chip select active high
 - spi-3wire       - (optional) Empty property indicating device requires
                    3-wire mode.
+- spi-tx-bus-width - (optional) The bus width(number of data wires) that
+                      used for MOSI. Defaults to 1 if not present.
+- spi-rx-bus-width - (optional) The bus width(number of data wires) that
+                      used for MISO. Defaults to 1 if not present.
+
+Some SPI controllers and devices support Dual and Quad SPI transfer mode.
+It allows data in SPI system transfered in 2 wires(DUAL) or 4 wires(QUAD).
+Now the value that spi-tx-bus-width and spi-rx-bus-width can receive is
+only 1(SINGLE), 2(DUAL) and 4(QUAD).
+Dual/Quad mode is not allowed when 3-wire mode is used.
 
 If a gpio chipselect is used for the SPI slave the gpio number will be passed
 via the cs_gpio
 
                        spi->mode |= SPI_3WIRE;
 
                /* Device DUAL/QUAD mode */
-               prop = of_get_property(nc, "spi-tx-nbits", &len);
+               prop = of_get_property(nc, "spi-tx-bus-width", &len);
                if (prop && len == sizeof(*prop)) {
                        switch (be32_to_cpup(prop)) {
                        case SPI_NBITS_SINGLE:
                                break;
                        default:
                                dev_err(&master->dev,
-                                       "spi-tx-nbits %d not supported\n",
+                                       "spi-tx-bus-width %d not supported\n",
                                        be32_to_cpup(prop));
                                spi_dev_put(spi);
                                continue;
                        }
                }
 
-               prop = of_get_property(nc, "spi-rx-nbits", &len);
+               prop = of_get_property(nc, "spi-rx-bus-width", &len);
                if (prop && len == sizeof(*prop)) {
                        switch (be32_to_cpup(prop)) {
                        case SPI_NBITS_SINGLE:
                                break;
                        default:
                                dev_err(&master->dev,
-                                       "spi-rx-nbits %d not supported\n",
+                                       "spi-rx-bus-width %d not supported\n",
                                        be32_to_cpup(prop));
                                spi_dev_put(spi);
                                continue;