path: root/recipes/linux/linux-2.6.29/micro2440/0002-S3C-Backported-openmoko-s-touchscreen-filters.patch

From fe4e1650cff50bff8e8ad62dc036609f53307442 Mon Sep 17 00:00:00 2001
From: Michel Pollet <buserror@gmail.com>
Date: Sat, 14 Mar 2009 10:24:07 +0000
Subject: [PATCH] S3C: Backported openmoko's touchscreen filters

Openmoko's touchscreen layer supports various filtering policy
for the ADC and touchscreen corrdinates. This is a staight port.
---
 drivers/input/touchscreen/Kconfig            |   48 ++++++
 drivers/input/touchscreen/Makefile           |    5 +
 drivers/input/touchscreen/ts_filter.c        |   73 +++++++++
 drivers/input/touchscreen/ts_filter.h        |   62 +++++++
 drivers/input/touchscreen/ts_filter_group.c  |  221 ++++++++++++++++++++++++++
 drivers/input/touchscreen/ts_filter_group.h  |   39 +++++
 drivers/input/touchscreen/ts_filter_linear.c |  173 ++++++++++++++++++++
 drivers/input/touchscreen/ts_filter_linear.h |   64 ++++++++
 drivers/input/touchscreen/ts_filter_mean.c   |  174 ++++++++++++++++++++
 drivers/input/touchscreen/ts_filter_mean.h   |   34 ++++
 drivers/input/touchscreen/ts_filter_median.c |  217 +++++++++++++++++++++++++
 drivers/input/touchscreen/ts_filter_median.h |   36 ++++
 12 files changed, 1146 insertions(+), 0 deletions(-)
 create mode 100644 drivers/input/touchscreen/ts_filter.c
 create mode 100644 drivers/input/touchscreen/ts_filter.h
 create mode 100644 drivers/input/touchscreen/ts_filter_group.c
 create mode 100644 drivers/input/touchscreen/ts_filter_group.h
 create mode 100644 drivers/input/touchscreen/ts_filter_linear.c
 create mode 100644 drivers/input/touchscreen/ts_filter_linear.h
 create mode 100644 drivers/input/touchscreen/ts_filter_mean.c
 create mode 100644 drivers/input/touchscreen/ts_filter_mean.h
 create mode 100644 drivers/input/touchscreen/ts_filter_median.c
 create mode 100644 drivers/input/touchscreen/ts_filter_median.h

diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig
index 9076492..75ff0a8 100644
--- a/drivers/input/touchscreen/Kconfig
+++ b/drivers/input/touchscreen/Kconfig
@@ -11,6 +11,54 @@ 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.
+
+if TOUCHSCREEN_FILTER
+
+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.
+
+endif
+
 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 fbcde99..4b0a03e 100644
--- a/drivers/input/touchscreen/Makefile
+++ b/drivers/input/touchscreen/Makefile
@@ -35,3 +35,8 @@ wm97xx-ts-$(CONFIG_TOUCHSCREEN_WM9712)	+= wm9712.o
 wm97xx-ts-$(CONFIG_TOUCHSCREEN_WM9713)	+= wm9713.o
 obj-$(CONFIG_TOUCHSCREEN_WM97XX_MAINSTONE)	+= mainstone-wm97xx.o
 obj-$(CONFIG_TOUCHSCREEN_S3C2410)	+= s3c2410_ts.o
+obj-$(CONFIG_TOUCHSCREEN_FILTER)	+= ts_filter.o
+obj-$(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.c b/drivers/input/touchscreen/ts_filter.c
new file mode 100644
index 0000000..832844d
--- /dev/null
+++ b/drivers/input/touchscreen/ts_filter.c
@@ -0,0 +1,73 @@
+/*
+ * 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@openmoko.com>
+ */
+
+#include <linux/kernel.h>
+#include <linux/device.h>
+#include "ts_filter.h"
+
+static DEFINE_MUTEX(chain_mutex);
+
+int ts_filter_create_chain(struct platform_device *pdev,
+			   struct ts_filter_api **api, void **config,
+			   struct ts_filter **arr, int count_coords)
+{
+	int count = 0;
+	struct ts_filter *last = NULL;
+
+	if (!api)
