linux-kernel - Re: [PATCH] OMAP GPIO - don't wake from suspend unless requested.

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Date:	Thu, 6 Sep 2012 16:26:06 +0300
From:	Felipe Balbi <balbi@...com>
To:	NeilBrown <neilb@...e.de>
Cc:	"Shilimkar, Santosh" <santosh.shilimkar@...com>,
	"Rafael J. Wysocki" <rjw@...k.pl>,
	Tarun Kanti DebBarma <tarun.kanti@...com>,
	Kevin Hilman <khilman@...com>,
	Tony Lindgren <tony@...mide.com>, Benoit <b-cousson@...com>,
	Grant Likely <grant.likely@...retlab.ca>,
	Felipe Balbi <balbi@...com>, linux-omap@...r.kernel.org,
	lkml <linux-kernel@...r.kernel.org>,
	Jon Hunter <jon-hunter@...com>
Subject: Re: [PATCH] OMAP GPIO - don't wake from suspend unless requested.

Hi,

On Thu, Sep 06, 2012 at 05:02:45PM +1000, NeilBrown wrote:
> On Thu, 6 Sep 2012 11:18:09 +0530 "Shilimkar, Santosh"
> <santosh.shilimkar@...com> wrote:
> 
> > On Thu, Sep 6, 2012 at 8:35 AM, NeilBrown <neilb@...e.de> wrote:
> > > On Mon, 3 Sep 2012 22:59:06 -0700 "Shilimkar, Santosh"
> > > <santosh.shilimkar@...com> wrote:
> 
> > >> After thinking bit more on this, the problem seems to be coming
> > >> mainly because the gpio device is runtime suspended bit early than
> > >> it should be. Similar issue seen with i2c driver as well. The i2c issue
> > >> was discussed with Rafael at LPC last week. The idea is to move
> > >> the pm_runtime_enable/disable() calls entirely up to the
> > >> _late/_early stage of device suspend/resume.
> > >> Will update this thread once I have further update.
> > >
> > > This won't be late enough.  IRQCHIP_MASK_ON_SUSPEND takes effect after all
> > > the _late callbacks have been called.
> > > I, too, spoke to Rafael about this in San Diego.  He seemed to agree with me
> > > that the interrupt needs to be masked in the ->suspend callback.  any later
> > > is too late.
> > >
> > Thanks for information about your discussion. Will wait for the patch then.
> > 
> > Regards
> > santosh
> 
> I already sent a patch - that is what started this thread :-)
> 
> I include it below.
> You said "The patch doesn't seems to be correct" but didn't expand on why.
> Do you still think it is not correct?  I wouldn't be surprised if there is
> some case that it doesn't handle quite right, but it seems right to me.
> 
> Thanks,
> NeilBrown
> 
> 
> From: NeilBrown <neilb@...e.de>
> Subject: [PATCH] OMAP GPIO - don't wake from suspend unless requested.
> 
> Current kernel will wake from suspend on an event on any active
> GPIO even if enable_irq_wake() wasn't called.
> 
> There are two reasons that the hardware wake-enable bit should be set:
> 
> 1/ while non-suspended the CPU might go into a deep sleep (off_mode)
>   in which the wake-enable bit is needed for an interrupt to be
>   recognised.
> 2/ while suspended the GPIO interrupt should wake from suspend if and
>    only if irq_wake as been enabled.
> 
> The code currently doesn't keep these two reasons separate so they get
> confused and sometimes the wakeup flags is set incorrectly.
> 
> This patch reverts:
>  commit 9c4ed9e6c01e7a8bd9079da8267e1f03cb4761fc
>     gpio/omap: remove suspend/resume callbacks
> and
>  commit 0aa2727399c0b78225021413022c164cb99fbc5e
>     gpio/omap: remove suspend_wakeup field from struct gpio_bank
> 
> and makes some minor changes so that we have separate flags for "GPIO
> should wake from deep idle" and "GPIO should wake from suspend".
> 
> With this patch, the GPIO from my touch screen doesn't wake my device
> any more, which is what I want.
> 
> Cc: Kevin Hilman <khilman@...com>
> Cc: Tony Lindgren <tony@...mide.com>
> Cc: Santosh Shilimkar <santosh.shilimkar@...com>
> Cc: Cousson Benoit <b-cousson@...com>
> Cc: Grant Likely <grant.likely@...retlab.ca>
> Cc: Tarun Kanti DebBarma <tarun.kanti@...com>
> Cc: Felipe Balbi <balbi@...com>
> Cc: Govindraj.R <govindraj.raja@...com>
> 
> Signed-off-by: NeilBrown <neilb@...e.de>
> 
> diff --git a/drivers/gpio/gpio-omap.c b/drivers/gpio/gpio-omap.c
> index 4fbc208..fdbad70 100644
> --- a/drivers/gpio/gpio-omap.c
> +++ b/drivers/gpio/gpio-omap.c
> @@ -57,6 +57,7 @@ struct gpio_bank {
>  	u16 irq;
>  	int irq_base;
>  	struct irq_domain *domain;
> +	u32 suspend_wakeup;
>  	u32 non_wakeup_gpios;
>  	u32 enabled_non_wakeup_gpios;
>  	struct gpio_regs context;
> @@ -522,11 +523,12 @@ static int _set_gpio_wakeup(struct gpio_bank *bank, int gpio, int enable)
>  
>  	spin_lock_irqsave(&bank->lock, flags);
>  	if (enable)
> -		bank->context.wake_en |= gpio_bit;
> +		bank->suspend_wakeup |= gpio_bit;
>  	else
> -		bank->context.wake_en &= ~gpio_bit;
> +		bank->suspend_wakeup &= ~gpio_bit;
>  
> -	__raw_writel(bank->context.wake_en, bank->base + bank->regs->wkup_en);
> +	if (!bank->loses_context)
> +		__raw_writel(bank->suspend_wakeup, bank->base + bank->regs->wkup_en);
>  	spin_unlock_irqrestore(&bank->lock, flags);
>  
>  	return 0;
> @@ -1157,6 +1159,51 @@ static int __devinit omap_gpio_probe(struct platform_device *pdev)
>  #ifdef CONFIG_ARCH_OMAP2PLUS
>  
>  #if defined(CONFIG_PM_RUNTIME)
> +
> +#if defined(CONFIG_PM_SLEEP)
> +static int omap_gpio_suspend(struct device *dev)
> +{
> +	struct platform_device *pdev = to_platform_device(dev);
> +	struct gpio_bank *bank = platform_get_drvdata(pdev);
> +	void __iomem *base = bank->base;
> +	unsigned long flags;
> +
> +	if (!bank->mod_usage || !bank->loses_context)
> +		return 0;
> +
> +	if (!bank->regs->wkup_en || !bank->context.wake_en)
> +		return 0;
> +
> +	spin_lock_irqsave(&bank->lock, flags);

shouldn't you be using _noirq methods instead ? Then this would become a
normal spin_lock()/spin_unlock().

-- 
balbi

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