drm: add usb framework

This adds an initial framework to plug USB graphics devices
into the drm/kms subsystem.

I've started writing a displaylink driver using this interface.
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/Makefile

@@ -12,7 +12,7 @@ drm-y       :=	drm_auth.o drm_buffer.o drm_bufs.o drm_cache.o \
 		drm_platform.o drm_sysfs.o drm_hashtab.o drm_sman.o drm_mm.o \
 		drm_crtc.o drm_modes.o drm_edid.o \
 		drm_info.o drm_debugfs.o drm_encoder_slave.o \
-		drm_trace_points.o drm_global.o
+		drm_trace_points.o drm_global.o drm_usb.o
 
 drm-$(CONFIG_COMPAT) += drm_ioc32.o
 

drivers/gpu/drm/drm_stub.c

@@ -463,6 +463,7 @@ void drm_put_dev(struct drm_device *dev)
 
 	drm_put_minor(&dev->primary);
 
+	list_del(&dev->driver_item);
 	if (dev->devname) {
 		kfree(dev->devname);
 		dev->devname = NULL;

drivers/gpu/drm/drm_usb.c

+#include "drmP.h"
+#include <linux/usb.h>
+
+#ifdef CONFIG_USB
+int drm_get_usb_dev(struct usb_interface *interface,
+		    const struct usb_device_id *id,
+		    struct drm_driver *driver)
+{
+	struct drm_device *dev;
+	struct usb_device *usbdev;
+	int ret;
+
+	DRM_DEBUG("\n");
+
+	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+	if (!dev)
+		return -ENOMEM;
+
+	usbdev = interface_to_usbdev(interface);
+	dev->usbdev = usbdev;
+	dev->dev = &usbdev->dev;
+
+	mutex_lock(&drm_global_mutex);
+
+	ret = drm_fill_in_dev(dev, NULL, driver);
+	if (ret) {
+		printk(KERN_ERR "DRM: Fill_in_dev failed.\n");
+		goto err_g1;
+	}
+
+	usb_set_intfdata(interface, dev);
+	ret = drm_get_minor(dev, &dev->control, DRM_MINOR_CONTROL);
+	if (ret)
+		goto err_g1;
+
+	ret = drm_get_minor(dev, &dev->primary, DRM_MINOR_LEGACY);
+	if (ret)
+		goto err_g2;
+
+	if (dev->driver->load) {
+		ret = dev->driver->load(dev, 0);
+		if (ret)
+			goto err_g3;
+	}
+
+	/* setup the grouping for the legacy output */
+	ret = drm_mode_group_init_legacy_group(dev,
+					       &dev->primary->mode_group);
+	if (ret)
+		goto err_g3;
+
+	list_add_tail(&dev->driver_item, &driver->device_list);
+
+	mutex_unlock(&drm_global_mutex);
+
+	DRM_INFO("Initialized %s %d.%d.%d %s on minor %d\n",
+		 driver->name, driver->major, driver->minor, driver->patchlevel,
+		 driver->date, dev->primary->index);
+
+	return 0;
+
+err_g3:
+	drm_put_minor(&dev->primary);
+err_g2:
+	drm_put_minor(&dev->control);
+err_g1:
+	kfree(dev);
+	mutex_unlock(&drm_global_mutex);
+	return ret;
+
+}
+EXPORT_SYMBOL(drm_get_usb_dev);
+
+static int drm_usb_get_irq(struct drm_device *dev)
+{
+	return 0;
+}
+
+static const char *drm_usb_get_name(struct drm_device *dev)
+{
+	return "USB";
+}
+
+static int drm_usb_set_busid(struct drm_device *dev,
+			       struct drm_master *master)
+{
+	return 0;
+}
+
+static struct drm_bus drm_usb_bus = {
+	.bus_type = DRIVER_BUS_USB,
+	.get_irq = drm_usb_get_irq,
+	.get_name = drm_usb_get_name,
+	.set_busid = drm_usb_set_busid,
+};
+    
+int drm_usb_init(struct drm_driver *driver, struct usb_driver *udriver)
+{
+	int res;
+	DRM_DEBUG("\n");
+
+	INIT_LIST_HEAD(&driver->device_list);
+	driver->kdriver.usb = udriver;
+	driver->bus = &drm_usb_bus;
+
+	res = usb_register(udriver);
+	return res;
+}
+EXPORT_SYMBOL(drm_usb_init);
+
+void drm_usb_exit(struct drm_driver *driver,
+		  struct usb_driver *udriver)
+{
+	usb_deregister(udriver);
+}
+EXPORT_SYMBOL(drm_usb_exit);
+#endif

include/drm/drmP.h

@@ -925,6 +925,7 @@ struct drm_driver {
 	union {
 		struct pci_driver *pci;
 		struct platform_device *platform_device;
+		struct usb_driver *usb;
 	} kdriver;
 	struct drm_bus *bus;
 
@@ -1130,6 +1131,7 @@ struct drm_device {
 #endif
 
 	struct platform_device *platformdev; /**< Platform device struture */
+	struct usb_device *usbdev;
 
 	struct drm_sg_mem *sg;	/**< Scatter gather memory */
 	int num_crtcs;                  /**< Number of CRTCs on this device */

include/drm/drm_usb.h

+#ifndef DRM_USB_H
+#define DRM_USB_H
+
+#include <drmP.h>
+
+#include <linux/usb.h>
+
+extern int drm_usb_init(struct drm_driver *driver, struct usb_driver *udriver);
+extern void drm_usb_exit(struct drm_driver *driver, struct usb_driver *udriver);
+
+int drm_get_usb_dev(struct usb_interface *interface,
+		    const struct usb_device_id *id,
+		    struct drm_driver *driver);
+
+#endif