+		return 0;
+
+	mutex_lock(&chain_mutex);
+
+	while (*api) {
+		*arr = ((*api)->create)(pdev, *config++, count_coords);
+		if (!*arr) {
+			printk(KERN_ERR "Filter %d failed init\n", count);
+			return count;
+		}
+		(*arr)->api = *api++;
+		if (last)
+			last->next = *arr;
+		last = *arr;
+		arr++;
+		count++;
+	}
+
+	mutex_unlock(&chain_mutex);
+
+	return count;
+}
+EXPORT_SYMBOL_GPL(ts_filter_create_chain);
+
+void ts_filter_destroy_chain(struct platform_device *pdev,
+			     struct ts_filter **arr)
+{
+	struct ts_filter **first = arr;
+
+	mutex_lock(&chain_mutex);
+
+	while (*arr) {
+		((*arr)->api->destroy)(pdev, *arr);
+		arr++;
+	}
+	*first = NULL;
+
+	mutex_unlock(&chain_mutex);
+}
+EXPORT_SYMBOL_GPL(ts_filter_destroy_chain);
+
diff --git a/drivers/input/touchscreen/ts_filter.h b/drivers/input/touchscreen/ts_filter.h
new file mode 100644
index 0000000..3746e45
--- /dev/null
+++ b/drivers/input/touchscreen/ts_filter.h
@@ -0,0 +1,62 @@
+#ifndef __TS_FILTER_H__
+#define __TS_FILTER_H__
+
+/*
+ * Touchscreen filter.
+ *
+ * (c) 2008 Andy Green <andy@openmoko.com>
+ */
+
+#include <linux/platform_device.h>
+
+#define MAX_TS_FILTER_CHAIN		8  /* Max. filters we can chain up. */
+#define MAX_TS_FILTER_COORDS		3  /* X, Y and Z (pressure). */
+
+struct ts_filter;
+
+/* Operations that a filter can perform. */
+
+struct ts_filter_api {
+	struct ts_filter * (*create)(struct platform_device *pdev, void *config,
+				     int count_coords);
+	void (*destroy)(struct platform_device *pdev, struct ts_filter *filter);
+	void (*clear)(struct ts_filter *filter);
+	int (*process)(struct ts_filter *filter, int *coords);
+	void (*scale)(struct ts_filter *filter, int *coords);
+};
+
+/*
+ * This is the common part of all filters.
+ * We use this type as an otherwise opaque handle on to
+ * the actual filter.  Therefore you need one of these
+ * at the start of your actual filter struct.
+ */
+
+struct ts_filter {
+	struct ts_filter *next;		/* Next in chain. */
+	struct ts_filter_api *api;	/* Operations to use for this object. */
+	int count_coords;
+	int coords[MAX_TS_FILTER_COORDS];
+};
+
+/*
+ * Helper to create a filter chain from an array of API pointers and
+ * array of config ints. Leaves pointers to created filters in arr
+ * array and fills in ->next pointers to create the chain.
+ */
+
+#ifdef CONFIG_TOUCHSCREEN_FILTER
+extern int ts_filter_create_chain(struct platform_device *pdev,
+				  struct ts_filter_api **api, void **config,
+				  struct ts_filter **arr, int count_coords);
+
+/* Helper to destroy a whole chain from the list of filter pointers. */
+
+extern void ts_filter_destroy_chain(struct platform_device *pdev,
+				    struct ts_filter **arr);
+#else
+#define ts_filter_create_chain(pdev, api, config, arr, count_coords) (0)
+#define ts_filter_destroy_chain(pdev, arr) do { } while (0)
+#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 0000000..f2ecd92
--- /dev/null
+++ b/drivers/input/touchscreen/ts_filter_group.c
@@ -0,0 +1,221 @@
+/*
+ * 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 samples that are not reliable. We consider
+ * that a sample is not reliable if it deviates form the Majority.
+ *
+ * 1) We collect S samples.
+ *
+ * 2) For each dimension:
+ *
+ *  - We sort the points.
+ *  - Points that are "close enough" are considered to be in the same set.
