linux-kernel - Re: [PATCHv2] Input: atmel_mxt_ts - fix reset-gpio for level based irqs

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Message-ID: <20180509142545.GC25131@amd>
Date:   Wed, 9 May 2018 16:25:45 +0200
From:   Pavel Machek <pavel@....cz>
To:     Sebastian Reichel <sebastian.reichel@...labora.co.uk>
Cc:     Nick Dyer <nick@...anahar.org>,
        Dmitry Torokhov <dmitry.torokhov@...il.com>,
        linux-input@...r.kernel.org, linux-kernel@...r.kernel.org,
        Ezequiel Garcia <ezequiel@...labora.com>, kernel@...labora.com
Subject: Re: [PATCHv2] Input: atmel_mxt_ts - fix reset-gpio for level based
 irqs

On Mon 2018-04-23 13:58:44, Sebastian Reichel wrote:
> 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.

Out of curiosity, what is "GE PPD"?

> Fixes: f657b00df22e ("Input: atmel_mxt_ts - add support for reset line")
> Signed-off-by: Sebastian Reichel <sebastian.reichel@...labora.co.uk>

Reviewed-by: Pavel Machek <pavel@....cz>

-- 
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