linux-kernel - Re: [PATCH 1/3] ARM/gpio: Push OMAP2 quirk down into TWL4030 driver

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Date:   Wed, 17 May 2023 11:57:10 +0200
From:   Bartosz Golaszewski <brgl@...ev.pl>
To:     Linus Walleij <linus.walleij@...aro.org>
Cc:     Tony Lindgren <tony@...mide.com>,
        Russell King <linux@...linux.org.uk>,
        Lee Jones <lee@...nel.org>,
        Andreas Kemnade <andreas@...nade.info>,
        Bartosz Golaszewski <bartosz.golaszewski@...aro.org>,
        linux-arm-kernel@...ts.infradead.org, linux-omap@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-gpio@...r.kernel.org
Subject: Re: [PATCH 1/3] ARM/gpio: Push OMAP2 quirk down into TWL4030 driver

On Thu, May 4, 2023 at 2:19 PM Linus Walleij <linus.walleij@...aro.org> wrote:
>
> On Wed, May 3, 2023 at 3:02 PM Bartosz Golaszewski <brgl@...ev.pl> wrote:
> > On Mon, May 1, 2023 at 11:05 AM Linus Walleij <linus.walleij@...aro.org> wrote:
> > >
> > > The TWL4030 GPIO driver has a custom platform data .set_up()
> > > callback to call back into the platform and do misc stuff such
> > > as hog and export a GPIO for WLAN PWR on a specific OMAP3 board.
> > >
> > > Avoid all the kludgery in the platform data and the boardfile
> > > and just put the quirks right into the driver. Make it
> > > conditional on OMAP3.
> > >
> > > I think the exported GPIO is used by some kind of userspace
> > > so ordinary DTS hogs will probably not work.
> > >
> >
> > While I haven't tested it (nor can I) so don't take my word for it, it
> > looks to me as if regular DTS hogs *should* work. If anything, the way
> > this quirk is implemented in your patch moves the export past the chip
> > registration, while ordinary hogs would be applied when the chip is
> > first added.
> >
> > Am I missing something?
>
> DTS hogs cannot do gpiod_export(), that's the problem. I think the OMAP2
> (Nokia phones?) need those exported GPIOs.
>
> Yours,
> Linus Walleij

Ah, it needs to manipulate the GPIOs then. Get it. I don't have a
better idea either.

Bart