linux-kernel - Re: [PATCH] gpio: omap: fix irq triggering in smart-idle wakeup mode

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Date:	Mon, 18 Apr 2016 17:01:44 -0700
From:	santosh shilimkar <santosh.shilimkar@...cle.com>
To:	Tony Lindgren <tony@...mide.com>,
	Grygorii Strashko <grygorii.strashko@...com>
Cc:	Linus Walleij <linus.walleij@...aro.org>,
	Alexandre Courbot <gnurou@...il.com>,
	Santosh Shilimkar <ssantosh@...nel.org>,
	Sekhar Nori <nsekhar@...com>,
	Linux-OMAP <linux-omap@...r.kernel.org>,
	"linux-gpio@...r.kernel.org" <linux-gpio@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Roger Quadros <rogerq@...com>
Subject: Re: [PATCH] gpio: omap: fix irq triggering in smart-idle wakeup mode

On 4/18/2016 4:36 PM, Tony Lindgren wrote:
> * Grygorii Strashko <grygorii.strashko@...com> [160418 08:59]:
>> On 04/15/2016 09:54 PM, Tony Lindgren wrote:
>>> * santosh shilimkar <santosh.shilimkar@...cle.com> [160415 08:22]:
>>>> On 4/15/2016 2:26 AM, Grygorii Strashko wrote:
>>>>>
>>>>> Santosh, Tony, do you want me to perform any additional actions regarding this patch?
>>>>>
>>>> This patch should be run across family of SOCs to make
>>>> sure wakeup works on all of those if not done already
>>>
>>> Also, I'm not sure if we can just drop this code in question.
>>>
>>> After this patch, what function updates the GPIO wkup_en registers
>>> depending on enable_irq_wake()/disable_irq_wake()?
>>>
>>
>> The main purpose of this patch is to *not* modify GPIO wkup_en registers
>> depending of enable_irq_wake()/disable_irq_wake() :), instead all
>> non wake up IRQs should be masked during suspend.
>
> OK that makes sense.
>
>> The GPIO wkup_en registers should be always in sync with GPIO irq_en when
>> GPIO IP is in smart-idle wakeup mode. And this is done now from
>> omap_gpio_unmask_irq/omap_gpio_mask_irq(). See also [1].
>>
>> In general, it is more or less similar to GIC + wakeupgen:
>> - during normal work (including cpuidle) GIC irq_en and Wakeupgen wkup_en
>> should be in sync always
>> - during suspend - only IRQs, marked as wake up sources, should be left
>> unmasked.
>>
>> Also, I've found old thread [2] where Santosh proposed to use IRQCHIP_MASK_ON_SUSPEND.
>> And it was not possible, at that time, but now IRQCHIP_MASK_ON_SUSPEND can be used :),
>> because OMAP GPIO driver was switched to use generic irq handler instead of chained, so
>> now OMAP GPIO irqs are properly handled by IRQ PM core.
>> [chained irqs (and chained irq handles) are not disabled during suspend/resume and they are
>>   not maintained by IRQ PM core as result they can trigger way too early on resume when
>>   OMAP GPIO is not ready/powered.]
>
> OK. For my tests this patch does not change anything. I noticed however
> that we still have some additional bug somewhere where GPIO wake up
> events work fine for omap3 PM runtime, but are flakey for suspend.
>
>> I've tested it on: am57x-evm, am437x-idk-evm, omap4-panda
>
> OK thanks! Based on my tests and the above:
>
> Acked-by: Tony Lindgren <tony@...mide.com>
>
If all works then consider my ack as well :-)