MIO 50 button read in Zybo z7-20 with Linux is always returning 1

[SuryaPrakash]

I am trying to read from MIO 50 button of Zybo Z7-20 in linux , I have changed the voltage from 1.8V to 3.3V in VIVADO and used the .XSA file and generated linux image in petalinux and I have used the following code to read from MIO 50.

Even if I don't press the MIO 50 button , I am still getting result as button pressed.

   int fd; //file handler.
   struct gpiohandle_request button;
   struct gpiohandle_data data; 

   /*Open the gpiochip0 file which is mapped to the gpio physical layer*/
   fd = open("/dev/gpiochip0", O_RDWR); //opening the file in read-write mode.
   if(fd < 0)
   {
      perror("File not present\n");
      return -1;
   }

   /*Set button (MIO-50) as input*/
   button.flags = GPIOHANDLE_REQUEST_INPUT;
   strcpy(button.consumer_label , "BUTTON");
   memset(button.default_values , 0 , sizeof(button.default_values));
   button.lines = 1;
   button.lineoffsets[0] = PS_SWITCH;

   /*Make request to make MIO50 as input*/
   if(ioctl(fd , GPIO_GET_LINEHANDLE_IOCTL,&button) < 0)
   {
     perror("GPIO input request failed\n");
     close(fd);
     close(led.fd);
     return -1;
   }

   //Intialize the data.values array to 0.
   memset(data.values , 0 , sizeof(data.values));

   if(ioctl(button.fd , GPIOHANDLE_GET_LINE_VALUES_IOCTL , &data) < 0)
   {
         perror("Getting value from GPIO input pin failed\n");
         close(fd);
         close(led.fd);
         close(button.fd);
         return -1;
   }

   if(data.values[0] == 1)
   {
       printf("\nBUTTON PRESS DETECTED\n");
   }
   else
   {
       printf("\nBUTTON PRESS NOT DETECTED\n");
   }

   close(fd);
   close(button.fd);
   return 0;