[PATCH] Input: atmel_mxt_ts - use mxt_acquire_irq in mxt_soft_reset

Nick Dyer
2016-04-11T09:39:33Z

If using IRQF_TRIGGER_FALLING, then there is a race here: if the reset
completes before we enable the IRQ, then CHG is already low and touch
will be broken.

This has been seen on Chromebook Pixel 2.

A workaround is to reconfig T18 COMMSCONFIG to enable the RETRIGEN bit
using mxt-app:
mxt-app -W -T18 44
mxt-app --backup

Tested-by: Tom Rini <trini@konsulko.com>
Signed-off-by: Nick Dyer <nick.dyer@itdev.co.uk>
---
drivers/input/touchscreen/atmel_mxt_ts.c | 28 ++++++++++++++--------------
1 file changed, 14 insertions(+), 14 deletions(-)

diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c b/drivers/input/touchscreen/atmel_mxt_ts.c
index 2160512..5af7907 100644
--- a/drivers/input/touchscreen/atmel_mxt_ts.c
+++ b/drivers/input/touchscreen/atmel_mxt_ts.c
@@ -1093,6 +1093,19 @@ static int mxt_t6_command(struct mxt_data *data, u16 cmd_offset,
return 0;
}

+static int mxt_acquire_irq(struct mxt_data *data)
+{
+ int error;
+
+ enable_irq(data->irq);
+
+ error = mxt_process_messages_until_invalid(data);
+ if (error)
+ return error;
+
+ return 0;
+}
+
static int mxt_soft_reset(struct mxt_data *data)
{
struct device *dev = &data->client->dev;
@@ -1111,7 +1124,7 @@ static int mxt_soft_reset(struct mxt_data *data)
/* Ignore CHG line for 100ms after reset */
msleep(100);

- enable_irq(data->irq);
+ mxt_acquire_irq(data);

ret = mxt_wait_for_completion(data, &data->reset_completion,
MXT_RESET_TIMEOUT);
@@ -1466,19 +1479,6 @@ release_mem:
return ret;
}

-static int mxt_acquire_irq(struct mxt_data *data)
-{
- int error;
-
- enable_irq(data->irq);
-
- error = mxt_process_messages_until_invalid(data);
- if (error)
- return error;
-
- return 0;
-}
-
static int mxt_get_info(struct mxt_data *data)
{
struct i2c_client *client = data->client;
--
2.5.0