts_filter_chain.h | 58 | ||||
| -rw-r--r-- | drivers/input/touchscreen/ts_filter_group.c | 330 | ||||
| -rw-r--r-- | drivers/input/touchscreen/ts_filter_group.h | 36 | ||||
| -rw-r--r-- | drivers/input/touchscreen/ts_filter_linear.c | 212 | ||||
| -rw-r--r-- | drivers/input/touchscreen/ts_filter_linear.h | 31 | ||||
| -rw-r--r-- | drivers/input/touchscreen/ts_filter_mean.c | 174 | ||||
| -rw-r--r-- | drivers/input/touchscreen/ts_filter_mean.h | 28 | ||||
| -rw-r--r-- | drivers/input/touchscreen/ts_filter_median.c | 261 | ||||
| -rw-r--r-- | drivers/input/touchscreen/ts_filter_median.h | 32 |
13 files changed, 1468 insertions, 0 deletions
diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig index 8cc453c85ea..faf929e5454 100644 --- a/drivers/input/touchscreen/Kconfig +++ b/drivers/input/touchscreen/Kconfig @@ -11,6 +11,50 @@ menuconfig INPUT_TOUCHSCREEN if INPUT_TOUCHSCREEN +menuconfig TOUCHSCREEN_FILTER + boolean "Touchscreen Filtering" + depends on INPUT_TOUCHSCREEN + select TOUCHSCREEN_FILTER_GROUP + select TOUCHSCREEN_FILTER_MEDIAN + select TOUCHSCREEN_FILTER_MEAN + select TOUCHSCREEN_FILTER_LINEAR + help + Select this to include kernel touchscreen filter support. The filters + can be combined in any order in your machine init and the parameters + for them can also be set there. + +config TOUCHSCREEN_FILTER_GROUP + bool "Group Touchscreen Filter" + depends on INPUT_TOUCHSCREEN && TOUCHSCREEN_FILTER + default Y + help + Say Y here if you want to use the Group touchscreen filter, it + avoids using atypical samples. + +config TOUCHSCREEN_FILTER_MEDIAN + bool "Median Average Touchscreen Filter" + depends on INPUT_TOUCHSCREEN && TOUCHSCREEN_FILTER + default Y + help + Say Y here if you want to use the Median touchscreen filter, it's + highly effective if you data is noisy with occasional excursions. + +config TOUCHSCREEN_FILTER_MEAN + bool "Mean Average Touchscreen Filter" + depends on INPUT_TOUCHSCREEN && TOUCHSCREEN_FILTER + default Y + help + Say Y here if you want to use the Mean touchscreen filter, it + can further improve decent quality data by removing jitter + +config TOUCHSCREEN_FILTER_LINEAR + bool "Linear Touchscreen Filter" + depends on INPUT_TOUCHSCREEN && TOUCHSCREEN_FILTER + default Y + help + Say Y here if you want to use the Linear touchscreen filter, it + enables the use of calibration data for the touchscreen. + config TOUCHSCREEN_ADS7846 tristate "ADS7846/TSC2046 and ADS7843 based touchscreens" depends on SPI_MASTER diff --git a/drivers/input/touchscreen/Makefile b/drivers/input/touchscreen/Makefile index 15fa62cffc7..322df12bb30 100644 --- a/drivers/input/touchscreen/Makefile +++ b/drivers/input/touchscreen/Makefile @@ -42,3 +42,8 @@ obj-$(CONFIG_TOUCHSCREEN_WM97XX_MAINSTONE) += mainstone-wm97xx.o obj-$(CONFIG_TOUCHSCREEN_WM97XX_ZYLONITE) += zylonite-wm97xx.o obj-$(CONFIG_TOUCHSCREEN_W90X900) += w90p910_ts.o obj-$(CONFIG_TOUCHSCREEN_PCAP) += pcap_ts.o +obj-$(CONFIG_TOUCHSCREEN_FILTER) += ts_filter_chain.o +obj-$(CONFIG_TOUCHSCREEN_FILTER_GROUP) += ts_filter_group.o +obj-$(CONFIG_TOUCHSCREEN_FILTER_LINEAR) += ts_filter_linear.o +obj-$(CONFIG_TOUCHSCREEN_FILTER_MEDIAN) += ts_filter_median.o +obj-$(CONFIG_TOUCHSCREEN_FILTER_MEAN) += ts_filter_mean.o diff --git a/drivers/input/touchscreen/ts_filter.h b/drivers/input/touchscreen/ts_filter.h new file mode 100644 index 00000000000..632e5fb3f4e --- /dev/null +++ b/drivers/input/touchscreen/ts_filter.h @@ -0,0 +1,74 @@ +#ifndef __TS_FILTER_H__ +#define __TS_FILTER_H__ + +/* + * Touchscreen filter. + * + * (c) 2008,2009 Andy Green <andy@warmcat.com> + */ + +#include <linux/platform_device.h> + +#define MAX_TS_FILTER_COORDS 3 /* X, Y and Z (pressure). */ + +struct ts_filter; +struct ts_filter_configuration; + +/* Operations that a filter can perform. */ + +struct ts_filter_api { + /* Create the filter - mandatory. */ + struct ts_filter * (*create)( + struct platform_device *pdev, + const struct ts_filter_configuration *config, + int count_coords); + /* Destroy the filter - mandatory. */ + void (*destroy)(struct ts_filter *filter); + /* Clear the filter - optional. */ + void (*clear)(struct ts_filter *filter); + + + /* + * The next three API functions only make sense if all of them are + * set for a filter. If a filter has the next three methods then + * it can propagate coordinates in the chain. + */ + + /* + * Process the filter. + * It returns non-zero if the filter reaches an error. + */ + int (*process)(struct ts_filter *filter, int *coords); + /* + * Is the filter ready to return a point? + * Please do not code side effects in this function. + */ + int (*haspoint)(struct ts_filter *filter); + /* + * Get a point. + * Do not call unless the filter actually has a point to deliver. + */ + void (*getpoint)(struct ts_filter *filter, int *coords); + + /* + * Scale the points - optional. + * A filter could only scale coordinates. + */ + void (*scale)(struct ts_filter *filter, int *coords); +}; + +/* + * Generic filter configuration. Actual configurations have this structure + * as a member. + */ +struct ts_filter_configuration { +}; + +struct