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
