spi: qup: Add device tree bindings information

The Qualcomm Universal Peripheral (QUP) core is an
AHB slave that provides a common data path (an output
FIFO and an input FIFO) for serial peripheral interface
(SPI) mini-core.
Signed-off-by: NIvan T. Ivanov <iivanov@mm-sol.com>
Signed-off-by: NMark Brown <broonie@linaro.org>

Documentation/devicetree/bindings/spi/qcom,spi-qup.txt

+Qualcomm Universal Peripheral (QUP) Serial Peripheral Interface (SPI)
+
+The QUP core is an AHB slave that provides a common data path (an output FIFO
+and an input FIFO) for serial peripheral interface (SPI) mini-core.
+
+SPI in master mode supports up to 50MHz, up to four chip selects, programmable
+data path from 4 bits to 32 bits and numerous protocol variants.
+
+Required properties:
+- compatible:     Should contain "qcom,spi-qup-v2.1.1" or "qcom,spi-qup-v2.2.1"
+- reg:            Should contain base register location and length
+- interrupts:     Interrupt number used by this controller
+
+- clocks:         Should contain the core clock and the AHB clock.
+- clock-names:    Should be "core" for the core clock and "iface" for the
+                  AHB clock.
+
+- #address-cells: Number of cells required to define a chip select
+                  address on the SPI bus. Should be set to 1.
+- #size-cells:    Should be zero.
+
+Optional properties:
+- spi-max-frequency: Specifies maximum SPI clock frequency,
+                     Units - Hz. Definition as per
+                     Documentation/devicetree/bindings/spi/spi-bus.txt
+
+SPI slave nodes must be children of the SPI master node and can contain
+properties described in Documentation/devicetree/bindings/spi/spi-bus.txt
+
+Example:
+
+	spi_8: spi@f9964000 { /* BLSP2 QUP2 */
+
+		compatible = "qcom,spi-qup-v2";
+		#address-cells = <1>;
+		#size-cells = <0>;
+		reg = <0xf9964000 0x1000>;
+		interrupts = <0 102 0>;
+		spi-max-frequency = <19200000>;
+
+		clocks = <&gcc GCC_BLSP2_QUP2_SPI_APPS_CLK>, <&gcc GCC_BLSP2_AHB_CLK>;
+		clock-names = "core", "iface";
+
+		pinctrl-names = "default";
+		pinctrl-0 = <&spi8_default>;
+
+		device@0 {
+			compatible = "arm,pl022-dummy";
+			#address-cells = <1>;
+			#size-cells = <1>;
+			reg = <0>; /* Chip select 0 */
+			spi-max-frequency = <19200000>;
+			spi-cpol;
+		};
+
+		device@1 {
+			compatible = "arm,pl022-dummy";
+			#address-cells = <1>;
+			#size-cells = <1>;
+			reg = <1>; /* Chip select 1 */
+			spi-max-frequency = <9600000>;
+			spi-cpha;
+		};
+
+		device@2 {
+			compatible = "arm,pl022-dummy";
+			#address-cells = <1>;
+			#size-cells = <1>;
+			reg = <2>; /* Chip select 2 */
+			spi-max-frequency = <19200000>;
+			spi-cpol;
+			spi-cpha;
+		};
+
+		device@3 {
+			compatible = "arm,pl022-dummy";
+			#address-cells = <1>;
+			#size-cells = <1>;
+			reg = <3>; /* Chip select 3 */
+			spi-max-frequency = <19200000>;
+			spi-cpol;
+			spi-cpha;
+			spi-cs-high;
+		};
+	};