ts_filter { + /* Operations for this filter. */ + const struct ts_filter_api *api; + /* Number of coordinates to process. */ + int count_coords; +}; + +#endif diff --git a/drivers/input/touchscreen/ts_filter_chain.c b/drivers/input/touchscreen/ts_filter_chain.c new file mode 100644 index 00000000000..17793ace144 --- /dev/null +++ b/drivers/input/touchscreen/ts_filter_chain.c @@ -0,0 +1,183 @@ +/* + * 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) 2008,2009 Andy Green <andy@warmcat.com> + */ + +#include <linux/kernel.h> +#include <linux/device.h> + +#include "ts_filter_chain.h" +#include "ts_filter.h" + +/* + * Tux, would you like the following function in /lib? + * It helps us avoid silly code. + */ + +/** + * sptrlen - Count how many non-null pointers are in a pointer array + * @arr: The array of pointers + */ +static int sptrlen(const void *arr) +{ + /* All pointers have the same size. */ + const int **p = (const int **)arr; + int len = 0; + + while (*(p++)) + len++; + + return len; +} + + +struct ts_filter_chain { + /* All of the filters. */ + struct ts_filter **arr; + /* Filters that can propagate values in the chain. */ + struct ts_filter **pchain; + /* Length of the pchain array. */ + int pchain_len; + /* FIXME: Add a spinlock and use it. */ +}; + +struct ts_filter_chain *ts_filter_chain_create( + struct platform_device *pdev, + const struct ts_filter_chain_configuration conf[], + int count_coords) +{ + struct ts_filter_chain *c; + int count = 0; + int len; + + BUG_ON((count_coords < 1)); + BUG_ON(count_coords > MAX_TS_FILTER_COORDS); + + c = kzalloc(sizeof(struct ts_filter_chain), GFP_KERNEL); + if (!c) + goto create_err_1; + + len = (sptrlen(conf) + 1); + /* Memory for two null-terminated arrays of filters. */ + c->arr = kzalloc(2 * sizeof(struct ts_filter *) * len, GFP_KERNEL); + if (!c->arr) + goto create_err_1; + c->pchain = c->arr + len; + + while (conf->api) { + /* TODO: Can we get away with only sending pdev->dev? */ + struct ts_filter *f = + (conf->api->create)(pdev, conf->config, count_coords); + if (!f) { + dev_info(&pdev->dev, "Filter %d creation failed\n", + count); + goto create_err_2; + } + + f->api = conf->api; + c->arr[count++] = f; + + if (f->api->haspoint && f->api->getpoint && f->api->process) + c->pchain[c->pchain_len++] = f; + + conf++; + } + + dev_info(&pdev->dev, "%d filter(s) initialized\n", count); + + return c; + +create_err_2: + ts_filter_chain_destroy(c); /* Also frees c. */ +create_err_1: + dev_info(&pdev->dev, "Error in filter chain initialization\n"); + /* + * FIXME: Individual filters have to return errors this way. + * We only have to forward the errors we find. + */ + return ERR_PTR(-ENOMEM); +} +EXPORT_SYMBOL_GPL(ts_filter_chain_create); + +void ts_filter_chain_destroy(struct ts_filter_chain *c) +{ + if (c->arr) { + struct ts_filter **a = c->arr; + while (*a) { + ((*a)->api->destroy)(*a); + a++; + } + kfree(c->arr); + } + kfree(c); +} +EXPORT_SYMBOL_GPL(ts_filter_chain_destroy); + +void ts_filter_chain_clear(struct ts_filter_chain *c) +{ + struct ts_filter **a = c->arr; + + while (*a) { + if ((*a)->api->clear) + ((*a)->api->clear)(*a); + a++; + } +} +EXPORT_SYMBOL_GPL(ts_filter_chain_clear); + +static void ts_filter_chain_scale(struct ts_filter_chain *c, int *coords) +{ + struct ts_filter **a = c->arr; + while (*a) { + if ((*a)->api->scale) + ((*a)->api->scale)(*a, coords); + a++; + } +} + +int ts_filter_chain_feed(struct ts_filter_chain *c, int *coords) +{ + int len = c->pchain_len; + int i = len - 1; + + if (!c->pchain[0]) + return 1; /* Nothing to do. */ + + BUG_ON(c->pchain[0]->api->haspoint(c->pchain[0])); + + if (c->pchain[0]->api->process(c->pchain[0], coords)) + return -1; + + while (i >= 0 && i < len) { + if (c->pchain[i]->api->haspoint(c->pchain[i])) { + c->pchain[i]->api->getpoint(c->pchain[i], coords); + if (++i < len && + c->pchain[i]->api->process(c->pchain[i], coords)) + return -1; /* Error. */ + } else { + i--; + } + } + + if (i >= 0) { /* Same as i == len. */ + ts_filter_chain_scale(c, coords); + return 1; + } + + return 0; +} +EXPORT_SYMBOL_GPL(ts_filter_chain_feed); + diff --git a/drivers/input/touchscreen/ts_filter_chain.h b/drivers/input/touchscreen/ts_filter_chain.h new file mode 100644 index 00000000000..065a6a026d2 --- /dev/null +++ b/drivers/input/touchscreen/ts_filter_chain.h @@ -0,0 +1,58 @@ +#ifndef __TS_FILTER_CHAIN_H__ +#define __TS_FILTER_CHAIN_H__ + +/* + * Touchscreen filter chains. + * + * (c) 2008,2009 Andy Green <andy@warmcat.com> + */ + +#include "ts_filter.h" + +#include <linux/err.h> + +struct ts_filter_chain_configuration { + /* API to use. */ + const struct ts_filter_api *api; + /* Generic filter configuration. Different for each filter. */ + const struct ts_filter_configuration *config; +}; + +struct ts_filter_chain; + +#ifdef CONFIG_TOUCHSCREEN_FILTER + +/* + * Create a filter chain. It will allocate an array of + * null-terminated pointers to filters. On error it will return + * an error you can check with IS_ERR. + */ +extern struct ts_filter_chain *ts_filter_chain_create( + struct platform_device *pdev, + const