Just a minor clarification for persons who are going to read an RSSI.
The 0x040F register contains the first 16 bits (most significant bits) and the 0x040E contains only 2 last bits (less significant bits). So the final RSSI value contains only 18 bits and should be obtained in the following way:
msbReg = LMS7002M_RD(0x040F);
lsbReg = LMS7002M_RD(0x040E);
return (msbReg << 2) | (lsbReg & 0x3);
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