Vijay Nikam wrote:

I added the gpio node as follows to mpc8313erdb.dts;

gpio@c00 {
	linux,phandle = <c00>;

Don't specify this explicitly.  Please base new development off of the 
device tree that is in upstream Linux, not the very old tree in your BSP.

	device_type = "gpio";

No device_type.

The only thing I need to know what should I write at 'compatible' tag
? ? ? the compatible tag format is "manufacturer,model" the
manufacturer is 'fsl' i.e. I think freescale but the model, as it is
the model number where I can find this model ? ? ? Please let me know
... thanks ...

compatible = "fsl,mpc8313-gpio", "fsl,mpc8349-gpio";

Also I would like to ask if the above device node is written according
to bindings ... I think it should be right as I referred
'bootingwithout-of.txt' ... but please correct me if I am worng ? ? ?

See also Documentation/powerpc/dts-bindings/fsl/8xxx_gpio.txt.

Also note that current Linux has a driver in 
arch/powerpc/sysdev/mpc8xxx_gpio.c.

-Scott