Current barebox,environment node only allows specifying a raw device or
partition to load an environment from.  Some boards, like OMAP and
SoCFPGA, instead want to use a file located in a FAT filesystem.
Extend the device tree bindings with a new property 'file-path' that
will trigger this behavior.

This allows any board using this driver to get the env from a file or
from a raw device, instead of each machine type being either raw
device only or file only.

Signed-off-by: Trent Piepho <tpiepho@kymetacorp.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

We could only point to partitions in the device tree by using
&norflash, "partname:barebox-environment". Allow to point to the
partition directly without having to parse the partition labels.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

Adjusted Sphinx markup for devicetree bindings pages.

Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

This is a rewrite of the Documentation in reStructuredText format using
Sphinx as build system, see http://sphinx-doc.org/.

The documentation is built into static html pages with 'make docs'.
The pages can be found under Documentation/html after building.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>