drm/ast: Move Gen7 device initialization into separate helper

Split off device initialization for Gen7 hardware into the helpers
ast_2600_device_create() and ast_2600_detect_wide_screen(). The new
functions are duplicates of their counterparts in ast_main.c, but
stripped from most non-Gen7 support.

Simplifies maintenance as the driver's number of supported hardware
generations grows.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com>
Link: https://lore.kernel.org/r/20250922083708.45564-12-tzimmermann@suse.de

drivers/gpu/drm/ast/ast_2600.c

@@ -26,6 +26,10 @@
  * Authors: Dave Airlie <airlied@redhat.com>
  */
 
+#include <linux/pci.h>
+
+#include <drm/drm_drv.h>
+
 #include "ast_drv.h"
 #include "ast_post.h"
 
@@ -42,3 +46,62 @@ int ast_2600_post(struct ast_device *ast)
 
 	return 0;
 }
+
+/*
+ * Device initialization
+ */
+
+static void ast_2600_detect_widescreen(struct ast_device *ast)
+{
+	ast->support_wsxga_p = true;
+	ast->support_fullhd = true;
+	if (__ast_2100_detect_wuxga(ast))
+		ast->support_wuxga = true;
+}
+
+struct drm_device *ast_2600_device_create(struct pci_dev *pdev,
+					  const struct drm_driver *drv,
+					  enum ast_chip chip,
+					  enum ast_config_mode config_mode,
+					  void __iomem *regs,
+					  void __iomem *ioregs,
+					  bool need_post)
+{
+	struct drm_device *dev;
+	struct ast_device *ast;
+	int ret;
+
+	ast = devm_drm_dev_alloc(&pdev->dev, drv, struct ast_device, base);
+	if (IS_ERR(ast))
+		return ERR_CAST(ast);
+	dev = &ast->base;
+
+	ast_device_init(ast, chip, config_mode, regs, ioregs);
+
+	ast_2300_detect_tx_chip(ast);
+
+	switch (ast->tx_chip) {
+	case AST_TX_ASTDP:
+		ret = ast_post_gpu(ast);
+		break;
+	default:
+		ret = 0;
+		if (need_post)
+			ret = ast_post_gpu(ast);
+		break;
+	}
+	if (ret)
+		return ERR_PTR(ret);
+
+	ret = ast_mm_init(ast);
+	if (ret)
+		return ERR_PTR(ret);
+
+	ast_2600_detect_widescreen(ast);
+
+	ret = ast_mode_config_init(ast);
+	if (ret)
+		return ERR_PTR(ret);
+
+	return dev;
+}

drivers/gpu/drm/ast/ast_drv.c

@@ -406,6 +406,10 @@ static int ast_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 		drm = ast_2500_device_create(pdev, &ast_driver, chip, config_mode,
 					     regs, ioregs, need_post);
 		break;
+	case 7:
+		drm = ast_2600_device_create(pdev, &ast_driver, chip, config_mode,
+					     regs, ioregs, need_post);
+		break;
 	default:
 		drm = ast_device_create(pdev, &ast_driver, chip, config_mode, regs, ioregs,
 					need_post);

drivers/gpu/drm/ast/ast_drv.h

@@ -490,6 +490,13 @@ struct drm_device *ast_2500_device_create(struct pci_dev *pdev,
 
 /* ast_2600.c */
 int ast_2600_post(struct ast_device *ast);
+struct drm_device *ast_2600_device_create(struct pci_dev *pdev,
+					  const struct drm_driver *drv,
+					  enum ast_chip chip,
+					  enum ast_config_mode config_mode,
+					  void __iomem *regs,
+					  void __iomem *ioregs,
+					  bool need_post);
 
 /* ast post */
 int ast_post_gpu(struct ast_device *ast);