[PATCH v4 18/43] usb: gadget: composite: usb_get_endpoint_address() function

[Robert Baldyga <r.baldyga@samsung.com>]

Introduce function returning address of given endpoint within the function.
This value can be useful during preparation of class or vendor specific
descriptors in prep_vendor_descs() callback. It can be also necessary
to handle some class or vendor specific setup requests.

Signed-off-by: Robert Baldyga <r.baldyga@samsung.com>
---
 drivers/usb/gadget/composite.c | 20 ++++++++++++++++++++
 include/linux/usb/composite.h  |  2 ++
 2 files changed, 22 insertions(+)

diff --git a/drivers/usb/gadget/composite.c b/drivers/usb/gadget/composite.c
index 7e3721d..417e2f9 100644
--- a/drivers/usb/gadget/composite.c
+++ b/drivers/usb/gadget/composite.c
@@ -688,6 +688,26 @@ int usb_get_interface_id(struct usb_function *f, int i)
 }
 EXPORT_SYMBOL_GPL(usb_get_interface_id);
 
+int usb_get_endpoint_address(struct usb_function *f, int i, int a, int e)
+{
+	struct usb_composite_ep *ep;
+
+	if (!f->descs)
+		return -ENODEV;
+	if (f->descs->intfs_num <= i)
+		return -ENODEV;
+	if (f->descs->intfs[i]->altsets_num <= a)
+		return -ENODEV;
+	if (f->descs->intfs[i]->altsets[a]->eps_num <= e)
+		return -ENODEV;
+	ep = f->descs->intfs[i]->altsets[a]->eps[e];
+	if (!ep->ep)
+		return -ENODEV;
+
+	return ep->ep->address;
+}
+EXPORT_SYMBOL_GPL(usb_get_endpoint_address);
+
 /**
  * usb_function_get_ep - obtains endpoint of given index from active
  *	altsetting of given interface
diff --git a/include/linux/usb/composite.h b/include/linux/usb/composite.h
index b2fb260..b6f1e0cc 100644
--- a/include/linux/usb/composite.h
+++ b/include/linux/usb/composite.h
@@ -427,6 +427,8 @@ int usb_ep_add_vendor_desc(struct usb_function *f, int i, int a, int e,
 
 int usb_get_interface_id(struct usb_function *f, int i);
 
+int usb_get_endpoint_address(struct usb_function *f, int i, int a, int e);
+
 struct usb_ep *usb_function_get_ep(struct usb_function *f, int intf, int ep);
 
 int usb_interface_id(struct usb_configuration *, struct usb_function *);
-- 
1.9.1