linux-kernel - Re: [PATCH v2] input: cros_ec

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Date:   Wed, 05 Apr 2017 09:20:10 +0800
From:   jeffy <jeffy.chen@...k-chips.com>
To:     Dmitry Torokhov <dmitry.torokhov@...il.com>,
        Brian Norris <briannorris@...omium.org>
CC:     linux-kernel@...r.kernel.org, dbasehore@...gle.com,
        dianders@...omium.org,
        Enric Balletbo i Serra <enric.balletbo@...labora.com>,
        gwendal@...omium.org, Lee Jones <lee.jones@...aro.org>
Subject: Re: [PATCH v2] input: cros_ec_keyb: Report wakeup events

Hi dmitry,

On 04/04/2017 06:41 AM, Dmitry Torokhov wrote:
> On Mon, Apr 03, 2017 at 01:53:53PM -0700, Brian Norris wrote:
>> + others
>>
>> On Mon, Apr 03, 2017 at 11:43:36AM -0700, Dmitry Torokhov wrote:
>>> On Sun, Apr 02, 2017 at 08:07:39AM +0800, Jeffy Chen wrote:
>>>> Report wakeup events when process events.
>>>>
>>>> Signed-off-by: Jeffy Chen <jeffy.chen@...k-chips.com>
>>>> ---
>>>>
>>>> Changes in v2:
>>>> Remove unneeded dts changes.
>>>>
>>>>   drivers/input/keyboard/cros_ec_keyb.c | 9 +++++++++
>>>>   1 file changed, 9 insertions(+)
>>>>
>>>> diff --git a/drivers/input/keyboard/cros_ec_keyb.c b/drivers/input/keyboard/cros_ec_keyb.c
>>>> index 6a250d6..a93d55f 100644
>>>> --- a/drivers/input/keyboard/cros_ec_keyb.c
>>>> +++ b/drivers/input/keyboard/cros_ec_keyb.c
>>>> @@ -286,6 +286,9 @@ static int cros_ec_keyb_work(struct notifier_block *nb,
>>>>   		return NOTIFY_DONE;
>>>>   	}
>>>>
>>>> +	if (device_may_wakeup(ckdev->dev))
>>>> +		pm_wakeup_event(ckdev->dev, 0);
>>>> +
>>>>   	return NOTIFY_OK;
>>>>   }
>>>>
>>>> @@ -632,6 +635,12 @@ static int cros_ec_keyb_probe(struct platform_device *pdev)
>>>>   		return err;
>>>>   	}
>>>>
>>>> +	err = device_init_wakeup(dev, 1);
>>>
>>> I would prefer if we did not mark cros_ec devices as wakeup sources
>>> unconditionally. Your original patch series was better (except it failed
>>> to parse the "wakeup-source" property that you introduced.
>>
>> I'm curious, why is this keyboard device different than any other keyboard
>> device? I see several other drivers in drivers/input/keyboard/ that do an
>> unconditional 'device_init_wakeup(..., 1)'. Keyboards tend to be wakeup
>> devices...
>
> If we did something before it does not mean we should continue doing
> this forever. I think providing an option to mark device as wakeup
> capable should be left to the platform.
>
>>
>> Also, what's the idea behind sub-devices vs. the main cros-ec device reporting
>> wakeups? Right now, we have this in drivers/mfd/cros_ec.c:
>>
>> static irqreturn_t ec_irq_thread(int irq, void *data)
>> {
>>          struct cros_ec_device *ec_dev = data;
>>          int ret;
>>
>>          if (device_may_wakeup(ec_dev->dev))
>>                  pm_wakeup_event(ec_dev->dev, 0);
>>
>>          ret = cros_ec_get_next_event(ec_dev);
>>          if (ret > 0)
>>                  blocking_notifier_call_chain(&ec_dev->event_notifier,
>>                                               0, ec_dev);
>>          return IRQ_HANDLED;
>> }
>>
>> But now, we're going to start double-reporting wakeups? Is that
>> expected?
>
> No, and not always (below).
>
>>
>> I think we have a similar overlap with the RTC driver (which is being
>> upstreamed now?):
>>
>> https://lkml.org/lkml/2017/2/14/658
>> [PATCH v3 3/4] rtc: cros-ec: add cros-ec-rtc driver.
>>
>> except that also goes through the trouble of enabling/disabling wakeup for the
>> EC IRQ. It seems to me (though I haven't dug in thoroughly) like the
>> main MFD shouldn't really be doing the wakeup reporting at all, and we
>> should depend on the sub-devices to do this. (i.e., the current patchset
>> is a step in the right direction, but it's not 100%.)
>>
>> Anyway, I could be wrong about the above, but I think we should make
>> sure there's a consistent answer across the drivers tree.
>
> Hm, it appears we have quite a mess. SPI-based EC declares entire EC as
> wakeup source (unconditionally I must add; we do mention "wakeup-source"
> in binding document at least). I2C-based EC does not call
> device_init_wakeup() at all, presumably that is what caused the calls to
> be added into sub-drivers.
>
> We need to resolve this one way or another. You probably do not want to
> wake up any time you move your device (accelerometer or other sensors),
> so I would try to move this property into individual devices, and try to
> come up with a reasonable binding.
right, we do have a issue about gyro sensor break 
suspend(https://partnerissuetracker.corp.google.com/issues/36705709)

it would be better if we move wakeup codes to sub drivers. and if you do 
this, it would also solve the original issue of this patchset ;)
>
> Thanks.
>