Add add SPI-NAND Flash controller driver for EN7581

Merge series from Lorenzo Bianconi <lorenzo@kernel.org>:

Introduce support for SPI-NAND driver of the Airoha NAND Flash Interface
found on Airoha ARM EN7581 SoCs.

Documentation/devicetree/bindings/spi/airoha,en7581-snand.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/spi/airoha,en7581-snand.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: SPI-NAND flash controller for Airoha ARM SoCs
+
+maintainers:
+  - Lorenzo Bianconi <lorenzo@kernel.org>
+
+allOf:
+  - $ref: spi-controller.yaml#
+
+properties:
+  compatible:
+    const: airoha,en7581-snand
+
+  reg:
+    items:
+      - description: spi base address
+      - description: nfi2spi base address
+
+  clocks:
+    maxItems: 1
+
+  clock-names:
+    items:
+      - const: spi
+
+required:
+  - compatible
+  - reg
+  - clocks
+  - clock-names
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/clock/en7523-clk.h>
+
+    soc {
+      #address-cells = <2>;
+      #size-cells = <2>;
+
+      spi@1fa10000 {
+        compatible = "airoha,en7581-snand";
+        reg = <0x0 0x1fa10000 0x0 0x140>,
+              <0x0 0x1fa11000 0x0 0x160>;
+
+        clocks = <&scuclk EN7523_CLK_SPI>;
+        clock-names = "spi";
+
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        flash@0 {
+          compatible = "spi-nand";
+          reg = <0>;
+          spi-tx-bus-width = <1>;
+          spi-rx-bus-width = <2>;
+        };
+      };
+    };

MAINTAINERS

@@ -653,6 +653,15 @@ S:	Supported
 F:	fs/aio.c
 F:	include/linux/*aio*.h
 
+AIROHA SPI SNFI DRIVER
+M:	Lorenzo Bianconi <lorenzo@kernel.org>
+M:	Ray Liu <ray.liu@airoha.com>
+L:	linux-arm-kernel@lists.infradead.org (moderated for non-subscribers)
+L:	linux-spi@vger.kernel.org
+S:	Maintained
+F:	Documentation/devicetree/bindings/spi/airoha,en7581-snand.yaml
+F:	drivers/spi/spi-airoha.c
+
 AIRSPY MEDIA DRIVER
 L:	linux-media@vger.kernel.org
 S:	Orphan

drivers/spi/Kconfig

@@ -57,6 +57,16 @@ config SPI_MEM
 
 comment "SPI Master Controller Drivers"
 
+config SPI_AIROHA_SNFI
+	tristate "Airoha SPI NAND Flash Interface"
+	depends on ARCH_AIROHA || COMPILE_TEST
+	depends on SPI_MASTER
+	select REGMAP_MMIO
+	help
+	  This enables support for SPI-NAND mode on the Airoha NAND
+	  Flash Interface found on Airoha ARM SoCs. This controller
+	  is implemented as a SPI-MEM controller.
+
 config SPI_ALTERA
 	tristate "Altera SPI Controller platform driver"
 	select SPI_ALTERA_CORE

drivers/spi/Makefile

@@ -14,6 +14,7 @@ obj-$(CONFIG_SPI_SPIDEV)		+= spidev.o
 obj-$(CONFIG_SPI_LOOPBACK_TEST)		+= spi-loopback-test.o
 
 # SPI master controller drivers (bus)
+obj-$(CONFIG_SPI_AIROHA_SNFI)		+= spi-airoha-snfi.o
 obj-$(CONFIG_SPI_ALTERA)		+= spi-altera-platform.o
 obj-$(CONFIG_SPI_ALTERA_CORE)		+= spi-altera-core.o
 obj-$(CONFIG_SPI_ALTERA_DFL)		+= spi-altera-dfl.o