usb/core: use bin2bcd() for bcdDevice in RH

The kernel's version number is used as decimal in the bcdDevice field of
the RH descriptor. For kernel version v3.12 we would see 3.0c in lsusb.
I am not sure how important it is to stick with bcd values since this is
this way since we started git history and nobody complained (however back
then we reported only 2.6).

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/core/hcd.c

@@ -22,6 +22,7 @@
  * Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  */
 
+#include <linux/bcd.h>
 #include <linux/module.h>
 #include <linux/version.h>
 #include <linux/kernel.h>
@@ -123,9 +124,8 @@ static inline int is_root_hub(struct usb_device *udev)
  */
 
 /*-------------------------------------------------------------------------*/
-
-#define KERNEL_REL	((LINUX_VERSION_CODE >> 16) & 0x0ff)
-#define KERNEL_VER	((LINUX_VERSION_CODE >> 8) & 0x0ff)
+#define KERNEL_REL	bin2bcd(((LINUX_VERSION_CODE >> 16) & 0x0ff))
+#define KERNEL_VER	bin2bcd(((LINUX_VERSION_CODE >> 8) & 0x0ff))
 
 /* usb 3.0 root hub device descriptor */
 static const u8 usb3_rh_dev_descriptor[18] = {

include/linux/bcd.h

@@ -3,7 +3,20 @@
 
 #include <linux/compiler.h>
 
-unsigned bcd2bin(unsigned char val) __attribute_const__;
-unsigned char bin2bcd(unsigned val) __attribute_const__;
+#define bcd2bin(x)					\
+		(__builtin_constant_p((u8 )(x)) ?	\
+		const_bcd2bin(x) :			\
+		_bcd2bin(x))
+
+#define bin2bcd(x)					\
+		(__builtin_constant_p((u8 )(x)) ?	\
+		const_bin2bcd(x) :			\
+		_bin2bcd(x))
+
+#define const_bcd2bin(x)	(((x) & 0x0f) + ((x) >> 4) * 10)
+#define const_bin2bcd(x)	((((x) / 10) << 4) + (x) % 10)
+
+unsigned _bcd2bin(unsigned char val) __attribute_const__;
+unsigned char _bin2bcd(unsigned val) __attribute_const__;
 
 #endif /* _BCD_H */

lib/bcd.c

@@ -1,14 +1,14 @@
 #include <linux/bcd.h>
 #include <linux/export.h>
 
-unsigned bcd2bin(unsigned char val)
+unsigned _bcd2bin(unsigned char val)
 {
 	return (val & 0x0f) + (val >> 4) * 10;
 }
-EXPORT_SYMBOL(bcd2bin);
+EXPORT_SYMBOL(_bcd2bin);
 
-unsigned char bin2bcd(unsigned val)
+unsigned char _bin2bcd(unsigned val)
 {
 	return ((val / 10) << 4) + val % 10;
 }
-EXPORT_SYMBOL(bin2bcd);
+EXPORT_SYMBOL(_bin2bcd);