usb: gadget: use a computation macro for INT endpoint interval

The 5+4 magic for HS tries to aim 32ms which is also what is intended
with 1 << 5 for FS. This little macro should make this easier to
understand.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Felipe Balbi <balbi@ti.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/include/linux/usb/composite.h b/include/linux/usb/composite.h
index f8dda0621800..8634a127bdd3 100644
--- a/include/linux/usb/composite.h
+++ b/include/linux/usb/composite.h
@@ -38,6 +38,7 @@
 #include <linux/version.h>
 #include <linux/usb/ch9.h>
 #include <linux/usb/gadget.h>
+#include <linux/log2.h>
 
 /*
  * USB function drivers should return USB_GADGET_DELAYED_STATUS if they
@@ -51,6 +52,7 @@
 /* big enough to hold our biggest descriptor */
 #define USB_COMP_EP0_BUFSIZ     1024
 
+#define USB_MS_TO_HS_INTERVAL(x)        (ilog2((x * 1000 / 125)) + 1)
 struct usb_configuration;
 
 /**