diff options
Diffstat (limited to 'Documentation/devicetree/bindings/spi/spi-bus.txt')
| -rw-r--r-- | Documentation/devicetree/bindings/spi/spi-bus.txt | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/Documentation/devicetree/bindings/spi/spi-bus.txt b/Documentation/devicetree/bindings/spi/spi-bus.txt index 296015e3c63..bbaa857dd68 100644 --- a/Documentation/devicetree/bindings/spi/spi-bus.txt +++ b/Documentation/devicetree/bindings/spi/spi-bus.txt @@ -55,9 +55,21 @@ contain the following properties. chip select active high - spi-3wire - (optional) Empty property indicating device requires 3-wire mode. +- spi-lsb-first - (optional) Empty property indicating device requires + LSB first 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 the SPI system to be transferred 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 +via the SPI master node cs-gpios property. SPI example for an MPC5200 SPI bus: spi@f00 { |