ramips: add support for D-Link DAP-1325-A1

This patch adds support for D-Link DAP-1325-A1 (Range Extender Wi-Fi N300)

Specifications:
- SoC: 580Mhz MT7628NN
- RAM: 64MB, DDR2 SDRAM
- Storage: 8MB, SPI (W25Q64JVSSIQ)
- Ethernet: 1x 10/100 LAN port
- WIFI: 2.4 GHz 802.11bgn
- LED: Status (2x to provide 3 colors), Wi-Fi Signal Strength (4x)
- Buttons: Reset, WPS
- UART: Serial console (57600, 8n1)
Row of 4 holes near LAN port, starting from square hole:
3.3V, TX,RX,GND
- FCC ID: fccid.io/KA2AP1325A1/

Installation:

Failsafe UI
Firmware can be uploaded with Failsafe UI web page:
- turn device off
- press and hold reset button
- turn device on
- keep holding reset until red wifi strength led turns on (ab. 10sec)
- connect to device through LAN port
PC must be configured with static ip (192.168.0.x)
- connect to 192.168.0.50
- select image to be flashed and upload.
Device will reboot after successful update

Serial port/TFTP server
- Connect through serial connectors on PCB (e.g. with teraterm)
- Set up a TFTP server, and connect through LAN with static IP
- Put image file in the root of the server
- Boot the device and select '2' at U-Boot startup
- Set device IP, server IP and image file name
- Start upload and flash

Signed-off-by: Giovanni Cascione <ing.cascione@gmail.com>
[fix whitespaces in DTS, convert to nvmem, add mtd-eeprom]
Signed-off-by: Adrian Schmutzler <freifunk@adrianschmutzler.de>

target/linux/ramips/dts/mt7628an_dlink_dap-1325-a1.dts

@@ -0,0 +1,139 @@
+// SPDX-License-Identifier: GPL-2.0-or-later OR MIT
+
+#include "mt7628an.dtsi"
+
+#include <dt-bindings/gpio/gpio.h>
+#include <dt-bindings/input/input.h>
+
+/ {
+	compatible = "dlink,dap-1325-a1", "mediatek,mt7628an-soc";
+	model = "D-Link DAP-1325 A1";
+
+	aliases {
+		led-boot = &led_status_green;
+		led-failsafe = &led_status_green;
+		led-running = &led_status_green;
+		led-upgrade = &led_status_red;
+	};
+
+	leds {
+		compatible = "gpio-leds";
+
+		led_status_red: status_red {
+			label = "red:status";
+			gpios = <&gpio 37 GPIO_ACTIVE_LOW>;
+		};
+
+		led_status_green: status_green {
+			label = "green:status";
+			gpios = <&gpio 11 GPIO_ACTIVE_LOW>;
+		};
+
+		wifi-high {
+			label = "green:wifi-high";
+			gpios = <&gpio 44 GPIO_ACTIVE_LOW>;
+		};
+
+		wifi-mid {
+			label = "green:wifi-mid";
+			gpios = <&gpio 3 GPIO_ACTIVE_LOW>;
+		};
+
+		wifi-low {
+			label = "green:wifi-low";
+			gpios = <&gpio 0 GPIO_ACTIVE_LOW>;
+		};
+
+		wifi-verylow {
+			label = "red:wifi-verylow";
+			gpios = <&gpio 2 GPIO_ACTIVE_LOW>;
+		};
+	};
+
+	keys {
+		compatible = "gpio-keys";
+
+		wps {
+			label = "wps";
+			gpios = <&gpio 45 GPIO_ACTIVE_LOW>;
+			linux,code = <KEY_WPS_BUTTON>;
+		};
+
+		reset {
+			label = "reset";
+			gpios = <&gpio 38 GPIO_ACTIVE_LOW>;
+			linux,code = <KEY_RESTART>;
+		};
+	};
+};
+
+&state_default {
+	gpio {
+		groups = "refclk", "gpio", "wled_an", "i2s", "uart1", "wdt";
+		function = "gpio";
+	};
+};
+
+&ethernet {
+	nvmem-cells = <&macaddr_factory_28>;
+	nvmem-cell-names = "mac-address";
+};
+
+&wmac {
+	status = "okay";
+
+	mediatek,mtd-eeprom = <&factory 0x0>;
+
+	nvmem-cells = <&macaddr_factory_28>;
+	nvmem-cell-names = "mac-address";
+};
+
+&spi0 {
+	status = "okay";
+
+	flash@0 {
+		compatible = "jedec,spi-nor";
+		reg = <0>;
+		spi-max-frequency = <50000000>;
+
+		partitions {
+			compatible = "fixed-partitions";
+			#address-cells = <1>;
+			#size-cells = <1>;
+
+			partition@0 {
+				label = "u-boot";
+				reg = <0x0 0x30000>;
+				read-only;
+			};
+
+			partition@30000 {
+				label = "u-boot-env";
+				reg = <0x30000 0x10000>;
+				read-only;
+			};
+
+			factory: partition@40000 {
+				label = "factory";
+				reg = <0x40000 0x10000>;
+				read-only;
+			};
+
+			partition@50000 {
+				compatible = "denx,uimage";
+				label = "firmware";
+				reg = <0x50000 0x7b0000>;
+			};
+		};
+	};
+};
+
+&factory {
+	compatible = "nvmem-cells";
+	#address-cells = <1>;
+	#size-cells = <1>;
+
+	macaddr_factory_28: macaddr@28 {
+		reg = <0x28 0x6>;
+	};
+};