target/linux/s3c24xx/files-2.6.30/drivers/input/touchscreen/ts_filter_chain.c

   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 Andy Green <andy@openmoko.com>
  17  */
  18
  19 #include <linux/kernel.h>
  20 #include <linux/device.h>
  21
  22 #include <linux/touchscreen/ts_filter_chain.h>
  23 #include <linux/touchscreen/ts_filter.h>
  24
  25 /*
  26  * Tux, would you like the following function in /lib?
  27  * It helps us avoid silly code.
  28  */
  29
  30 /**
  31  * sptrlen - Count how many non-null pointers are in a pointer array
  32  * @arr: The array of pointers
  33  */
  34 static int sptrlen(const void *arr)
  35 {
  36         /* All pointers have the same size. */
  37         const int **p = (const int **)arr;
  38         int len = 0;
  39
  40         while (*(p++))
  41                 len++;
  42
  43         return len;
  44 }
  45
  46
  47 struct ts_filter_chain {
  48         /* All of the filters. */
  49         struct ts_filter **arr;
  50         /* Filters that can propagate values in the chain. */
  51         struct ts_filter **pchain;
  52         /* Length of the pchain array. */
  53         int pchain_len;
  54         /* FIXME: Add a spinlock and use it. */
  55 };
  56
  57 struct ts_filter_chain *ts_filter_chain_create(
  58         struct platform_device *pdev,
  59         const struct ts_filter_chain_configuration conf[],
  60         int count_coords)
  61 {
  62         struct ts_filter_chain *c;
  63         int count = 0;
  64         int len;
  65
  66         BUG_ON((count_coords < 1));
  67         BUG_ON(count_coords > MAX_TS_FILTER_COORDS);
  68
  69         c = kzalloc(sizeof(struct ts_filter_chain), GFP_KERNEL);
  70         if (!c)
  71                 goto create_err_1;
  72
  73         len = (sptrlen(conf) + 1);
  74         /* Memory for two null-terminated arrays of filters. */
  75         c->arr = kzalloc(2 * sizeof(struct ts_filter *) * len, GFP_KERNEL);
  76         if (!c->arr)
  77                 goto create_err_1;
  78         c->pchain = c->arr + len;
  79
  80         while (conf->api) {
  81                 /* TODO: Can we get away with only sending pdev->dev? */
  82                 struct ts_filter *f =
  83                         (conf->api->create)(pdev, conf->config, count_coords);
  84                 if (!f) {
  85                         dev_info(&pdev->dev, "Filter %d creation failed\n",
  86                                  count);
  87                         goto create_err_2;
  88                 }
  89
  90                 f->api = conf->api;
  91                 c->arr[count++] = f;
  92
  93                 if (f->api->haspoint && f->api->getpoint && f->api->process)
  94                         c->pchain[c->pchain_len++] = f;
  95
  96                 conf++;
  97         }
  98
  99         dev_info(&pdev->dev, "%d filter(s) initialized\n", count);
 100
 101         return c;
 102
 103 create_err_2:
 104         ts_filter_chain_destroy(c); /* Also frees c. */
 105 create_err_1:
 106         dev_info(&pdev->dev, "Error in filter chain initialization\n");
 107         /*
 108          * FIXME: Individual filters have to return errors this way.
 109          * We only have to forward the errors we find.
 110          */
 111         return ERR_PTR(-ENOMEM);
 112 }
 113 EXPORT_SYMBOL_GPL(ts_filter_chain_create);
 114
 115 void ts_filter_chain_destroy(struct ts_filter_chain *c)
 116 {
 117         if (c->arr) {
 118                 struct ts_filter **a = c->arr;
 119                 while (*a) {
 120                         ((*a)->api->destroy)(*a);
 121                         a++;
 122                 }
 123                 kfree(c->arr);
 124         }
 125         kfree(c);
 126 }
 127 EXPORT_SYMBOL_GPL(ts_filter_chain_destroy);
 128
 129 void ts_filter_chain_clear(struct ts_filter_chain *c)
 130 {
 131         struct ts_filter **a = c->arr;
 132
 133         while (*a) {
 134                 if ((*a)->api->clear)
 135                         ((*a)->api->clear)(*a);
 136                 a++;
 137         }
 138 }
 139 EXPORT_SYMBOL_GPL(ts_filter_chain_clear);
 140
 141 static void ts_filter_chain_scale(struct ts_filter_chain *c, int *coords)
 142 {
 143         struct ts_filter **a = c->arr;
 144         while (*a) {
 145                 if ((*a)->api->scale)
 146                         ((*a)->api->scale)(*a, coords);
 147                 a++;
 148         }
 149 }
 150
 151 int ts_filter_chain_feed(struct ts_filter_chain *c, int *coords)
 152 {
 153         int len = c->pchain_len;
 154         int i = len - 1;
 155
 156         if (!c->pchain[0])
 157                 return 1; /* Nothing to do. */
 158
 159         BUG_ON(c->pchain[0]->api->haspoint(c->pchain[0]));
 160
 161         if (c->pchain[0]->api->process(c->pchain[0], coords))
 162                 return -1;
 163
 164         while (i >= 0 && i < len) {
 165                 if (c->pchain[i]->api->haspoint(c->pchain[i])) {
 166                         c->pchain[i]->api->getpoint(c->pchain[i], coords);
 167                         if (++i < len &&
 168                             c->pchain[i]->api->process(c->pchain[i], coords))
 169                                 return -1; /* Error. */
 170                 } else {
 171                         i--;
 172                 }
 173         }
 174
 175         if (i >= 0) {   /* Same as i == len. */
 176                 ts_filter_chain_scale(c, coords);
 177                 return 1;
 178         }
 179
 180         return 0;
 181 }
 182 EXPORT_SYMBOL_GPL(ts_filter_chain_feed);
 183