+ *  - We choose the set with more elements. If more than "threshold"
+ *    points are in this set we use the first and the last point of the set
+ *    to define the valid range for this dimension [min, max], otherwise we
+ *    discard all the points 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 <linux/sort.h>
+#include "ts_filter_group.h"
+
+static void ts_filter_group_clear_internal(struct ts_filter_group *tsfg,
+					   int attempts)
+{
+	tsfg->N = 0;
+	tsfg->tries_left = attempts;
+}
+
+static void ts_filter_group_clear(struct ts_filter *tsf)
+{
+	struct ts_filter_group *tsfg = (struct ts_filter_group *)tsf;
+
+	ts_filter_group_clear_internal(tsfg, tsfg->config->attempts);
+
+	if (tsf->next) /* chain */
+		(tsf->next->api->clear)(tsf->next);
+}
+
+static struct ts_filter *ts_filter_group_create(struct platform_device *pdev,
+						void *conf, int count_coords)
+{
+	struct ts_filter_group *tsfg;
+	int i;
+
+	BUG_ON((count_coords < 1) || (count_coords > MAX_TS_FILTER_COORDS));
+
+	tsfg = kzalloc(sizeof(struct ts_filter_group), GFP_KERNEL);
+	if (!tsfg)
+		return NULL;
+
+	tsfg->config = (struct ts_filter_group_configuration *)conf;
+	tsfg->tsf.count_coords = count_coords;
+
+	BUG_ON(tsfg->config->attempts <= 0);
+
+	tsfg->samples[0] = kmalloc((2 + count_coords) * sizeof(int) *
+				   tsfg->config->extent, 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->extent;
+	tsfg->sorted_samples = tsfg->samples[0] + count_coords *
+			       tsfg->config->extent;
+	tsfg->group_size = tsfg->samples[0] + (1 + count_coords) *
+			       tsfg->config->extent;
+
+	ts_filter_group_clear_internal(tsfg, tsfg->config->attempts);
+
+	printk(KERN_INFO"  Created group ts filter len %d depth %d close %d "
+			"thresh %d\n", tsfg->config->extent, count_coords,
+			tsfg->config->close_enough, tsfg->config->threshold);
+
+	return &tsfg->tsf;
+}
+
+static void ts_filter_group_destroy(struct platform_device *pdev,
+				    struct ts_filter *tsf)
+{
+	struct ts_filter_group *tsfg = (struct ts_filter_group *)tsf;
+
+	kfree(tsfg->samples[0]); /* first guy has pointer from kmalloc */
+	kfree(tsf);
+}
+
+static void ts_filter_group_scale(struct ts_filter *tsf, int *coords)
+{
+	if (tsf->next)
+		(tsf->next->api->scale)(tsf->next, coords);
+}
+
+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;
+}
+
+static int ts_filter_group_process(struct ts_filter *tsf, int *coords)
+{
+	struct ts_filter_group *tsfg = (struct ts_filter_group *)tsf;
+	int n;
+	int i;
+	int ret = 0; /* ask for more samples by default */
+
+	BUG_ON(tsfg->N >= tsfg->config->extent);
+
+	for (n = 0; n < tsf->count_coords; n++)
+		tsfg->samples[n][tsfg->N] = coords[n];
+
+	if (++tsfg->N < tsfg->config->extent)
+		return 0;	/* we meed more samples */
+
+	for (n = 0; n < tsfg->tsf.count_coords; n++) {
+		int *v = tsfg->sorted_samples;
+		int ngroups = 0;
+		int best_size;
+		int best_idx = 0;
+		int idx = 0;
+
+		memcpy(v, tsfg->samples[n], tsfg->N * sizeof(int));
+		sort(v, tsfg->N, sizeof(int), int_cmp, NULL);
+
+		tsfg->group_size[0] = 1;
+		for (i = 1; i < tsfg->N; ++i) {
+			if (v[i] - v[i - 1] <= tsfg->config->close_enough)
+				tsfg->group_size[ngroups]++;
+			else
+				tsfg->group_size[++ngroups] = 1;
+		}
+		ngroups++;
+
+		best_size = tsfg->group_size[0];
+		for (i = 1; i < ngroups; i++) {
+			idx += tsfg->group_size[i - 1];
+			if (best_size < tsfg->group_size[i]) {
+				best_size = tsfg->group_size[i];
+				best_idx = idx;
+			}
+		}
+
+		if (best_size < tsfg->config->threshold) {
+			/* this set is not good enough for us */
+			if (--tsfg->tries_left) {
+				ts_filter_group_clear_internal
+					(tsfg, tsfg->tries_left);
+				return 0; /* ask for more samples */
+			}
+			return -1; /* we give up */
+		}
+
+		tsfg->range_min[n] = v[best_idx];
+		tsfg->range_max[n] = v[best_idx + best_size - 1];
