Somewhere I found the source code of built in shaders in Unity. So I just added emission property and apply it to result output and it works.
Hope might be helpful who needed it.
Shader "Custom/MobileBumpedDiffuse" {
Properties {
_Shininess ("Shininess", Range(0.03, 1)) = 0.078125
_MainTex ("Base (RGB)", 2D) = "white" {}
_Glossiness ("Glossiness", 2D) = "black" {}
_BumpMap ("Normalmap", 2D) = "bump" {}
}
SubShader {
Tags { "RenderType"="Opaque" }
LOD 300
CGPROGRAM
#pragma surface surf MobileBlinnPhong exclude_path:prepass nolightmap noforwardadd halfasview
inline fixed4 LightingMobileBlinnPhong(SurfaceOutput s, fixed lightDir, fixed3 halfDir, fixed atten)
{
fixed diff = max(0, dot(s.Normal, lightDir));
fixed nh = max(0, dot(s.Normal, halfDir));
fixed spec = pow(nh, s.Specular * 128) * s.Gloss;
fixed4 c;
c.rgb = (s.Albedo * _LightColor0.rgb * diff + _LightColor0.rgb * spec) * (atten * 2);
c.a = 0.0;
return c;
}
sampler2D _MainTex;
sampler2D _Glossiness;
sampler2D _BumpMap;
half _Shininess;
struct Input {
float2 uv_MainTex;
};
void surf(Input IN, inout SurfaceOutput o) {
fixed4 tex = tex2D(_MainTex, IN.uv_MainTex);
o.Albedo = tex.rgb;
o.Gloss = tex2D(_Glossiness, IN.uv_MainTex).rgb;
o.Alpha = tex.a;
o.Specular = _Shininess;
o.Normal = UnpackNormal(tex2D(_BumpMap, IN.uv_MainTex));
}
ENDCG
}
Fallback "Mobile/VertexLit"
}