linux-kernel - Re: gpio-omap: wakeup mask

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Message-ID: <20140709104142.GO28884@atomide.com>
Date:	Wed, 9 Jul 2014 03:41:42 -0700
From:	Tony Lindgren <tony@...mide.com>
To:	Pascal Huerst <pascal.huerst@...il.com>
Cc:	santosh.shilimkar@...com, khilman@...prootsystems.com,
	linus.walleij@...aro.org, gnurou@...il.com,
	linux-omap@...r.kernel.org, linux-gpio@...r.kernel.org,
	linux-kernel@...r.kernel.org, Daniel Mack <daniel@...que.org>
Subject: Re: gpio-omap: wakeup mask

* Pascal Huerst <pascal.huerst@...il.com> [140709 03:18]:
> Hey Tony, all
> 
> On 04.07.2014 09:27, Tony Lindgren wrote:
> > * Pascal Huerst <pascal.huerst@...il.com> [140702 05:12]:
> >> Hi everyone,
> >>
> >> we have a device with an am335x and are using some gpios on bank0 to
> >> wake up the device from suspend to ram.
> >>
> >> We have some user buttons which are configured in the devicetree as
> >> gpio-keys and one power-key which should wake up the device:
> >>
> >> &buttons {
> >>         power {
> >>                 label = "Power";
> >>                 gpios = <&gpio0 6 1>;
> >>                 linux,code = <116>;
> >>                 gpio-key,wakeup;
> >>         };
> >>
> >>         one {
> >>                 label = "One";
> >>                 gpios = <&gpio0 11 1>;
> >>                 linux,code = <2>;
> >>         };
> >>
> >>         : : :
> >> }
> >>
> >> The problem is, that the device wakes up on any trigger on bank 0. No
> >> matter which button was pressed. "gpio-key,wakeup" seems not to have any
> >> influence.
> >>
> >> Now, if I comment the following lines out in drivers/gpio/gpio-omap.c :
> >> set_gpio_trigger(...).
> >>
> >> 321
> >> 322 if (likely(!(bank->non_wakeup_gpios & gpio_bit))) {
> >> 323    _gpio_rmw(base, bank->regs->wkup_en, gpio_bit, trigger != 0);
> >> 324      bank->context.wake_en =
> >> 325        readl_relaxed(bank->base + bank->regs->wkup_en);
> >> 326 }
> >> 327
> >>
> >> Everything works as expected. But I don't really understand why? Is this
> >> a bug, or does this break something else I have not discovered yet?
> > 
> > The GPIO wake-up events are working from off-idle for omap3
> > the last time I checked, so sounds like this is some am335x
> > related issue.
> 
> Ok, that sounds reasonable.
> 
> > What does your bank->context.wake_en mask get set to with this code?
> 
> by calling 'echo mem > /sys/power/state' followed by a wakeup, I get the
> following:
> 
> [   28.992866] bank->context->wake_en = 00080040
> [   29.020974] PM: noirq resume of devices complete after 22.439 msecs

I guess that's for gpio bank 0 with no bit 11 as your dts has it
configured. If you just comment out the _gpio_rmw part above do
things work as expected?

Then if that works as expected, maybe write only some unused bits
into wkup_en register and see if it still wakes to all events while
it should not?

It might be worth comparing the GPIO registers between am37xx and
am335x for the wkup_en register.

Regards,

Tony
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