USB OTG: add support for ulpi connected external transceivers

This adds support for OTG transceivers directly connected to the ULPI
interface. In particular, the following details are added

- a struct for low level io functions (read/write)
- a priv field to be used as 'viewport' by low level access functions
- an (*init) and (*shutdown) callbacks, along with static inline helpers
- a (*set_vbus) callback to switch the port power on and off
- a flags field for per-transceiver settings
- some defines for the flags bitmask to configure platform specific
details

Signed-off-by: Daniel Mack <[e-mail]>
Cc: Heikki Krogerus <[e-mail]>
Cc: David Brownell <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

include/linux/usb/otg.h

···
 	OTG_STATE_A_VBUS_ERR,
 };
 
+#define USB_OTG_PULLUP_ID		(1 << 0)
+#define USB_OTG_PULLDOWN_DP		(1 << 1)
+#define USB_OTG_PULLDOWN_DM		(1 << 2)
+#define USB_OTG_EXT_VBUS_INDICATOR	(1 << 3)
+#define USB_OTG_DRV_VBUS		(1 << 4)
+#define USB_OTG_DRV_VBUS_EXT		(1 << 5)
+
+struct otg_transceiver;
+
+/* for transceivers connected thru an ULPI interface, the user must
+ * provide access ops
+ */
+struct otg_io_access_ops {
+	int (*read)(struct otg_transceiver *otg, u32 reg);
+	int (*write)(struct otg_transceiver *otg, u32 val, u32 reg);
+};
+
 /*
  * the otg driver needs to interact with both device side and host side
  * usb controllers.  it decides which controller is active at a given
···
 struct otg_transceiver {
 	struct device		*dev;
 	const char		*label;
+	unsigned int		 flags;
 
 	u8			default_a;
 	enum usb_otg_state	state;
···
 	struct usb_bus		*host;
 	struct usb_gadget	*gadget;
 
+	struct otg_io_access_ops	*io_ops;
+	void __iomem			*io_priv;
+
 	/* to pass extra port status to the root hub */
 	u16			port_status;
 	u16			port_change;
+
+	/* initialize/shutdown the OTG controller */
+	int	(*init)(struct otg_transceiver *otg);
+	void	(*shutdown)(struct otg_transceiver *otg);
 
 	/* bind/unbind the host controller */
 	int	(*set_host)(struct otg_transceiver *otg,
···
 	/* effective for B devices, ignored for A-peripheral */
 	int	(*set_power)(struct otg_transceiver *otg,
 				unsigned mA);
+
+	/* effective for A-peripheral, ignored for B devices */
+	int	(*set_vbus)(struct otg_transceiver *otg,
+				bool enabled);
 
 	/* for non-OTG B devices: set transceiver into suspend mode */
 	int	(*set_suspend)(struct otg_transceiver *otg,
···
 extern void usb_nop_xceiv_register(void);
 extern void usb_nop_xceiv_unregister(void);
 
+/* helpers for direct access thru low-level io interface */
+static inline int otg_io_read(struct otg_transceiver *otg, u32 reg)
+{
+	if (otg->io_ops && otg->io_ops->read)
+		return otg->io_ops->read(otg, reg);
+
+	return -EINVAL;
+}
+
+static inline int otg_io_write(struct otg_transceiver *otg, u32 reg, u32 val)
+{
+	if (otg->io_ops && otg->io_ops->write)
+		return otg->io_ops->write(otg, reg, val);
+
+	return -EINVAL;
+}
+
+static inline int
+otg_init(struct otg_transceiver *otg)
+{
+	if (otg->init)
+		return otg->init(otg);
+
+	return 0;
+}
+
+static inline void
+otg_shutdown(struct otg_transceiver *otg)
+{
+	if (otg->shutdown)
+		otg->shutdown(otg);
+}
 
 /* for usb host and peripheral controller drivers */
 extern struct otg_transceiver *otg_get_transceiver(void);
···
 	return otg->start_hnp(otg);
 }
 
+/* Context: can sleep */
+static inline int
+otg_set_vbus(struct otg_transceiver *otg, bool enabled)
+{
+	return otg->set_vbus(otg, enabled);
+}
 
 /* for HCDs */
 static inline int
···
 {
 	return otg->set_host(otg, host);
 }
-
 
 /* for usb peripheral controller drivers */