musb: Add Phy programming for using external Vbus

MUSB PHY on OMAP3EVM Rev >= E uses external Vbus supply to support
500mA of power.We need to program MUSB PHY to use external Vbus
for this purpose.

Adding 'extvbus' member in musb_config structure which should be set
by all the boards where MUSB interface is using external Vbus supply.

Also added ULPI bus control register read/write abstraction for
Blackfin processor as it doesn't have ULPI registers.

CC: Remy Bohmer <linux@bohmer.net>
Signed-off-by: Ajay Kumar Gupta <ajay.gupta@ti.com>
Acked-by: Mike Frysinger <vapier@gentoo.org>

drivers/usb/musb/musb_core.c

@@ -34,6 +34,7 @@ void musb_start(void)
 {
 #if defined(CONFIG_MUSB_HCD)
 	u8 devctl;
+	u8 busctl;
 #endif
 
 	/* disable all interrupts */
@@ -45,6 +46,12 @@ void musb_start(void)
 	/* put into basic highspeed mode and start session */
 	writeb(MUSB_POWER_HSENAB, &musbr->power);
 #if defined(CONFIG_MUSB_HCD)
+	/* Program PHY to use EXT VBUS if required */
+	if (musb_cfg.extvbus == 1) {
+		busctl = musb_read_ulpi_buscontrol(musbr);
+		musb_write_ulpi_buscontrol(musbr, busctl | ULPI_USE_EXTVBUS);
+	}
+
 	devctl = readb(&musbr->devctl);
 	writeb(devctl | MUSB_DEVCTL_SESSION, &musbr->devctl);
 #endif

drivers/usb/musb/musb_core.h

@@ -112,7 +112,10 @@ struct musb_regs {
 	u16	rxfifoadd;
 	u32	vcontrol;
 	u16	hwvers;
-	u16	reserved2[5];
+	u16	reserved2a[1];
+	u8	ulpi_busctl;
+	u8	reserved2b[1];
+	u16	reserved2[3];
 	u8	epinfo;
 	u8	raminfo;
 	u8	linkinfo;
@@ -181,6 +184,10 @@ struct musb_regs {
 #define MUSB_DEVCTL_HR		0x02
 #define MUSB_DEVCTL_SESSION	0x01
 
+/* ULPI VBUSCONTROL */
+#define ULPI_USE_EXTVBUS	0x01
+#define ULPI_USE_EXTVBUSIND	0x02
+
 /* TESTMODE */
 #define MUSB_TEST_FORCE_HOST	0x80
 #define MUSB_TEST_FIFO_ACCESS	0x40
@@ -341,6 +348,7 @@ struct musb_config {
 	struct	musb_regs	*regs;
 	u32			timeout;
 	u8			musb_speed;
+	u8			extvbus;
 };
 
 /* externally defined data */
@@ -361,6 +369,26 @@ extern void read_fifo(u8 ep, u32 length, void *fifo_data);
 # define readb(addr)     (u8)bfin_read16(addr)
 # undef  writeb
 # define writeb(b, addr) bfin_write16(addr, b)
+/*
+ * The USB PHY on current Blackfin processors is a UTMI+ level 2 PHY.
+ * However, it has no ULPI support - so there are no registers at all.
+ * That means accesses to ULPI_BUSCONTROL have to be abstracted away.
+ */
+static inline u8 musb_read_ulpi_buscontrol(struct musb_regs *musbr)
+{
+	return 0;
+}
+static inline void musb_write_ulpi_buscontrol(struct musb_regs *musbr, u8 val)
+{}
+#else
+static inline u8 musb_read_ulpi_buscontrol(struct musb_regs *musbr)
+{
+	return readb(&musbr->ulpi_busctl);
+}
+static inline void musb_write_ulpi_buscontrol(struct musb_regs *musbr, u8 val)
+{
+	writeb(val, &musbr->ulpi_busctl);
+}
 #endif
 
 #endif	/* __MUSB_HDRC_DEFS_H__ */