mt7621_spi_read
reg = mt7621_spi_read(rs, MT7621_SPI_MASTER);
status = mt7621_spi_read(rs, MT7621_SPI_TRANS);
val = mt7621_spi_read(rs, MT7621_SPI_TRANS);
val = mt7621_spi_read(rs, MT7621_SPI_DATA0 + i);
val = mt7621_spi_read(rs, MT7621_SPI_OPCODE + (len & ~3));
host = mt7621_spi_read(rs, MT7621_SPI_MASTER);