[PATCH v6 25/48] Input: atmel_mxt_ts - delay enabling IRQ when not using regulators

[Jiada Wang <jiada_wang@xxxxxxxxxx>]

From: Nick Dyer <nick.dyer@xxxxxxxxxxx>

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.

Signed-off-by: Nick Dyer <nick.dyer@xxxxxxxxxxx>
(cherry picked from ndyer/linux/for-upstream commit 64c9dadc4a3250a185baf06ab0f628be45d5d9a0)
[gdavis: Resolve forward port conflicts due to v4.14-rc1 commit
	 8cc8446b9b62 ("Input: atmel_mxt_ts - use more managed
	 resources") and applying upstream commit 96a938aa214e ("Input:
	 atmel_mxt_ts - remove platform data support").]
Signed-off-by: George G. Davis <george_davis@xxxxxxxxxx>
Signed-off-by: Jiada Wang <jiada_wang@xxxxxxxxxx>
---
 drivers/input/touchscreen/atmel_mxt_ts.c | 40 +++++++++++++++---------
 1 file changed, 26 insertions(+), 14 deletions(-)

diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c b/drivers/input/touchscreen/atmel_mxt_ts.c
index 842d407efc86..f5d67e43a786 100644
--- a/drivers/input/touchscreen/atmel_mxt_ts.c
+++ b/drivers/input/touchscreen/atmel_mxt_ts.c
@@ -1451,9 +1451,24 @@ static int mxt_acquire_irq(struct mxt_data *data)
 {
 	int error;
 
-	enable_irq(data->irq);
+	if (!data->irq) {
+		error = devm_request_threaded_irq(&data->client->dev,
+						  data->client->irq,
+						  NULL, mxt_interrupt,
+						  IRQF_ONESHOT,
+						  data->client->name, data);
+		if (error) {
+			dev_err(&data->client->dev, "Error requesting irq\n");
+			return error;
+		}
+
+		/* Presence of data->irq means IRQ initialised */
+		data->irq = data->client->irq;
+	} else {
+		enable_irq(data->irq);
+	}
 
-	if (data->use_retrigen_workaround) {
+	if (data->object_table && data->use_retrigen_workaround) {
 		error = mxt_process_messages_until_invalid(data);
 		if (error)
 			return error;
@@ -3373,7 +3388,9 @@ static int mxt_load_fw(struct device *dev)
 			goto release_firmware;
 	}
 
-	enable_irq(data->irq);
+	ret = mxt_acquire_irq(data);
+	if (ret)
+		goto release_firmware;
 
 	/* Poll after 0.1s if no interrupt received */
 	schedule_delayed_work(&data->flash->work, msecs_to_jiffies(100));
@@ -3800,7 +3817,6 @@ static int mxt_probe(struct i2c_client *client, const struct i2c_device_id *id)
 		 client->adapter->nr, client->addr);
 
 	data->client = client;
-	data->irq = client->irq;
 	i2c_set_clientdata(client, data);
 
 	init_completion(&data->chg_completion);
@@ -3828,26 +3844,22 @@ static int mxt_probe(struct i2c_client *client, const struct i2c_device_id *id)
 		return error;
 	}
 
-	error = devm_request_threaded_irq(&client->dev, client->irq,
-					  NULL, mxt_interrupt, IRQF_ONESHOT,
-					  client->name, data);
-	if (error) {
-		dev_err(&client->dev, "Failed to register interrupt\n");
-		return error;
-	}
-
 	if (data->suspend_mode == MXT_SUSPEND_REGULATOR) {
+		error = mxt_acquire_irq(data);
+		if (error)
+			return error;
+
 		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