Jetson Nano SPI: how to control delay between words within one transfer

When transmitting multiple 8-bit words in a SPI transfer, some SPI clients require delay before sending/receiving next word. The following picture shows the delay between words within one SPI transfer on Raspberry Pi:

The upper trace is SPI CLK and lower trace is SPI CS. But there is no such delay on Jetson Nano as shown in the following picture:

For the above picture SPI CLK frequency is 1 MHz, and delay_usecs in struct spi_ioc_transfer is 4us. Changing delay_usecs did not create the delay between words.

Does anyone know how to control the delay between words? Is this a bug in SPI driver?


Thanks for reporting this issue, we will investigate it and update once clarified.

Hi kayccc,
I meet the same question, set .delay_usecs does not work.

struct spi_transfer	tr = 
            .tx_buf	= txdata,
            .rx_buf = rxdata,
            .len	= 3,
            .delay_usecs = 10,