linux-kernel - Re: [PATCH] pinctrl: cherryview: Do not mask all interrupts on probe

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Message-ID: <20160915154233.GH1811@lahna.fi.intel.com>
Date:   Thu, 15 Sep 2016 18:42:33 +0300
From:   Mika Westerberg <mika.westerberg@...ux.intel.com>
To:     Linus Walleij <linus.walleij@...aro.org>
Cc:     Marc Zyngier <marc.zyngier@....com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Phidias Chiang <phidias.chiang@...onical.com>,
        Anisse Astier <anisse@...ier.eu>,
        Heikki Krogerus <heikki.krogerus@...ux.intel.com>,
        Yu C Chen <yu.c.chen@...el.com>,
        "linux-gpio@...r.kernel.org" <linux-gpio@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] pinctrl: cherryview: Do not mask all interrupts on probe

On Thu, Sep 15, 2016 at 02:39:47PM +0200, Linus Walleij wrote:
> On Wed, Sep 14, 2016 at 5:12 PM, Mika Westerberg
> <mika.westerberg@...ux.intel.com> wrote:
> > On Wed, Sep 14, 2016 at 02:46:01PM +0200, Linus Walleij wrote:
> >> > I'm going to re-read the hardware spec and see if there is anything we
> >> > can do about this. The newer hardware (Skylake, Broxton) has a bit that
> >> > tells the IRQ is routed directly to I/O-APIC but unfortunately Braswell
> >> > misses that. There may be something else, though.
> >>
> >> So as far as we can determine:
> >>
> >> (A) we are running on Braswell and
> >> (B) we are probing this driver
> >>
> >> we can conclude that
> >>
> >> (C) IRQs A,B,C are reserved by BIOS?
> >>
> >> That sounds doable?
> >
> > Yes, it's doable but that requires some hard coding in the driver :-/
> 
> >From my point of view that is the lesser of two evils.
> 
> We only have hard-coding (syntactic) madness over having
> behaviour-dependent (semantic) madness.

I re-read the hardware spec now and it occured to me that for north and
southwest community, only the first 8 IRQs can be used as interrupts
(all GPIOs which have IntSel value < 8). Rest can only trigger GPEs
which are used for EC events.

I'll submit patches shortly using this information and valid_mask as you
suggested.