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>

drivers/usb/gadget/f_acm.c

@@ -87,7 +87,7 @@ static inline struct f_acm *port_to_acm(struct gserial *p)
 
 /* notification endpoint uses smallish and infrequent fixed-size messages */
 
-#define GS_LOG2_NOTIFY_INTERVAL		5	/* 1 << 5 == 32 msec */
+#define GS_NOTIFY_INTERVAL_MS		32
 #define GS_NOTIFY_MAXPACKET		10	/* notification + 2 bytes */
 
 /* interface and class descriptors: */
@@ -167,7 +167,7 @@ static struct usb_endpoint_descriptor acm_fs_notify_desc = {
 	.bEndpointAddress =	USB_DIR_IN,
 	.bmAttributes =		USB_ENDPOINT_XFER_INT,
 	.wMaxPacketSize =	cpu_to_le16(GS_NOTIFY_MAXPACKET),
-	.bInterval =		1 << GS_LOG2_NOTIFY_INTERVAL,
+	.bInterval =		GS_NOTIFY_INTERVAL_MS,
 };
 
 static struct usb_endpoint_descriptor acm_fs_in_desc = {
@@ -199,14 +199,13 @@ static struct usb_descriptor_header *acm_fs_function[] = {
 };
 
 /* high speed support: */
-
 static struct usb_endpoint_descriptor acm_hs_notify_desc = {
 	.bLength =		USB_DT_ENDPOINT_SIZE,
 	.bDescriptorType =	USB_DT_ENDPOINT,
 	.bEndpointAddress =	USB_DIR_IN,
 	.bmAttributes =		USB_ENDPOINT_XFER_INT,
 	.wMaxPacketSize =	cpu_to_le16(GS_NOTIFY_MAXPACKET),
-	.bInterval =		GS_LOG2_NOTIFY_INTERVAL+4,
+	.bInterval =		USB_MS_TO_HS_INTERVAL(GS_NOTIFY_INTERVAL_MS),
 };
 
 static struct usb_endpoint_descriptor acm_hs_in_desc = {

drivers/usb/gadget/f_ecm.c

@@ -91,7 +91,7 @@ static inline unsigned ecm_bitrate(struct usb_gadget *g)
  * encapsulated commands (vendor-specific, using control-OUT).
  */
 
-#define LOG2_STATUS_INTERVAL_MSEC	5	/* 1 << 5 == 32 msec */
+#define ECM_STATUS_INTERVAL_MS		32
 #define ECM_STATUS_BYTECOUNT		16	/* 8 byte header + data */
 
 
@@ -192,7 +192,7 @@ static struct usb_endpoint_descriptor fs_ecm_notify_desc = {
 	.bEndpointAddress =	USB_DIR_IN,
 	.bmAttributes =		USB_ENDPOINT_XFER_INT,
 	.wMaxPacketSize =	cpu_to_le16(ECM_STATUS_BYTECOUNT),
-	.bInterval =		1 << LOG2_STATUS_INTERVAL_MSEC,
+	.bInterval =		ECM_STATUS_INTERVAL_MS,
 };
 
 static struct usb_endpoint_descriptor fs_ecm_in_desc = {
@@ -239,7 +239,7 @@ static struct usb_endpoint_descriptor hs_ecm_notify_desc = {
 	.bEndpointAddress =	USB_DIR_IN,
 	.bmAttributes =		USB_ENDPOINT_XFER_INT,
 	.wMaxPacketSize =	cpu_to_le16(ECM_STATUS_BYTECOUNT),
-	.bInterval =		LOG2_STATUS_INTERVAL_MSEC + 4,
+	.bInterval =		USB_MS_TO_HS_INTERVAL(ECM_STATUS_INTERVAL_MS),
 };
 
 static struct usb_endpoint_descriptor hs_ecm_in_desc = {
@@ -288,7 +288,7 @@ static struct usb_endpoint_descriptor ss_ecm_notify_desc = {
 	.bEndpointAddress =	USB_DIR_IN,
 	.bmAttributes =		USB_ENDPOINT_XFER_INT,
 	.wMaxPacketSize =	cpu_to_le16(ECM_STATUS_BYTECOUNT),
-	.bInterval =		LOG2_STATUS_INTERVAL_MSEC + 4,
+	.bInterval =		USB_MS_TO_HS_INTERVAL(ECM_STATUS_INTERVAL_MS),
 };
 
 static struct usb_ss_ep_comp_descriptor ss_ecm_intr_comp_desc = {

drivers/usb/gadget/f_ncm.c

@@ -121,7 +121,7 @@ static struct usb_cdc_ncm_ntb_parameters ntb_parameters = {
  * waste less bandwidth.
  */
 
