linux-kernel - Re: [PATCH v2] regmap: irq: fix ack-invert

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Date:   Fri, 9 Mar 2018 10:51:58 -0800
From:   Tim Harvey <tharvey@...eworks.com>
To:     Mark Brown <broonie@...nel.org>
Cc:     Tony Lindgren <tony@...mide.com>, linux-kernel@...r.kernel.org,
        Benjamin Gaignard <benjamin.gaignard@...aro.org>,
        Lee Jones <lee.jones@...aro.org>, Guo Zeng <Guo.Zeng@....com>
Subject: Re: [PATCH v2] regmap: irq: fix ack-invert

On Wed, Mar 7, 2018 at 6:36 AM, Mark Brown <broonie@...nel.org> wrote:
> On Tue, Mar 06, 2018 at 06:57:49AM -0800, Tony Lindgren wrote:
>
>> > By using regmap_irq_update_bits to ACK the interrupts we use the masked
>> > status bits so we take care not to affect any other bits then use
>> > ack_invert to determine if we clear or set those bits.
>
>> This change to use regmap_irq_update_bits() now breaks things for
>> me with cpcap interrupts. So it seems to cause a non-inverted mode
>> regression. There should be no need to read the ack register, I
>> gues that's the whole idea of having a separate ack register :)
>
> Yes, that'd be my expectation as well - the register should be just
> write only.  regmap_update_bits() definitely isn't the right thing here
> since it will suppress the write part of the read/modify/write cycle if
> it detects that it didn't actually modify anything as an optimization.

understood. I will put together a v3 soon.

Thanks,

Tim