linux-kernel - Re: [PATCH v3 4/4] gpio: brcmstb: support wakeup from S5 cold boot

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Message-ID: <CADtm3G5sokwoKcHd3fXBmreKfuUstNWcqeVRScHObxhBeG28LA@mail.gmail.com>
Date:	Mon, 13 Jul 2015 19:31:01 -0700
From:	Gregory Fong <gregory.0xf0@...il.com>
To:	Linus Walleij <linus.walleij@...aro.org>
Cc:	"linux-gpio@...r.kernel.org" <linux-gpio@...r.kernel.org>,
	Alexandre Courbot <gnurou@...il.com>,
	bcm-kernel-feedback-list <bcm-kernel-feedback-list@...adcom.com>,
	Brian Norris <computersforpeace@...il.com>,
	"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
	Florian Fainelli <f.fainelli@...il.com>,
	Ian Campbell <ijc+devicetree@...lion.org.uk>,
	Kumar Gala <galak@...eaurora.org>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Mark Rutland <mark.rutland@....com>,
	Pawel Moll <pawel.moll@....com>,
	Rob Herring <robh+dt@...nel.org>,
	Russell King <linux@....linux.org.uk>
Subject: Re: [PATCH v3 4/4] gpio: brcmstb: support wakeup from S5 cold boot

On Mon, Jul 13, 2015 at 6:03 AM, Linus Walleij <linus.walleij@...aro.org> wrote:
> On Thu, Jun 18, 2015 at 3:00 AM, Gregory Fong <gregory.0xf0@...il.com> wrote:
>
>> For wake from S5, we need to:
>> - register a reboot handler
>> - set wakeup capability before requesting IRQ so wakeup count is
>>   incremented
>> - mask all GPIO IRQs and clear any pending interrupts during driver
>>   probe to since no driver will yet be registered to handle any IRQs
>>   carried over from boot at that time, and it's possible that the
>>   booted kernel does not request the same IRQ anyway.
>>
>> This means that /sys/.../power/wakeup_count is valid at boot time, and
>> we can properly account for S5 wakeup stats. e.g.:
>>
>>   ### After waking from S5 from a GPIO key
>>   # cat /sys/bus/platform/drivers/brcmstb-gpio/f04172c0.gpio/power/wakeup
>>   enabled
>>   # cat /sys/bus/platform/drivers/brcmstb-gpio/f04172c0.gpio/power/wakeup_count
>>   1
>>
>> Signed-off-by: Gregory Fong <gregory.0xf0@...il.com>
>
> (...)
>> -static int brcmstb_gpio_irq_set_wake(struct irq_data *d, unsigned int enable)
>> +static int __brcmstb_gpio_irq_set_wake(struct brcmstb_gpio_priv *priv,
>> +               unsigned int enable)
>>  {
>> -       struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
>> -       struct brcmstb_gpio_priv *priv = brcmstb_gpio_gc_to_priv(gc);
>>         int ret = 0;
>
> I don't usually like to refactor code with __foo wrapper functions with
> underscores or double underscores in front of them.
>
> Is it possible to give this a more unique name?

Sure, just have to come up with a good one :-).

>
>> +               /*
>> +                * Mask all interrupts by default, since wakeup interrupts may
>> +                * be retained from S5 cold boot
>> +                */
>> +               bank->bgc.write_reg(reg_base + GIO_MASK(bank->id), 0);
>
> Aha I see, that's some clever code, nice.
>
> Yours,
> Linus Walleij
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