usb: otg: move usb_otg_state_string to usb-common.c

otg.c only had a single function definition
which might make more sense to be placed in
usb-common.c. While doing that, we also delete
otg.c since it's now empty.

Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/otg/Makefile

@@ -5,9 +5,6 @@
 ccflags-$(CONFIG_USB_DEBUG)		:= -DDEBUG
 ccflags-$(CONFIG_USB_GADGET_DEBUG)	+= -DDEBUG
 
-# infrastructure
-obj-$(CONFIG_USB_OTG_UTILS)	+= otg.o
-
 # transceiver drivers
 obj-$(CONFIG_USB_GPIO_VBUS)	+= gpio_vbus.o
 obj-$(CONFIG_ISP1301_OMAP)	+= isp1301_omap.o

drivers/usb/usb-common.c

@@ -14,6 +14,32 @@
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/usb/ch9.h>
+#include <linux/usb/otg.h>
+
+const char *usb_otg_state_string(enum usb_otg_state state)
+{
+	static const char *const names[] = {
+		[OTG_STATE_A_IDLE] = "a_idle",
+		[OTG_STATE_A_WAIT_VRISE] = "a_wait_vrise",
+		[OTG_STATE_A_WAIT_BCON] = "a_wait_bcon",
+		[OTG_STATE_A_HOST] = "a_host",
+		[OTG_STATE_A_SUSPEND] = "a_suspend",
+		[OTG_STATE_A_PERIPHERAL] = "a_peripheral",
+		[OTG_STATE_A_WAIT_VFALL] = "a_wait_vfall",
+		[OTG_STATE_A_VBUS_ERR] = "a_vbus_err",
+		[OTG_STATE_B_IDLE] = "b_idle",
+		[OTG_STATE_B_SRP_INIT] = "b_srp_init",
+		[OTG_STATE_B_PERIPHERAL] = "b_peripheral",
+		[OTG_STATE_B_WAIT_ACON] = "b_wait_acon",
+		[OTG_STATE_B_HOST] = "b_host",
+	};
+
+	if (state < 0 || state >= ARRAY_SIZE(names))
+		return "UNDEFINED";
+
+	return names[state];
+}
+EXPORT_SYMBOL_GPL(usb_otg_state_string);
 
 const char *usb_speed_string(enum usb_device_speed speed)
 {

include/linux/usb/otg.h

@@ -36,14 +36,7 @@ struct usb_otg {
 
 };
 
-#ifdef CONFIG_USB_OTG_UTILS
 extern const char *usb_otg_state_string(enum usb_otg_state state);
-#else
-static inline const char *usb_otg_state_string(enum usb_otg_state state)
-{
-	return NULL;
-}
-#endif
 
 /* Context: can sleep */
 static inline int