arch/arm/mach-omap2/include/mach/board-zoom.h - kernel/msm-4.9 - Gitiles

 /*
  * Defines for zoom boards
  */
 extern int __init zoom_debugboard_init(void);
 extern void __init zoom_peripherals_init(void);

 #define ZOOM2_HEADSET_EXTMUTE_GPIO	153
	/*
	* Defines for zoom boards
	*/
	extern int __init zoom_debugboard_init(void);
	extern void __init zoom_peripherals_init(void);

	#define ZOOM2_HEADSET_EXTMUTE_GPIO 153