[PATCH v11 33/56] Input: atmel_mxt_ts - delay enabling IRQ when not using regulators

[Jiada Wang]

The path of enabling the IRQ in the probe function is not safe in level
triggered operation, if it was already powered up and there is a message
waiting on the device (eg finger down) because the object table has not yet
been read. This forces the ISR into a hard loop.

Delay enabling the interrupt until it is first needed, by set flag
IRQ_NOAUTOEN.

Signed-off-by: Jiada Wang <jiada_wang@xxxxxxxxxx>
CC: Dmitry Osipenko <digetx@xxxxxxxxx>
---
 drivers/input/touchscreen/atmel_mxt_ts.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c b/drivers/input/touchscreen/atmel_mxt_ts.c
index 7c9a738e633a..ab4eceac8fe7 100644
--- a/drivers/input/touchscreen/atmel_mxt_ts.c
+++ b/drivers/input/touchscreen/atmel_mxt_ts.c
@@ -3822,6 +3822,7 @@ static int mxt_probe(struct i2c_client *client, const struct i2c_device_id *id)
 		return error;
 	}
 
+	irq_set_status_flags(client->irq, IRQ_NOAUTOEN);
 	error = devm_request_threaded_irq(&client->dev, client->irq,
 					  NULL, mxt_interrupt, IRQF_ONESHOT,
 					  client->name, data);
@@ -3831,17 +3832,19 @@ static int mxt_probe(struct i2c_client *client, const struct i2c_device_id *id)
 	}
 
 	if (data->suspend_mode == MXT_SUSPEND_REGULATOR) {
+		enable_irq(data->irq);
+
 		error = mxt_probe_regulators(data);
 		if (error)
 			return error;
+
+		disable_irq(data->irq);
 	} else if (data->reset_gpio) {
 		msleep(MXT_RESET_GPIO_TIME);
 		gpiod_set_value(data->reset_gpio, 1);
 		msleep(MXT_RESET_INVALID_CHG);
 	}
 
-	disable_irq(data->irq);
-
 	error = mxt_initialize(data);
 	if (error)
 		return error;
-- 
2.17.1