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Subject[PATCH] Input: atmel_mxt_ts - fix reset-gpio for level based irqs
Date
The current reset-gpio support triggers an interrupt storm on platforms
using the maxtouch with level based interrupt. The Motorola Droid 4,
which I used for some of the tests is not affected, since it uses a level
based interrupt.

This change avoids the interrupt storm by enabling the device while
its interrupt is disabled. The following mxt_initialize() requires,
that the device is responsive (at least mxt224E is unresponsive for
~22ms), so we wait some time. We don't wait for leaving bootloader
mode anymore, since mxt_initialize() checks for it anyways.

This fixes a boot problem on GE PPD (watchdog kills device) and also
has been tested on the Droid 4.

Fixes: f657b00df22e ("Input: atmel_mxt_ts - add support for reset line")
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk>
---
drivers/input/touchscreen/atmel_mxt_ts.c | 15 +++++----------
1 file changed, 5 insertions(+), 10 deletions(-)

diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c b/drivers/input/touchscreen/atmel_mxt_ts.c
index 5d9699fe1b55..f8a9f2a47e78 100644
--- a/drivers/input/touchscreen/atmel_mxt_ts.c
+++ b/drivers/input/touchscreen/atmel_mxt_ts.c
@@ -194,6 +194,7 @@ enum t100_type {

/* Delay times */
#define MXT_BACKUP_TIME 50 /* msec */
+#define MXT_RESET_GPIO_TIME 20 /* msec */
#define MXT_RESET_TIME 200 /* msec */
#define MXT_RESET_TIMEOUT 3000 /* msec */
#define MXT_CRC_TIMEOUT 1000 /* msec */
@@ -3167,20 +3168,14 @@ static int mxt_probe(struct i2c_client *client, const struct i2c_device_id *id)
return error;
}

+ disable_irq(client->irq);
+
if (data->reset_gpio) {
- data->in_bootloader = true;
- msleep(MXT_RESET_TIME);
- reinit_completion(&data->bl_completion);
+ msleep(MXT_RESET_GPIO_TIME);
gpiod_set_value(data->reset_gpio, 1);
- error = mxt_wait_for_completion(data, &data->bl_completion,
- MXT_RESET_TIMEOUT);
- if (error)
- return error;
- data->in_bootloader = false;
+ msleep(MXT_RESET_TIME);
}

- disable_irq(client->irq);
-
error = mxt_initialize(data);
if (error)
return error;
--
2.17.0
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