linux-kernel - Re: [PATCH v1 03/63] Input: atmel_mxt_ts - only read messages in mxt_acquire

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Date:   Fri, 16 Aug 2019 10:16:22 -0700
From:   Dmitry Torokhov <dmitry.torokhov@...il.com>
To:     Jiada Wang <jiada_wang@...tor.com>
Cc:     nick@...anahar.org, linux-input@...r.kernel.org,
        linux-kernel@...r.kernel.org, george_davis@...tor.com
Subject: Re: [PATCH v1 03/63] Input: atmel_mxt_ts - only read messages in
 mxt_acquire_irq() when necessary

On Fri, Aug 16, 2019 at 05:28:52PM +0900, Jiada Wang wrote:
> From: Nick Dyer <nick.dyer@...ev.co.uk>
> 
> The workaround of reading all messages until an invalid is received is a
> way of forcing the CHG line high, which means that when using
> edge-triggered interrupts the interrupt can be acquired.
> 
> With level-triggered interrupts the workaround is unnecessary.
> 
> Also, most recent maXTouch chips have a feature called RETRIGEN which, when
> enabled, reasserts the interrupt line every cycle if there are messages
> waiting. This also makes the workaround unnecessary.
> 
> Note: the RETRIGEN feature is only in some firmware versions/chips, it's
> not valid simply to enable the bit.

Instead of trying to work around of misconfiguration for IRQ/firmware,
can we simply error out of probe if we see a level interrupt with
!RETRIGEN firmware?

Thanks.

-- 
Dmitry