drm/xlnx: Use devm_drm_dev_alloc

Gets rid of drmm_add_final_kfree, which I want to unexport so that it
stops confusion people about this transitional state of rolling drm
managed memory out.

This also fixes the missing drm_dev_put in the error path of the probe
code.

v2: Drop the misplaced drm_dev_put from zynqmp_dpsub_drm_init (all
other paths leaked on error, this should have been in
zynqmp_dpsub_probe), now that subsumed by the auto-cleanup of
devm_drm_dev_alloc.
Reviewed-by: Hyun Kwon <hyun.kwon@xilinx.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: Hyun Kwon <hyun.kwon@xilinx.com>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Michal Simek <michal.simek@xilinx.com>
Cc: linux-arm-kernel@lists.infradead.org
Link: https://patchwork.freedesktop.org/patch/msgid/20200907082225.150837-1-daniel.vetter@ffwll.ch

drivers/gpu/drm/xlnx/zynqmp_dpsub.c

@@ -111,7 +111,7 @@ static int zynqmp_dpsub_drm_init(struct zynqmp_dpsub *dpsub)
 	/* Initialize mode config, vblank and the KMS poll helper. */
 	ret = drmm_mode_config_init(drm);
 	if (ret < 0)
-		goto err_dev_put;
+		return ret;
 
 	drm->mode_config.funcs = &zynqmp_dpsub_mode_config_funcs;
 	drm->mode_config.min_width = 0;
@@ -121,7 +121,7 @@ static int zynqmp_dpsub_drm_init(struct zynqmp_dpsub *dpsub)
 
 	ret = drm_vblank_init(drm, 1);
 	if (ret)
-		goto err_dev_put;
+		return ret;
 
 	drm->irq_enabled = 1;
 
@@ -154,8 +154,6 @@ static int zynqmp_dpsub_drm_init(struct zynqmp_dpsub *dpsub)
 
 err_poll_fini:
 	drm_kms_helper_poll_fini(drm);
-err_dev_put:
-	drm_dev_put(drm);
 	return ret;
 }
 
@@ -208,27 +206,16 @@ static int zynqmp_dpsub_probe(struct platform_device *pdev)
 	int ret;
 
 	/* Allocate private data. */
-	dpsub = kzalloc(sizeof(*dpsub), GFP_KERNEL);
-	if (!dpsub)
-		return -ENOMEM;
+	dpsub = devm_drm_dev_alloc(&pdev->dev, &zynqmp_dpsub_drm_driver,
+				   struct zynqmp_dpsub, drm);
+	if (IS_ERR(dpsub))
+		return PTR_ERR(dpsub);
 
 	dpsub->dev = &pdev->dev;
 	platform_set_drvdata(pdev, dpsub);
 
 	dma_set_mask(dpsub->dev, DMA_BIT_MASK(ZYNQMP_DISP_MAX_DMA_BIT));
 
-	/*
-	 * Initialize the DRM device early, as the DRM core mandates usage of
-	 * the managed memory helpers tied to the DRM device.
-	 */
-	ret = drm_dev_init(&dpsub->drm, &zynqmp_dpsub_drm_driver, &pdev->dev);
-	if (ret < 0) {
-		kfree(dpsub);
-		return ret;
-	}
-
-	drmm_add_final_kfree(&dpsub->drm, dpsub);
-
 	/* Try the reserved memory. Proceed if there's none. */
 	of_reserved_mem_device_init(&pdev->dev);
 
@@ -286,8 +273,6 @@ static int zynqmp_dpsub_remove(struct platform_device *pdev)
 	clk_disable_unprepare(dpsub->apb_clk);
 	of_reserved_mem_device_release(&pdev->dev);
 
-	drm_dev_put(drm);
-
 	return 0;
 }