[v2,1/3] usb: phy: add usb phy notify port status API

  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.

Signed-off-by: Stanley Chang <stanley_chang@realtek.com>
---
v1 to v2 change:
    No change
---
 drivers/usb/core/hub.c  | 13 +++++++++++++
 include/linux/usb/phy.h | 14 ++++++++++++++
 2 files changed, 27 insertions(+)
  

On Thu, May 25, 2023 at 10:26:02AM +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.
> 
> Signed-off-by: Stanley Chang <stanley_chang@realtek.com>
> ---
> v1 to v2 change:
>     No change
> ---
>  drivers/usb/core/hub.c  | 13 +++++++++++++
>  include/linux/usb/phy.h | 14 ++++++++++++++
>  2 files changed, 27 insertions(+)
> 
> diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
> index 97a0f8faea6e..b4fbbeae1927 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) {
> +			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);
> +		}
> +	}
> +
>  	return ret;
>  }
>  
> diff --git a/include/linux/usb/phy.h b/include/linux/usb/phy.h
> index e4de6bc1f69b..53bf3540098f 100644
> --- a/include/linux/usb/phy.h
> +++ b/include/linux/usb/phy.h
> @@ -144,6 +144,10 @@ struct usb_phy {
>  	 */
>  	int	(*set_wakeup)(struct usb_phy *x, bool enabled);
>  
> +	/* notify phy port status change */
> +	int	(*notify_port_status)(struct usb_phy *x,
> +		int port, u16 portstatus, u16 portchange);
> +
>  	/* notify phy connect status change */
>  	int	(*notify_connect)(struct usb_phy *x,
>  			enum usb_device_speed speed);

Why can't this be part of the same notify_connect() callback?

What makes it different somehow?  Please document this much better.


> @@ -316,6 +320,16 @@ usb_phy_set_wakeup(struct usb_phy *x, bool enabled)
>  		return 0;
>  }
>  
> +static inline int
> +usb_phy_notify_port_status(struct usb_phy *x, int port, u16 portstatus,
> +	    u16 portchange)
> +{
> +	if (x && x->notify_port_status)

How can x ever be NULL?

thanks,

greg k-h
  

Hi Greg,

> > --- a/include/linux/usb/phy.h
> > +++ b/include/linux/usb/phy.h
> > @@ -144,6 +144,10 @@ struct usb_phy {
> >        */
> >       int     (*set_wakeup)(struct usb_phy *x, bool enabled);
> >
> > +     /* notify phy port status change */
> > +     int     (*notify_port_status)(struct usb_phy *x,
> > +             int port, u16 portstatus, u16 portchange);
> > +
> >       /* notify phy connect status change */
> >       int     (*notify_connect)(struct usb_phy *x,
> >                       enum usb_device_speed speed);
> 
> Why can't this be part of the same notify_connect() callback?

The notify connect is at device ready. But I want notify port status change before port reset.

> What makes it different somehow?  Please document this much better.

In Realtek phy driver, we have designed to dynamically adjust disconnection level and calibrate phy parameters.
So we do this when the device connected bit changes and when the disconnected bit changes.
Port status change notification:
1. Check if portstatus is USB_PORT_STAT_CONNECTION and portchange is USB_PORT_STAT_C_CONNECTION.
  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.

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.


> 
> > @@ -316,6 +320,16 @@ usb_phy_set_wakeup(struct usb_phy *x, bool
> enabled)
> >               return 0;
> >  }
> >
> > +static inline int
> > +usb_phy_notify_port_status(struct usb_phy *x, int port, u16 portstatus,
> > +         u16 portchange)
> > +{
> > +     if (x && x->notify_port_status)
> 
> How can x ever be NULL?

It is possible.
If the controller not use usb-phy driver. It  is NULL.

Thanks,
Stanley
  

On Tue, May 30, 2023 at 02:19:45AM +0000, Stanley Chang[昌育德] wrote:
> Hi Greg,
> 
> > > --- a/include/linux/usb/phy.h
> > > +++ b/include/linux/usb/phy.h
> > > @@ -144,6 +144,10 @@ struct usb_phy {
> > >        */
> > >       int     (*set_wakeup)(struct usb_phy *x, bool enabled);
> > >
> > > +     /* notify phy port status change */
> > > +     int     (*notify_port_status)(struct usb_phy *x,
> > > +             int port, u16 portstatus, u16 portchange);
> > > +
> > >       /* notify phy connect status change */
> > >       int     (*notify_connect)(struct usb_phy *x,
> > >                       enum usb_device_speed speed);
> > 
> > Why can't this be part of the same notify_connect() callback?
> 
> The notify connect is at device ready. But I want notify port status change before port reset.
> 
> > What makes it different somehow?  Please document this much better.
> 
> In Realtek phy driver, we have designed to dynamically adjust disconnection level and calibrate phy parameters.
> So we do this when the device connected bit changes and when the disconnected bit changes.
> Port status change notification:
> 1. Check if portstatus is USB_PORT_STAT_CONNECTION and portchange is USB_PORT_STAT_C_CONNECTION.
>   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.
> 
> 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.

Please put this type of information in the changelog and in the comments
for the callback when you resubmit it.

thanks,

greg k-h
  

Hi Greg,

> > Why can't this be part of the same notify_connect() callback?
> >
> > The notify connect is at device ready. But I want notify port status change
> before port reset.
> >
> > > What makes it different somehow?  Please document this much better.
> >
> > In Realtek phy driver, we have designed to dynamically adjust disconnection
> level and calibrate phy parameters.
> > So we do this when the device connected bit changes and when the
> disconnected bit changes.
> > Port status change notification:
> > 1. Check if portstatus is USB_PORT_STAT_CONNECTION and portchange is
> USB_PORT_STAT_C_CONNECTION.
> >   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.
> >
> > 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.
> 
> Please put this type of information in the changelog and in the comments for
> the callback when you resubmit it.

Okay, I will add this information at next version.

Thanks,
Stanley