ath79: add support for ALFA Network WiFi CampPro Nano Duo

ALFA Network WiFi CampPro Nano Duo is a dual-radio Wi-Fi signal extender
(router) in USB dongle form-factor (Type-A plug is used only for power),
based on combination of two radio chipsets: Qualcomm QCA9531 (main SOC)
and MediaTek MT7610U (connected over USB 2.0 interface).

Specifications:

- SOC:      QCA9531 v2 (650 MHz)
- DRAM:     DDR2 128 MiB (Nanya NT5TU64M16HG-AC)
- Flash:    16 MiB SPI NOR (Macronix MX25L12835F)
- Ethernet: 1x 10/100 Mbps Ethernet (QCA9531)
- Wi-Fi:    2x2:2 2.4   GHz Wi-Fi 4 (QCA9531)
            1x1:1 2.4/5 GHz Wi-Fi 5 (MT7610U)
- Antenna:  3x RP-SMA (female) antenna connectors
- LED:      1x orange (RJ45, power indicator)
            2x green  (status + RJ45 activity/link)
            1x blue   (Wi-Fi 2.4 GHz status)
- Button:   1x button (reset)
- UART:     1x 4-pin, 2.00 mm pitch header on PCB
- Other:    external h/w watchdog (EM6324QYSP5B, enabled by default)
            GPIO-controlled USB power for MT7610U

MAC addresses:

- LAN:                 00:c0:ca:xx:xx:6d (art 0x2, -1)
- 2.4 GHz (QCA9531):   00:c0:ca:xx:xx:6e (art 0x2, device's label)
- 2.4/5 GHz (MT7610U): 00:c0:ca:xx:xx:6f (from eeprom)

Flash instructions:

You can use sysupgrade image directly in vendor firmware which is based
on LEDE/OpenWrt. Alternatively, you can use web recovery mode in U-Boot:

1. Configure PC with static IP 192.168.1.2/24.
2. Connect PC with RJ45 port, press the reset button, power up device,
   wait for first blink of status LED (indicates network setup), then
   keep button for 3 following blinks and release it.
3. Open 192.168.1.1 address in your browser and upload sysupgrade image.

Signed-off-by: Piotr Dymacz <pepe2k@gmail.com>

target/linux/ath79/dts/qca9531_alfa-network_wifi-camppro-nano-duo.dts

@@ -0,0 +1,60 @@
+// SPDX-License-Identifier: GPL-2.0-or-later OR MIT
+
+#include <dt-bindings/leds/common.h>
+
+#include "qca9531_alfa-network_r36a.dtsi"
+
+/ {
+	model = "ALFA Network WiFi CampPro Nano Duo";
+	compatible = "alfa-network,wifi-camppro-nano-duo", "qca,qca9531";
+
+	aliases {
+		led-boot = &led_status;
+		led-failsafe = &led_status;
+		led-running = &led_status;
+		led-upgrade = &led_status;
+	};
+
+	leds {
+		compatible = "gpio-leds";
+
+		pinctrl-names = "default";
+		pinctrl-0 = <&enable_gpio4>;
+
+		lan {
+			function = LED_FUNCTION_LAN;
+			color = <LED_COLOR_ID_GREEN>;
+			gpios = <&gpio 4 GPIO_ACTIVE_LOW>;
+		};
+
+		led_status: status {
+			function = LED_FUNCTION_STATUS;
+			color = <LED_COLOR_ID_GREEN>;
+			gpios = <&gpio 12 GPIO_ACTIVE_LOW>;
+		};
+
+		wlan2g {
+			function = LED_FUNCTION_WLAN_2GHZ;
+			color = <LED_COLOR_ID_BLUE>;
+			gpios = <&gpio 11 GPIO_ACTIVE_LOW>;
+			linux,default-trigger = "phy1tpt";
+		};
+	};
+};
+
+&eth0 {
+	nvmem-cells = <&macaddr_art_1002 (-1)>;
+	nvmem-cell-names = "mac-address";
+};
+
+&eth1 {
+	compatible = "syscon", "simple-mfd";
+};
+
+&gpio_export {
+	usb-power {
+		gpio-export,name = "usb-power";
+		gpio-export,output = <0>;
+		gpios = <&gpio 3 GPIO_ACTIVE_LOW>;
+	};
+};

target/linux/ath79/generic/base-files/etc/board.d/01_leds

@@ -22,6 +22,7 @@ alcatel,hh40v)
 	;;
 alfa-network,ap121f|\
 alfa-network,ap121fe|\
+alfa-network,wifi-camppro-nano-duo|\
 avm,fritz450e|\
 glinet,6408|\
 glinet,6416|\

target/linux/ath79/generic/base-files/etc/board.d/02_network

@@ -14,6 +14,7 @@ ath79_setup_interfaces()
 	alfa-network,ap121f|\
 	alfa-network,pi-wifi4|\
 	alfa-network,tube-2hq|\
+	alfa-network,wifi-camppro-nano-duo|\
 	araknis,an-300-ap-i-n|\
 	araknis,an-500-ap-i-ac|\
 	araknis,an-700-ap-i-ac|\
@@ -622,6 +623,7 @@ ath79_setup_macs()
 	alfa-network,pi-wifi4|\
 	alfa-network,r36a|\
 	alfa-network,tube-2hq|\
+	alfa-network,wifi-camppro-nano-duo|\
 	engenius,eap300-v2|\
 	engenius,ens202ext-v1)
 		label_mac=$(mtd_get_mac_binary art 0x1002)

target/linux/ath79/image/generic.mk

@@ -346,6 +346,16 @@ define Device/alfa-network_tube-2hq
 endef
 TARGET_DEVICES += alfa-network_tube-2hq
 
+define Device/alfa-network_wifi-camppro-nano-duo
+  SOC := qca9531
+  DEVICE_VENDOR := ALFA Network
+  DEVICE_MODEL := WiFi CampPro Nano Duo
+  DEVICE_PACKAGES := kmod-usb2 kmod-mt76x0u -swconfig
+  IMAGE_SIZE := 15872k
+  SUPPORTED_DEVICES += campnano-duo
+endef
+TARGET_DEVICES += alfa-network_wifi-camppro-nano-duo
+
 define Device/allnet_all-wap02860ac
   $(Device/senao_loader_okli)
   SOC := qca9558