dts/bindings: flash_controller: Add stm32 qspi-nor flash controller

Add a binding to describe stm32 qspi-nor flash controller

Signed-off-by: Erwan Gouriou <[email protected]>

Author: erwango

dts/bindings/flash_controller/st,stm32-qspi-nor.yaml

@@ -0,0 +1,35 @@
+# Copyright (c) 2020, Linaro limited
+# SPDX-License-Identifier: Apache-2.0
+
+description: |
+    STM32 QSPI Flash controller supporting the JEDEC CFI interface
+
+    Representation of a serial flash on a quadspi bus:
+
+        mx25r6435f: qspi-nor-flash@0 {
+                compatible = "st,stm32-qspi-nor";
+                label = "MX25R6435F";
+                reg = <0>;
+                spi-max-frequency = <80000000>;
+                size = <0x4000000>;
+                status = "okay";
+        };
+
+compatible: "st,stm32-qspi-nor"
+
+include: [flash-controller.yaml, jesd216.yaml]
+
+on-bus: qspi
+
+properties:
+    reg:
+      required: true
+    spi-max-frequency:
+      type: int
+      required: true
+      description: Maximum clock frequency of device's SPI interface in Hz
+    label:
+      required: true
+    size:
+      required: true
+      description: Flash Memory size in bits