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>

1 files changed, 7 insertions, 11 deletions

diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c b/drivers/input/touchscreen/atmel_mxt_ts.c
index 4ac49c6c0006..54fe190fd4bc 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 */
@@ -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;