drm/tve200: Use drm_fbdev_generic_setup()

The CMA helper is already using the drm_fb_helper_generic_probe part of
the generic fbdev emulation. This patch makes full use of the generic
fbdev emulation by using its drm_client callbacks. This means that
drm_mode_config_funcs->output_poll_changed and drm_driver->lastclose are
now handled by the emulation code. Additionally fbdev unregister happens
automatically on drm_dev_unregister().

The drm_fbdev_generic_setup() call is put after drm_dev_register() in the
driver. This is done to highlight the fact that fbdev emulation is an
internal client that makes use of the driver, it is not part of the
driver as such. If fbdev setup fails, an error is printed, but the driver
succeeds probing.

Cc: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20180908134648.2582-18-noralf@tronnes.org

drivers/gpu/drm/tve200/tve200_drv.c

@@ -126,12 +126,6 @@ static int tve200_modeset_init(struct drm_device *dev)
 	}
 
 	drm_mode_config_reset(dev);
-
-	/*
-	 * Passing in 16 here will make the RGB656 mode the default
-	 * Passing in 32 will use XRGB8888 mode
-	 */
-	drm_fb_cma_fbdev_init(dev, 16, 0);
 	drm_kms_helper_poll_init(dev);
 
 	goto finish;
@@ -149,7 +143,6 @@ DEFINE_DRM_GEM_CMA_FOPS(drm_fops);
 static struct drm_driver tve200_drm_driver = {
 	.driver_features =
 		DRIVER_MODESET | DRIVER_GEM | DRIVER_PRIME | DRIVER_ATOMIC,
-	.lastclose = drm_fb_helper_lastclose,
 	.ioctls = NULL,
 	.fops = &drm_fops,
 	.name = "tve200",
@@ -245,6 +238,12 @@ static int tve200_probe(struct platform_device *pdev)
 	if (ret < 0)
 		goto clk_disable;
 
+	/*
+	 * Passing in 16 here will make the RGB565 mode the default
+	 * Passing in 32 will use XRGB8888 mode
+	 */
+	drm_fbdev_generic_setup(drm, 16);
+
 	return 0;
 
 clk_disable:
@@ -260,7 +259,6 @@ static int tve200_remove(struct platform_device *pdev)
 	struct tve200_drm_dev_private *priv = drm->dev_private;
 
 	drm_dev_unregister(drm);
-	drm_fb_cma_fbdev_fini(drm);
 	if (priv->panel)
 		drm_panel_bridge_remove(priv->bridge);
 	drm_mode_config_cleanup(drm);