diff options
| -rw-r--r-- | drivers/input/touchscreen/ads7846.c | 72 | ||||
| -rw-r--r-- | include/linux/spi/ads7846.h | 6 |
2 files changed, 61 insertions, 17 deletions
diff --git a/drivers/input/touchscreen/ads7846.c b/drivers/input/touchscreen/ads7846.c index 1aaa153..1494175 100644 --- a/drivers/input/touchscreen/ads7846.c +++ b/drivers/input/touchscreen/ads7846.c @@ -71,6 +71,7 @@ struct ts_event { __be16 x; __be16 y; __be16 z1, z2; + int ignore; }; struct ads7846 { @@ -81,6 +82,7 @@ struct ads7846 { u16 model; u16 vref_delay_usecs; u16 x_plate_ohms; + u16 pressure_max; u8 read_x, read_y, read_z1, read_z2, pwrdown; u16 dummy; /* for the pwrdown read */ @@ -88,12 +90,15 @@ struct ads7846 { struct spi_transfer xfer[10]; struct spi_message msg[5]; + struct spi_message *last_msg; int msg_idx; int read_cnt; + int read_rep; int last_read; u16 debounce_max; u16 debounce_tol; + u16 debounce_rep; spinlock_t lock; struct timer_list timer; /* P: lock */ @@ -354,6 +359,14 @@ static void ads7846_rx(void *ads) } else Rt = 0; + /* Sample found inconsistent by debouncing or pressure is beyond + * the maximum. Don't report it to user space, repeat at least + * once more the measurement */ + if (ts->tc.ignore || Rt > ts->pressure_max) { + mod_timer(&ts->timer, jiffies + TS_POLL_PERIOD); + return; + } + /* NOTE: "pendown" is inferred from pressure; we don't rely on * being able to check nPENIRQ status, or "friendly" trigger modes * (both-edges is much better than just-falling or low-level). @@ -402,25 +415,45 @@ static void ads7846_debounce(void *ads) struct ads7846 *ts = ads; struct spi_message *m; struct spi_transfer *t; - u16 val; + int val; int status; m = &ts->msg[ts->msg_idx]; t = list_entry(m->transfers.prev, struct spi_transfer, transfer_list); val = (*(u16 *)t->rx_buf) >> 3; - - if (!ts->read_cnt || (abs(ts->last_read - val) > ts->debounce_tol - && ts->read_cnt < ts->debounce_max)) { - /* Repeat it, if this was the first read or the read wasn't - * consistent enough - */ - ts->read_cnt++; - ts->last_read = val; + if (!ts->read_cnt || (abs(ts->last_read - val) > ts->debounce_tol)) { + /* Repeat it, if this was the first read or the read + * wasn't consistent enough. */ + if (ts->read_cnt < ts->debounce_max) { + ts->last_read = val; + ts->read_cnt++; + } else { + /* Maximum number of debouncing reached and still + * not enough number of consistent readings. Abort + * the whole sample, repeat it in the next sampling + * period. + */ + ts->tc.ignore = 1; + ts->read_cnt = 0; + /* Last message will contain ads7846_rx() as the + * completion function. + */ + m = ts->last_msg; + } + /* Start over collecting consistent readings. */ + ts->read_rep = 0; } else { - /* Go for the next read */ - ts->msg_idx++; - ts->read_cnt = 0; - m++; + if (++ts->read_rep > ts->debounce_rep) { + /* Got a good reading for this coordinate, + * go for the next one. */ + ts->tc.ignore = 0; + ts->msg_idx++; + ts->read_cnt = 0; + ts->read_rep = 0; + m++; + } else + /* Read more values that are consistent. */ + ts->read_cnt++; } status = spi_async(ts->spi, m); if (status) @@ -609,8 +642,15 @@ static int __devinit ads7846_probe(struct spi_device *spi) ts->model = pdata->model ? : 7846; ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100; ts->x_plate_ohms = pdata->x_plate_ohms ? : 400; - ts->debounce_max = pdata->debounce_max ? : 1; - ts->debounce_tol = pdata->debounce_tol ? : 10; + ts->pressure_max = pdata->pressure_max ? : ~0; + if (pdata->debounce_max) { + ts->debounce_max = pdata->debounce_max; + ts->debounce_tol = pdata->debounce_tol; + ts->debounce_rep = pdata->debounce_rep; + if (ts->debounce_rep > ts->debounce_max + 1) + ts->debounce_rep = ts->debounce_max - 1; + } else + ts->debounce_tol = ~0; ts->get_pendown_state = pdata->get_pendown_state; snprintf(ts->phys, sizeof(ts->phys), "%s/input0", spi->dev.bus_id); @@ -728,6 +768,8 @@ static int __devinit ads7846_probe(struct spi_device *spi) m->complete = ads7846_rx; m->context = ts; + ts->last_msg = m; + if (request_irq(spi->irq, ads7846_irq, SA_SAMPLE_RANDOM | SA_TRIGGER_FALLING, spi->dev.bus_id, ts)) { diff --git a/include/linux/spi/ads7846.h b/include/linux/spi/ads7846.h index d8823e2..adb3daf 100644 --- a/include/linux/spi/ads7846.h +++ b/include/linux/spi/ads7846.h @@ -15,9 +15,11 @@ struct ads7846_platform_data { u16 y_min, y_max; u16 pressure_min, pressure_max; - u16 debounce_max; /* max number of readings per sample */ + u16 debounce_max; /* max number of additional readings + * per sample */ u16 debounce_tol; /* tolerance used for filtering */ - + u16 debounce_rep; /* additional consecutive good readings + * required after the first two */ int (*get_pendown_state)(void); }; |