diff options
| -rw-r--r-- | Documentation/devicetree/bindings/spi/spi-bus.txt | 10 | ||||
| -rw-r--r-- | drivers/spi/spi.c | 77 |
2 files changed, 47 insertions, 40 deletions
diff --git a/Documentation/devicetree/bindings/spi/spi-bus.txt b/Documentation/devicetree/bindings/spi/spi-bus.txt index 296015e3c632..800dafe5b01b 100644 --- a/Documentation/devicetree/bindings/spi/spi-bus.txt +++ b/Documentation/devicetree/bindings/spi/spi-bus.txt @@ -55,6 +55,16 @@ contain the following properties. 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 diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index 6ef349f82b5f..9e039c60c068 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -886,48 +886,44 @@ static void of_register_spi_devices(struct spi_master *master) spi->mode |= SPI_3WIRE; /* Device DUAL/QUAD mode */ - prop = of_get_property(nc, "spi-tx-nbits", &len); - if (!prop || len < sizeof(*prop)) { - dev_err(&master->dev, "%s has no 'spi-tx-nbits' property\n", - nc->full_name); - spi_dev_put(spi); - continue; - } - switch (be32_to_cpup(prop)) { - case SPI_NBITS_SINGLE: - break; - case SPI_NBITS_DUAL: - spi->mode |= SPI_TX_DUAL; - break; - case SPI_NBITS_QUAD: - spi->mode |= SPI_TX_QUAD; - break; - default: - dev_err(&master->dev, "spi-tx-nbits value is not supported\n"); - spi_dev_put(spi); - continue; + 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; + case SPI_NBITS_DUAL: + spi->mode |= SPI_TX_DUAL; + break; + case SPI_NBITS_QUAD: + spi->mode |= SPI_TX_QUAD; + break; + default: + dev_err(&master->dev, + "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); - if (!prop || len < sizeof(*prop)) { - dev_err(&master->dev, "%s has no 'spi-rx-nbits' property\n", - nc->full_name); - spi_dev_put(spi); - continue; - } - switch (be32_to_cpup(prop)) { - case SPI_NBITS_SINGLE: - break; - case SPI_NBITS_DUAL: - spi->mode |= SPI_RX_DUAL; - break; - case SPI_NBITS_QUAD: - spi->mode |= SPI_RX_QUAD; - break; - default: - dev_err(&master->dev, "spi-rx-nbits value is not supported\n"); - spi_dev_put(spi); - continue; + 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; + case SPI_NBITS_DUAL: + spi->mode |= SPI_RX_DUAL; + break; + case SPI_NBITS_QUAD: + spi->mode |= SPI_RX_QUAD; + break; + default: + dev_err(&master->dev, + "spi-rx-bus-width %d not supported\n", + be32_to_cpup(prop)); + spi_dev_put(spi); + continue; + } } /* Device speed */ @@ -1480,6 +1476,7 @@ static int __spi_async(struct spi_device *spi, struct spi_message *message) return -EINVAL; if (xfer->speed_hz && master->max_speed_hz && xfer->speed_hz > master->max_speed_hz) + return -EINVAL; if (xfer->tx_buf && !xfer->tx_nbits) xfer->tx_nbits = SPI_NBITS_SINGLE; |