+	}
+
+	for (i = 0; i < tsfg->N; ++i) {
+		int r;
+
+		for (n = 0; n < tsfg->tsf.count_coords; ++n) {
+			coords[n] = tsfg->samples[n][i];
+			if (coords[n] < tsfg->range_min[n] ||
+			    coords[n] > tsfg->range_max[n])
+				break;
+		}
+
+		if (n != tsfg->tsf.count_coords) /* sample not OK */
+			continue;
+
+		if (tsf->next) {
+			r = (tsf->next->api->process)(tsf->next, coords);
+			if (r)  {
+				ret = r;
+				break;
+			}
+		} else if (i == tsfg->N - 1) {
+			ret = 1;
+		}
+	}
+
+	ts_filter_group_clear_internal(tsfg, tsfg->config->attempts);
+
+	return ret;
+}
+
+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,
+	.scale = ts_filter_group_scale,
+};
+
diff --git a/drivers/input/touchscreen/ts_filter_group.h b/drivers/input/touchscreen/ts_filter_group.h
new file mode 100644
index 0000000..c411080
--- /dev/null
+++ b/drivers/input/touchscreen/ts_filter_group.h
@@ -0,0 +1,39 @@
+#ifndef __TS_FILTER_GROUP_H__
+#define __TS_FILTER_GROUP_H__
+
+#include "ts_filter.h"
+
+/*
+ * Touchscreen group filter.
+ *
+ * Copyright (C) 2008 by Openmoko, Inc.
+ * Author: Nelson Castillo <arhuaco@freaks-unidos.net>
+ *
+ */
+
+struct ts_filter_group_configuration {
+	int extent;
+	int close_enough;
+	int threshold;
+	int attempts;
+};
+
+struct ts_filter_group {
+	struct ts_filter tsf;
+	struct ts_filter_group_configuration *config;
+
+	int N;		/* How many samples we have */
+	int *samples[MAX_TS_FILTER_COORDS];	/* the samples, our input */
+
+	int *group_size;	/* used for temporal computations */
+	int *sorted_samples;	/* used for temporal computations */
+
+	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 don't get enough samples */
+};
+
+extern 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 0000000..c336252
--- /dev/null
+++ b/drivers/input/touchscreen/ts_filter_linear.c
@@ -0,0 +1,173 @@
+/*
+ * 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 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 "ts_filter_linear.h"
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+
+
+/* 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,
+						 void *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 = (struct ts_filter_linear_configuration *)conf;
+	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;
+	}
+
+	printk(KERN_INFO"  Created Linear ts filter depth %d\n", count_coords);
+
+	return &tsfl->tsf;
+}
+
+static void ts_filter_linear_destroy(struct platform_device *pdev,
+				     struct ts_filter *tsf)
+{
+	struct ts_filter_linear *tsfl = (struct ts_filter_linear *)tsf;
+
+	/* kernel frees tsfl in const_release */
+	kobject_put(&tsfl->c_obj.kobj);
+}
+
+static void ts_filter_linear_clear(struct ts_filter *tsf)
+{
+	if (tsf->next) /* chain */
+		(tsf->next->api->clear)(tsf->next);
+}
+
+
+static void ts_filter_linear_scale(struct ts_filter *tsf, int *coords)
+{
+	struct ts_filter_linear *tsfl = (struct ts_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];
+
+	if (tsf->next)
+		(tsf->next->api->scale)(tsf->next, coords);
+}
+
+static int ts_filter_linear_process(struct ts_filter *tsf, int *coords)
+{
+	if (tsf->next)
+		return (tsf->next->api->process)(tsf->next, coords);
+
+	return 1;
+}
+
+struct ts_filter_api ts_filter_linear_api = {
+	.create = ts_filter_linear_create,
+	.destroy = ts_filter_linear_destroy,
+	.clear = ts_filter_linear_clear,
+	.process = ts_filter_linear_process,
+	.scale = ts_filter_linear_scale,
+};
diff --git a/drivers/input/touchscreen/ts_filter_linear.h b/drivers/input/touchscreen/ts_filter_linear.h
new file mode 100644
index 0000000..fc27cf7
--- /dev/null
+++ b/drivers/input/touchscreen/ts_filter_linear.h
@@ -0,0 +1,64 @@
+#ifndef __TS_FILTER_LINEAR_H__
+#define __TS_FILTER_LINEAR_H__
+
+#include "ts_filter.h"
+#include <linux/kobject.h>
+
+/*
+ * Touchscreen linear filter.
