linux-kernel - Re: [PATCH 2/2] gpio/omap: add *remove* callback in platform

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Date:	Wed, 11 Jul 2012 16:25:44 -0700
From:	Kevin Hilman <khilman@...com>
To:	Tarun Kanti DebBarma <tarun.kanti@...com>
Cc:	<linux-omap@...r.kernel.org>,
	<linux-arm-kernel@...ts.infradead.org>,
	<linux-kernel@...r.kernel.org>, Rajendra Nayak <rnayak@...com>,
	Santosh Shilimkar <santosh.shilimkar@...com>,
	"Cousson\, Benoit" <b-cousson@...com>,
	Paul Walmsley <paul@...an.com>
Subject: Re: [PATCH 2/2] gpio/omap: add *remove* callback in platform_driver

Tarun Kanti DebBarma <tarun.kanti@...com> writes:

> Add *remove* callback so that necessary cleanup operations are
> performed when device is unregistered. 

How was this tested?  on what platforms?  

> The device is deleted
> from the list and associated clock handle is released by
> calling clk_put() and irq descriptor is released using the
> irq_free_desc() api.

There is quite a bit of other things to do in remove to properly cleanup
what is done in probe.

Also, what happens when a 'remove' is triwhen there are GPIOs that 
are still requested and in use, especially if they are GPIO IRQs.

Also, what about runtime PM?

In short, this seems very premature and I suspect untested.

Kevin

> Signed-off-by: Tarun Kanti DebBarma <tarun.kanti@...com>
> Reported-by: Paul Walmsley <paul@...an.com>
> Reviewed-by: Jon Hunter <jon-hunter@...com>
> Cc: Kevin Hilman <khilman@...com>
> Cc: Rajendra Nayak <rnayak@...com>
> Cc: Santosh Shilimkar <santosh.shilimkar@...com>
> Cc: Cousson, Benoit <b-cousson@...com>
> Cc: Paul Walmsley <paul@...an.com>
> ---
>  drivers/gpio/gpio-omap.c |   30 ++++++++++++++++++++++++++++++
>  1 files changed, 30 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/gpio/gpio-omap.c b/drivers/gpio/gpio-omap.c
> index afecdcc..08929d5 100644
> --- a/drivers/gpio/gpio-omap.c
> +++ b/drivers/gpio/gpio-omap.c
> @@ -1140,6 +1140,35 @@ static int __devinit omap_gpio_probe(struct platform_device *pdev)
>  	return ret;
>  }
>  
> +/**
> + * omap_gpio_remove - cleanup a registered gpio device
> + * @pdev:       pointer to current gpio platform device
> + *
> + * Called by driver framework whenever a gpio device is unregistered.
> + * GPIO is deleted from the list and associated clock handle freed.
> + */
> +static int __devexit omap_gpio_remove(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct gpio_bank *bank;
> +	unsigned long flags;
> +	int ret = -EINVAL;
> +
> +	list_for_each_entry(bank, &omap_gpio_list, node) {
> +		spin_lock_irqsave(&bank->lock, flags);
> +		if (bank->dev == dev) {
> +			list_del(&bank->node);
> +			clk_put(bank->dbck);
> +			irq_free_desc(bank->irq_base);
> +			ret = 0;
> +			spin_unlock_irqrestore(&bank->lock, flags);
> +			break;
> +		}
> +		spin_unlock_irqrestore(&bank->lock, flags);
> +	}
> +	return ret;
> +}
> +
>  #ifdef CONFIG_ARCH_OMAP2PLUS
>  
>  #if defined(CONFIG_PM_RUNTIME)
> @@ -1466,6 +1495,7 @@ MODULE_DEVICE_TABLE(of, omap_gpio_match);
>  
>  static struct platform_driver omap_gpio_driver = {
>  	.probe		= omap_gpio_probe,
> +	.remove = __devexit_p(omap_gpio_remove),
>  	.driver		= {
>  		.name	= "omap_gpio",
>  		.pm	= &gpio_pm_ops,
--
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