Input: atmel_mxt_ts - fix reset-gpio for level based irqs

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.reichel@collabora.co.uk>
Reviewed-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c b/drivers/input/touchscreen/atmel_mxt_ts.c
index 4ac49c6c00060f91493fdbc157e14d188d172380..54fe190fd4bc62b3de83d509ca28c0d0c4ec6696 100644 (file)
--- 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 */
@@ -1208,7 +1210,7 @@ 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);
 
@@ -3082,20 +3084,14 @@ 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;