Documentation: bindings: add DT documentation for rkflash driver

Change-Id: I88c079435e6d1623eedc7317438fca9bf3f21759
Signed-off-by: Dingqiang Lin <jon.lin@rock-chips.com>

Documentation/devicetree/bindings/rkflash/nandc.txt

@@ -0,0 +1,21 @@
+Rockchip NANDC Controller for SOC
+
+Required properties:
+- compatible : "rockchip,nandc".
+- reg : shall contain registers location and length for data and reg.
+- interrupts : shall define the nandc controller interrupt.
+- clocks : shall reference nandc controller clocks.
+- clock-names : nandc controller internal clock names. Shall contain :
+    * "clk_nandc" : nand controller clock
+    * "hclk_nandc" : nandc ahb clock gate
+    * "g_clk_nandc" : nandc enable clock gate
+
+Examples:
+nandc: nandc@30100000 {
+	compatible = "rockchip,nandc";
+	reg = <0x30100000 0x1000>;
+	interrupts = <GIC_SPI 14 IRQ_TYPE_LEVEL_HIGH>;
+	clocks = <&clk_nandc>, <&clk_gates15 3>, <&clk_gates5 3>;
+	clock-names = "clk_nandc", "hclk_nandc", "g_clk_nandc";
+	status = "disabled";
+};

Documentation/devicetree/bindings/rkflash/sfc.txt

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+Rockchip SFC Controller for SOC
+
+Required properties:
+- compatible : "rockchip,sfc".
+- reg : shall contain registers location and length for data and reg.
+- interrupts : shall define the nand controller interrupt.
+- clocks : shall reference sfc controller clocks.
+- clock-names : nand controller internal clock names. Shall contain :
+    * "clk_sfc" : sfc controller clock
+    * "hclk_sfc" : sfc ahb clock gate
+
+Examples:
+sfc: sfc@301c0000 {
+	compatible = "rockchip,sfc";
+	reg = <0x301c0000 0x200>;
+	interrupts = <GIC_SPI 56 IRQ_TYPE_LEVEL_HIGH>;
+	clocks = <&clk_sfc>, <&clk_gates15 10>;
+	clock-names = "clk_sfc", "hclk_sfc";
+	status = "okay";
+};