linux-kernel - Re: [PATCH v2 6/6] Input: Add ChromeOS EC keyboard driver

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Date:	Fri, 15 Feb 2013 19:56:56 -0800
From:	Simon Glass <sjg@...omium.org>
To:	Dmitry Torokhov <dmitry.torokhov@...il.com>
Cc:	LKML <linux-kernel@...r.kernel.org>,
	Samuel Ortiz <sameo@...ux.intel.com>,
	Luigi Semenzato <semenzato@...omium.org>,
	Vincent Palatin <vpalatin@...omium.org>,
	Grant Likely <grant.likely@...retlab.ca>,
	Rob Herring <rob.herring@...xeda.com>,
	Rob Landley <rob@...dley.net>, Felipe Balbi <balbi@...com>,
	Sourav Poddar <sourav.poddar@...com>,
	Tony Lindgren <tony@...mide.com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	"Mike A. Chan" <mikechan@...gle.com>,
	Jun Nakajima <jun.nakajima@...el.com>,
	Tom Keel <thomas.keel@...el.com>,
	devicetree-discuss@...ts.ozlabs.org, linux-doc@...r.kernel.org,
	linux-input@...r.kernel.org
Subject: Re: [PATCH v2 6/6] Input: Add ChromeOS EC keyboard driver

Hi Dmitry,

On Thu, Feb 14, 2013 at 9:31 AM, Dmitry Torokhov
<dmitry.torokhov@...il.com> wrote:
> On Wed, Feb 13, 2013 at 10:45:07PM -0800, Simon Glass wrote:
>> >>
>> >> +config KEYBOARD_CROS_EC
>> >> +     tristate "ChromeOS EC keyboard"
>> >> +     select INPUT_MATRIXKMAP
>> >> +     select MFD_CROS_EC
>> >
>> > Is this select safe? I.e. does MFD_CROS_EC depend on anything else?
>>
>> I'll remove it, since it isn't required, and it's true that it does
>> need other things.
>
> Instead of droppign the dependency completely I think it should "depens
> on MFD_CROS_EC"

OK, done.

>
>> >> +
>> >> +static void cros_ec_keyb_close(struct input_dev *dev)
>> >> +{
>> >> +     struct cros_ec_keyb *ckdev = input_get_drvdata(dev);
>> >> +
>> >> +     blocking_notifier_chain_unregister(&ckdev->ec->event_notifier,
>> >> +                                        &ckdev->notifier);
>> >> +     blocking_notifier_chain_unregister(&ckdev->ec->wake_notifier,
>> >> +                                        &ckdev->wake_notifier);
>> >
>> > Why is this done via a notifier instead of regular resume method?
>>
>> Because we only call the notifer in resume when we were not waking on
>> a keyboard event. We use it to flush the keyboard. It was a late
>> change so there might be a better way, but this driver does not have a
>> resume handler.
>
> Right and the question is why does not it have resume handler and why
> you inventing your own resume infrastructure instead of using the
> standard one.

I will fix that.

>
>> >> +
>> >> +static int cros_ec_keyb_probe(struct platform_device *pdev)
>> >> +{
>> >> +     struct cros_ec_device *ec = dev_get_drvdata(pdev->dev.parent);
>> >> +     struct device *dev = ec->dev;
>> >> +     struct cros_ec_keyb *ckdev = NULL;
>> >> +     struct input_dev *idev = NULL;
>> >> +     struct device_node *np;
>> >> +     int err;
>> >> +
>> >> +     np = of_find_matching_node(NULL, cros_ec_kbc_of_match);
>> >
>> > And if we don't find it?
>>
>> Added error checking.
>>
>> >
>> >> +
>> >> +     ckdev = kzalloc(sizeof(*ckdev), GFP_KERNEL);
>> >> +     if (!ckdev) {
>> >> +             dev_err(dev, "cannot allocate memory for ckdev\n");
>> >> +             return -ENOMEM;
>> >> +     }
>> >> +     pdev->dev.of_node = np;
>> >
>> > Huh? I'd expect the platform device be fully set up (including DT data)
>> > before the driver is called.
>>
>> This is a child of the mfd driver cros_ec, so I don't think that
>> works. Or maybe I'm just not sure how to plumb it in so it is
>> automatic. Or maybe I just need to add the id to the device info
>> below?
>
> Who creates this device? Whoever does this should set up the
> pdev->dev.of_node. This is not this driver's responsibility.
>
> And then you add the id to the table below and matching is done
> automatically.

OK I see - it comes from mfd and it is easy enough to make it do the
right thing.

Thanks for your comments and patience. I will send a new patch.

Regards,
Simon

>
> Thanks.
>
> --
> Dmitry
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