>
> 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?
The status change of connection is before port reset.
In this stage, the device is not port enable, and it will not trigger disconnection.
> >
> > 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.
I will add a comment :
/* Only notify roothub. That is, when hdev->parent is empty. */
> > + 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.
>
I will add a comment:
/*
* There is no need to lock status_mutex here, because status_mutex
* protects hub->status, and the phy driver only checks the port
* status without changing the status.
*/
Thanks,
Stanley
.
