Hi,

Baolin Wang <baolin.wang@linaro.org> writes:
> For some mobile devices with strict power management, we also want to suspend
> the host when the slave is detached for power saving. Thus we add the host
> suspend/resume functions to support this requirement.
>
> Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
> ---
> Changes since v4:
>  - Remove Kconfig and just enable host suspend/resume.
>  - Simplify the dwc3_host_suspend/resume() function.
>
> Changes since v3:
>  - No updates.
>
> Changes since v2:
>  - Remove pm_children_suspended() and other unused macros.
>
> Changes since v1:
>  - Add pm_runtime.h head file to avoid kbuild error.
> ---
>  drivers/usb/dwc3/core.c |   26 +++++++++++++++++++++++++-
>  drivers/usb/dwc3/core.h |    7 +++++++
>  drivers/usb/dwc3/host.c |   21 +++++++++++++++++++++
>  3 files changed, 53 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
> index 9a4a5e4..7ad4bc3 100644
> --- a/drivers/usb/dwc3/core.c
> +++ b/drivers/usb/dwc3/core.c
> @@ -1091,6 +1091,7 @@ static int dwc3_probe(struct platform_device *pdev)
>  	pm_runtime_use_autosuspend(dev);
>  	pm_runtime_set_autosuspend_delay(dev, DWC3_DEFAULT_AUTOSUSPEND_DELAY);
>  	pm_runtime_enable(dev);
> +	pm_suspend_ignore_children(dev, true);
>  	ret = pm_runtime_get_sync(dev);
>  	if (ret < 0)
>  		goto err1;
> @@ -1215,15 +1216,27 @@ static int dwc3_remove(struct platform_device *pdev)
>  static int dwc3_suspend_common(struct dwc3 *dwc)
>  {
>  	unsigned long	flags;
> +	int		ret;
>  
>  	switch (dwc->dr_mode) {
>  	case USB_DR_MODE_PERIPHERAL:
> +		spin_lock_irqsave(&dwc->lock, flags);
> +		dwc3_gadget_suspend(dwc);
> +		spin_unlock_irqrestore(&dwc->lock, flags);
> +		break;
>  	case USB_DR_MODE_OTG:
> +		ret = dwc3_host_suspend(dwc);
> +		if (ret)
> +			return ret;
> +
>  		spin_lock_irqsave(&dwc->lock, flags);
>  		dwc3_gadget_suspend(dwc);
>  		spin_unlock_irqrestore(&dwc->lock, flags);
>  		break;
>  	case USB_DR_MODE_HOST:
> +		ret = dwc3_host_suspend(dwc);
> +		if (ret)
> +			return ret;
>  	default:
>  		/* do nothing */
>  		break;
> @@ -1245,12 +1258,23 @@ static int dwc3_resume_common(struct dwc3 *dwc)
>  
>  	switch (dwc->dr_mode) {
>  	case USB_DR_MODE_PERIPHERAL:
> +		spin_lock_irqsave(&dwc->lock, flags);
> +		dwc3_gadget_resume(dwc);
> +		spin_unlock_irqrestore(&dwc->lock, flags);
> +		break;
>  	case USB_DR_MODE_OTG:
> +		ret = dwc3_host_resume(dwc);
> +		if (ret)
> +			return ret;
> +
>  		spin_lock_irqsave(&dwc->lock, flags);
>  		dwc3_gadget_resume(dwc);
>  		spin_unlock_irqrestore(&dwc->lock, flags);
> -		/* FALLTHROUGH */
> +		break;
>  	case USB_DR_MODE_HOST:
> +		ret = dwc3_host_resume(dwc);
> +		if (ret)
> +			return ret;
>  	default:
>  		/* do nothing */
>  		break;
> diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
> index b585a30..1099168 100644
> --- a/drivers/usb/dwc3/core.h
> +++ b/drivers/usb/dwc3/core.h
> @@ -1158,11 +1158,18 @@ static inline bool dwc3_is_usb31(struct dwc3 *dwc)
>  #if IS_ENABLED(CONFIG_USB_DWC3_HOST) || IS_ENABLED(CONFIG_USB_DWC3_DUAL_ROLE)
>  int dwc3_host_init(struct dwc3 *dwc);
>  void dwc3_host_exit(struct dwc3 *dwc);
> +int dwc3_host_suspend(struct dwc3 *dwc);
> +int dwc3_host_resume(struct dwc3 *dwc);
>  #else
>  static inline int dwc3_host_init(struct dwc3 *dwc)
>  { return 0; }
>  static inline void dwc3_host_exit(struct dwc3 *dwc)
>  { }
> +
> +static inline int dwc3_host_suspend(struct dwc3 *dwc)
> +{ return 0; }
> +static inline int dwc3_host_resume(struct dwc3 *dwc)
> +{ return 0; }
>  #endif
>  
>  #if IS_ENABLED(CONFIG_USB_DWC3_GADGET) || IS_ENABLED(CONFIG_USB_DWC3_DUAL_ROLE)
> diff --git a/drivers/usb/dwc3/host.c b/drivers/usb/dwc3/host.c
> index ed82464..7959ef0 100644
> --- a/drivers/usb/dwc3/host.c
> +++ b/drivers/usb/dwc3/host.c
> @@ -16,6 +16,7 @@
>   */
>  
>  #include <linux/platform_device.h>
> +#include <linux/pm_runtime.h>
>  
>  #include "core.h"
>  
> @@ -130,3 +131,23 @@ void dwc3_host_exit(struct dwc3 *dwc)
>  			  dev_name(&dwc->xhci->dev));
>  	platform_device_unregister(dwc->xhci);
>  }
> +
> +int dwc3_host_suspend(struct dwc3 *dwc)
> +{
> +	struct device *xhci = &dwc->xhci->dev;
> +
> +	/*
> +	 * Note: if we get the -EBUSY, which means the xHCI children devices are
> +	 * not in suspend state yet, the glue layer need to wait for a while and
> +	 * try to suspend xHCI device again.
> +	 */
> +	return pm_runtime_put_sync(xhci);
> +}
> +
> +int dwc3_host_resume(struct dwc3 *dwc)
> +{
> +	struct device *xhci = &dwc->xhci->dev;
> +
> +	/* Resume the xHCI device synchronously. */
> +	return pm_runtime_get_sync(xhci);
> +}
> -- 
> 1.7.9.5

I can't take this without Mathias taking xhci side of things.

-- 
balbi