Check out this post for the value...
I didn't find anything about labeling the tick marks... you're on your own...

I am able to fetch the value using println(myKnobA.getValue());

The link above used that value as the knob's label (in other words, where you have "KNOB")...

Yeah but i want it next to the arc end representing the actual value. trying to figure out functions for the same but no luck so far.

I see... I don't know ControlP5, but I think you have to do this manually...
You'll need the location of the knob ( knobX, knobY), the radius of the knob ( knobRadius), the rotational value to display the text at ( rot), of course, the label, and a little bit of trigonometry...

1. void displayLabel(String label, float knobX, float knobY, float knobRadius, float rot) {
2.   float x = knobX + cos(rot) * (knobRadius + 10); //Trigonometry - 10 is a buffer, make it negative to draw inside, although it will get cramped...
   
3.   float y = knobY + sin(rot) * (knobRadius + 10);
4.  
   
5.   //This section determines what side of the knob the text is on, therefor affecting how the text should be displayed
   
6.   int modRot = rot % TWO_PI;
7.   if(modRot < TWO_PI / 6 || modRot > TWO_PI / 6 * 5 || (modRot > TWO_PI / 6 * 2 && modeRot < TWO_PI / 6 * 4)) textAlign(CENTER, CENTER);
   
8.   if(modRot >= TWO_PI / 6 && modRot <= TWO_PI / 6 * 2) textAlign(RIGHT, CENTER);
   
9.   if(modRot <= TWO_PI / 6 * 5 && modRot >= TWO_PI / 6 * 4) textAlign(LEFT, CENTER);
10.  
    
11.   text(label, x, y);
    
12. }

@anisha26

Don't double post. Especially since your other similar post is in the wrong section.

To define a custom View for a controller (such as a Knob) you can use the ContollerView interface.

See the ControlP5customView example.