drm/armada: Run DRM default client setup

Rework fbdev probing to support fbdev_probe in struct drm_driver
and remove the old fb_probe callback. Provide an initializer macro
for struct drm_driver that sets the callback according to the kernel
configuration.

Call drm_client_setup() to run the kernel's default client setup
for DRM. Set fbdev_probe in struct drm_driver, so that the client
setup can start the common fbdev client.

The armada driver specifies a preferred color mode of 32. As this
is the default if no format has been given, leave it out entirely.

v5:
- select DRM_CLIENT_SELECTION
v4:
- revert an unrelated cleanup (Javier)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Russell King <linux@armlinux.org.uk>
Acked-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240924071734.98201-74-tzimmermann@suse.de

Author: tdz

drivers/gpu/drm/armada/Kconfig

@@ -2,6 +2,7 @@
 config DRM_ARMADA
 	tristate "DRM support for Marvell Armada SoCs"
 	depends on DRM && HAVE_CLK && ARM && MMU
+	select DRM_CLIENT_SELECTION
 	select DRM_KMS_HELPER
 	select FB_IOMEM_HELPERS if DRM_FBDEV_EMULATION
 	help

drivers/gpu/drm/armada/armada_drm.h

@@ -16,6 +16,8 @@ struct armada_crtc;
 struct armada_gem_object;
 struct clk;
 struct drm_display_mode;
+struct drm_fb_helper;
+struct drm_fb_helper_surface_size;
 
 static inline void
 armada_updatel(uint32_t val, uint32_t mask, void __iomem *ptr)
@@ -74,10 +76,13 @@ struct armada_private {
 #define drm_to_armada_dev(dev) container_of(dev, struct armada_private, drm)
 
 #if defined(CONFIG_DRM_FBDEV_EMULATION)
-void armada_fbdev_setup(struct drm_device *dev);
+int armada_fbdev_driver_fbdev_probe(struct drm_fb_helper *fbh,
+				    struct drm_fb_helper_surface_size *sizes);
+#define ARMADA_FBDEV_DRIVER_OPS \
+	.fbdev_probe = armada_fbdev_driver_fbdev_probe
 #else
-static inline void armada_fbdev_setup(struct drm_device *dev)
-{ }
+#define ARMADA_FBDEV_DRIVER_OPS \
+	.fbdev_probe = NULL
 #endif
 
 int armada_overlay_plane_create(struct drm_device *, unsigned long);

drivers/gpu/drm/armada/armada_drv.c

@@ -12,6 +12,7 @@
 
 #include <drm/drm_aperture.h>
 #include <drm/drm_atomic_helper.h>
+#include <drm/drm_client_setup.h>
 #include <drm/drm_drv.h>
 #include <drm/drm_ioctl.h>
 #include <drm/drm_managed.h>
@@ -39,6 +40,7 @@ DEFINE_DRM_GEM_FOPS(armada_drm_fops);
 static const struct drm_driver armada_drm_driver = {
 	.gem_prime_import	= armada_gem_prime_import,
 	.dumb_create		= armada_gem_dumb_create,
+	ARMADA_FBDEV_DRIVER_OPS,
 	.major			= 1,
 	.minor			= 0,
 	.name			= "armada-drm",
@@ -137,7 +139,7 @@ static int armada_drm_bind(struct device *dev)
 	armada_drm_debugfs_init(priv->drm.primary);
 #endif
 
-	armada_fbdev_setup(&priv->drm);
+	drm_client_setup(&priv->drm, NULL);
 
 	return 0;
 

drivers/gpu/drm/armada/armada_fbdev.c

@@ -39,8 +39,10 @@ static const struct fb_ops armada_fb_ops = {
 	.fb_destroy	= armada_fbdev_fb_destroy,
 };
 