struct ts_filter_chain_configuration conf[], + int count_coords); + +/* Destroy the chain. */ +extern void ts_filter_chain_destroy(struct ts_filter_chain *c); + +/* Clear the filter chain. */ +extern void ts_filter_chain_clear(struct ts_filter_chain *c); + +/* + * Try to get one point. Returns 0 if no points are available. + * coords will be used as temporal space, thus you supply a point + * using coords but you shouldn't rely on its value on return unless + * it returns a nonzero value that is not -1. + * If one of the filters find an error then this function will + * return -1. + */ +int ts_filter_chain_feed(struct ts_filter_chain *c, int *coords); + +#else /* !CONFIG_TOUCHSCREEN_FILTER */ +#define ts_filter_chain_create(pdev, config, count_coords) (NULL) +#define ts_filter_chain_destroy(c) do { } while (0) +#define ts_filter_chain_clear(c) do { } while (0) +#define ts_filter_chain_feed(c, coords) (1) +#endif + +#endif diff --git a/drivers/input/touchscreen/ts_filter_group.c b/drivers/input/touchscreen/ts_filter_group.c new file mode 100644 index 00000000000..722e8dfbdae --- /dev/null +++ b/drivers/input/touchscreen/ts_filter_group.c @@ -0,0 +1,330 @@ +/* + * 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) 2008,2009 by Openmoko, Inc. + * Author: Nelson Castillo <arhuaco@freaks-unidos.net> + * All rights reserved. + * + * + * This filter is useful to reject samples that are not reliable. We consider + * that a sample is not reliable if it deviates form the Majority. + * This filter mixes information from all the available dimensions. It means + * that for two dimensions we draw a rectangle where the thought-to-be good + * points can be found. + * + * The implementation would be more efficient with a double-linked list but + * let's keep it simple for now. + * + * 1) We collect S samples and keep it in sorted sets. + * - Points that are "close enough" are considered to be in the same set. + * We don't actually keep the sets but ranges of points. + * + * 2) For each dimension: + * - We choose the range with more elements. If more than "threshold" + * points are in this range we use the minimum and the maximum point + * of the range to define the valid range for this dimension [min, max], + * otherwise we discard all the points and the ranges and go to step 1. + * + * 3) We consider the unsorted S samples and try to feed them to the next + * filter in the chain. If one of the points of each sample + * is not in the allowed range for its dimension we discard the sample. + * + */ + +#include <linux/kernel.h> +#include <linux/slab.h> +#include "ts_filter_group.h" + +struct coord_range { + int min; /* Minimum value of the range. */ + int max; /* Maximum value of the range */ + int N; /* Number of points in the range. */ +}; + +struct ts_filter_group { + /* Private filter configuration. */ + struct ts_filter_group_configuration *config; + /* Filter API. */ + struct ts_filter tsf; + + int N; /* How many samples we have. */ + int *samples[MAX_TS_FILTER_COORDS]; /* The samples: our input. */ + + /* Temporal values that help us compute range_min and range_max. */ + struct coord_range *ranges[MAX_TS_FILTER_COORDS]; /* Ranges. */ + int n_ranges[MAX_TS_FILTER_COORDS]; /* Number of ranges */ + + /* Computed ranges that help us filter the points. */ + int range_max[MAX_TS_FILTER_COORDS]; /* Max. computed ranges. */ + int range_min[MAX_TS_FILTER_COORDS]; /* Min. computed ranges. */ + + int tries_left; /* We finish if we can't get enough samples. */ + int ready; /* If we are ready to deliver samples. */ + int result; /* Index of the point being returned. */ +}; + +#define ts_filter_to_filter_group(f) \ + container_of(f, struct ts_filter_group, tsf) + + +static void ts_filter_group_clear_internal(struct ts_filter_group *tsfg, + int attempts) +{ + int n; + tsfg->N = 0; + tsfg->tries_left = attempts; + tsfg->ready = 0; + tsfg->result = 0; + for (n = 0; n < tsfg->tsf.count_coords; n++) + tsfg->n_ranges[n] = 0; +} + +static void ts_filter_group_clear(struct ts_filter *tsf) +{ + struct ts_filter_group *tsfg = ts_filter_to_filter_group(tsf); + + ts_filter_group_clear_internal(tsfg, tsfg->config->attempts); +} + +static struct ts_filter *ts_filter_group_create( + struct platform_device *pdev, + const struct ts_filter_configuration *conf, + int count_coords) +{ + struct ts_filter_group *tsfg; + int i; + + tsfg = kzalloc(sizeof(struct ts_filter_group), GFP_KERNEL); + if (!tsfg) + return NULL; + + tsfg->config = container_of(conf, + struct ts_filter_group_configuration, + config); + tsfg->tsf.count_coords = count_coords; + + BUG_ON(tsfg->config->attempts <= 0); + BUG_ON(tsfg->config->length < tsfg->config->threshold); + + tsfg->samples[0] = kmalloc(count_coords * sizeof(int) * + tsfg->config->length, GFP_KERNEL); + if (!tsfg->samples[0]) { + kfree(tsfg); + return NULL; + } + for (i = 1; i < count_coords; ++i) + tsfg->samples[i] = tsfg->samples[0] + i * tsfg->config->length; + + tsfg->ranges[0] = kmalloc(count_coords * sizeof(struct coord_range) * + tsfg->config->length, GFP_KERNEL); + if (!tsfg->ranges[0]) { + kfree(tsfg->samples[0]); + kfree(tsfg); + return NULL; + } + for (i = 1; i < count_coords; ++i) + tsfg->ranges[i] = tsfg->ranges[0] + i * tsfg->config->length; + + ts_filter_group_clear_internal(tsfg, tsfg->config->attempts); + + dev_info(&pdev->dev, "Created Group filter len:%d coords:%d close:%d " + "thresh:%d\n", tsfg->config->length, count_coords, + tsfg->config->close_enough, tsfg->config->threshold); + + return &tsfg->tsf; +} + +static void ts_filter_group_destroy(struct ts_filter *tsf) +{ + struct ts_filter_group *tsfg = ts_filter_to_filter_group(tsf); + + kfree(tsfg->samples[0]); + kfree(tsfg->ranges[0]); + kfree(tsf); +} + +static void ts_filter_group_prepare_next(struct ts_filter *tsf); + +#define MIN(a, b) ((a) < (b) ? (a) : (b)) +#define MAX(a, b) ((a) > (b) ? (a) : (b)) +#define IN_RANGE(c, r) ((c) >= (r).min - tsfg->config->close_enough && \ + (c) <= (r).max + tsfg->config->close_enough) + +static void delete_spot(struct coord_range *v, int n, int size) +{ + int i; + for (i = n; i < size - 1; ++i) + v[i] = v[i + 1]; +} + +static int ts_filter_group_process(struct ts_filter *tsf, int *coords) +{ + struct ts_filter_group *tsfg = ts_filter_to_filter_group(tsf); + int n; + int j; + + BUG_ON(tsfg->N >= tsfg->config->length); + BUG_ON(tsfg->ready); + + for (n = 0; n < tsfg->tsf.count_coords; n++) { + int i; + struct coord_range *range = tsfg->ranges[n]; + int *n_ranges = &tsfg->n_ranges[n]; + int found = 0; + + tsfg->samples[n][tsfg->N] = coords[n]; + + for (i = 0; i < *n_ranges; ++i) { + if (IN_RANGE(coords[n], range[i])) { + range[i].min = MIN(range[i].min, coords[n]); + range[i].max = MAX(range[i].max, coords[n]); + range[i].N++; + found = 1; + break; + } else if (coords[n] <= range[i].min) + break; /* We need to insert a range. */ + } + if (found) { /* We might need to melt ranges. */ + if (i && range[i - 1].max + tsfg->config->close_enough + >= range[i].min) { + BUG_ON(range[i - 1].max >= range[i].max); + range[i - 1].max = range[i].max; + range[i - 1].N += range[i].N; + delete_spot(range, i, *n_ranges); + (*n_ranges)--; + i--; + } + if (i < *n_ranges - 1 && range[i + 1].min - + tsfg->config->close_enough <= range[i].max) { + range[i].max = range[i + 1].max; + range[i].N += range[i + 1].N; + delete_spot(range, i + 1, *n_ranges); + (*n_ranges)--; + } + } else { + BUG_ON((*n_ranges) >= tsfg->config->length); + (*n_ranges)++; + for (j = *n_ranges - 1; j > i; --j) + range[j] = range[j - 1]; + range[i].N = 1; + range[i].min = coords[n]; + range[i].max = coords[n]; + } + } + + if (++tsfg->N < tsfg->config->length) + return 0; + + for (n = 0; n < tsfg->tsf.count_coords; ++n) { + int best = 0; + for (j = 1; j < tsfg->n_ranges[n]; ++j) + if (tsfg->ranges[n][best].N < tsfg->ranges[n][j].N) + best = j; + if (tsfg->ranges[n][best].N < tsfg->config->threshold) { + /* This set of points is not good enough for us. */ + if (--tsfg->tries_left) { + ts_filter_group_clear_internal + (tsfg, tsfg->tries_left); + /* No errors but we need more samples. */ + return 0; + } + return 1; /* We give up: error. */ + } + tsfg->range_min[n] = tsfg->ranges[n][best].min; + tsfg->range_max[n] = tsfg->ranges[n][best].max; + } + + ts_filter_group_prepare_next(tsf); + + return 0; +} + +/* + * This private function prepares a point that will be returned + * in ts_filter_group_getpoint if it is available. It updates + * the priv->ready state also. + */ +static void ts_filter_group_prepare_next(struct ts_filter *tsf) +{ + struct ts_filter_group *priv = ts_filter_to_filter_group(tsf); + int n; + + while (priv->result < priv->N) { + for (n = 0; n < priv->tsf.count_coords; ++n) { + if (priv->samples[n][priv->result] < + priv->range_min[n] || + priv->samples[n][priv->result] > priv->range_max[n]) + break; + } + + if (n == priv->tsf.count_coords) /* Sample is OK. */ + break; + + priv->result++; + } + + if (unlikely(priv->result >= priv->N)) { /* No sample to deliver. */ + ts_filter_group_clear_internal(priv, priv->config->attempts); + priv->ready = 0; + } else { + priv->ready = 1; + } +} + +static int ts_filter_group_haspoint(struct ts_filter *tsf) +{ + struct ts_filter_group *priv = ts_filter_to_filter_group(tsf); + + return priv->ready; +} + +static void ts_filter_group_getpoint(struct ts_filter *tsf, int *point) +{ + struct ts_filter_group *priv = ts_filter_to_filter_group(tsf); + int n; + + BUG_ON(!priv->ready); + + for (n = 0; n < priv->tsf.count_coords; n++) + point[n] = priv->samples[n][priv->result]; + + priv->result++; + + /* This call will update priv->ready. */ + ts_filter_group_prepare_next(tsf); +} + +/* + * Get ready to process the next batch of points, forget + * points we could have delivered. + */ +static void ts_filter_group_scale(struct ts_filter *tsf, int *coords) +{ + struct ts_filter_group *priv = ts_filter_to_filter_group(tsf); + + ts_filter_group_clear_internal(priv, priv->config->attempts); +} + +const struct ts_filter_api ts_filter_group_api = { + .create = ts_filter_group_create, + .destroy = ts_filter_group_destroy, + .clear = ts_filter_group_clear, + .process = ts_filter_group_process, + .haspoint = ts_filter_group_haspoint, + .getpoint = ts_filter_group_getpoint, + .scale = ts_filter_group_scale, +}; +EXPORT_SYMBOL_GPL(ts_filter_group_api); + diff --git a/drivers/input/touchscreen/ts_filter_group.h b/drivers/input/touchscreen/ts_filter_group.h new file mode 100644 index 00000000000..d1e3590e936 --- /dev/null +++ b/drivers/input/touchscreen/ts_filter_group.h @@ -0,0 +1,36 @@ +#ifndef __TS_FILTER_GROUP_H__ +#define __TS_FILTER_GROUP_H__ + +#include "ts_filter.h" + +/* + * Touchscreen group filter. + * + * Copyright (C) 2008,2009 by Openmoko, Inc. + * Author: Nelson Castillo <arhuaco@freaks-unidos.net> + * + */ + +struct ts_filter_group_configuration { + /* Size of the filter. */ + int length; + /* + * If two points are separated by this distance or less they + * are considered to be members of the same group. + */ + int close_enough; + /* Minimum allowed size for the biggest group in the sample set. */ + int threshold; + /* + * Number of times we try to get a group of points with at least + * threshold points. + */ + int attempts; + + /* Generic filter configuration. */ + struct ts_filter_configuration config; +}; + +extern const struct ts_filter_api ts_filter_group_api; + +#endif diff --git a/drivers/input/touchscreen/ts_filter_linear.c b/drivers/input/touchscreen/ts_filter_linear.c new file mode 100644 index 00000000000..7718bbc6e6d --- /dev/null +++ b/drivers/input/touchscreen/ts_filter_linear.c @@ -0,0 +1,212 @@ +/* + * 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; 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) 2008,2009 by Openmoko, Inc. + * Author: Nelson Castillo <arhuaco@freaks-unidos.net> + * All rights reserved. + * + * Linearly scale touchscreen values. + * + * Expose the TS_FILTER_LINEAR_NCONSTANTS for the linear transformation + * using sysfs. + * + */ + +#include <linux/kernel.h> +#include <linux/slab.h> +#include <linux/string.h> + +#include "ts_filter_linear.h" + +struct ts_filter_linear; + +/* Sysfs code. */ + +struct const_obj { + /* The actual private object. */ + struct ts_filter_linear *tsfl; + /* Our kobject. */ + struct kobject kobj; +}; + +#define to_const_obj(x) container_of(x, struct const_obj, kobj) + +struct const_attribute { + struct attribute attr; + ssize_t (*show)(struct const_obj *const, struct const_attribute *attr, + char *buf); + ssize_t (*store)(struct const_obj *const, struct const_attribute *attr, + const char *buf, size_t count); +}; + +#define to_const_attr(x) container_of(x, struct const_attribute, attr) + + +/* Private linear filter structure. */ + +struct ts_filter_linear { + /* Private configuration for this filter. */ + struct ts_filter_linear_configuration *config; + + /* Generic filter API. */ + struct ts_filter tsf; + + /* Linear constants for the transformation. */ + int constants[TS_FILTER_LINEAR_NCONSTANTS]; + + /* Sysfs. */ + + /* Our const_object. */ + struct const_obj c_obj; + /* Our type. We will stick operations to it. */ + struct kobj_type const_ktype; + /* Attrs. of the virtual files. */ + struct const_attribute kattrs[TS_FILTER_LINEAR_NCONSTANTS]; + /* Default Attrs. Always NULL for us. */ + struct attribute *attrs[TS_FILTER_LINEAR_NCONSTANTS + 1]; + /* Storage for the name of the virtual files. */ + char attr_names[TS_FILTER_LINEAR_NCONSTANTS][2]; +}; + +#define ts_filter_to_filter_linear(f) \ + container_of(f, struct ts_filter_linear, tsf) + +/* Sysfs functions. */ + +static ssize_t const_attr_show(struct kobject *kobj, + struct attribute *attr, + char *buf) +{ + struct const_attribute *a = to_const_attr(attr); + + return a->show(to_const_obj(kobj), a, buf); +} + +static ssize_t const_attr_store(struct kobject *kobj, + struct attribute *attr, + const char *buf, size_t len) +{ + struct const_attribute *a = to_const_attr(attr); + + return a->store(to_const_obj(kobj), a, buf, len); +} + +static struct sysfs_ops const_sysfs_ops = { + .show = const_attr_show, + .store = const_attr_store, +}; + +static void const_release(struct kobject *kobj) +{ + kfree(to_const_obj(kobj)->tsfl); +} + +static ssize_t const_show(struct const_obj *obj, struct const_attribute *attr, + char *buf) +{ + int who; + + sscanf(attr->attr.name, "%d", &who); + return sprintf(buf, "%d\n", obj->tsfl->constants[who]); +} + +static ssize_t const_store(struct const_obj *obj, struct const_attribute *attr, + const char *buf, size_t count) +{ + int who; + + sscanf(attr->attr.name, "%d", &who); + sscanf(buf, "%d", &obj->tsfl->constants[who]); + return count; +} + +/* Filter functions. */ + +static struct ts_filter *ts_filter_linear_create( + struct platform_device *pdev, + const struct ts_filter_configuration *conf, + int count_coords) +{ + struct ts_filter_linear *tsfl; + int i; + int ret; + + tsfl = kzalloc(sizeof(struct ts_filter_linear), GFP_KERNEL); + if (!tsfl) + return NULL; + + tsfl->config = container_of(conf, + struct ts_filter_linear_configuration, + config); + + tsfl->tsf.count_coords = count_coords; + + for (i = 0; i < TS_FILTER_LINEAR_NCONSTANTS; ++i) { + tsfl->constants[i] = tsfl->config->constants[i]; + + /* sysfs */ + sprintf(tsfl->attr_names[i], "%d", i); + tsfl->kattrs[i].attr.name = tsfl->attr_names[i]; + tsfl->kattrs[i].attr.mode = 0666; + tsfl->kattrs[i].show = const_show; + tsfl->kattrs[i].store = const_store; + tsfl->attrs[i] = &tsfl->kattrs[i].attr; + } + tsfl->attrs[i] = NULL; + + tsfl->const_ktype.sysfs_ops = &const_sysfs_ops; + tsfl->const_ktype.release = const_release; + tsfl->const_ktype.default_attrs = tsfl->attrs; + tsfl->c_obj.tsfl = tsfl; /* kernel frees tsfl in const_release */ + + ret = kobject_init_and_add(&tsfl->c_obj.kobj, &tsfl->const_ktype, + &pdev->dev.kobj, "calibration"); + if (ret) { + kobject_put(&tsfl->c_obj.kobj); + return NULL; + } + + dev_info(&pdev->dev, "Created Linear filter coords:%d\n", count_coords); + + return &tsfl->tsf; +} + +static void ts_filter_linear_destroy(struct ts_filter *tsf) +{ + struct ts_filter_linear *tsfl = ts_filter_to_filter_linear(tsf); + + /* Kernel frees tsfl in const_release. */ + kobject_put(&tsfl->c_obj.kobj); +} + +static void ts_filter_linear_scale(struct ts_filter *tsf, int *coords) +{ + struct ts_filter_linear *tsfl = ts_filter_to_filter_linear(tsf); + + int *k = tsfl->constants; + int c0 = coords[tsfl->config->coord0]; + int c1 = coords[tsfl->config->coord1]; + + coords[tsfl->config->coord0] = (k[2] + k[0] * c0 + k[1] * c1) / k[6]; + coords[tsfl->config->coord1] = (k[5] + k[3] * c0 + k[4] * c1) / k[6]; +} + +const struct ts_filter_api ts_filter_linear_api = { + .create = ts_filter_linear_create, + .destroy = ts_filter_linear_destroy, + .scale = ts_filter_linear_scale, +}; +EXPORT_SYMBOL_GPL(ts_filter_linear_api); + diff --git a/drivers/input/touchscreen/ts_filter_linear.h b/drivers/input/touchscreen/ts_filter_linear.h new file mode 100644 index 00000000000..82df3d25b50 --- /dev/null +++ b/drivers/input/touchscreen/ts_filter_linear.h @@ -0,0 +1,31 @@ +#ifndef __TS_FILTER_LINEAR_H__ +#define __TS_FILTER_LINEAR_H__ + +#include "ts_filter.h" +#include <linux/kobject.h> + +/* + * Touchscreen linear filter. + * + * Copyright (C) 2008,2009 by Openmoko, Inc. + * Author: Nelson Castillo <arhuaco@freaks-unidos.net> + * + */ + +#define TS_FILTER_LINEAR_NCONSTANTS 7 + +struct ts_filter_linear_configuration { + /* Calibration constants. */ + int constants[TS_FILTER_LINEAR_NCONSTANTS]; + /* First coordinate. */ + int coord0; + /* Second coordinate. */ + int coord1; + + /* Generic filter configuration. */ + struct ts_filter_configuration config; +}; + +extern const struct ts_filter_api ts_filter_linear_api; + +#endif diff --git a/drivers/input/touchscreen/ts_filter_mean.c b/drivers/input/touchscreen/ts_filter_mean.c new file mode 100644 index 00000000000..0c604321713 --- /dev/null +++ b/drivers/input/touchscreen/ts_filter_mean.c @@ -0,0 +1,174 @@ +/* + * 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) 2008,2009 + * Andy Green <andy@warmcat.com> + * Nelson Castillo <arhuaco@freaks-unidos.net> + * + * Simple mean filter. + * + */ + +#include <linux/errno.h> +#include <linux/kernel.h> +#include <linux/slab.h> + +#include "ts_filter_mean.h" + +struct ts_filter_mean { + /* Copy of the private filter configuration. */ + struct ts_filter_mean_configuration *config; + /* Filter API. */ + struct ts_filter tsf; + + /* Index on a circular buffer. */ + int curr; + /* Useful to tell if the circular buffer is full(read:ready). */ + int count; + /* Sumation used to compute the mean. */ + int sum[MAX_TS_FILTER_COORDS]; + /* Keep point values and decrement them from the sum on time. */ + int *fifo[MAX_TS_FILTER_COORDS]; + /* Store the output of this filter. */ + int ready; +}; + +#define ts_filter_to_filter_mean(f) container_of(f, struct ts_filter_mean, tsf) + + +static void ts_filter_mean_clear(struct ts_filter *tsf); + +static struct ts_filter *ts_filter_mean_create( + struct platform_device *pdev, + const struct ts_filter_configuration *conf, + int count_coords) +{ + struct ts_filter_mean *priv; + int *v; + int n; + + priv = kzalloc(sizeof(struct ts_filter_mean), GFP_KERNEL); + if (!priv) + return NULL; + + priv->tsf.count_coords = count_coords; + priv->config = container_of(conf, + struct ts_filter_mean_configuration, + config); + + BUG_ON(priv->config->length <= 0); + + v = kmalloc(priv->config->length * sizeof(int) * count_coords, + GFP_KERNEL); + if (!v) + return NULL; + + for (n = 0; n < count_coords; n++) { + priv->fifo[n] = v; + v += priv->config->length; + } + + ts_filter_mean_clear(&priv->tsf); + + dev_info(&pdev->dev, "Created Mean filter len:%d coords:%d\n", + priv->config->length, count_coords); + + return &priv->tsf; +} + +static void ts_filter_mean_destroy(struct ts_filter *tsf) +{ + struct ts_filter_mean *priv = ts_filter_to_filter_mean(tsf); + + kfree(priv->fifo[0]); /* first guy has pointer from kmalloc */ + kfree(tsf); +} + +static void ts_filter_mean_clear(struct ts_filter *tsf) +{ + struct ts_filter_mean *priv = ts_filter_to_filter_mean(tsf); + + priv->count = 0; + priv->curr = 0; + priv->ready = 0; + memset(priv->sum, 0, tsf->count_coords * sizeof(int)); +} + +static int ts_filter_mean_process(struct ts_filter *tsf, int *coords) +{ + struct ts_filter_mean *priv = ts_filter_to_filter_mean(tsf); + int