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Date:   Wed, 28 Nov 2018 10:39:59 -0700
From:   Lina Iyer <ilina@codeaurora.org>
To:     Stephen Boyd <swboyd@chromium.org>
Cc:     evgreen@chromium.org, marc.zyngier@arm.com,
        linux-kernel@vger.kernel.org, rplsssn@codeaurora.org,
        linux-arm-msm@vger.kernel.org, devicetree@vger.kernel.org,
        thierry.reding@gmail.com
Subject: Re: [RFC v3 2/3] dt-bindings: sdm845-pinctrl: add wakeup interrupt
 parent for GPIO
Message-ID: <20181128173959.GC18262@codeaurora.org>
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On Tue, Nov 27 2018 at 14:45 -0700, Stephen Boyd wrote:
>Quoting Lina Iyer (2018-11-27 10:21:23)
>> On Tue, Nov 27 2018 at 02:12 -0700, Stephen Boyd wrote:
>> >
>> >Two reasons. First, simplicity. The TLMM driver just needs to pass the
>> >gpio number up to the PDC gpio domain and then that domain can figure
>> >out what hwirq it maps to within the PDC hw irq space. I don't see any
>> >reason why we have to know the hwirq of PDC within the TLMM driver
>> >besides "let's not be different".
>> >
>> >And second, it makes it easier for us to implement the MPM case in the
>> >TLMM driver by letting the TLMM code just ask "should I mask the irq
>> >here or not?" by passing that with a wrapper struct around the fwspec
>> >and a dedicated domain in the PDC/MPM driver. Keeping less things in the
>> >TLMM driver and not driving the decision from DT but from tables in the
>> >PDC driver also keeps things simple and reduces DT parsing code/time.
>> >
>> Couldn't this be simply achieved by matching the compatible flags for
>> PDC/MPM bindings for the wakeup-parent in the TLMM driver?
>>
>
>It could be, but then we would be making TLMM highly aware of the wakeup
>parent
It is is not aware of anything about the wakeup parent, just the
compatible that indicates whether it needs to be mask locally or not.

>and have to do compatible string matching in two places, instead
>of making TLMM more abstractly aware that it needs to keep things masked
>while irq parent deals with the interrupts.
>
Your approach seems too complex just to circumvent a simple match node.
I think we are stretching too much to support something that is not a
priority.

-- Lina