dt-bindings: Add devicetree bindings

Add snapshot of device tree bindings from keystone common kernel, branch
"android-mainline-keystone-qcom-release" at c4c12103f9c0 ("Snap for 9228065
from e32903b9a63bb558df8b803b076619c53c16baad to
android-mainline-keystone-qcom-release").

Change-Id: I7682079615cbd9f29340a5c1f2a1d84ec441a1f1
Signed-off-by: Melody Olvera <quic_molvera@quicinc.com>

bindings/i2c/i2c-synquacer.txt

@@ -0,0 +1,29 @@
+Socionext SynQuacer I2C
+
+Required properties:
+- compatible      : Must be "socionext,synquacer-i2c"
+- reg             : Offset and length of the register set for the device
+- interrupts      : A single interrupt specifier
+- #address-cells  : Must be <1>;
+- #size-cells     : Must be <0>;
+- clock-names     : Must contain "pclk".
+- clocks          : Must contain an entry for each name in clock-names.
+                    (See the common clock bindings.)
+
+Optional properties:
+- clock-frequency : Desired I2C bus clock frequency in Hz. As only Normal and
+                    Fast modes are supported, possible values are 100000 and
+                    400000.
+
+Example :
+
+    i2c@51210000 {
+        compatible = "socionext,synquacer-i2c";
+        reg = <0x51210000 0x1000>;
+        interrupts = <GIC_SPI 165 IRQ_TYPE_LEVEL_HIGH>;
+        #address-cells = <1>;
+        #size-cells = <0>;
+        clock-names = "pclk";
+        clocks = <&clk_i2c>;
+        clock-frequency = <400000>;
+    };