dt-bindings: rng: Document Freescale i.MX21 and i.MX31 RNGA compatibles

Freescale i.MX21 and i.MX31 SoCs contain a Random Number Generator
Accelerator module (RNGA), which is replaced by RNGB and RNGC modules
on later i.MX SoC series, the change adds a new compatible property
to describe the controller.

Since all versions of Freescale RNG modules are legacy, apparently
the documentation file has no more potential for further extensions,
nevertheless generalize it by removing explicit RNGC specifics.

Signed-off-by: Vladimir Zapolskiy <vz@mleia.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Fabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 20 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/rng/imx-rng.txt b/Documentation/devicetree/bindings/rng/imx-rng.txt
new file mode 100644
index 000000000000..405c2b00ccb0
--- /dev/null
+++ b/Documentation/devicetree/bindings/rng/imx-rng.txt
@@ -0,0 +1,20 @@
+Freescale RNGA/RNGB/RNGC (Random Number Generator Versions A, B and C)
+
+Required properties:
+- compatible : should be one of
+               "fsl,imx21-rnga"
+               "fsl,imx31-rnga" (backward compatible with "fsl,imx21-rnga")
+               "fsl,imx25-rngb"
+               "fsl,imx35-rngc"
+- reg : offset and length of the register set of this block
+- interrupts : the interrupt number for the RNG block
+- clocks : the RNG clk source
+
+Example:
+
+rng@53fb0000 {
+	compatible = "fsl,imx25-rngb";
+	reg = <0x53fb0000 0x4000>;
+	interrupts = <22>;
+	clocks = <&trng_clk>;
+};