+ *
+ * Copyright (C) 2008 by Openmoko, Inc.
+ * Author: Nelson Castillo <arhuaco@freaks-unidos.net>
+ *
+ */
+
+#define TS_FILTER_LINEAR_NCONSTANTS 7
+
+/* sysfs */
+
+struct ts_filter_linear;
+
+struct const_obj {
+	struct ts_filter_linear *tsfl;
+	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)
+
+/* filter configuration */
+
+struct ts_filter_linear_configuration {
+	int constants[TS_FILTER_LINEAR_NCONSTANTS];
+	int coord0;
+	int coord1;
+};
+
+/* the filter */
+
+struct ts_filter_linear {
+	struct ts_filter tsf;
+	struct ts_filter_linear_configuration *config;
+
+	int constants[TS_FILTER_LINEAR_NCONSTANTS];
+
+	/* sysfs */
+	struct const_obj c_obj;
+	struct kobj_type const_ktype;
+	struct const_attribute kattrs[TS_FILTER_LINEAR_NCONSTANTS];
+	struct attribute *attrs[TS_FILTER_LINEAR_NCONSTANTS + 1];
+	char attr_names[TS_FILTER_LINEAR_NCONSTANTS][2];
+};
+
+extern 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 0000000..e4e0f2a
--- /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 Andy Green <andy@openmoko.com>
+ *
+ *
+ * Mean has no effect if the samples are changing by more that the
+ * threshold set by averaging_threshold in the configuration.
+ *
+ * However while samples come in that don't go outside this threshold from
+ * the last reported sample, Mean replaces the samples with a simple mean
+ * of a configurable number of samples (set by bits_filter_length in config,
+ * which is 2^n, so 5 there makes 32 sample averaging).
+ *
+ * Mean works well if the input data is already good quality, reducing + / - 1
+ * sample jitter when the stylus is still, or moving very slowly, without
+ * introducing abrupt transitions or reducing ability to follow larger
+ * movements.  If you set the threshold higher than the dynamic range of the
+ * coordinates, you can just use it as a simple mean average.
+ */
+
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include "ts_filter_mean.h"
+
+static void ts_filter_mean_clear_internal(struct ts_filter *tsf)
+{
+	struct ts_filter_mean *tsfs = (struct ts_filter_mean *)tsf;
+	int n;
+
+	for (n = 0; n < tsfs->tsf.count_coords; n++) {
+		tsfs->fhead[n] = 0;
+		tsfs->ftail[n] = 0;
+		tsfs->lowpass[n] = 0;
+	}
+}
+
+static void ts_filter_mean_clear(struct ts_filter *tsf)
+{
+	ts_filter_mean_clear_internal(tsf);
+
+	if (tsf->next) /* chain */
+		(tsf->next->api->clear)(tsf->next);
+}
+
+static struct ts_filter *ts_filter_mean_create(struct platform_device *pdev,
+					       void *config, int count_coords)
+{
+	int *p;
+	int n;
+	struct ts_filter_mean *tsfs = kzalloc(
+				  sizeof(struct ts_filter_mean), GFP_KERNEL);
+
+	if (!tsfs)
+		return NULL;
+
+	BUG_ON((count_coords < 1) || (count_coords > MAX_TS_FILTER_COORDS));
+	tsfs->tsf.count_coords = count_coords;
+
+	tsfs->config = (struct ts_filter_mean_configuration *)config;
+
+	tsfs->config->extent = 1 << tsfs->config->bits_filter_length;
+	BUG_ON((tsfs->config->extent > 256) || (!tsfs->config->extent));
+
+	p = kmalloc(tsfs->config->extent * sizeof(int) * count_coords,
+								    GFP_KERNEL);
+	if (!p)
+		return NULL;
+
+	for (n = 0; n < count_coords; n++) {
+		tsfs->fifo[n] = p;
+		p += tsfs->config->extent;
+	}
+
+	if (!tsfs->config->averaging_threshold)
+		tsfs->config->averaging_threshold = 0xffff; /* always active */
+
+	ts_filter_mean_clear_internal(&tsfs->tsf);
+
+	printk(KERN_INFO"  Created Mean ts filter len %d depth %d thresh %d\n",
+	       tsfs->config->extent, count_coords,
+	       tsfs->config->averaging_threshold);
+
+	return &tsfs->tsf;
+}
+
+static void ts_filter_mean_destroy(struct platform_device *pdev,
+				   struct ts_filter *tsf)
+{
+	struct ts_filter_mean *tsfs = (struct ts_filter_mean *)tsf;
+
+	kfree(tsfs->fifo[0]); /* first guy has pointer from kmalloc */
+	kfree(tsf);
+}
+
+static void ts_filter_mean_scale(struct ts_filter *tsf, int *coords)
+{
+	if (tsf->next) /* chain */
+		(tsf->next->api->scale)(tsf->next, coords);
+}
+
+/*
+ * Give us the raw sample data in x and y, and if we return 1 then you can
+ * get a filtered coordinate from tsm->x and tsm->y. If we return 0 you didn't
+ * fill the filter with samples yet.
