Re: [PATCH 1/5] misc: rtsx_usb: Use USB remote wakeup signaling for card insertion detection
From: Alan Stern
Date: Mon Jul 23 2018 - 10:19:46 EST
On Mon, 23 Jul 2018, Kai-Heng Feng wrote:
> Although rtsx_usb doesn't support card removal detection, card insertion
> will resume rtsx_usb by USB remote wakeup signaling.
>
> When rtsx_usb gets resumed, also resumes its child devices,
> rtsx_usb_sdmmc and rtsx_usb_ms, to notify them there's a card in its
> slot.
>
> Signed-off-by: Kai-Heng Feng <kai.heng.feng@xxxxxxxxxxxxx>
> ---
> drivers/misc/cardreader/rtsx_usb.c | 13 +++++++++++++
> 1 file changed, 13 insertions(+)
>
> diff --git a/drivers/misc/cardreader/rtsx_usb.c b/drivers/misc/cardreader/rtsx_usb.c
> index b97903ff1a72..fed83453e5c5 100644
> --- a/drivers/misc/cardreader/rtsx_usb.c
> +++ b/drivers/misc/cardreader/rtsx_usb.c
> @@ -723,8 +723,20 @@ static int rtsx_usb_suspend(struct usb_interface *intf, pm_message_t message)
> return 0;
> }
>
> +static int rtsx_usb_resume_child(struct device *dev, void *data)
> +{
> + /* No need to wake up self again */
> + if (dev == data)
> + return 0;
Is this test actually needed? device_for_each_child() won't enumerate
the device it is called for, only that device's children.
> +
> + dev_dbg(dev, "%s called\n", __func__);
Not necessary. People can use ftrace if they want this information.
Alan Stern
> + pm_request_resume(dev);
> + return 0;
> +}
> +
> static int rtsx_usb_resume(struct usb_interface *intf)
> {
> + device_for_each_child(&intf->dev, &intf->dev, rtsx_usb_resume_child);
> return 0;
> }
>
> @@ -734,6 +746,7 @@ static int rtsx_usb_reset_resume(struct usb_interface *intf)
> (struct rtsx_ucr *)usb_get_intfdata(intf);
>
> rtsx_usb_reset_chip(ucr);
> + device_for_each_child(&intf->dev, &intf->dev, rtsx_usb_resume_child);
> return 0;
> }
>
>