How to improve SPI speed at TX1

Autonomous Machines Jetson & Embedded Systems Jetson TX1
1

Dear,

SPI of TX1 is enabled and gathering data from FLIR Repton 3.5 module.
Here, Lepton requires under 125us to read 1 packet for normal operation.
Jetson TX1, however, spends 250~350us to do.

It seems like that TX1 waits some time about 200us between TX and RX or interrupts.
Would you advise how to improve SPI Speed here?

Thanks,

2

Could you try add below to your DT to try.
spi@xxxxx{

  •   nvidia,polling-mode;

  •   nvidia,disable-runtime-pm;
  status = "okay";
    };
3

Shane,

Thanks for your advice. but it did not improve this situation.

If I add something,

  • after JetPack upgrading from 28.2.1 to 28.3, speed slightly improved.
    (250~350us to 170~220us)
    for this job, tegra_spi_clear_status(in spi-tegra114.c) function has small modification as follows;
/* Read back status register to confirm interrrupt is cleared */
	val = tegra_spi_readl(tspi, SPI_TRANS_STATUS);

But Repton should receive data within 125us to accomplish 1 packet, this time is too long.
tegra_spi_status_pollfunction may read SPI_TRANS_STATUS to figure out SPI_RDY is set or not.
This bit/register,IMO, seems to need time to be set.

How to improve it?

Thanks

4

Does boost to performance mode help on this. (sudo ./jetson_clocks.sh)

5

Thanks Shane,

Boost helped here!