n; + + BUG_ON(priv->ready); + + for (n = 0; n < tsf->count_coords; n++) { + priv->sum[n] += coords[n]; + priv->fifo[n][priv->curr] = coords[n]; + } + + if (priv->count + 1 == priv->config->length) + priv->ready = 1; + else + priv->count++; + + priv->curr = (priv->curr + 1) % priv->config->length; + + return 0; /* No error. */ +} + +static int ts_filter_mean_haspoint(struct ts_filter *tsf) +{ + struct ts_filter_mean *priv = ts_filter_to_filter_mean(tsf); + + return priv->ready; +} + +static void ts_filter_mean_getpoint(struct ts_filter *tsf, int *point) +{ + struct ts_filter_mean *priv = ts_filter_to_filter_mean(tsf); + int n; + + BUG_ON(!priv->ready); + + for (n = 0; n < tsf->count_coords; n++) { + point[n] = priv->sum[n]; + priv->sum[n] -= priv->fifo[n][priv->curr]; + } + + priv->ready = 0; +} + +static void ts_filter_mean_scale(struct ts_filter *tsf, int *coords) +{ + int n; + struct ts_filter_mean *priv = ts_filter_to_filter_mean(tsf); + + for (n = 0; n < tsf->count_coords; n++) { + coords[n] += priv->config->length >> 1; /* Rounding. */ + coords[n] /= priv->config->length; + } +} + +const struct ts_filter_api ts_filter_mean_api = { + .create = ts_filter_mean_create, + .destroy = ts_filter_mean_destroy, + .clear = ts_filter_mean_clear, + .process = ts_filter_mean_process, + .scale = ts_filter_mean_scale, + .haspoint = ts_filter_mean_haspoint, + .getpoint = ts_filter_mean_getpoint, +}; +EXPORT_SYMBOL_GPL(ts_filter_mean_api); + diff --git a/drivers/input/touchscreen/ts_filter_mean.h b/drivers/input/touchscreen/ts_filter_mean.h new file mode 100644 index 00000000000..80f9b215dff --- /dev/null +++ b/drivers/input/touchscreen/ts_filter_mean.h @@ -0,0 +1,28 @@ +#ifndef __TS_FILTER_MEAN_H__ +#define __TS_FILTER_MEAN_H__ + +#include "ts_filter.h" + +/* + * Touchscreen filter. + * + * mean + * + * (c) 2008,2009 + * Andy Green <andy@warmcat.com> + * Nelson Castillo <arhuaco@freaks-unidos.net> + */ + +/* Configuration for this filter. */ +struct ts_filter_mean_configuration { + /* Number of points for the mean. */ + int length; + + /* Generic filter configuration. */ + struct ts_filter_configuration config; +}; + +/* API functions for the mean filter */ +extern const struct ts_filter_api ts_filter_mean_api; + +#endif /* __TS_FILTER_MEAN_H__ */ diff --git a/drivers/input/touchscreen/ts_filter_median.c b/drivers/input/touchscreen/ts_filter_median.c new file mode 100644 index 00000000000..6f8aae5941d --- /dev/null +++ b/drivers/input/touchscreen/ts_filter_median.c @@ -0,0 +1,261 @@ +/* + * 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 Andy Green <andy@warmcat.com> + * + * + * Median averaging stuff. We sort incoming raw samples into an array of + * MEDIAN_SIZE length, discarding the oldest sample each time once we are full. + * We then return the sum of the middle three samples for X and Y. It means + * the final result must be divided by (3 * scaling factor) to correct for + * avoiding the repeated /3. + * + * This strongly rejects brief excursions away from a central point that is + * sticky in time compared to the excursion duration. + * + * Thanks to Dale Schumacher (who wrote some example code) and Carl-Daniel + * Halifinger who pointed out this would be a good method. + */ + +#include <linux/errno.h> +#include <linux/kernel.h> +#include <linux/slab.h> +#include "ts_filter_median.h" + +struct ts_filter_median { + /* Private configuration. */ + struct ts_filter_median_configuration *config; + /* Generic Filter API. */ + struct ts_filter tsf; + + /* Count raw samples we get. */ + int samples_count; + /* + * Remember the last coordinates we got in order to know if + * we are moving slow or fast. + */ + int last_issued[MAX_TS_FILTER_COORDS]; + /* How many samples in the sort buffer are valid. */ + int valid; + /* Samples taken for median in sorted form. */ + int *sort[MAX_TS_FILTER_COORDS]; + /* Samples taken for median. */ + int *fifo[MAX_TS_FILTER_COORDS]; + /* Where we are in the fifo sample memory. */ + int pos; + /* Do we have a sample to deliver? */ + int ready; +}; + +#define ts_filter_to_filter_median(f) \ + container_of(f, struct ts_filter_median, tsf) + + +static void ts_filter_median_insert(int *p, int sample, int count) +{ + int n; + + /* Search through what we got so far to find where to put sample. */ + for (n = 0; n < count; n++) + if (sample < p[n]) { /* We met somebody bigger than us? */ + /* Starting from the end, push bigger guys down one. */ + for (count--; count >= n; count--) + p[count + 1] = p[count]; + p[n] = sample; /* Put us in place of first bigger. */ + return; + } + + p[count] = sample; /* Nobody was bigger than us, add us on the end. */ +} + +static void ts_filter_median_del(int *p, int value, int count) +{ + int index; + + for (index = 0; index < count; index++) + if (p[index] == value) { + for (; index < count; index++) + p[index] = p[index + 1]; + return; + } +} + + +static void ts_filter_median_clear(struct ts_filter *tsf) +{ + struct ts_filter_median *tsfm = ts_filter_to_filter_median(tsf); + + tsfm->pos = 0; + tsfm->valid = 0; + tsfm->ready = 