[PATCH v7 25/48] Input: atmel_mxt_ts - delay enabling IRQ when not using regulators

From: Jiada Wang
Date: Wed Feb 12 2020 - 03:45:38 EST


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 07601539ac27..ff9a801e9e5e 100644
--- a/drivers/input/touchscreen/atmel_mxt_ts.c
+++ b/drivers/input/touchscreen/atmel_mxt_ts.c
@@ -1448,9 +1448,24 @@ 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;
+ }

- if (data->use_retrigen_workaround) {
+ /* Presence of data->irq means IRQ initialised */
+ data->irq = data->client->irq;
+ } else {
+ enable_irq(data->irq);
+ }
+
+ if (data->object_table && data->use_retrigen_workaround) {
error = mxt_process_messages_until_invalid(data);
if (error)
return error;
@@ -3370,7 +3385,9 @@ 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));
@@ -3797,7 +3814,6 @@ 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);
@@ -3825,26 +3841,22 @@ 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