+ */
+
+static int ts_filter_mean_process(struct ts_filter *tsf, int *coords)
+{
+	struct ts_filter_mean *tsfs = (struct ts_filter_mean *)tsf;
+	int n;
+	int len;
+
+	for (n = 0; n < tsf->count_coords; n++) {
+
+		/*
+		 * Has he moved far enough away that we should abandon current
+		 * low pass filtering state?
+		 */
+		if ((coords[n] < (tsfs->reported[n] -
+					  tsfs->config->averaging_threshold)) ||
+		    (coords[n] > (tsfs->reported[n] +
+					  tsfs->config->averaging_threshold))) {
+			tsfs->fhead[n] = 0;
+			tsfs->ftail[n] = 0;
+			tsfs->lowpass[n] = 0;
+		}
+
+		/* capture this sample into fifo and sum */
+		tsfs->fifo[n][tsfs->fhead[n]++] = coords[n];
+		if (tsfs->fhead[n] == tsfs->config->extent)
+			tsfs->fhead[n] = 0;
+		tsfs->lowpass[n] += coords[n];
+
+		/* adjust the sum into an average and use that*/
+		len = (tsfs->fhead[n] - tsfs->ftail[n]) &
+						     (tsfs->config->extent - 1);
+		coords[n] = (tsfs->lowpass[n] + (len >> 1)) / len;
+		tsfs->reported[n] = coords[n];
+
+		/* remove oldest sample if we are full */
+		if (len == (tsfs->config->extent - 1)) {
+			tsfs->lowpass[n] -= tsfs->fifo[n][tsfs->ftail[n]++];
+			if (tsfs->ftail[n] == tsfs->config->extent)
+				tsfs->ftail[n] = 0;
+		}
+	}
+
+	if (tsf->next) /* chain */
+		return (tsf->next->api->process)(tsf->next, coords);
+
+	return 1;
+}
+
+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,
+};
diff --git a/drivers/input/touchscreen/ts_filter_mean.h b/drivers/input/touchscreen/ts_filter_mean.h
new file mode 100644
index 0000000..44c506c
--- /dev/null
+++ b/drivers/input/touchscreen/ts_filter_mean.h
@@ -0,0 +1,34 @@
+#ifndef __TS_FILTER_MEAN_H__
+#define __TS_FILTER_MEAN_H__
+
+#include "ts_filter.h"
+
+/*
+ * Touchscreen filter.
