diff options
Diffstat (limited to 'drivers/input/touchscreen/ts_filter_chain.c')
| -rw-r--r-- | drivers/input/touchscreen/ts_filter_chain.c | 183 |
1 files changed, 183 insertions, 0 deletions
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); + |