usb: gadget: add 'quirk_zlp_not_supp' to usb_gadget

Due to some UDC controllers may not support zlp, usb gadget layer
needs to provide a generic way to inform gadget functions about non-standard
hardware limitations.

This patch adds 'quirk_zlp_not_supp' field to struct usb_gadget and helper
function gadget_is_zlp_supported(). It also sets 'quirk_zlp_not_supp'
to 1 in musb UDC driver, which has such limitation.

[ balbi@ti.com : make it build ]

Signed-off-by: Robert Baldyga <r.baldyga@samsung.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

1 files changed, 10 insertions, 0 deletions

diff --git a/include/linux/usb/gadget.h b/include/linux/usb/gadget.h
index f195a76548f6..353a72096dda 100644
--- a/include/linux/usb/gadget.h
+++ b/include/linux/usb/gadget.h
@@ -574,6 +574,7 @@ struct usb_gadget {
         unsigned                        quirk_ep_out_aligned_size:1;
         unsigned                        quirk_altset_not_supp:1;
         unsigned                        quirk_stall_not_supp:1;
+        unsigned                        quirk_zlp_not_supp:1;
         unsigned                        is_selfpowered:1;
         unsigned                        deactivated:1;
         unsigned                        connected:1;
@@ -631,6 +632,15 @@ static inline int gadget_is_stall_supported(struct usb_gadget *g)
 }
 
 /**
+ * gadget_is_zlp_supported - return true iff the hardware supports zlp
+ * @g: controller to check for quirk
+ */
+static inline int gadget_is_zlp_supported(struct usb_gadget *g)
+{
+        return !g->quirk_zlp_not_supp;
+}
+
+/**
  * gadget_is_dualspeed - return true iff the hardware handles high speed
  * @g: controller that might support both high and full speeds
  */