Re: [PATCH v2 1/3] usb: phy: add usb phy notify port status API - Greg Kroah-Hartman

From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Stanley Chang <stanley_chang@realtek.com>
Cc: Vinod Koul <vkoul@kernel.org>,
	Kishon Vijay Abraham I <kishon@kernel.org>,
	Rob Herring <robh+dt@kernel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
	Conor Dooley <conor+dt@kernel.org>,
	Alan Stern <stern@rowland.harvard.edu>,
	Michael Grzeschik <m.grzeschik@pengutronix.de>,
	Bagas Sanjaya <bagasdotme@gmail.com>,
	Flavio Suligoi <f.suligoi@asem.it>,
	Matthias Kaehlcke <mka@chromium.org>,
	Mathias Nyman <mathias.nyman@linux.intel.com>,
	Ray Chi <raychi@google.com>,
	linux-phy@lists.infradead.org, devicetree@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org
Subject: Re: [PATCH v2 1/3] usb: phy: add usb phy notify port status API
Date: Mon, 29 May 2023 15:27:16 +0100	[thread overview]
Message-ID: <2023052905-maimed-studied-3563@gregkh> (raw)
In-Reply-To: <20230525022617.30537-1-stanley_chang@realtek.com>

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

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