drivers/video: implement a simple framebuffer driver

A simple frame-buffer describes a raw memory region that may be rendered
to, with the assumption that the display hardware has already been set
up to scan out from that buffer.

This is useful in cases where a bootloader exists and has set up the
display hardware, but a Linux driver doesn't yet exist for the display
hardware.

Examples use-cases include:

* The built-in LCD panels on the Samsung ARM chromebook, and Tegra
  devices, and likely many other ARM or embedded systems.  These cannot
  yet be supported using a full graphics driver, since the panel control
  should be provided by the CDF (Common Display Framework), which has been
  stuck in design/review for quite some time.  One could support these
  panels using custom SoC-specific code, but there is a desire to use
  common infra-structure rather than having each SoC vendor invent their
  own code, hence the desire to wait for CDF.

* Hardware for which a full graphics driver is not yet available, and
  the path to obtain one upstream isn't yet clear.  For example, the
  Raspberry Pi.

* Any hardware in early stages of upstreaming, before a full graphics
  driver has been tackled.  This driver can provide a graphical boot
  console (even full X support) much earlier in the upstreaming process,
  thus making new SoC or board support more generally useful earlier.

[akpm@linux-foundation.org: make simplefb_formats[] static]
Signed-off-by: Stephen Warren <swarren@wwwdotorg.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Acked-by: Olof Johansson <olof@lixom.net>
Cc: Rob Clark <robclark@gmail.com>
Cc: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
Cc: Tomasz Figa <tomasz.figa@gmail.com>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 17 insertions, 0 deletions

diff --git a/drivers/video/Kconfig b/drivers/video/Kconfig
index d71d60f94fc..62460561077 100644
--- a/drivers/video/Kconfig
+++ b/drivers/video/Kconfig
@@ -2453,6 +2453,23 @@ config FB_HYPERV
 	help
 	  This framebuffer driver supports Microsoft Hyper-V Synthetic Video.
 
+config FB_SIMPLE
+	bool "Simple framebuffer support"
+	depends on (FB = y) && OF
+	select FB_CFB_FILLRECT
+	select FB_CFB_COPYAREA
+	select FB_CFB_IMAGEBLIT
+	help
+	  Say Y if you want support for a simple frame-buffer.
+
+	  This driver assumes that the display hardware has been initialized
+	  before the kernel boots, and the kernel will simply render to the
+	  pre-allocated frame buffer surface.
+
+	  Configuration re: surface address, size, and format must be provided
+	  through device tree, or potentially plain old platform data in the
+	  future.
+
 source "drivers/video/omap/Kconfig"
 source "drivers/video/omap2/Kconfig"
 source "drivers/video/exynos/Kconfig"