media: imx-pxp: Add media controller support

Register a media device for the PXP, using the v4l2-mem2mem MC
infrastructure to populate the media graph. No media device operation is
implemented, the main use of the MC API is to allow consistent discovery
of media devices for userspace.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Michael Tretter <m.tretter@pengutronix.de>
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

drivers/media/platform/nxp/imx-pxp.c

@@ -24,6 +24,7 @@
 #include <linux/sched.h>
 #include <linux/slab.h>
 
+#include <media/media-device.h>
 #include <media/v4l2-ctrls.h>
 #include <media/v4l2-device.h>
 #include <media/v4l2-event.h>
@@ -201,6 +202,9 @@ struct pxp_pdata {
 struct pxp_dev {
 	struct v4l2_device	v4l2_dev;
 	struct video_device	vfd;
+#ifdef CONFIG_MEDIA_CONTROLLER
+	struct media_device	mdev;
+#endif
 
 	struct clk		*clk;
 	void __iomem		*mmio;
@@ -1815,8 +1819,34 @@ static int pxp_probe(struct platform_device *pdev)
 		goto err_m2m;
 	}
 
+#ifdef CONFIG_MEDIA_CONTROLLER
+	dev->mdev.dev = &pdev->dev;
+	strscpy(dev->mdev.model, MEM2MEM_NAME, sizeof(dev->mdev.model));
+	media_device_init(&dev->mdev);
+	dev->v4l2_dev.mdev = &dev->mdev;
+
+	ret = v4l2_m2m_register_media_controller(dev->m2m_dev, vfd,
+						 MEDIA_ENT_F_PROC_VIDEO_PIXEL_FORMATTER);
+	if (ret) {
+		dev_err(&pdev->dev, "Failed to initialize media device\n");
+		goto err_vfd;
+	}
+
+	ret = media_device_register(&dev->mdev);
+	if (ret) {
+		dev_err(&pdev->dev, "Failed to register media device\n");
+		goto err_m2m_mc;
+	}
+#endif
+
 	return 0;
 
+#ifdef CONFIG_MEDIA_CONTROLLER
+err_m2m_mc:
+	v4l2_m2m_unregister_media_controller(dev->m2m_dev);
+err_vfd:
+	video_unregister_device(vfd);
+#endif
 err_m2m:
 	v4l2_m2m_release(dev->m2m_dev);
 err_v4l2:
@@ -1837,6 +1867,11 @@ static int pxp_remove(struct platform_device *pdev)
 	clk_disable_unprepare(dev->clk);
 
 	v4l2_info(&dev->v4l2_dev, "Removing " MEM2MEM_NAME);
+
+#ifdef CONFIG_MEDIA_CONTROLLER
+	media_device_unregister(&dev->mdev);
+	v4l2_m2m_unregister_media_controller(dev->m2m_dev);
+#endif
 	video_unregister_device(&dev->vfd);
 	v4l2_m2m_release(dev->m2m_dev);
 	v4l2_device_unregister(&dev->v4l2_dev);