[PATCHv5 4/4] USB: gadget: atmel_usba_udc: Add suspend/resume with wakeup support

[Boris Brezillon]

Hi Sylvain,

On Wed, 21 Jan 2015 20:31:14 +0100
Sylvain Rochet <sylvain.rochet at finsecur.com> wrote:

> This patch add suspend/resume with wakeup support for Atmel USBA.
> 
> On suspend: We stay continuously clocked if Vbus signal is not
> available. If Vbus signal is available we set the Vbus signal as a wake
> up source then we stop the USBA itself and all clocks used by USBA.
> 
> On resume: We recover clocks and USBA we stopped them. If a device is
> connected, i.e. connected while we were suspended without wakeup
> enabled, we enable the controller.
> 
> Signed-off-by: Sylvain Rochet <sylvain.rochet at finsecur.com>
> ---
>  drivers/usb/gadget/udc/atmel_usba_udc.c | 61 +++++++++++++++++++++++++++++++++
>  1 file changed, 61 insertions(+)
> 
> diff --git a/drivers/usb/gadget/udc/atmel_usba_udc.c b/drivers/usb/gadget/udc/atmel_usba_udc.c
> index 963e398..326725e 100644
> --- a/drivers/usb/gadget/udc/atmel_usba_udc.c
> +++ b/drivers/usb/gadget/udc/atmel_usba_udc.c
> @@ -2115,6 +2115,7 @@ static int usba_udc_probe(struct platform_device *pdev)
>  	ret = usb_add_gadget_udc(&pdev->dev, &udc->gadget);
>  	if (ret)
>  		return ret;
> +	device_init_wakeup(&pdev->dev, 1);
>  
>  	usba_init_debugfs(udc);
>  	for (i = 1; i < udc->num_ep; i++)
> @@ -2130,6 +2131,7 @@ static int __exit usba_udc_remove(struct platform_device *pdev)
>  
>  	udc = platform_get_drvdata(pdev);
>  
> +	device_init_wakeup(&pdev->dev, 0);
>  	usb_del_gadget_udc(&udc->gadget);
>  
>  	for (i = 1; i < udc->num_ep; i++)
> @@ -2139,6 +2141,62 @@ static int __exit usba_udc_remove(struct platform_device *pdev)
>  	return 0;
>  }
>  
> +#ifdef CONFIG_PM
> +static int usba_udc_suspend(struct device *dev)
> +{
> +	struct usba_udc *udc = dev_get_drvdata(dev);
> +
> +	/* Not started */
> +	if (!udc->driver)
> +		return 0;
> +
> +	if (!device_may_wakeup(dev)) {
> +		usba_stop(udc);
> +		return 0;
> +	}
> +
> +	/*
> +	 * Device may wake up. We stay clocked if we failed
> +	 * to request vbus irq, assuming always on.
> +	 */
> +	if (gpio_is_valid(udc->vbus_pin)) {
> +		usba_stop(udc);
> +		/* Only wake up on device connection */
> +		irq_set_irq_type(gpio_to_irq(udc->vbus_pin),
> +			udc->vbus_pin_inverted ?
> +			IRQ_TYPE_EDGE_FALLING : IRQ_TYPE_EDGE_RISING);

If I'm correct, you're testing on a at91sam9x5 platform. Be careful,
this driver is used by older SoCs (at91sam9rl and avr32 SoCs) which do
not support configuring the interrupt on a specific edge (they trigger
on both edges).

This leaves two solutions here:
1) keep the IRQ_TYPE_EDGE_BOTH setting.
2) add new compatible strings to this driver and make this specific
edge change dependent on the SoC capability.

Best Regards,

Boris

-- 
Boris Brezillon, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com