drm/tegra: 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 tegra 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

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Mikko Perttunen <mperttunen@nvidia.com>
Cc: Jonathan Hunter <jonathanh@nvidia.com>
Acked-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240924071734.98201-79-tzimmermann@suse.de

Author: tdz

drivers/gpu/drm/tegra/Kconfig

@@ -5,6 +5,7 @@ config DRM_TEGRA
 	depends on COMMON_CLK
 	depends on DRM
 	depends on OF
+	select DRM_CLIENT_SELECTION
 	select DRM_DISPLAY_DP_HELPER
 	select DRM_DISPLAY_HDMI_HELPER
 	select DRM_DISPLAY_HELPER

drivers/gpu/drm/tegra/drm.c

@@ -15,6 +15,7 @@
 #include <drm/drm_aperture.h>
 #include <drm/drm_atomic.h>
 #include <drm/drm_atomic_helper.h>
+#include <drm/drm_client_setup.h>
 #include <drm/drm_debugfs.h>
 #include <drm/drm_drv.h>
 #include <drm/drm_fourcc.h>
@@ -891,6 +892,8 @@ static const struct drm_driver tegra_drm_driver = {
 
 	.dumb_create = tegra_bo_dumb_create,
 
+	TEGRA_FBDEV_DRIVER_OPS,
+
 	.ioctls = tegra_drm_ioctls,
 	.num_ioctls = ARRAY_SIZE(tegra_drm_ioctls),
 	.fops = &tegra_drm_fops,
@@ -1268,7 +1271,7 @@ static int host1x_drm_probe(struct host1x_device *dev)
 	if (err < 0)
 		goto hub;
 
-	tegra_fbdev_setup(drm);
+	drm_client_setup(drm, NULL);
 
 	return 0;
 

drivers/gpu/drm/tegra/drm.h

@@ -25,6 +25,9 @@
 /* XXX move to include/uapi/drm/drm_fourcc.h? */
 #define DRM_FORMAT_MOD_NVIDIA_SECTOR_LAYOUT BIT_ULL(22)
 
+struct drm_fb_helper;
+struct drm_fb_helper_surface_size;
+
 struct edid;
 struct reset_control;
 
@@ -190,10 +193,13 @@ struct drm_framebuffer *tegra_fb_create(struct drm_device *drm,
 					const struct drm_mode_fb_cmd2 *cmd);
 
 #ifdef CONFIG_DRM_FBDEV_EMULATION
-void tegra_fbdev_setup(struct drm_device *drm);
+int tegra_fbdev_driver_fbdev_probe(struct drm_fb_helper *helper,
+				   struct drm_fb_helper_surface_size *sizes);
+#define TEGRA_FBDEV_DRIVER_OPS \
+	.fbdev_probe = tegra_fbdev_driver_fbdev_probe
 #else
-static inline void tegra_fbdev_setup(struct drm_device *drm)
-{ }
+#define TEGRA_FBDEV_DRIVER_OPS \
+	.fbdev_probe = NULL
 #endif
 
 extern struct platform_driver tegra_display_hub_driver;

drivers/gpu/drm/tegra/fbdev.c

@@ -66,8 +66,11 @@ static const struct fb_ops tegra_fb_ops = {
 	.fb_destroy = tegra_fbdev_fb_destroy,
 };
 
-static int tegra_fbdev_probe(struct drm_fb_helper *helper,
-			     struct drm_fb_helper_surface_size *sizes)
+static const struct drm_fb_helper_funcs tegra_fbdev_helper_funcs = {
+};
+
+int tegra_fbdev_driver_fbdev_probe(struct drm_fb_helper *helper,
+				   struct drm_fb_helper_surface_size *sizes)
 {
 	struct tegra_drm *tegra = helper->dev->dev_private;
 	struct drm_device *drm = helper->dev;
@@ -112,6 +115,7 @@ static int tegra_fbdev_probe(struct drm_fb_helper *helper,
 		return PTR_ERR(fb);
 	}
 
+	helper->funcs = &tegra_fbdev_helper_funcs;
 	helper->fb = fb;
 	helper->info = info;
 
@@ -144,93 +148,3 @@ static int tegra_fbdev_probe(struct drm_fb_helper *helper,
 	drm_framebuffer_remove(fb);
 	return err;
 }
-
-static const struct drm_fb_helper_funcs tegra_fb_helper_funcs = {
-	.fb_probe = tegra_fbdev_probe,
-};
-
-/*
- * struct drm_client
- */
-
-static void tegra_fbdev_client_unregister(struct drm_client_dev *client)
-{
-	struct drm_fb_helper *fb_helper = drm_fb_helper_from_client(client);
-
-	if (fb_helper->info) {
-		drm_fb_helper_unregister_info(fb_helper);
-	} else {
-		drm_client_release(&fb_helper->client);
-		drm_fb_helper_unprepare(fb_helper);
-		kfree(fb_helper);
-	}
-}
-
-static int tegra_fbdev_client_restore(struct drm_client_dev *client)
-{
-	drm_fb_helper_lastclose(client->dev);
-
-	return 0;
-}
-
-static int tegra_fbdev_client_hotplug(struct drm_client_dev *client)
-{
-	struct drm_fb_helper *fb_helper = 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, fb_helper);
-	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(fb_helper);
-	if (ret)
-		goto err_drm_fb_helper_fini;
-
-	return 0;
-
-err_drm_fb_helper_fini:
-	drm_fb_helper_fini(fb_helper);
-err_drm_err:
-	drm_err(dev, "Failed to setup fbdev emulation (ret=%d)\n", ret);
-	return ret;
-}
-
-static const struct drm_client_funcs tegra_fbdev_client_funcs = {
-	.owner		= THIS_MODULE,
-	.unregister	= tegra_fbdev_client_unregister,
-	.restore	= tegra_fbdev_client_restore,
-	.hotplug	= tegra_fbdev_client_hotplug,
-};
-
-void tegra_fbdev_setup(struct drm_device *dev)
-{
-	struct drm_fb_helper *helper;
-	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");
-
-	helper = kzalloc(sizeof(*helper), GFP_KERNEL);
-	if (!helper)
-		return;
-	drm_fb_helper_prepare(dev, helper, 32, &tegra_fb_helper_funcs);
-
-	ret = drm_client_init(dev, &helper->client, "fbdev", &tegra_fbdev_client_funcs);
-	if (ret)
-		goto err_drm_client_init;
-
-	drm_client_register(&helper->client);
-
-	return;
-
-err_drm_client_init:
-	drm_fb_helper_unprepare(helper);
-	kfree(helper);
-}