+ *
+ * mean
+ *
+ * (c) 2008 Andy Green <andy@openmoko.com>
+ */
+
+struct ts_filter_mean_configuration {
+	int bits_filter_length;
+	int averaging_threshold;
+
+	int extent;
+};
+
+struct ts_filter_mean {
+	struct ts_filter tsf;
+	struct ts_filter_mean_configuration *config;
+
+	int reported[MAX_TS_FILTER_COORDS];
+	int lowpass[MAX_TS_FILTER_COORDS];
+	int *fifo[MAX_TS_FILTER_COORDS];
+	int fhead[MAX_TS_FILTER_COORDS];
+	int ftail[MAX_TS_FILTER_COORDS];
+};
+
+extern struct ts_filter_api ts_filter_mean_api;
+
+#endif
diff --git a/drivers/input/touchscreen/ts_filter_median.c b/drivers/input/touchscreen/ts_filter_median.c
new file mode 100644
index 0000000..b3b6a9c
--- /dev/null
+++ b/drivers/input/touchscreen/ts_filter_median.c
@@ -0,0 +1,217 @@
+/*
+ * 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@openmoko.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"
+
+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++)
+		 /* we met somebody bigger than us? */
+		if (sample < p[n]) {
+			/* starting from the end, push bigger guys down one */
+			for (count--; count >= n; count--)
+				p[count + 1] = p[count];
+			p[n] = sample; /* and 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_internal(struct ts_filter *tsf)
+{
+	struct ts_filter_median *tsfm = (struct ts_filter_median *)tsf;
+
+	tsfm->pos = 0;
+	tsfm->valid = 0;
+
+}
+static void ts_filter_median_clear(struct ts_filter *tsf)
+{
+	ts_filter_median_clear_internal(tsf);
+
+	if (tsf->next) /* chain */
+		(tsf->next->api->clear)(tsf->next);
+}
+
+static struct ts_filter *ts_filter_median_create(struct platform_device *pdev,
+						 void *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 = (struct ts_filter_median_configuration *)conf;
+	BUG_ON((count_coords < 1) || (count_coords > MAX_TS_FILTER_COORDS));
+	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_internal(&tsfm->tsf);
+
+	printk(KERN_INFO"  Created Median ts filter len %d depth %d dec %d\n",
+	       tsfm->config->extent, count_coords,
+	       tsfm->config->decimation_threshold);
+
+	return &tsfm->tsf;
+}
+
+static void ts_filter_median_destroy(struct platform_device *pdev,
+				     struct ts_filter *tsf)
+{
+	struct ts_filter_median *tsfm = (struct ts_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;
+
+	if (tsf->next) /* chain */
+		(tsf->next->api->scale)(tsf->next, coords);
+}
+
+/*
+ * 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 = (struct ts_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;
+
+	/* we have finished a median sampling? */
+	if (++tsfm->valid != tsfm->config->extent)
+		return 0; /* no valid sample to use */
+
+	/* discard the oldest sample in median sorted array */
+	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 is called.
+	 */
+	for (n = 0; n < tsfm->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->decimation_count--;
+	if (tsfm->decimation_count >= 0)
+		return 0;
+
+	for (n = 0; n < tsfm->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) /* fast */
+		tsfm->decimation_count = tsfm->config->decimation_above;
+	else
+		tsfm->decimation_count = tsfm->config->decimation_below;
+
+	memcpy(&tsfm->last_issued[0], coords,
+	       tsfm->tsf.count_coords * sizeof(int));
+
+	if (tsf->next) /* chain */
+		return (tsf->next->api->process)(tsf->next, coords);
+
+	return 1;
+}
+
+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,
+};
diff --git a/drivers/input/touchscreen/ts_filter_median.h b/drivers/input/touchscreen/ts_filter_median.h
new file mode 100644
index 0000000..8f25e27
--- /dev/null
+++ b/drivers/input/touchscreen/ts_filter_median.h
@@ -0,0 +1,36 @@
+#ifndef __TS_FILTER_MEDIAN_H__
+#define __TS_FILTER_MEDIAN_H__
+
+#include "ts_filter.h"
+
+/*
+ * Touchscreen filter.
+ *
+ * median
+ *
+ * (c) 2008 Andy Green <andy@openmoko.com>
+ */
+
+struct ts_filter_median_configuration {
+	int extent;
+	int midpoint;
+	int decimation_threshold;
+	int decimation_above;
+	int decimation_below;
+};
+
+struct ts_filter_median {
+	struct ts_filter tsf;
+	struct ts_filter_median_configuration *config;
+
+	int decimation_count;
+	int last_issued[MAX_TS_FILTER_COORDS];
+	int valid; /* how many samples in the sort buffer are valid */
+	int *sort[MAX_TS_FILTER_COORDS]; /* samples taken for median */
+	int *fifo[MAX_TS_FILTER_COORDS]; /* samples taken for median */
+	int pos; /* where we are in the fifo sample memory */
+};
+
+extern struct ts_filter_api ts_filter_median_api;
+
+#endif
-- 
1.5.6.3