USB: pxa27x_udc: add otg transceiver support

When a transceiver driver is used, no automatic udc enable
is done. The transceiver (OTG or not) should :
 - take care of VBus sensing
 - call usb_gadget_vbus_connect()
 - call usb_gadget_vbus_disconnect()

The pullup should remain within this driver's management,
either by gpio_pullup of udc_command() fields.
Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/gadget/Kconfig

@@ -254,6 +254,7 @@ config USB_PXA25X_SMALL
 config USB_GADGET_PXA27X
 	boolean "PXA 27x"
 	depends on ARCH_PXA && PXA27x
+	select USB_OTG_UTILS
 	help
 	   Intel's PXA 27x series XScale ARM v5TE processors include
 	   an integrated full speed USB 1.1 device controller.

drivers/usb/gadget/pxa27x_udc.c

@@ -1779,10 +1779,21 @@ int usb_gadget_register_driver(struct usb_gadget_driver *driver)
 	dev_dbg(udc->dev, "registered gadget driver '%s'\n",
 		driver->driver.name);
 
+	if (udc->transceiver) {
+		retval = otg_set_peripheral(udc->transceiver, &udc->gadget);
+		if (retval) {
+			dev_err(udc->dev, "can't bind to transceiver\n");
+			goto transceiver_fail;
+		}
+	}
+
 	if (should_enable_udc(udc))
 		udc_enable(udc);
 	return 0;
 
+transceiver_fail:
+	if (driver->unbind)
+		driver->unbind(&udc->gadget);
 bind_fail:
 	device_del(&udc->gadget.dev);
 add_fail:
@@ -1840,9 +1851,11 @@ int usb_gadget_unregister_driver(struct usb_gadget_driver *driver)
 	udc->driver = NULL;
 
 	device_del(&udc->gadget.dev);
-
 	dev_info(udc->dev, "unregistered gadget driver '%s'\n",
 		 driver->driver.name);
+
+	if (udc->transceiver)
+		return otg_set_peripheral(udc->transceiver, NULL);
 	return 0;
 }
 EXPORT_SYMBOL(usb_gadget_unregister_driver);
@@ -2359,6 +2372,7 @@ static int __init pxa_udc_probe(struct platform_device *pdev)
 
 	udc->dev = &pdev->dev;
 	udc->mach = pdev->dev.platform_data;
+	udc->transceiver = otg_get_transceiver();
 
 	gpio = udc->mach->gpio_pullup;
 	if (gpio_is_valid(gpio)) {
@@ -2431,6 +2445,9 @@ static int __exit pxa_udc_remove(struct platform_device *_dev)
 	if (gpio_is_valid(gpio))
 		gpio_free(gpio);
 
+	otg_put_transceiver(udc->transceiver);
+
+	udc->transceiver = NULL;
 	platform_set_drvdata(_dev, NULL);
 	the_controller = NULL;
 	clk_put(udc->clk);

drivers/usb/gadget/pxa27x_udc.h

@@ -26,6 +26,7 @@
 #include <linux/types.h>
 #include <linux/spinlock.h>
 #include <linux/io.h>
+#include <linux/usb/otg.h>
 
 /*
  * Register definitions
@@ -421,6 +422,7 @@ struct udc_stats {
  * @driver: bound gadget (zero, g_ether, g_file_storage, ...)
  * @dev: device
  * @mach: machine info, used to activate specific GPIO
+ * @transceiver: external transceiver to handle vbus sense and D+ pullup
  * @ep0state: control endpoint state machine state
  * @stats: statistics on udc usage
  * @udc_usb_ep: array of usb endpoints offered by the gadget
@@ -446,6 +448,7 @@ struct pxa_udc {
 	struct usb_gadget_driver		*driver;
 	struct device				*dev;
 	struct pxa2xx_udc_mach_info		*mach;
+	struct otg_transceiver			*transceiver;
 
 	enum ep0_state				ep0state;
 	struct udc_stats			stats;