0; + memset(&tsfm->last_issued[0], 1, tsf->count_coords * sizeof(int)); +} + +static struct ts_filter *ts_filter_median_create( + struct platform_device *pdev, + const struct ts_filter_configuration *conf, + int count_coords) +{ + int *p; + int n; + struct ts_filter_median *tsfm = kzalloc(sizeof(struct ts_filter_median), + GFP_KERNEL); + + if (!tsfm) + return NULL; + + tsfm->config = container_of(conf, + struct ts_filter_median_configuration, + config); + + tsfm->tsf.count_coords = count_coords; + + tsfm->config->midpoint = (tsfm->config->extent >> 1) + 1; + + p = kmalloc(2 * count_coords * sizeof(int) * (tsfm->config->extent + 1), + GFP_KERNEL); + if (!p) { + kfree(tsfm); + return NULL; + } + + for (n = 0; n < count_coords; n++) { + tsfm->sort[n] = p; + p += tsfm->config->extent + 1; + tsfm->fifo[n] = p; + p += tsfm->config->extent + 1; + } + + ts_filter_median_clear(&tsfm->tsf); + + dev_info(&pdev->dev, + "Created Median filter len:%d coords:%d dec_threshold:%d\n", + tsfm->config->extent, count_coords, + tsfm->config->decimation_threshold); + + return &tsfm->tsf; +} + +static void ts_filter_median_destroy(struct ts_filter *tsf) +{ + struct ts_filter_median *tsfm = ts_filter_to_filter_median(tsf); + + kfree(tsfm->sort[0]); /* First guy has pointer from kmalloc. */ + kfree(tsf); +} + +static void ts_filter_median_scale(struct ts_filter *tsf, int *coords) +{ + int n; + + for (n = 0; n < tsf->count_coords; n++) + coords[n] = (coords[n] + 2) / 3; +} + +/* + * 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_median_process(struct ts_filter *tsf, int *coords) +{ + struct ts_filter_median *tsfm = ts_filter_to_filter_median(tsf); + int n; + int movement = 1; + + for (n = 0; n < tsf->count_coords; n++) { + /* Grab copy in insertion order to remove when oldest. */ + tsfm->fifo[n][tsfm->pos] = coords[n]; + /* Insert these samples in sorted order in the median arrays. */ + ts_filter_median_insert(tsfm->sort[n], coords[n], tsfm->valid); + } + /* Move us on in the fifo. */ + if (++tsfm->pos == (tsfm->config->extent + 1)) + tsfm->pos = 0; + + /* Have we finished a median sampling? */ + if (++tsfm->valid < tsfm->config->extent) + goto process_exit; /* No valid sample to use. */ + + BUG_ON(tsfm->valid != tsfm->config->extent); + + tsfm->valid--; + + /* + * Sum the middle 3 in the median sorted arrays. We don't divide back + * down which increases the sum resolution by a factor of 3 until the + * scale API function is called. + */ + for (n = 0; n < tsf->count_coords; n++) + /* Perform the deletion of the oldest sample. */ + ts_filter_median_del(tsfm->sort[n], tsfm->fifo[n][tsfm->pos], + tsfm->valid); + + tsfm->samples_count--; + if (tsfm->samples_count >= 0) + goto process_exit; + + for (n = 0; n < tsf->count_coords; n++) { + /* Give the coordinate result from summing median 3. */ + coords[n] = tsfm->sort[n][tsfm->config->midpoint - 1] + + tsfm->sort[n][tsfm->config->midpoint] + + tsfm->sort[n][tsfm->config->midpoint + 1]; + + movement += abs(tsfm->last_issued[n] - coords[n]); + } + + if (movement > tsfm->config->decimation_threshold) /* Moving fast. */ + tsfm->samples_count = tsfm->config->decimation_above; + else + tsfm->samples_count = tsfm->config->decimation_below; + + memcpy(&tsfm->last_issued[0], coords, tsf->count_coords * sizeof(int)); + + tsfm->ready = 1; + +process_exit: + return 0; +} + +static int ts_filter_median_haspoint(struct ts_filter *tsf) +{ + struct ts_filter_median *priv = ts_filter_to_filter_median(tsf); + + return priv->ready; +} + +static void ts_filter_median_getpoint(struct ts_filter *tsf, int *point) +{ + struct ts_filter_median *priv = ts_filter_to_filter_median(tsf); + + BUG_ON(!priv->ready); + + memcpy(point, &priv->last_issued[0], tsf->count_coords * sizeof(int)); + + priv->ready = 0; +} + +const struct ts_filter_api ts_filter_median_api = { + .create = ts_filter_median_create, + .destroy = ts_filter_median_destroy, + .clear = ts_filter_median_clear, + .process = ts_filter_median_process, + .scale = ts_filter_median_scale, + .haspoint = ts_filter_median_haspoint, + .getpoint = ts_filter_median_getpoint, +}; +EXPORT_SYMBOL_GPL(ts_filter_median_api); + diff --git a/drivers/input/touchscreen/ts_filter_median.h b/drivers/input/touchscreen/ts_filter_median.h new file mode 100644 index 00000000000..b13f361bb6a --- /dev/null +++ b/drivers/input/touchscreen/ts_filter_median.h @@ -0,0 +1,32 @@ +#ifndef __TS_FILTER_MEDIAN_H__ +#define __TS_FILTER_MEDIAN_H__ + +#include "ts_filter.h" + +/* + * Touchscreen filter. + * + * median + * + * (c) 2008 Andy Green <andy@warmcat.com> + */ + +struct ts_filter_median_configuration { + /* Size of the filter. */ + int extent; + /* Precomputed midpoint. */ + int midpoint; + /* A reference value for us to check if we are going fast or slow. */ + int decimation_threshold; + /* How many points to replace if we're going fast. */ + int decimation_above; + /* How many points to replace if we're going slow. */ + int decimation_below; + + /* Generic configuration. */ + struct ts_filter_configuration config; +}; + +extern const struct ts_filter_api ts_filter_median_api; + +#endif |