--- /dev/null
+/*
+ * 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 <linux/touchscreen/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);
+
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