Re: [PATCH v3 03/12] usb: gadget: Expose sublink speed attributes

[Chunfeng Yun <chunfeng.yun@mediatek.com>]

On Fri, 2020-07-24 at 16:38 -0700, Thinh Nguyen wrote:
> The USB 3.2 specification supports dual-lane and different transfer
> rates for super-speed-plus. Devices operating in super-speed-plus can
> be gen2x1, gen1x2, or gen2x2.
> 
> A gadget driver may need to know the gadget's sublink speeds to properly
> setup its transfer requests and describe its capability in its
> descriptors. To describe the transfer rate in super-speed-plus fully,
> let's expose the lane count and sublink speed attributes when operating
> in super-speed-plus.
> 
> Signed-off-by: Thinh Nguyen <thinhn@synopsys.com>
> ---
>  Changes in v3:
>  - None
>  Changes in v2:
>  - None
> 
>  include/linux/usb/gadget.h | 20 ++++++++++++++++++++
>  1 file changed, 20 insertions(+)
> 
> diff --git a/include/linux/usb/gadget.h b/include/linux/usb/gadget.h
> index 52ce1f6b8f83..bd982669609c 100644
> --- a/include/linux/usb/gadget.h
> +++ b/include/linux/usb/gadget.h
> @@ -339,6 +339,15 @@ struct usb_gadget_ops {
>   * @speed: Speed of current connection to USB host.
>   * @max_speed: Maximal speed the UDC can handle.  UDC must support this
>   *      and all slower speeds.
> + * @num_lanes: Number of lanes in use.
> + * @max_num_lanes: Maximum number of lanes the UDC supports.
> + * @ssac: Sublink speed attribute count. The number of sublink speed
> + *	attributes is ssac + 1.
> + * @sublink_speed: Array of sublink speed attributes the UDC supports. Sublink
> + *	speed attributes are paired, and an RX followed by a TX attribute.
> + * @speed_ssid: Current sublink speed attribute ID in use.
> + * @min_speed_ssid: Sublink speed attribute ID with the minimum speed.
> + * @max_speed_ssid: Sublink speed attribute ID with the maximum speed.
>   * @state: the state we are now (attached, suspended, configured, etc)
>   * @name: Identifies the controller hardware type.  Used in diagnostics
>   *	and sometimes configuration.
> @@ -406,6 +415,17 @@ struct usb_gadget {
>  	struct list_head		ep_list;	/* of usb_ep */
>  	enum usb_device_speed		speed;
>  	enum usb_device_speed		max_speed;
> +
> +	/* SSP only */
> +	unsigned			num_lanes;
> +	unsigned			max_num_lanes;
> +	unsigned			ssac;
> +#define USB_GADGET_MAX_SSAC 3
> +	struct usb_sublink_speed	sublink_speed[USB_GADGET_MAX_SSAC + 1];
> +	unsigned			speed_ssid;
> +	unsigned			min_speed_ssid;
> +	unsigned			max_speed_ssid;
checkpatch warning:

WARNING:UNSPECIFIED_INT: Prefer 'unsigned int' to bare use of 'unsigned'

> +
>  	enum usb_device_state		state;
>  	const char			*name;
>  	struct device			dev;