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 edge
based interrupt.
This change avoids the interrupt storm by enabling the device while its
interrupt is disabled. Afterwards we wait 100ms. This is important for
two reasons: The device is unresponsive for some time (~22ms for
mxt224E) and the CHG (interrupt) line is not working properly for 100ms.
We don't need to wait for any following interrupts, since the following
mxt_initialize() checks for bootloader mode anyways.
This fixes a boot issue on GE PPD (watchdog kills device due to
interrupt storm) and does not cause regression on Motorola Droid 4.
Fixes: f657b00df22e ("Input: atmel_mxt_ts - add support for reset line")
Signed-off-by: Sebastian Reichel <sebastian.reic...@collabora.co.uk>
---
Changes since PATCHv2:
* fix patch description
* use same timeout value for soft and gpio-reset
---
drivers/input/touchscreen/atmel_mxt_ts.c | 18 +++++++-----------
1 file changed, 7 insertions(+), 11 deletions(-)
diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c
b/drivers/input/touchscreen/atmel_mxt_ts.c
index 5d9699fe1b55..f97fbb0af020 100644
--- a/drivers/input/touchscreen/atmel_mxt_ts.c
+++ b/drivers/input/touchscreen/atmel_mxt_ts.c
@@ -194,6 +194,8 @@ enum t100_type {
/* Delay times */
#define MXT_BACKUP_TIME 50 /* msec */
+#define MXT_RESET_GPIO_TIME 20 /* msec */
+#define MXT_RESET_INVALID_CHG 100 /* msec */
#define MXT_RESET_TIME 200 /* msec */
#define MXT_RESET_TIMEOUT 3000 /* msec */
#define MXT_CRC_TIMEOUT 1000 /* msec */
@@ -1206,7 +1208,7 @@ static int mxt_soft_reset(struct mxt_data *data)
return ret;
/* Ignore CHG line for 100ms after reset */
- msleep(100);
+ msleep(MXT_RESET_INVALID_CHG);
mxt_acquire_irq(data);
@@ -3167,20 +3169,14 @@ 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_INVALID_CHG);
}
- disable_irq(client->irq);
-
error = mxt_initialize(data);
if (error)
return error;
--
2.17.0
