linux-kernel - Re: [PATCH v3] regmap: regmap-irq/gpio-max77620: add level-irq support

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Date:   Fri, 4 Jan 2019 10:02:24 +0200
From:   Matti Vaittinen <matti.vaittinen@...rohmeurope.com>
To:     Charles Keepax <ckeepax@...nsource.cirrus.com>
Cc:     Mark Brown <broonie@...nel.org>,
        Geert Uytterhoeven <geert@...ux-m68k.org>,
        mazziesaccount@...il.com, heikki.haikola@...rohmeurope.com,
        mikko.mutanen@...rohmeurope.com,
        Greg KH <gregkh@...uxfoundation.org>,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        Linus Walleij <linus.walleij@...aro.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        "open list:GPIO SUBSYSTEM" <linux-gpio@...r.kernel.org>,
        Vladimir Zapolskiy <vladimir_zapolskiy@...tor.com>,
        Linux-Renesas <linux-renesas-soc@...r.kernel.org>
Subject: Re: [PATCH v3] regmap: regmap-irq/gpio-max77620: add level-irq
 support

On Thu, Jan 03, 2019 at 05:20:08PM +0000, Charles Keepax wrote:
> On Wed, Jan 02, 2019 at 09:42:51AM +0200, Matti Vaittinen wrote:
> > On Mon, Dec 31, 2018 at 07:11:27PM +0000, Mark Brown wrote:
> > > On Fri, Dec 28, 2018 at 10:05:33AM +0200, Matti Vaittinen wrote:
> > > 
> > > > Last night - just when I was about to get some sleep - it stroke me. I
> > > > think the correct thing to do would be leaving the irq_set_type to NULL
> > > > for those IRQ chips which do not support type setting. If we do that,
> > > > then the irq core will take care of situations where user requests type
> > > > setting but the chip does not support it. Which means the regmap-irq
> > > > would be no different from any other irq chip where type setting is not
> > > > supported.
> > > 
> > > Yes, this is the best fix - let the framework handle things properly.
> > > We'll need a second set of operations and to select which to use based
> > > on having type information but that's fine.
> > > 
> > > > So at the cost of removing "const" from regmap_irq_chip we could do:
> > > 
> > > ...
> > > 
> > > > Mark, Geert, what do you think? (And maybe same for the .irq_set_wake -
> > > > but I did omit this as I have never looked at the wake functionality
> > > > before).
> > > 
> > > We need a separate struct as otherwise if there's multiple devices with
> > > regmap irq_chip implementations then they'll collide with each other
> > 
> > Right. I must admit I didn't notice this! I was about to make a nasty
> > error there...
> > 
> 
> Looking at the code I think it just copies the struct anyway,
> basically using it as a template so I think this should be fine.

Rigth. It seems to be:

d->irq_chip = regmap_irq_chip;
not:
d->irq_chip = &regmap_irq_chip;

and

struct regmap_irq_chip_data {
        struct mutex lock;
        struct irq_chip irq_chip;

        struct regmap *map;
	...
};

not
struct regmap_irq_chip_data {
        struct mutex lock;
        struct irq_chip *irq_chip;

        struct regmap *map;
	...
};
 
> > > you're probably right that we need to do the same thing for the wake
> > > configuration.  I'll still look at applying your patch as a temporary
> > > fix though.

I won't touch the wake thing (at least not yet) as I am not familiar
with it. Is it Ok to change it with another patch later?

> > 
> > Thanks Mark. I try to cook a patch with copying of struct irq_chip still
> > at this week but I wont rush it (I have some other topics under work) as
> > the regression should be fixed by the other patch.
> > 
> 
> Just to check that is this patch here:
> 
> https://lore.kernel.org/lkml/20181227084443.GA23991@localhost.localdomain/
> 
> Just want to check what will be applied so I know it will fix the
> regression I am seeing as well.

Yep. That's the patch Mark did apply.

> 
> Thanks,
> Charles

-- 
Matti Vaittinen
ROHM Semiconductors

~~~ "I don't think so," said Rene Descartes.  Just then, he vanished ~~~