[PATCH v2 08/11] video: lcdif: register simplefb fixup and enable framebuffer at probe

[Johannes Schneider]

From: Thomas Haemmerle <thomas.haemmerle at leica-geosystems.com>

Two changes are needed to use lcdif_drv as the primary barebox boot
framebuffer:

  - register_framebuffer() leaves the cdev disabled; the splash command
    opens fb0 via the fb API and never goes through the cdev open path
    that triggers fb_enable lazily, so it bails on
    "fb_open: No such file or directory".  fb_enable() at the end of
    register_fb so the controller is up by the time anything blits.

  - Set info->register_simplefb and call fb_register_simplefb() so
    DRM_SIMPLEDRM in Linux sees the boot framebuffer as a
    simple-framebuffer DT node and keeps the splash visible until its
    native LCDIF driver binds.

Signed-off-by: Thomas Haemmerle <thomas.haemmerle at leica-geosystems.com>
---
 drivers/video/lcdif_kms.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/video/lcdif_kms.c b/drivers/video/lcdif_kms.c
index 5487d1298c..e3d1985dc9 100644
--- a/drivers/video/lcdif_kms.c
+++ b/drivers/video/lcdif_kms.c
@@ -459,6 +459,16 @@ static int lcdif_register_fb(struct lcdif_drm_private *lcdif)
 	if (ret)
 		return ret;
 
+	/* expose as simple-framebuffer for Linux DRM_SIMPLEDRM handoff */
+	info->register_simplefb = 1;
+	fb_register_simplefb(info);
+
+	/* enable now so the splash command can blit into a live fb */
+	ret = fb_enable(info);
+	if (ret)
+		dev_warn(lcdif->dev, "failed to enable framebuffer: %pe\n",
+			 ERR_PTR(ret));
+
 	dev_info(lcdif->dev, "Registered %s on LCDIF%d, type primary\n",
 		 info->cdev.name, lcdif->id);
 
-- 
2.43.0