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since buttons are associated with GPIO, we can do the export wps gpio using its number 
→ In mt7988a-bananapi-bpi-r4-nand.dts file, we can see WPS is defined with 14 
    wps {
                        label = "wps";
                        linux,code = <KEY_WPS_BUTTON>;
                        gpios = <&pio 14 GPIO_ACTIVE_LOW>;
                };
root@Filogic-GW:~# cd /sys/class/gpio/
export       gpiochip428/ unexport
→ Here by using 14+428=442, 428 (gpiochip428 refers to a GPIO controller that manages GPIO pins, starting from GPIO number 428.)
→ export the WPS pin number
root@Filogic-GW:/sys/class/gpio# echo 442 > /sys/class/gpio/export
root@Filogic-GW:/sys/class/gpio/gpio442# cat value
1
→ Whenever we press the WPS, this gpio442 value is changed to 0 
root@Filogic-GW:/sys/class/gpio/gpio442# cat value
0

WPS Block diagram

Concept

Conceptual Process

When a WPS PBC request is initiated in your system:

1. 1. PBC Activation:
      • Your code calls the RDK-WiFi-HAL API for WPS PBC
      • The HAL communicates this to hostapd via its control interface
      • hostapd sets the access point into "WPS waiting" mode
   2. Registration Window:
      • A 2-minute window opens where the access point is receptive to WPS registration
      • The AP broadcasts its WPS capability in beacons
      • The AP listens for probe requests with WPS information elements
   3. Device Discovery:
      • When a client device (like your mobile phone) activates WPS PBC
      • It sends probe requests with WPS information elements
      • Your access point responds to these probes
   4. Credential Exchange:
      • The client and AP establish an EAP (Extensible Authentication Protocol) session
      • They perform a handshake to validate each other
      • The AP sends the encrypted network credentials to the client
      • The client configures itself with these credentials
   5. Connection Completion:
      • The client connects to the network using the received credentials
      • The AP notifies the system (through hostapd → nl80211 → RDK-WiFi-HAL) of successful registration
      • The WPS PBC mode on the AP ends

Technical Implementation Details

In your specific setup with RDK-WiFi-HAL and hostapd 2.10:

1. 1. 1. RDK-WiFi-HAL WPS Functions:
         • The HAL typically provides functions like wifi_pushButtonPBC()
         • These functions handle the communication with hostapd
      2. hostapd Control Communication:
         • hostapd 2.10 provides a control interface via Unix domain sockets
         • RDK-WiFi-HAL connects to this socket and sends "WPS_PBC" commands
      3. nl80211 Commands Used:
         • hostapd uses NL80211_CMD_START_WPS with attributes:
           • NL80211_ATTR_IFINDEX: Specifies the wireless interface
           • NL80211_ATTR_WPS_MODE: Set to NL80211_WPS_PBC for push button method
      4. Event Monitoring:
         • WPS events flow back from the driver → nl80211 → hostapd → RDK-WiFi-HAL
         • These events include connection attempts, successful registrations, and timeouts