linux-kernel - Re: [PATCH 3/3] soc: ti: Add ti_sci_pm

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Message-ID: <CAPDyKFo0Cb90BbY7ra6VDjb5frC5=VtmE3V6tDK=VosfPmod7Q@mail.gmail.com>
Date:   Thu, 8 Sep 2016 11:27:52 +0200
From:   Ulf Hansson <ulf.hansson@...aro.org>
To:     Kevin Hilman <khilman@...libre.com>
Cc:     Dave Gerlach <d-gerlach@...com>, Nishanth Menon <nm@...com>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Keerthy <j-keerthy@...com>,
        Peter Ujfalusi <peter.ujfalusi@...com>,
        Tero Kristo <t-kristo@...com>,
        Russell King <rmk+kernel@...linux.org.uk>,
        Sudeep Holla <sudeep.holla@....com>,
        Santosh Shilimkar <ssantosh@...nel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
        Jon Hunter <jonathanh@...dia.com>
Subject: Re: [PATCH 3/3] soc: ti: Add ti_sci_pm_domains driver

[...]

>
> One more idea...
>
> Since you don't really have a domain (a group of devices), what you
> really have is each device having an independent power switch, so as Ulf
> suggested, what you really need is for all the devices to share the same
> set of runtime PM callbacks that call SCI.  The only difference is the
> unique ID.
>
> Rather than using all of genpd, you could also just use a pm_domain
> which is what genpd is built on top of (and also omap_device, which
> you're probably familiar with also.)

Even if this would work as well, the downside would be that you need
to re-invent the parts related to the DT parsing, the probing/removal
and attaching/detaching of the device to the PM domain.

You probably don't want to go there... :-)

>
> That would allow you to keep the drivers completely generic, yet share
> all the SCI specific "domain" code inside a pm_domain.
>
> Kevin

Kind regards
Uffe