Date:   Wed, 21 Jun 2017 16:40:12 +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>,
        Mark Brown <broonie@...nel.org>
Subject: Re: [PATCH v2] input: cros_ec_keyb: Report wakeup events

Hi guys,

On 04/05/2017 09:20 AM, jeffy wrote:
> 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.

right, so i'll add this:
+       device_init_wakeup(dev,
+                       device_property_read_bool(dev, "wakeup-source"));

>>
>>>
>>> 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?

the double-reporting wakeup could be harmless, but i saw we added a wake 
mask in our 4.4 kernel(for non-wake events):
         if (device_may_wakeup(ec_dev->dev) && wake_event)
                 pm_wakeup_event(ec_dev->dev, 0);

maybe we can do something similar to filter out wakeup events already 
handled by sub devices?

>>
>> 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.
hmmm, it looks like the i2c-based ec also do this, but through i2c-core:

         if (of_get_property(node, "wakeup-source", NULL))
                 info.flags |= I2C_CLIENT_WAKE;
...
         if (client->flags & I2C_CLIENT_WAKE) {
                 device_init_wakeup(&client->dev, true);

exynos5250-spring.dts:
         cros_ec: embedded-controller@1e {
                 compatible = "google,cros-ec-i2c";
...
                 wakeup-source;

and the binding document said we need to add wakeup-source for cros ec spi:
Documentation/devicetree/bindings/mfd/cros-ec.txt

spi@...b0000 {
         ec@0 {
                 compatible = "google,cros-ec-spi";
                 reg = <0x0>;
                 interrupts = <14 0>;
                 interrupt-parent = <&wakeup_eint>;
                 wakeup-source;


so do we need to add wakeup-source property support in cros_ec_spi? or 
maybe even in spi core(like i2c core)?
>>
>> 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.
we have this https://chromium-review.googlesource.com/c/372399/ in cros 
4.4 kernel, but somehow not upstream.

but it would still be good to move wakeup to sub devices.
> 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.
>>
>

so i'll try to add wakeup-source property for spi core and 
cros-ec-keyboard as a first step

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