linux-kernel - Re: [PATCH 4/5] input: touchscreen: support Allwinner SoCs' touchscreen

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Message-ID: <20160721064140.GA17658@dtor-ws>
Date:	Wed, 20 Jul 2016 23:41:40 -0700
From:	Dmitry Torokhov <dmitry.torokhov@...il.com>
To:	Maxime Ripard <maxime.ripard@...e-electrons.com>
Cc:	Quentin Schulz <quentin.schulz@...e-electrons.com>,
	jic23@...nel.org, knaack.h@....de, lars@...afoo.de,
	pmeerw@...erw.net, wens@...e.org, lee.jones@...aro.org,
	antoine.tenart@...e-electrons.com,
	thomas.petazzoni@...e-electrons.com, linux-kernel@...r.kernel.org,
	linux-iio@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	linux-input@...r.kernel.org
Subject: Re: [PATCH 4/5] input: touchscreen: support Allwinner SoCs'
 touchscreen

On Thu, Jul 21, 2016 at 08:29:50AM +0200, Maxime Ripard wrote:
> On Wed, Jul 20, 2016 at 10:29:10AM +0200, Quentin Schulz wrote:
> > +	irq = regmap_irq_get_virq(sunxi_gpadc_mfd_dev->regmap_irqc, irq);
> > +	ret = devm_request_any_context_irq(&pdev->dev, irq,
> > +					   sunxi_gpadc_tp_up_irq_handler, 0,
> > +					   "tp_up", info);
> > +	if (ret < 0) {
> > +		dev_err(&pdev->dev,
> > +			"could not request TP_UP_PENDING interrupt: %d\n", ret);
> > +		goto err;
> > +	}
> 
> You enable the interrupts...
> 
> > +	info->tp_up_irq = irq;
> > +	disable_irq(irq);
> > +
> > +	ret = input_register_device(input);
> > +	if (ret) {
> > +		dev_err(&pdev->dev, "failed to register input device\n");
> > +		goto err;
> > +	}
> 
> ... but your driver isn't registered yet. How does input_report and
> input_sync behave in such a case?

This is explicitly allowed:

"
...
 * NOTE: input_event() may be safely used right after input device was
 * allocated with input_allocate_device(), even before it is registered
 * with input_register_device(), but the event will not reach any of the
 * input handlers. Such early invocation of input_event() may be used
 * to 'seed' initial state of a switch or initial position of absolute
 * axis, etc.
 */
"

Thanks.


-- 
Dmitry