On Mon, 28 May 2012, rajeev k wrote:
> Hello stern,
>
> I am working on Synopsys DesignWare OTG USB Linux driver (dwc_otg), worked
> on by Applied Micro. The controller is written in such a way that it will
> support only high speed device. Looking into flag, which dwc_otg driver is
> passing for controller initialization, supports only high speed. Please
> find below the structure controller initialization.
>
> static const struct hc_driver dwc_otg_hc_driver = {
> .description = dwc_otg_hcd_name,
> .product_desc = "DWC OTG Controller",
> .hcd_priv_size = sizeof(struct dwc_hcd),
> .irq = dwc_otg_hcd_irq,
> .flags = HCD_MEMORY | HCD_USB2,
> .start = dwc_otg_hcd_start,
> .stop = dwc_otg_hcd_stop,
> .urb_enqueue = dwc_otg_hcd_urb_enqueue,
> .urb_dequeue = dwc_otg_hcd_urb_dequeue,
> .endpoint_disable = dwc_otg_hcd_endpoint_disable,
> .get_frame_number = dwc_otg_hcd_get_frame_number,
> .hub_status_data = dwc_otg_hcd_hub_status_data,
> .hub_control = dwc_otg_hcd_hub_control,
> .bus_suspend = dwc_otg_hcd_suspend,
> .bus_resume = dwc_otg_hcd_resume,
> };
>
>
> You can find it in on
> https://lkml.org/lkml/2012/5/3/170 also.
>
> In the above structure the flag shows, it only support USB2 devices.
No, that's not what HCD_USB2 means. It means the controller supports
version 2 of the USB protocol and it indicates the controller's maximum
speed.
Don't forget, USB-2 and even USB-1.1 controllers will support USB-3
devices. (They will not be able to communicate at SuperSpeed, but they
will be able to communicate.)
> Now I need to support both full speed as well as high speed devices. So my
> questions are:-
> 1. What all changes I need to do to get Full speed support ?
Not knowing anything about the dwc hardware, I can't answer this
question.
> 2. Is there any flag available which will solve my limitation ? (start
> supporting full speed as well as high speed)
This has nothing to do with flags. Adding a flag to your driver won't
magically enable it to handle full speed communications.
Alan Stern
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