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#ifndef __TS_FILTER_H__
#define __TS_FILTER_H__
/*
* Touchscreen filter.
*
* (c) 2008,2009 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 {
/* Create the filter - mandatory. */
struct ts_filter * (*create)(struct platform_device *pdev, void *config,
int count_coords);
/* Destroy the filter - mandatory. */
void (*destroy)(struct ts_filter *filter);
/* Clear the filter - optional. */
void (*clear)(struct ts_filter *filter);
/*
* The next three API functions only make sense if all of them are
* set for a filter. If a filter has the next three methods then
* it can propagate coordinates in the chain.
*/
/*
* Process the filter.
* It returns non-zero if the filter reaches an error.
*/
int (*process)(struct ts_filter *filter, int *coords);
/*
* Is the filter ready to return a point?
* Please do not code side effects in this function.
*/
int (*haspoint)(struct ts_filter *filter);
/*
* Get a point.
* Do not call unless the filter actually has a point to deliver.
*/
void (*getpoint)(struct ts_filter *filter, int *coords);
/*
* Scale the points - optional.
* A filter could only scale coordinates.
*/
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_api *api; /* operations for this filter */
int count_coords; /* how many coordinates to process */
int coords[MAX_TS_FILTER_COORDS]; /* count_coords coordinates */
};
#ifdef CONFIG_TOUCHSCREEN_FILTER
/*
* Helper to create a filter chain. It will allocate an array of
* null-terminated pointers to filters.
*/
extern struct ts_filter **ts_filter_chain_create(
struct platform_device *pdev,
struct ts_filter_api **api, void **config, int count_coords);
/* Helper to destroy a whole chain from the list of filter pointers. */
extern void ts_filter_chain_destroy(struct ts_filter **arr);
/* Helper to call the clear API function */
extern void ts_filter_chain_clear(struct ts_filter **arr);
/*
* Try to get one point. Returns 0 if no points are available.
* coords will be used as temporal space, thus you supply a point
* using coords but you shouldn't rely on its value on return unless
* it returns a nonzero value that is not -1.
* If one of the filters find an error then this function will
* return -1.
*/
int ts_filter_chain_feed(struct ts_filter **arr, int *coords);
#else /* !CONFIG_TOUCHSCREEN_FILTER */
#define ts_filter_chain_create(pdev, api, config, arr, count_coords) (0)
#define ts_filter_chain_destroy(pdev, arr) do { } while (0)
#define ts_filter_chain_clear(arr) do { } while (0)
#define ts_filter_chain_feed(arr, coords) (1)
#endif
#endif
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