spmi: add generic SPMI controller binding documentation

Signed-off-by: Josh Cartwright <joshc@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/Documentation/devicetree/bindings/spmi/spmi.txt b/Documentation/devicetree/bindings/spmi/spmi.txt
new file mode 100644 (file)
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+System Power Management Interface (SPMI) Controller
+
+This document defines a generic set of bindings for use by SPMI controllers.  A
+controller is modelled in device tree as a node with zero or more child nodes,
+each representing a unique slave on the bus.
+
+Required properties:
+- #address-cells : must be set to 2
+- #size-cells : must be set to 0
+
+Child nodes:
+
+An SPMI controller node can contain zero or more child nodes representing slave
+devices on the bus.  Child 'reg' properties are specified as an address, type
+pair.  The address must be in the range 0-15 (4 bits).  The type must be one of
+SPMI_USID (0) or SPMI_GSID (1) for Unique Slave ID or Group Slave ID respectively.
+These are the identifiers "statically assigned by the system integrator", as
+per the SPMI spec.
+
+Each child node must have one and only one 'reg' entry of type SPMI_USID.
+
+#include <dt-bindings/spmi/spmi.h>
+
+       spmi@.. {
+               compatible = "...";
+               reg = <...>;
+
+               #address-cells = <2>;
+               #size-cells <0>;
+
+               child@0 {
+                       compatible = "...";
+                       reg = <0 SPMI_USID>;
+               };
+
+               child@7 {
+                       compatible = "...";
+                       reg = <7 SPMI_USID
+                              3 SPMI_GSID>;
+               };
+       };