fbdev: Introduce devm_register_framebuffer()

Introduce a device-managed variant of register_framebuffer() which
automatically unregisters the framebuffer on device destruction.
This can simplify the error handling and resource management in drivers.
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Helge Deller <deller@gmx.de>

drivers/video/fbdev/core/fbmem.c

@@ -544,6 +544,36 @@ unregister_framebuffer(struct fb_info *fb_info)
 }
 EXPORT_SYMBOL(unregister_framebuffer);
 
+static void devm_unregister_framebuffer(void *data)
+{
+	struct fb_info *info = data;
+
+	unregister_framebuffer(info);
+}
+
+/**
+ *	devm_register_framebuffer - resource-managed frame buffer device registration
+ *	@dev: device the framebuffer belongs to
+ *	@fb_info: frame buffer info structure
+ *
+ *	Registers a frame buffer device @fb_info to device @dev.
+ *
+ *	Returns negative errno on error, or zero for success.
+ *
+ */
+int
+devm_register_framebuffer(struct device *dev, struct fb_info *fb_info)
+{
+	int ret;
+
+	ret = register_framebuffer(fb_info);
+	if (ret)
+		return ret;
+
+	return devm_add_action_or_reset(dev, devm_unregister_framebuffer, fb_info);
+}
+EXPORT_SYMBOL(devm_register_framebuffer);
+
 /**
  *	fb_set_suspend - low level driver signals suspend
  *	@info: framebuffer affected

include/linux/fb.h

@@ -601,6 +601,7 @@ extern ssize_t fb_sys_write(struct fb_info *info, const char __user *buf,
 /* fbmem.c */
 extern int register_framebuffer(struct fb_info *fb_info);
 extern void unregister_framebuffer(struct fb_info *fb_info);
+extern int devm_register_framebuffer(struct device *dev, struct fb_info *fb_info);
 extern char* fb_get_buffer_offset(struct fb_info *info, struct fb_pixmap *buf, u32 size);
 extern void fb_pad_unaligned_buffer(u8 *dst, u32 d_pitch, u8 *src, u32 idx,
 				u32 height, u32 shift_high, u32 shift_low, u32 mod);