Unnamed

#define HWREG2(name, v, args...) (hal->ah_version == AR5K_AR ## v ? name ## _ ## v : name ## _ ## args)
#define HWREG3(name, v, args...) (hal->ah_version == AR5K_AR ## v ? name ## _ ## v : HWREG2(name, args))
#define HWREG4(name, v, args...) (hal->ah_version == AR5K_AR ## v ? name ## _ ## v : HWREG4(name, args))

enum {
    AR5K_EEPROM_DATA_5211 = 0x6004,
    AR5K_EEPROM_DATA_5210 = 0x6800,
};

data = HWREG2(AR5K_EEPROM_DATA, 5210, 5211)
// or:
data = HWREG3(AR5K_EEPROM_DATA, 5210, 5211, 5212)