On 10/05/16 06:14, Peter Chen wrote: > On Mon, May 09, 2016 at 12:45:38PM +0300, Roger Quadros wrote: >> On 06/05/16 12:41, Peter Chen wrote: >>> On Mon, May 02, 2016 at 03:18:46PM +0300, Roger Quadros wrote: >>>> The OTG core will use struct otg_hcd_ops to interface >>>> with the HCD controller. >>>> >>>> The main purpose of this interface is to avoid directly >>>> calling HCD APIs from the OTG core as they >>>> wouldn't be defined in the built-in symbol table if >>>> CONFIG_USB is m. >>>> >>>> Signed-off-by: Roger Quadros <rogerq@xxxxxx> >>>> Acked-by: Peter Chen <peter.chen@xxxxxxx> >>> >>> Roger, after thinking more, I still think current dependency between >>> OTG, HCD and gadget are too complicated. Since the OTG can't work >>> if it is built as module, I suggest letting OTG depends on HCD && >>> USB_GADGET, and it is a boolean, in that case, we don't need to >>> export any HCD and gadget ops, things will be much simpler. >>> What's your opinion? >> >> How will it work if HCD and USB_GADGET are modules and OTG is built-in? >> > > The OTG will not be compiled at this situation, since it is boolean. > In fact, like I mentioned at above, OTG or USB function can't work if > it is built as module. Isn't this a limitation? As per the current implementation dual role works fine even with both USB_GADGET and HCD as module. In the real world it is unlikely that GADGET and HCD will be built-in. cheers, -roger > > Peter >> cheers, >> -roger >> >>> >>> Peter >>> >>>> --- >>>> include/linux/usb/hcd.h | 24 ++++++++++++++++++++++++ >>>> 1 file changed, 24 insertions(+) >>>> >>>> diff --git a/include/linux/usb/hcd.h b/include/linux/usb/hcd.h >>>> index b98f831..861ccaa 100644 >>>> --- a/include/linux/usb/hcd.h >>>> +++ b/include/linux/usb/hcd.h >>>> @@ -399,6 +399,30 @@ struct hc_driver { >>>> >>>> }; >>>> >>>> +/** >>>> + * struct otg_hcd_ops - Interface between OTG core and HCD >>>> + * >>>> + * Provided by the HCD core to allow the OTG core to interface with the HCD >>>> + * >>>> + * @add: function to add the HCD >>>> + * @remove: function to remove the HCD >>>> + * @usb_bus_start_enum: function to immediately start bus enumeration >>>> + * @usb_control_msg: function to build and send of a control urb >>>> + * @usb_hub_find_child: function to get pointer to the child device >>>> + */ >>>> +struct otg_hcd_ops { >>>> + int (*add)(struct usb_hcd *hcd, >>>> + unsigned int irqnum, unsigned long irqflags); >>>> + void (*remove)(struct usb_hcd *hcd); >>>> + int (*usb_bus_start_enum)(struct usb_bus *bus, unsigned int port_num); >>>> + int (*usb_control_msg)(struct usb_device *dev, unsigned int pipe, >>>> + __u8 request, __u8 requesttype, __u16 value, >>>> + __u16 index, void *data, __u16 size, >>>> + int timeout); >>>> + struct usb_device * (*usb_hub_find_child)(struct usb_device *hdev, >>>> + int port1); >>>> +}; >>>> + >>>> static inline int hcd_giveback_urb_in_bh(struct usb_hcd *hcd) >>>> { >>>> return hcd->driver->flags & HCD_BH; >>>> -- >>>> 2.7.4 >>>> >>>> -- >>>> To unsubscribe from this list: send the line "unsubscribe linux-usb" in >>>> the body of a message to majordomo@xxxxxxxxxxxxxxx >>>> More majordomo info at http://vger.kernel.org/majordomo-info.html >>> > -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html