| 1 | /* |
| 2 | * This program is free software; you can redistribute it and/or modify |
| 3 | * it under the terms of the GNU General Public License as published by |
| 4 | * the Free Software Foundation; either version 2 of the License, or |
| 5 | * (at your option) any later version. |
| 6 | * |
| 7 | * This program is distributed in the hope that it will be useful, |
| 8 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 9 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 10 | * GNU General Public License for more details. |
| 11 | * |
| 12 | * You should have received a copy of the GNU General Public License |
| 13 | * along with this program; if not, write to the Free Software |
| 14 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
| 15 | * |
| 16 | * Copyright (c) 2008,2009 |
| 17 | * Andy Green <andy@openmoko.com> |
| 18 | * Nelson Castillo <arhuaco@freaks-unidos.net> |
| 19 | * |
| 20 | * Simple mean filter. |
| 21 | * |
| 22 | */ |
| 23 | |
| 24 | #include <linux/errno.h> |
| 25 | #include <linux/kernel.h> |
| 26 | #include <linux/slab.h> |
| 27 | |
| 28 | #include <linux/touchscreen/ts_filter_mean.h> |
| 29 | |
| 30 | struct ts_filter_mean { |
| 31 | /* Copy of the private filter configuration. */ |
| 32 | struct ts_filter_mean_configuration *config; |
| 33 | /* Filter API. */ |
| 34 | struct ts_filter tsf; |
| 35 | |
| 36 | /* Index on a circular buffer. */ |
| 37 | int curr; |
| 38 | /* Useful to tell if the circular buffer is full(read:ready). */ |
| 39 | int count; |
| 40 | /* Sumation used to compute the mean. */ |
| 41 | int sum[MAX_TS_FILTER_COORDS]; |
| 42 | /* Keep point values and decrement them from the sum on time. */ |
| 43 | int *fifo[MAX_TS_FILTER_COORDS]; |
| 44 | /* Store the output of this filter. */ |
| 45 | int ready; |
| 46 | }; |
| 47 | |
| 48 | #define ts_filter_to_filter_mean(f) container_of(f, struct ts_filter_mean, tsf) |
| 49 | |
| 50 | |
| 51 | static void ts_filter_mean_clear(struct ts_filter *tsf); |
| 52 | |
| 53 | static struct ts_filter *ts_filter_mean_create( |
| 54 | struct platform_device *pdev, |
| 55 | const struct ts_filter_configuration *conf, |
| 56 | int count_coords) |
| 57 | { |
| 58 | struct ts_filter_mean *priv; |
| 59 | int *v; |
| 60 | int n; |
| 61 | |
| 62 | priv = kzalloc(sizeof(struct ts_filter_mean), GFP_KERNEL); |
| 63 | if (!priv) |
| 64 | return NULL; |
| 65 | |
| 66 | priv->tsf.count_coords = count_coords; |
| 67 | priv->config = container_of(conf, |
| 68 | struct ts_filter_mean_configuration, |
| 69 | config); |
| 70 | |
| 71 | BUG_ON(priv->config->length <= 0); |
| 72 | |
| 73 | v = kmalloc(priv->config->length * sizeof(int) * count_coords, |
| 74 | GFP_KERNEL); |
| 75 | if (!v) |
| 76 | return NULL; |
| 77 | |
| 78 | for (n = 0; n < count_coords; n++) { |
| 79 | priv->fifo[n] = v; |
| 80 | v += priv->config->length; |
| 81 | } |
| 82 | |
| 83 | ts_filter_mean_clear(&priv->tsf); |
| 84 | |
| 85 | dev_info(&pdev->dev, "Created Mean filter len:%d coords:%d\n", |
| 86 | priv->config->length, count_coords); |
| 87 | |
| 88 | return &priv->tsf; |
| 89 | } |
| 90 | |
| 91 | static void ts_filter_mean_destroy(struct ts_filter *tsf) |
| 92 | { |
| 93 | struct ts_filter_mean *priv = ts_filter_to_filter_mean(tsf); |
| 94 | |
| 95 | kfree(priv->fifo[0]); /* first guy has pointer from kmalloc */ |
| 96 | kfree(tsf); |
| 97 | } |
| 98 | |
| 99 | static void ts_filter_mean_clear(struct ts_filter *tsf) |
| 100 | { |
| 101 | struct ts_filter_mean *priv = ts_filter_to_filter_mean(tsf); |
| 102 | |
| 103 | priv->count = 0; |
| 104 | priv->curr = 0; |
| 105 | priv->ready = 0; |
| 106 | memset(priv->sum, 0, tsf->count_coords * sizeof(int)); |
| 107 | } |
| 108 | |
| 109 | static int ts_filter_mean_process(struct ts_filter *tsf, int *coords) |
| 110 | { |
| 111 | struct ts_filter_mean *priv = ts_filter_to_filter_mean(tsf); |
| 112 | int n; |
| 113 | |
| 114 | BUG_ON(priv->ready); |
| 115 | |
| 116 | for (n = 0; n < tsf->count_coords; n++) { |
| 117 | priv->sum[n] += coords[n]; |
| 118 | priv->fifo[n][priv->curr] = coords[n]; |
| 119 | } |
| 120 | |
| 121 | if (priv->count + 1 == priv->config->length) |
| 122 | priv->ready = 1; |
| 123 | else |
| 124 | priv->count++; |
| 125 | |
| 126 | priv->curr = (priv->curr + 1) % priv->config->length; |
| 127 | |
| 128 | return 0; /* No error. */ |
| 129 | } |
| 130 | |
| 131 | static int ts_filter_mean_haspoint(struct ts_filter *tsf) |
| 132 | { |
| 133 | struct ts_filter_mean *priv = ts_filter_to_filter_mean(tsf); |
| 134 | |
| 135 | return priv->ready; |
| 136 | } |
| 137 | |
| 138 | static void ts_filter_mean_getpoint(struct ts_filter *tsf, int *point) |
| 139 | { |
| 140 | struct ts_filter_mean *priv = ts_filter_to_filter_mean(tsf); |
| 141 | int n; |
| 142 | |
| 143 | BUG_ON(!priv->ready); |
| 144 | |
| 145 | for (n = 0; n < tsf->count_coords; n++) { |
| 146 | point[n] = priv->sum[n]; |
| 147 | priv->sum[n] -= priv->fifo[n][priv->curr]; |
| 148 | } |
| 149 | |
| 150 | priv->ready = 0; |
| 151 | } |
| 152 | |
| 153 | static void ts_filter_mean_scale(struct ts_filter *tsf, int *coords) |
| 154 | { |
| 155 | int n; |
| 156 | struct ts_filter_mean *priv = ts_filter_to_filter_mean(tsf); |
| 157 | |
| 158 | for (n = 0; n < tsf->count_coords; n++) { |
| 159 | coords[n] += priv->config->length >> 1; /* Rounding. */ |
| 160 | coords[n] /= priv->config->length; |
| 161 | } |
| 162 | } |
| 163 | |
| 164 | const struct ts_filter_api ts_filter_mean_api = { |
| 165 | .create = ts_filter_mean_create, |
| 166 | .destroy = ts_filter_mean_destroy, |
| 167 | .clear = ts_filter_mean_clear, |
| 168 | .process = ts_filter_mean_process, |
| 169 | .scale = ts_filter_mean_scale, |
| 170 | .haspoint = ts_filter_mean_haspoint, |
| 171 | .getpoint = ts_filter_mean_getpoint, |
| 172 | }; |
| 173 | EXPORT_SYMBOL_GPL(ts_filter_mean_api); |
| 174 | |
| 175 | |
