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path: root/drivers/input/touchscreen/eeti_ts.c
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Diffstat (limited to 'drivers/input/touchscreen/eeti_ts.c')
-rw-r--r--drivers/input/touchscreen/eeti_ts.c71
1 files changed, 56 insertions, 15 deletions
diff --git a/drivers/input/touchscreen/eeti_ts.c b/drivers/input/touchscreen/eeti_ts.c
index c6b85ba7f991..2e1404cd09ec 100644
--- a/drivers/input/touchscreen/eeti_ts.c
+++ b/drivers/input/touchscreen/eeti_ts.c
@@ -28,6 +28,7 @@ struct eeti_ts {
struct input_dev *input;
struct gpio_desc *attn_gpio;
struct touchscreen_properties props;
+ struct mutex mutex;
bool running;
};
@@ -62,42 +63,80 @@ static void eeti_ts_report_event(struct eeti_ts *eeti, u8 *buf)
input_sync(eeti->input);
}
+static int eeti_ts_read(struct eeti_ts *eeti)
+{
+ int len, error;
+ char buf[6];
+
+ len = i2c_master_recv(eeti->client, buf, sizeof(buf));
+ if (len != sizeof(buf)) {
+ error = len < 0 ? len : -EIO;
+ dev_err(&eeti->client->dev,
+ "failed to read touchscreen data: %d\n",
+ error);
+ return error;
+ }
+
+ /* Motion packet */
+ if (buf[0] & 0x80)
+ eeti_ts_report_event(eeti, buf);
+
+ return 0;
+}
+
static irqreturn_t eeti_ts_isr(int irq, void *dev_id)
{
struct eeti_ts *eeti = dev_id;
- int len;
int error;
- char buf[6];
+
+ mutex_lock(&eeti->mutex);
do {
- len = i2c_master_recv(eeti->client, buf, sizeof(buf));
- if (len != sizeof(buf)) {
- error = len < 0 ? len : -EIO;
- dev_err(&eeti->client->dev,
- "failed to read touchscreen data: %d\n",
- error);
+ /*
+ * If we have attention GPIO, trust it. Otherwise we'll read
+ * once and exit. We assume that in this case we are using
+ * level triggered interrupt and it will get raised again
+ * if/when there is more data.
+ */
+ if (eeti->attn_gpio &&
+ !gpiod_get_value_cansleep(eeti->attn_gpio)) {
break;
}
- if (buf[0] & 0x80) {
- /* Motion packet */
- eeti_ts_report_event(eeti, buf);
- }
- } while (eeti->running &&
- eeti->attn_gpio && gpiod_get_value_cansleep(eeti->attn_gpio));
+ error = eeti_ts_read(eeti);
+ if (error)
+ break;
+
+ } while (eeti->running && eeti->attn_gpio);
+ mutex_unlock(&eeti->mutex);
return IRQ_HANDLED;
}
static void eeti_ts_start(struct eeti_ts *eeti)
{
+ mutex_lock(&eeti->mutex);
+
eeti->running = true;
- wmb();
enable_irq(eeti->client->irq);
+
+ /*
+ * Kick the controller in case we are using edge interrupt and
+ * we missed our edge while interrupt was disabled. We expect
+ * the attention GPIO to be wired in this case.
+ */
+ if (eeti->attn_gpio && gpiod_get_value_cansleep(eeti->attn_gpio))
+ eeti_ts_read(eeti);
+
+ mutex_unlock(&eeti->mutex);
}
static void eeti_ts_stop(struct eeti_ts *eeti)
{
+ /*
+ * Not locking here, just setting a flag and expect that the
+ * interrupt thread will notice the flag eventually.
+ */
eeti->running = false;
wmb();
disable_irq(eeti->client->irq);
@@ -140,6 +179,8 @@ static int eeti_ts_probe(struct i2c_client *client,
return -ENOMEM;
}
+ mutex_init(&eeti->mutex);
+
input = devm_input_allocate_device(dev);
if (!input) {
dev_err(dev, "Failed to allocate input device.\n");