flash: nios2_qspi: Add dts binding and nodes for NIOS2 QSPI flash

Add dts bindings for the NIOS2 QSPI controller and flash device and
add nodes to the dts files for these devices as well.

Signed-off-by: Kumar Gala <galak@kernel.org>

boards/nios2/altera_max10/altera_max10.dts

@@ -2,6 +2,7 @@
 
 /dts-v1/;
 
+#include <mem.h>
 #include <intel/nios2f.dtsi>
 
 / {
@@ -29,3 +30,12 @@
 	status = "okay";
 	clock-frequency = <I2C_BITRATE_ULTRA>;
 };
+
+&qspi {
+	status = "okay";
+	n25q512ax3: n25q512ax3@0 {
+		compatible = "altr,nios2-qspi-nor";
+		size = <DT_SIZE_M(64*8)>;	/* in bits */
+		reg = <0>;
+	};
+};

dts/bindings/flash_controller/altr,nios2-qspi-nor.yaml

@@ -0,0 +1,17 @@
+# Copyright (c) 2020, Linaro limited
+# SPDX-License-Identifier: Apache-2.0
+
+description: Altera NIOS2 QSPI Flash controller supporting the JEDEC CFI interface
+
+compatible: "altr,nios2-qspi-nor"
+
+include: ["flash-controller.yaml", "jedec,jesd216.yaml"]
+
+on-bus: qspi
+
+properties:
+    reg:
+      required: true
+    size:
+      required: true
+      description: Flash Memory size in bits

dts/bindings/qspi/altr,nios2-qspi.yaml

@@ -0,0 +1,14 @@
+# Copyright (c) 2022, Kumar Gala <galak@kernel.org>
+# SPDX-License-Identifier: Apache-2.0
+
+description: Altera NIOS2 QSPI
+
+compatible: "altr,nios2-qspi"
+
+include: [base.yaml]
+
+bus: qspi
+
+properties:
+    reg:
+      required: true

dts/nios2/intel/nios2f.dtsi

@@ -65,5 +65,15 @@
 			interrupts = <3 3>;
 			#dma-cells = <0>;
 		};
+
+
+		qspi: qspi@100240 {
+			compatible = "altr,nios2-qspi";
+			#address-cells = <1>;
+			#size-cells = <0>;
+			reg = <0x100240 0x40>, <0x8000000 0x4000000>;
+			reg-names = "qspi", "qspi_mm";
+			status = "disabled";
+		};
 	};
 };