[PATCH] Input: atmel_mxt_ts - use mxt_acquire_irq in mxt_soft_reset

[Nick Dyer]

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 <tr...@konsulko.com>
Signed-off-by: Nick Dyer <nick.d...@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