linux-kernel - Re: [PATCH 1/2] input: misc: add twl4030-pwrbutton driver

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Date:	Sat, 28 Feb 2009 14:23:03 -0800
From:	Dmitry Torokhov <dmitry.torokhov@...il.com>
To:	Felipe Balbi <me@...ipebalbi.com>
Cc:	linux-kernel@...r.kernel.org, linux-input@...r.kernel.org,
	Andrew Morton <akpm@...ux-foundation.org>,
	Felipe Balbi <felipe.balbi@...ia.com>,
	David Brownell <dbrownell@...rs.sourceforge.net>,
	Samuel Ortiz <sameo@...nedhand.com>
Subject: Re: [PATCH 1/2] input: misc: add twl4030-pwrbutton driver

Hi Felipe,

On Fri, Feb 27, 2009 at 09:28:02PM +0200, Felipe Balbi wrote:
> From: Felipe Balbi <felipe.balbi@...ia.com>
> 
> This is part of the twl4030 multifunction device driver.
> 
> With this driver we add support for reporting KEY_POWER
> events via the input layer.

...

> 
> +
> +	err = twl4030_i2c_read_u8(TWL4030_MODULE_PM_MASTER, &value,
> +				  STS_HW_CONDITIONS);
> +	if (!err)  {
> +		input_report_key(powerbutton_dev, KEY_POWER,
> +				 value & PWR_PWRON_IRQ);

input_sync() here please.

> +	} else {
> +		dev_err(dbg_dev, "twl4030: i2c error %d while reading TWL4030"
> +			" PM_MASTER STS_HW_CONDITIONS register\n", err);
> +	}
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static int __devinit twl4030_pwrbutton_probe(struct platform_device *pdev)
> +{
> +	int err = 0;
> +	int irq = platform_get_irq(pdev, 0);
> +
> +	dbg_dev = &pdev->dev;
> +
> +	/* PWRBTN == PWRON */
> +	err = request_irq(irq, powerbutton_irq,
> +			IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING,
> +			"twl4030-pwrbutton", NULL);

Requesting IRQ before allocating input device seems unsafe. If IRQ
arrives right now we'll go boom.


> +	if (err < 0) {
> +		dev_dbg(&pdev->dev, "Can't get IRQ for pwrbutton: %d\n", err);
> +		goto out;
> +	}
> +
> +	powerbutton_dev = input_allocate_device();
> +	if (!powerbutton_dev) {
> +		dev_dbg(&pdev->dev, "Can't allocate power button\n");
> +		err = -ENOMEM;
> +		goto free_irq_and_out;
> +	}
> +
> +	powerbutton_dev->evbit[0] = BIT_MASK(EV_KEY);
> +	powerbutton_dev->keybit[BIT_WORD(KEY_POWER)] = BIT_MASK(KEY_POWER);
> +	powerbutton_dev->name = "triton2-pwrbutton";

powerbutton_dev->dev.parent = &pdev->dev;

Any chance we could set up phys as well? BUS_I2C seems to be in order as
well.

> +
> +	err = input_register_device(powerbutton_dev);
> +	if (err) {
> +		dev_dbg(&pdev->dev, "Can't register power button: %d\n", err);
> +		goto free_input_dev;
> +	}
> +
> +	dev_info(&pdev->dev, "triton2 power button driver initialized\n");
> +
> +	return 0;
> +
> +
> +free_input_dev:
> +	input_free_device(powerbutton_dev);
> +free_irq_and_out:
> +	free_irq(TWL4030_PWRIRQ_PWRBTN, NULL);
> +out:
> +	return err;
> +}
> +
> +static int __devexit twl4030_pwrbutton_remove(struct platform_device *pdev)
> +{
> +	int irq = platform_get_irq(pdev, 0);
> +
> +	free_irq(irq, NULL);
> +	input_unregister_device(powerbutton_dev);
> +	input_free_device(powerbutton_dev);

Do not call free after unregistering, unregister will drop last
reference and will cause device structure be freed.

-- 
Dmitry
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