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path: root/drivers/input/touchscreen/ads7846.c
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Diffstat (limited to 'drivers/input/touchscreen/ads7846.c')
-rw-r--r--drivers/input/touchscreen/ads7846.c80
1 files changed, 79 insertions, 1 deletions
diff --git a/drivers/input/touchscreen/ads7846.c b/drivers/input/touchscreen/ads7846.c
index 1c9069cd3ba..96581d08774 100644
--- a/drivers/input/touchscreen/ads7846.c
+++ b/drivers/input/touchscreen/ads7846.c
@@ -95,7 +95,7 @@ struct ads7846 {
u16 dummy; /* for the pwrdown read */
struct ts_event tc;
- struct spi_transfer xfer[10];
+ struct spi_transfer xfer[18];
struct spi_message msg[5];
struct spi_message *last_msg;
int msg_idx;
@@ -107,6 +107,8 @@ struct ads7846 {
u16 debounce_tol;
u16 debounce_rep;
+ u16 penirq_recheck_delay_usecs;
+
spinlock_t lock;
struct hrtimer timer;
unsigned pendown:1; /* P: lock */
@@ -553,6 +555,15 @@ static void ads7846_rx(void *ads)
return;
}
+ /* Maybe check the pendown state before reporting. This discards
+ * false readings when the pen is lifted.
+ */
+ if (ts->penirq_recheck_delay_usecs) {
+ udelay(ts->penirq_recheck_delay_usecs);
+ if (!ts->get_pendown_state())
+ Rt = 0;
+ }
+
/* NOTE: We can't rely on the pressure to determine the pen down
* state, even this controller has a pressure sensor. The pressure
* value can fluctuate for quite a while after lifting the pen and
@@ -896,6 +907,10 @@ static int __devinit ads7846_probe(struct spi_device *spi)
ts->filter = ads7846_no_filter;
ts->get_pendown_state = pdata->get_pendown_state;
+ if (pdata->penirq_recheck_delay_usecs)
+ ts->penirq_recheck_delay_usecs =
+ pdata->penirq_recheck_delay_usecs;
+
snprintf(ts->phys, sizeof(ts->phys), "%s/input0", spi->dev.bus_id);
input_dev->name = "ADS784x Touchscreen";
@@ -936,6 +951,24 @@ static int __devinit ads7846_probe(struct spi_device *spi)
x->len = 2;
spi_message_add_tail(x, m);
+ /* the first sample after switching drivers can be low quality;
+ * optionally discard it, using a second one after the signals
+ * have had enough time to stabilize.
+ */
+ if (pdata->settle_delay_usecs) {
+ x->delay_usecs = pdata->settle_delay_usecs;
+
+ x++;
+ x->tx_buf = &ts->read_y;
+ x->len = 1;
+ spi_message_add_tail(x, m);
+
+ x++;
+ x->rx_buf = &ts->tc.y;
+ x->len = 2;
+ spi_message_add_tail(x, m);
+ }
+
m->complete = ads7846_rx_val;
m->context = ts;
@@ -954,6 +987,21 @@ static int __devinit ads7846_probe(struct spi_device *spi)
x->len = 2;
spi_message_add_tail(x, m);
+ /* ... maybe discard first sample ... */
+ if (pdata->settle_delay_usecs) {
+ x->delay_usecs = pdata->settle_delay_usecs;
+
+ x++;
+ x->tx_buf = &ts->read_x;
+ x->len = 1;
+ spi_message_add_tail(x, m);
+
+ x++;
+ x->rx_buf = &ts->tc.x;
+ x->len = 2;
+ spi_message_add_tail(x, m);
+ }
+
m->complete = ads7846_rx_val;
m->context = ts;
@@ -973,6 +1021,21 @@ static int __devinit ads7846_probe(struct spi_device *spi)
x->len = 2;
spi_message_add_tail(x, m);
+ /* ... maybe discard first sample ... */
+ if (pdata->settle_delay_usecs) {
+ x->delay_usecs = pdata->settle_delay_usecs;
+
+ x++;
+ x->tx_buf = &ts->read_z1;
+ x->len = 1;
+ spi_message_add_tail(x, m);
+
+ x++;
+ x->rx_buf = &ts->tc.z1;
+ x->len = 2;
+ spi_message_add_tail(x, m);
+ }
+
m->complete = ads7846_rx_val;
m->context = ts;
@@ -990,6 +1053,21 @@ static int __devinit ads7846_probe(struct spi_device *spi)
x->len = 2;
spi_message_add_tail(x, m);
+ /* ... maybe discard first sample ... */
+ if (pdata->settle_delay_usecs) {
+ x->delay_usecs = pdata->settle_delay_usecs;
+
+ x++;
+ x->tx_buf = &ts->read_z2;
+ x->len = 1;
+ spi_message_add_tail(x, m);
+
+ x++;
+ x->rx_buf = &ts->tc.z2;
+ x->len = 2;
+ spi_message_add_tail(x, m);
+ }
+
m->complete = ads7846_rx_val;
m->context = ts;
}