diff options
Diffstat (limited to 'include/spi.h')
| -rw-r--r-- | include/spi.h | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/include/spi.h b/include/spi.h index 10286accab..b06f266d0c 100644 --- a/include/spi.h +++ b/include/spi.h @@ -85,6 +85,29 @@ int spi_transaction(const struct spi_device_t *spi_device, const uint8_t *txdata, int txlen, uint8_t *rxdata, int rxlen); +/* Issue a part of SPI transaction. Assumes SPI port has already been enabled. + * + * If CS is not asserted, asserts it first. + * Transmits <txlen> bytes from <txdata>, throwing away the corresponding + * received data, then transmits <rxlen> unused bytes, saving the received data + * in <rxdata>. + * If SPI_READBACK_ALL is set in <rxlen>, the received data during transmission + * is recorded in rxdata buffer and it assumes that the real <rxlen> is equal + * to <txlen>. + * If 'final' is true, deasserts CS once transfer is completed. + * + * @param spi_device the SPI device to use + * @param txdata buffer to transmit + * @param txlen number of bytes in txdata. + * @param rxdata receive buffer. + * @param rxlen number of bytes in rxdata or SPI_READBACK_ALL. + * @param deassert_cs flag indicating that CS needs to be deasserted in the + * end of this sub transaction. + */ +int spi_sub_transaction(const struct spi_device_t *spi_device, + const uint8_t *txdata, int txlen, uint8_t *rxdata, + int rxlen, bool deassert_cs); + /* Similar to spi_transaction(), but hands over to DMA for reading response. * Must call spi_transaction_flush() after this to make sure the response is * received. |