Add configurability via devicetree

This adds the possibility to configure the place for the environment
from the devicetree and to partition devices from the devicetree.

Configuration has the general form of devices with a regular compatible
property. This allows to later add additional drivers or drivers with
different behaviour (for example to add support for redundant environment).

The configuration is all in the /chosen/barebox/ hierarchy of the
devicetree. This separates the configuration from the hardware
description. Also it makes it possible to store the configuration
in a completely separate devicetree (or devicetree overlay). For
the same reason all configuration is done using nodepathes rather
than phandles.

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

2 files changed, 35 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/barebox.txt b/Documentation/devicetree/bindings/barebox.txt
new file mode 100644
index 0000000000..5e8d461733
--- /dev/null
+++ b/Documentation/devicetree/bindings/barebox.txt
@@ -0,0 +1,10 @@
+barebox specific devicetree bindings
+====================================
+
+barebox uses some barebox specific devicetree bindings. All of these
+are under the /chosen/ hierarchy in the devicetree.
+
+The bindings have the form of a device with regular 'compatible' properties.
+drivers matching these devices do not handle physical devices but instead
+influence / configure certain behaviours of barebox like the place where to
+find the persistent environment.
diff --git a/Documentation/devicetree/bindings/barebox/barebox,environment.txt b/Documentation/devicetree/bindings/barebox/barebox,environment.txt
new file mode 100644
index 0000000000..5a8bf9c13b
--- /dev/null
+++ b/Documentation/devicetree/bindings/barebox/barebox,environment.txt
@@ -0,0 +1,25 @@
+barebox environment
+===================
+
+This driver provides an environment for barebox from the devicetree.
+
+Required properties:
+- compatible: should be "barebox,environment"
+- device-path: path to the environment
+
+The device-path is a multistring property. The first string should be a
+nodepath to the node containing the physical device of the environment.
+The subsequent strings are of the form <type>:<options> to further describe
+the path to the environment. Supported values for <type>:
+
+partname:<partname>  This describes a partition on a device. <partname> can
+                     be the label for mtd partitions, the number for DOS
+		     partitions (beginning with 0) or the name for GPT
+		     partitions
+
+Example:
+
+environment@0 {
+	compatible = "barebox,environment";
+	device-path = &flash, "partname:barebox-environment";
+};