-static int armada_fbdev_create(struct drm_fb_helper *fbh,
-	struct drm_fb_helper_surface_size *sizes)
+static const struct drm_fb_helper_funcs armada_fbdev_helper_funcs;
+
+int armada_fbdev_driver_fbdev_probe(struct drm_fb_helper *fbh,
+				    struct drm_fb_helper_surface_size *sizes)
 {
 	struct drm_device *dev = fbh->dev;
 	struct drm_mode_fb_cmd2 mode;
@@ -98,6 +100,7 @@ static int armada_fbdev_create(struct drm_fb_helper *fbh,
 	info->fix.smem_len = obj->obj.size;
 	info->screen_size = obj->obj.size;
 	info->screen_base = ptr;
+	fbh->funcs = &armada_fbdev_helper_funcs;
 	fbh->fb = &dfb->fb;
 
 	drm_fb_helper_fill_info(info, fbh, sizes);
@@ -112,109 +115,3 @@ static int armada_fbdev_create(struct drm_fb_helper *fbh,
 	dfb->fb.funcs->destroy(&dfb->fb);
 	return ret;
 }
-
-static int armada_fb_probe(struct drm_fb_helper *fbh,
-	struct drm_fb_helper_surface_size *sizes)
-{
-	int ret = 0;
-
-	if (!fbh->fb) {
-		ret = armada_fbdev_create(fbh, sizes);
-		if (ret == 0)
-			ret = 1;
-	}
-	return ret;
-}
-
-static const struct drm_fb_helper_funcs armada_fb_helper_funcs = {
-	.fb_probe	= armada_fb_probe,
-};
-
-/*
- * Fbdev client and struct drm_client_funcs
- */
-
-static void armada_fbdev_client_unregister(struct drm_client_dev *client)
-{
-	struct drm_fb_helper *fbh = drm_fb_helper_from_client(client);
-
-	if (fbh->info) {
-		drm_fb_helper_unregister_info(fbh);
-	} else {
-		drm_client_release(&fbh->client);
-		drm_fb_helper_unprepare(fbh);
-		kfree(fbh);
-	}
-}
-
-static int armada_fbdev_client_restore(struct drm_client_dev *client)
-{
-	drm_fb_helper_lastclose(client->dev);
-
-	return 0;
-}
-
-static int armada_fbdev_client_hotplug(struct drm_client_dev *client)
-{
-	struct drm_fb_helper *fbh = drm_fb_helper_from_client(client);
-	struct drm_device *dev = client->dev;
-	int ret;
-
-	if (dev->fb_helper)
-		return drm_fb_helper_hotplug_event(dev->fb_helper);
-
-	ret = drm_fb_helper_init(dev, fbh);
-	if (ret)
-		goto err_drm_err;
-
-	if (!drm_drv_uses_atomic_modeset(dev))
-		drm_helper_disable_unused_functions(dev);
-
-	ret = drm_fb_helper_initial_config(fbh);
-	if (ret)
-		goto err_drm_fb_helper_fini;
-
-	return 0;
-
-err_drm_fb_helper_fini:
-	drm_fb_helper_fini(fbh);
-err_drm_err:
-	drm_err(dev, "armada: Failed to setup fbdev emulation (ret=%d)\n", ret);
-	return ret;
-}
-
-static const struct drm_client_funcs armada_fbdev_client_funcs = {
-	.owner		= THIS_MODULE,
-	.unregister	= armada_fbdev_client_unregister,
-	.restore	= armada_fbdev_client_restore,
-	.hotplug	= armada_fbdev_client_hotplug,
-};
-
-void armada_fbdev_setup(struct drm_device *dev)
-{
-	struct drm_fb_helper *fbh;
-	int ret;
-
-	drm_WARN(dev, !dev->registered, "Device has not been registered.\n");
-	drm_WARN(dev, dev->fb_helper, "fb_helper is already set!\n");
-
-	fbh = kzalloc(sizeof(*fbh), GFP_KERNEL);
-	if (!fbh)
-		return;
-	drm_fb_helper_prepare(dev, fbh, 32, &armada_fb_helper_funcs);
-
-	ret = drm_client_init(dev, &fbh->client, "fbdev", &armada_fbdev_client_funcs);
-	if (ret) {
-		drm_err(dev, "Failed to register client: %d\n", ret);
-		goto err_drm_client_init;
-	}
-
-	drm_client_register(&fbh->client);
-
-	return;
-
-err_drm_client_init:
-	drm_fb_helper_unprepare(fbh);
-	kfree(fbh);
-	return;
-}