Commit ca1cd36c authored May 24, 2018 by Sebastian Reichel Committed by Dmitry Torokhov May 24, 2018

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: f657b00d ("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>

parent 7cf432bf

drivers/input/touchscreen/atmel_mxt_ts.c

+7 −11

Original line number	Diff line number	Diff line
		@@ -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;

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