Implement direct pineview backlight control.

drivers/gpu/drm/i915/i915_dma.c

 /* i915_dma.c -- DMA support for the I915 -*- linux-c -*-
  */
 /*
  * Copyright 2003 Tungsten Graphics, Inc., Cedar Park, Texas.
  * All Rights Reserved.
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
  * copy of this software and associated documentation files (the
  * "Software"), to deal in the Software without restriction, including
  * without limitation the rights to use, copy, modify, merge, publish,
@@ skipping 1486 matching lines @@
                         DRM_ERROR("failed to init modeset\n");
                         goto out_workqueue_free;
                 }
         }
 
         /* Must be done after probing outputs */
         intel_opregion_init(dev, 0);
 
         setup_timer(&dev_priv->hangcheck_timer, i915_hangcheck_elapsed,
                     (unsigned long) dev);
+
+        i915_backlight_init(dev);
+
         return 0;
 
 out_workqueue_free:
         destroy_workqueue(dev_priv->wq);
 out_iomapfree:
         io_mapping_free(dev_priv->mm.gtt_mapping);
 out_rmmap:
         iounmap(dev_priv->regs);
 put_bridge:
         pci_dev_put(dev_priv->bridge_dev);
 free_priv:
         kfree(dev_priv);
         return ret;
 }
 
 int i915_driver_unload(struct drm_device *dev)
 {
         struct drm_i915_private *dev_priv = dev->dev_private;
 
+        i915_backlight_exit(dev);
+
         destroy_workqueue(dev_priv->wq);
         del_timer_sync(&dev_priv->hangcheck_timer);
 
         io_mapping_free(dev_priv->mm.gtt_mapping);
         if (dev_priv->mm.gtt_mtrr >= 0) {
                 mtrr_del(dev_priv->mm.gtt_mtrr, dev->agp->base,
                          dev->agp->agp_info.aper_size * 1024 * 1024);
                 dev_priv->mm.gtt_mtrr = -1;
         }
 
@@ skipping 154 matching lines @@
  *
  * \param dev   The device to be tested.
  *
  * \returns
  * A value of 1 is always retured to indictate every i9x5 is AGP.
  */
 int i915_driver_device_is_agp(struct drm_device * dev)
 {
         return 1;
 }