Code to read pin value

/* Include Files */
#include "xparameters.h"
#include "xgpio.h"
#include "xstatus.h"
#include "xil_printf.h"


/* Definitions */
#define GPIO_DEVICE_ID  XPAR_AXI_GPIO_0_DEVICE_ID /* GPIO device that LEDs are connected to */
#define LED 0xFC          /* Initial LED value - XX0000XX */
#define PMOD 0xFC         /* Initial LED value - XX0000XX */
#define LED_DELAY 1000000000       /* Software delay length */
#define LED_CHANNEL 1        /* GPIO port for LEDs */
#define PMOD_CHANNEL 1        /* GPIO port for PMODs */
#define printf xil_printf       /* smaller, optimised printf */
#define PMOD_JA1_DEVICE_ID  XPAR_AXI_GPIO_1_DEVICE_ID


XGpio Gpio, GpioP;           /* GPIO Device driver instance */





int LEDOutputExample(void)
{


 volatile int Delay;
 int Status;
 int led = LED; /* Hold current LED value. Initialise to LED definition */
 int pmod = PMOD;
 u32 x;




  /* GPIO driver initialisation */
  Status = XGpio_Initialize(&Gpio, GPIO_DEVICE_ID);
  if (Status != XST_SUCCESS) {
   return XST_FAILURE;
  }
  Status = XGpio_Initialize(&GpioP, PMOD_JA1_DEVICE_ID);
   if (Status != XST_SUCCESS) {
    return XST_FAILURE;
  }


  /*Set the direction for the LEDs to output. */
  XGpio_SetDataDirection(&Gpio, LED_CHANNEL, 0x00);


  /*Set the direction for the LEDs to output. */
    XGpio_SetDataDirection(&GpioP, PMOD_CHANNEL, 0x11111111);


  /* Loop forever blinking the LED. */
   while (1) {
    /* Write output to the LEDs. */
    XGpio_DiscreteWrite(&Gpio, LED_CHANNEL, led);



    /* Flip LEDs. */
    led = ~led;


    /* Write output to the LEDs. */
    //XGpio_DiscreteWrite(&GpioP, PMOD_CHANNEL, pmod);
    x = XGpio_DiscreteRead(&GpioP,PMOD_CHANNEL);
        printf("The voltage on pin 3 is %d",x);

    /* Flip LEDs. */
   // pmod = ~pmod;


    /* Wait a small amount of time so that the LED blinking is visible. */
    for (Delay = 0; Delay < LED_DELAY; Delay++);
   }


  return XST_SUCCESS; /* Should be unreachable */
}


/* Main function. */
int main(void){


 int Status;


 /* Execute the LED output. */
 Status = LEDOutputExample();
 if (Status != XST_SUCCESS) {
  xil_printf("GPIO output to the LEDs failed!\r\n");
 }


 return 0;
}