drm/ast: Managed device release

This turns the ast's device cleanup code into a managed release helper
function. Note that the code uses devres helpers. The release function
switches the device back to VGA mode and therefore runs during HW device
cleanup; not at DRM device cleanup.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20200730135206.30239-10-tzimmermann@suse.de

drivers/gpu/drm/ast/ast_drv.c

@@ -120,35 +120,24 @@ static int ast_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 		return ret;
 
 	ast = ast_device_create(&ast_driver, pdev, ent->driver_data);
-	if (IS_ERR(ast)) {
-		ret = PTR_ERR(ast);
-		goto err_drm_dev_put;
-	}
+	if (IS_ERR(ast))
+		return PTR_ERR(ast);
 	dev = &ast->base;
 
 	ret = drm_dev_register(dev, ent->driver_data);
 	if (ret)
-		goto err_ast_device_destroy;
+		return ret;
 
 	drm_fbdev_generic_setup(dev, 32);
 
 	return 0;
-
-err_ast_device_destroy:
-	ast_device_destroy(ast);
-err_drm_dev_put:
-	drm_dev_put(dev);
-	return ret;
 }
 
 static void ast_pci_remove(struct pci_dev *pdev)
 {
 	struct drm_device *dev = pci_get_drvdata(pdev);
-	struct ast_private *ast = to_ast_private(dev);
 
 	drm_dev_unregister(dev);
-	ast_device_destroy(ast);
-	drm_dev_put(dev);
 }
 
 static int ast_drm_freeze(struct drm_device *dev)

drivers/gpu/drm/ast/ast_drv.h

@@ -162,7 +162,6 @@ static inline struct ast_private *to_ast_private(struct drm_device *dev)
 struct ast_private *ast_device_create(struct drm_driver *drv,
 				      struct pci_dev *pdev,
 				      unsigned long flags);
-void ast_device_destroy(struct ast_private *ast);
 
 #define AST_IO_AR_PORT_WRITE		(0x40)
 #define AST_IO_MISC_PORT_WRITE		(0x42)

drivers/gpu/drm/ast/ast_main.c

@@ -380,6 +380,18 @@ static int ast_get_dram_info(struct drm_device *dev)
 	return 0;
 }
 
+/*
+ * Run this function as part of the HW device cleanup; not
+ * when the DRM device gets released.
+ */
+static void ast_device_release(void *data)
+{
+	struct ast_private *ast = data;
+
+	/* enable standard VGA decode */
+	ast_set_index_reg(ast, AST_IO_CRTC_PORT, 0xa1, 0x04);
+}
+
 struct ast_private *ast_device_create(struct drm_driver *drv,
 				      struct pci_dev *pdev,
 				      unsigned long flags)
@@ -438,11 +450,9 @@ struct ast_private *ast_device_create(struct drm_driver *drv,
 	if (ret)
 		return ERR_PTR(ret);
 
-	return ast;
-}
+	ret = devm_add_action_or_reset(dev->dev, ast_device_release, ast);
+	if (ret)
+		return ERR_PTR(ret);
 
-void ast_device_destroy(struct ast_private *ast)
-{
-	/* enable standard VGA decode */
-	ast_set_index_reg(ast, AST_IO_CRTC_PORT, 0xa1, 0x04);
+	return ast;
 }