On Fri, Jul 07, 2023 at 02:47:00PM +0800, Stanley Chang wrote: > In Realtek SoC, the parameter of usb phy is designed to can dynamic > tuning base on port status. Therefore, add a notify callback of phy > driver when usb port status change. > > The Realtek phy driver is designed to dynamically adjust disconnection > level and calibrate phy parameters. When the device connected bit changes > and when the disconnected bit changes, do port status change notification: > > Check if portstatus is USB_PORT_STAT_CONNECTION and portchange is > USB_PORT_STAT_C_CONNECTION. > 1. The device is connected, the driver lowers the disconnection level and > calibrates the phy parameters. > 2. The device disconnects, the driver increases the disconnect level and > calibrates the phy parameters. > > When controller to notify connect that device is already ready. If we > adjust the disconnection level in notify_connect, the disconnect may have > been triggered at this stage. So we need to change that as early as > possible. Therefore, we add an api to notify phy the port status changes. How do you know that the disconnect will not have already been triggered at this point, when the status changes? > > Signed-off-by: Stanley Chang <stanley_chang@xxxxxxxxxxx> > --- > v6 to v7 change: > No change > v5 to v6 change: > No change > v4 to v5 change: > No change > v3 to v4 change: > Fix the warning for checkpatch with strict. > v2 to v3 change: > Add more comments about the reason for adding this api > v1 to v2 change: > No change > --- > drivers/usb/core/hub.c | 13 +++++++++++++ > include/linux/usb/phy.h | 13 +++++++++++++ > 2 files changed, 26 insertions(+) > > diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c > index a739403a9e45..8433ff89dea6 100644 > --- a/drivers/usb/core/hub.c > +++ b/drivers/usb/core/hub.c > @@ -614,6 +614,19 @@ static int hub_ext_port_status(struct usb_hub *hub, int port1, int type, > ret = 0; > } > mutex_unlock(&hub->status_mutex); > + > + if (!ret) { > + struct usb_device *hdev = hub->hdev; > + > + if (hdev && !hdev->parent) { Why the check for no parent? Please document that here in a comment. > + struct usb_hcd *hcd = bus_to_hcd(hdev->bus); > + > + if (hcd->usb_phy) > + usb_phy_notify_port_status(hcd->usb_phy, > + port1 - 1, *status, *change); > + } > + } > + This is safe to notify with the hub mutex unlocked? Again, a comment would be helpful to future people explaining why that is so. thanks, greg k-h