Re: [PATCH v2] input/imx_keypad: add pm suspend and resume functions

[Sascha Hauer <s.hauer@pengutronix.de>]

On Thu, Oct 13, 2011 at 10:13:33AM +0800, Hui Wang wrote:
> The imx_keypad driver is set wake capable in the imx_keypad_probe(),
> but it doesn't implement suspend and reusme callback interface.
> 
> From the i.MX series MCU Reference Manual, the kpp (keypad port) is
> a major wake up source which can detect any key press even in low
> power modes and even when there is no clock.
> 
> Now add suspend and resume callback functions for this driver.
> 
> Signed-off-by: Hui Wang <jason77.wang@gmail.com>
> ---
> 
> Sorry for resending this patch, the previous sent patch with [v2]
> as a prefix, i am afraid that patch was filtered out from mailing list.
> Now resending this patch with [PATCH v2] as a prefix.
> 
> In the V2:
> 1) add a check for input->users before disable clock.
> 2) add mutex_lock/unlock to protect input->users checking.
> 3) use SIMPLE_DEV_PM_OPS.
> 
>  drivers/input/keyboard/imx_keypad.c |   46 +++++++++++++++++++++++++++++++++++
>  1 files changed, 46 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/input/keyboard/imx_keypad.c b/drivers/input/keyboard/imx_keypad.c
> index d92c15c..c43fa97 100644
> --- a/drivers/input/keyboard/imx_keypad.c
> +++ b/drivers/input/keyboard/imx_keypad.c
> @@ -567,10 +567,56 @@ static int __devexit imx_keypad_remove(struct platform_device *pdev)
>  	return 0;
>  }
>  
> +#ifdef CONFIG_PM
> +static int imx_kbd_suspend(struct device *dev)
> +{
> +	struct platform_device *pdev = to_platform_device(dev);
> +	struct imx_keypad *kbd = platform_get_drvdata(pdev);
> +	struct input_dev *input_dev = kbd->input_dev;
> +
> +	/* imx kbd can wake up system even clock is disabled */
> +	mutex_lock(&input_dev->mutex);
> +
> +	if (input_dev->users)
> +		clk_disable(kbd->clk);
> +
> +	mutex_unlock(&input_dev->mutex);
> +
> +	if (device_may_wakeup(&pdev->dev))
> +		enable_irq_wake(kbd->irq);

enable_irq_wake can fail. More specifically it *will* fail on all non
tzic i.MX boards as this function is not yet implemented for the avic
irq controller.
You should check the return value.

Sascha



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