ath79: add support for AirTight C-75

AirTight Networks (later renamed to Mojo Networks) C-75 is a dual-band
access point, also sold by WatchGuard under name AP320.

Specification
SoC: Qualcomm Atheros QCA9550
RAM: 128 MiB DDR2
Flash: 2x 16 MiB SPI NOR
WIFI: 2.4 GHz 3T3R integrated
      5 GHz 3T3R QCA9890 oversized Mini PCIe card
Ethernet: 2x 10/100/1000 Mbps QCA8334
          port labeled LAN1 is PoE capable (802.3at)
USB: 1x 2.0
LEDs: 7x which two are GPIO controlled, four switch controlled, one
      controlled by wireless driver
Buttons: 1x GPIO controlled
Serial: RJ-45 port, Cisco pinout
        baud: 115200, parity: none, flow control: none
JTAG: Yes, pins marked J1 on PCB

Installation
1. Prepare TFTP server with OpenWrt initramfs-kernel image.
2. Connect to one of LAN ports.
3. Connect to serial port.
4. Power on the device and when prompted to stop autoboot, hit any key.
5. Adjust "ipaddr" and "serverip" addresses in U-Boot environment, use
   'setenv' to do that, then run following commands:
    tftpboot 0x81000000 <openwrt_initramfs-kernel_image_name>
    bootm 0x81000000
6. Wait about 1 minute for OpenWrt to boot.
7. Transfer OpenWrt sysupgrade image to /tmp directory and flash it
   with:
    sysupgrade -n /tmp/<openwrt_sysupgrade_image_name>
8. After flashing, the access point will reboot to OpenWrt. Wait few
   minutes, until the Power LED stops blinking, then it's ready for
   configuration.

Known issues
Green power LED does not work.

Additional information
The U-Boot fails to initialise ethernet ports correctly when a UART
adapter is attached to UART pins (marked J3 on PCB).

Cc: Vladimir Georgievsky <vladimir.georgievsky@yahoo.com>
Signed-off-by: Tomasz Maciej Nowak <tmn505@gmail.com>

