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

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Date:   Tue, 6 Mar 2018 06:57:49 -0800
From:   Tony Lindgren <tony@...mide.com>
To:     Tim Harvey <tharvey@...eworks.com>
Cc:     linux-kernel@...r.kernel.org, Mark Brown <broonie@...nel.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

Hi,

* Tim Harvey <tharvey@...eworks.com> [180305 20:59]:
> When acking irqs we need to take into account the ack-invert case.
> Without this chips that require 0's to ACK interrupts will never clear
> the interrupt.
> 
> 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 :)

> The only user of ack_invert currently appears to be the motorola-cpcap
> driver which we find is incorrectly setting ack_invert and thus we
> fix that at the same time as otherwise it would break.

Regards,

Tony