Skip filter for touchscreen values.
Problem: The first and the last sample might be unreliable. We provide
this filter as a separate function in order to keep the event_send_timer_f
function simple. This filter:
* Skips NHEAD points after IE_DOWN
* Skips NTAIL points before IE_UP
* Ignores a click if we have less than (NHEAD + NTAIL + 1) points
Right now the filter is embedded in the driver. We have two #defines with
the parameters SKIP_NHEAD and SKIP_NTAIL. I didn't store their values in
struct skip_filter on purpose.
Signed-off-by: Nelson Castillo <[EMAIL PROTECTED]>
---
0 files changed, 0 insertions(+), 0 deletions(-)
diff --git a/drivers/input/touchscreen/s3c2410_ts.c
b/drivers/input/touchscreen/s3c2410_ts.c
index 5a31c4f..a880163 100644
--- a/drivers/input/touchscreen/s3c2410_ts.c
+++ b/drivers/input/touchscreen/s3c2410_ts.c
@@ -102,6 +102,9 @@ static char *s3c2410ts_name = "s3c2410 TouchScreen";
#define TS_STATE_RELEASE_PENDING 3
#define TS_STATE_RELEASE 4
+#define SKIP_NHEAD 2
+#define SKIP_NTAIL 2
+
/*
* Per-touchscreen data.
*/
@@ -119,6 +122,9 @@ static struct s3c2410ts ts;
static void __iomem *base_addr;
+/*
+ * A few low level functions.
+ */
static inline void s3c2410_ts_connect(void)
{
@@ -140,18 +146,18 @@ static void s3c2410_ts_start_adc_conversion(void)
* Just send the input events.
*/
-enum ts_input_event {IE_DOWN = 0, IE_UP, IE_UPDATE};
+enum ts_input_event {IE_DOWN = 0, IE_UP};
static void ts_input_report(int event, int coords[])
{
#ifdef CONFIG_TOUCHSCREEN_S3C2410_DEBUG
- static char *s[] = {"down", "up", "update"};
+ static char *s[] = {"down", "up"};
struct timeval tv;
do_gettimeofday(&tv);
#endif
- if (event == IE_DOWN || event == IE_UPDATE) {
+ if (event == IE_DOWN) {
input_report_abs(ts.dev, ABS_X, coords[0]);
input_report_abs(ts.dev, ABS_Y, coords[1]);
input_report_key(ts.dev, BTN_TOUCH, 1);
@@ -174,10 +180,93 @@ static void ts_input_report(int event, int coords[])
input_sync(ts.dev);
}
+
/*
- * Manage state of the touchscreen and send events.
+ * Skip filter for touchscreen values.
+ *
+ * Problem: The first and the last sample might be unreliable. We provide
+ * this filter as a separate function in order to keep the event_send_timer_f
+ * function simple. This filter:
+ *
+ * - Skips NHEAD points after IE_DOWN
+ * - Skips NTAIL points before IE_UP
+ * - Ignores a click if we have less than (NHEAD + NTAILl + 1) points
*/
+struct skip_filter_event {
+ int coords[2];
+};
+
+struct skip_filter {
+ unsigned N;
+ unsigned M;
+ int sent;
+ struct skip_filter_event buf[SKIP_NTAIL];
+};
+
+struct skip_filter ts_skip;
+
+static void ts_skip_filter_reset(void)
+{
+ ts_skip.N = 0;
+ ts_skip.M = 0;
+ ts_skip.sent = 0;
+}
+
+static void ts_skip_filter(int event, int coords[])
+{
+ /* skip the first N samples */
+ if (ts_skip.N < SKIP_NHEAD) {
+ if (IE_UP == event)
+ ts_skip_filter_reset();
+ else
+ ts_skip.N++;
+ return;
+ }
+
+ /* We didn't send DOWN -- Ignore UP */
+ if (IE_UP == event && !ts_skip.sent) {
+ ts_skip_filter_reset();
+ return;
+ }
+
+ /* Just accept the event if NTAIL == 0 */
+ if (!SKIP_NTAIL) {
+ ts_input_report(event, coords);
+ if (IE_UP == event)
+ ts_skip_filter_reset();
+ else
+ ts_skip.sent = 1;
+ return;
+ }
+
+ /* NTAIL > 0, Queue current point if we need to */
+ if (!ts_skip.sent && ts_skip.M < SKIP_NTAIL) {
+ memcpy(&ts_skip.buf[ts_skip.M++].coords[0], &coords[0],
+ sizeof(int) * 2);
+ return;
+ }
+
+ /* queue full: accept one, queue one */
+
+ if (ts_skip.M >= SKIP_NTAIL)
+ ts_skip.M = 0;
+
+ ts_input_report(event, ts_skip.buf[ts_skip.M].coords);
+
+ if (event == IE_UP) {
+ ts_skip_filter_reset();
+ } else {
+ memcpy(&ts_skip.buf[ts_skip.M++].coords[0], &coords[0],
+ sizeof(int) * 2);
+ ts_skip.sent = 1;
+ }
+}
+
+
+/*
+ * Manage the state of the touchscreen. Send events to the skip filter.
+ */
static void event_send_timer_f(unsigned long data);
@@ -189,7 +278,6 @@ static void event_send_timer_f(unsigned long data)
static unsigned long running;
static int noop_counter;
int event_type;
- static unsigned n_points;
if (unlikely(test_and_set_bit(0, &running))) {
mod_timer(&event_send_timer,
@@ -225,14 +313,7 @@ static void event_send_timer_f(unsigned long data)
!= sizeof(int) * 2))
goto ts_exit_error;
- if (n_points++ < 2)
- break;
-
- if (ts.state == TS_STATE_PRESSED_PENDING)
- ts_input_report(IE_DOWN, buf);
- else
- ts_input_report(IE_UPDATE, buf);
-
+ ts_skip_filter(IE_DOWN, buf);
ts.state = TS_STATE_PRESSED;
break;
@@ -251,11 +332,8 @@ static void event_send_timer_f(unsigned long data)
* while to avoid jitter. If we get a DOWN
* event we do not send it. */
- if (n_points > 2)
- ts_input_report(IE_UP, NULL);
-
+ ts_skip_filter(IE_UP, NULL);
ts.state = TS_STATE_STANDBY;
- n_points = 0;
if (ts.tsf[0])
(ts.tsf[0]->api->clear)(ts.tsf[0]);
@@ -438,6 +516,8 @@ static int __init s3c2410ts_probe(struct platform_device
*pdev)
ts.dev->id.version = S3C2410TSVERSION;
ts.state = TS_STATE_STANDBY;
+ ts_skip_filter_reset();
+
/* create the filter chain set up for the 2 coordinates we produce */
ret = ts_filter_create_chain(
(struct ts_filter_api **)&info->filter_sequence,