target/linux/ath79/dts/qca9550_airtight_c-75.dts

@@ -0,0 +1,169 @@
+// SPDX-License-Identifier: GPL-2.0-or-later OR MIT
+
+#include "qca955x.dtsi"
+
+#include <dt-bindings/gpio/gpio.h>
+#include <dt-bindings/input/input.h>
+
+/ {
+	model = "AirTight Networks C-75";
+	compatible = "airtight,c-75", "qca,qca9550", "qca,qca9558";
+
+	aliases {
+		label-mac-device = &eth0;
+		led-boot = &led_power;
+		led-failsafe = &led_power;
+		led-upgrade = &led_power;
+	};
+
+	keys {
+		compatible = "gpio-keys";
+
+		reset {
+			label = "reset";
+			linux,code = <KEY_RESTART>;
+			gpios = <&gpio 17 GPIO_ACTIVE_LOW>;
+		};
+	};
+
+	leds {
+		compatible = "gpio-leds";
+
+		led_power: power {
+			label = "amber:power";
+			gpios = <&gpio 14 GPIO_ACTIVE_HIGH>;
+			default-state = "on";
+		};
+
+		wlan2g {
+			label = "green:wlan2g";
+			gpios = <&gpio 13 GPIO_ACTIVE_LOW>;
+			linux,default-trigger = "phy1tpt";
+		};
+	};
+};
+
+&eth0 {
+	status = "okay";
+
+	mtd-mac-address = <&art 0x0>;
+	phy-handle = <&phy0>;
+	pll-data = <0xa6000000 0x00000101 0x00001616>;
+};
+
+&mdio0 {
+	status = "okay";
+
+	phy0: ethernet-phy@0 {
+		reg = <0>;
+		qca,ar8327-initvals = <
+			0x04 0x07600000 /* PORT0 PAD MODE CTRL */
+			0x0c 0x00080080 /* PORT6 PAD MODE CTRL */
+			0x58 0xc935c935 /* LED2 CTRL */
+			0x5c 0x03ffff00 /* LED3 CTRL */
+			0x7c 0x0000007e /* PORT0_STATUS */
+			0x94 0x0000007e /* PORT6_STATUS */
+		>;
+	};
+};
+
+&eth1 {
+	status = "okay";
+
+	mtd-mac-address = <&art 0x6>;
+	pll-data = <0x03000101 0x00000101 0x00001616>;
+
+	fixed-link {
+		speed = <1000>;
+		full-duplex;
+	};
+};
+
+&pcie0 {
+	status = "okay";
+
+	wifi@0,0 {
+		compatible = "qcom,ath10k";
+		reg = <0x0000 0 0 0 0>;
+	};
+};
+
+&spi {
+	status = "okay";
+
+	flash@0 {
+		compatible = "jedec,spi-nor";
+		reg = <0>;
+		spi-max-frequency = <25000000>;
+
+		partitions {
+			compatible = "fixed-partitions";
+			#address-cells = <1>;
+			#size-cells = <1>;
+
+			partition@0 {
+				label = "u-boot";
+				reg = <0x000000 0x040000>;
+				read-only;
+			};
+
+			partition@40000 {
+				label = "u-boot-env";
+				reg = <0x040000 0x010000>;
+			};
+
+			partition@50000 {
+				label = "wlandrv";
+				reg = <0x050000 0x010000>;
+				read-only;
+			};
+
+			partition@60000 {
+				label = "firmware";
+				reg = <0x060000 0xf90000>;
+				compatible = "denx,uimage";
+			};
+
+			art: partition@ff0000 {
+				label = "art";
+				reg = <0xff0000 0x010000>;
+				read-only;
+			};
+		};
+	};
+
+	flash@1 {
+		compatible = "jedec,spi-nor";
+		reg = <1>;
+		spi-max-frequency = <25000000>;
+
+		partitions {
+			compatible = "fixed-partitions";
+			#address-cells = <1>;
+			#size-cells = <1>;
+
+			partition@0 {
+				label = "opt";
+				reg = <0x0 0x1000000>;
+			};
+		};
+	};
+};
+
+&uart {
+	status = "okay";
+};
+
+&usb_phy0 {
+	status = "okay";
+};
+
+&usb0 {
+	status = "okay";
+};
+
+&wmac {
+	status = "okay";
+
+	mtd-cal-data = <&art 0x1000>;
+};

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

@@ -81,6 +81,10 @@ ath79_setup_interfaces()
 	winchannel,wb2000)
 		ucidef_set_interface_lan "eth0"
 		;;
+	airtight,c-75)
+		ucidef_add_switch "switch0" \
+			"0@eth0" "2:wan" "3:lan" "6@eth1"
+		;;
 	alfa-network,ap121fe)
 		ucidef_set_interface_lan "eth0 usb0"
 		;;

target/linux/ath79/image/generic.mk

@@ -237,6 +237,19 @@ define Device/adtran_bsap1840
 endef
 TARGET_DEVICES += adtran_bsap1840
 
+define Device/airtight_c-75
+  SOC := qca9550
+  DEVICE_VENDOR := AirTight Networks
+  DEVICE_MODEL := C-75
+  DEVICE_ALT0_VENDOR := Mojo Networks
+  DEVICE_ALT0_MODEL := C-75
+  DEVICE_ALT1_VENDOR := WatchGuard
+  DEVICE_ALT1_MODEL := AP320
+  DEVICE_PACKAGES := ath10k-firmware-qca988x-ct kmod-ath10k-ct kmod-usb2
+  IMAGE_SIZE := 15936k
+endef
+TARGET_DEVICES += airtight_c-75
+
 define Device/alfa-network_ap121f
   SOC := ar9331
   DEVICE_VENDOR := ALFA Network