-#define LOG2_STATUS_INTERVAL_MSEC	5	/* 1 << 5 == 32 msec */
+#define NCM_STATUS_INTERVAL_MS		32
 #define NCM_STATUS_BYTECOUNT		16	/* 8 byte header + data */
 
 static struct usb_interface_assoc_descriptor ncm_iad_desc __initdata = {
@@ -230,7 +230,7 @@ static struct usb_endpoint_descriptor fs_ncm_notify_desc __initdata = {
 	.bEndpointAddress =	USB_DIR_IN,
 	.bmAttributes =		USB_ENDPOINT_XFER_INT,
 	.wMaxPacketSize =	cpu_to_le16(NCM_STATUS_BYTECOUNT),
-	.bInterval =		1 << LOG2_STATUS_INTERVAL_MSEC,
+	.bInterval =		NCM_STATUS_INTERVAL_MS,
 };
 
 static struct usb_endpoint_descriptor fs_ncm_in_desc __initdata = {
@@ -275,7 +275,7 @@ static struct usb_endpoint_descriptor hs_ncm_notify_desc __initdata = {
 	.bEndpointAddress =	USB_DIR_IN,
 	.bmAttributes =		USB_ENDPOINT_XFER_INT,
 	.wMaxPacketSize =	cpu_to_le16(NCM_STATUS_BYTECOUNT),
-	.bInterval =		LOG2_STATUS_INTERVAL_MSEC + 4,
+	.bInterval =		USB_MS_TO_HS_INTERVAL(NCM_STATUS_INTERVAL_MS),
 };
 static struct usb_endpoint_descriptor hs_ncm_in_desc __initdata = {
 	.bLength =		USB_DT_ENDPOINT_SIZE,

drivers/usb/gadget/f_rndis.c

@@ -101,7 +101,7 @@ static unsigned int bitrate(struct usb_gadget *g)
 /*
  */
 
-#define LOG2_STATUS_INTERVAL_MSEC	5	/* 1 << 5 == 32 msec */
+#define RNDIS_STATUS_INTERVAL_MS	32
 #define STATUS_BYTECOUNT		8	/* 8 bytes data */
 
 
@@ -190,7 +190,7 @@ static struct usb_endpoint_descriptor fs_notify_desc = {
 	.bEndpointAddress =	USB_DIR_IN,
 	.bmAttributes =		USB_ENDPOINT_XFER_INT,
 	.wMaxPacketSize =	cpu_to_le16(STATUS_BYTECOUNT),
-	.bInterval =		1 << LOG2_STATUS_INTERVAL_MSEC,
+	.bInterval =		RNDIS_STATUS_INTERVAL_MS,
 };
 
 static struct usb_endpoint_descriptor fs_in_desc = {
@@ -236,7 +236,7 @@ static struct usb_endpoint_descriptor hs_notify_desc = {
 	.bEndpointAddress =	USB_DIR_IN,
 	.bmAttributes =		USB_ENDPOINT_XFER_INT,
 	.wMaxPacketSize =	cpu_to_le16(STATUS_BYTECOUNT),
-	.bInterval =		LOG2_STATUS_INTERVAL_MSEC + 4,
+	.bInterval =		USB_MS_TO_HS_INTERVAL(RNDIS_STATUS_INTERVAL_MS)
 };
 
 static struct usb_endpoint_descriptor hs_in_desc = {
@@ -284,7 +284,7 @@ static struct usb_endpoint_descriptor ss_notify_desc = {
 	.bEndpointAddress =	USB_DIR_IN,
 	.bmAttributes =		USB_ENDPOINT_XFER_INT,
 	.wMaxPacketSize =	cpu_to_le16(STATUS_BYTECOUNT),
-	.bInterval =		LOG2_STATUS_INTERVAL_MSEC + 4,
+	.bInterval =		USB_MS_TO_HS_INTERVAL(RNDIS_STATUS_INTERVAL_MS)
 };
 
 static struct usb_ss_ep_comp_descriptor ss_intr_comp_desc = {

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;
 
 /**