请问D1怎么才能通过命令行动态给SPI调速？

[ubuntu]

https://stackoverflow.com/questions/57262938/is-there-a-shell-command-can-change-spi-clock-for-raspberry-pi-zero

echo -ne "\x06\x04" > /sys/class/spi_master/spi0/of_node/spi-max-frequency

请问D1怎么才能通过命令行动态给SPI调速？

这里 /sys/class/spi_master/ 下面啥文件也没有：

root@TinaLinux:/# ls /sys/class/spi_master/
root@TinaLinux:/#

[memory]

root@TinaLinux:/# hexdump  /sys/firmware/devicetree/base/soc@3000000/spi@4025000
/spi-nand@0/spi-max-frequency
0000000 f505 00e1
0000004
root@TinaLinux:/#

只找到这个节点，而且只读，不能写。

[ubuntu]

是呀，我也发现了。

https://community.toradex.com/t/imx8x-max-frequency-of-spidev/10970

小飞的也可以重设SPI速率

[Jingyan]

使用spidev-test测试命令的-s参数可以调整spi速率

Usage: ./spidev_test [-DsbdlHOLC3vpNR24SI]
  -D --device   device to use (default /dev/spidev1.1)
  -s --speed    max speed (Hz)
  -d --delay    delay (usec)
  -b --bpw      bits per word
  -i --input    input data from a file (e.g. "test.bin")
  -o --output   output data to a file (e.g. "results.bin")
  -l --loop     loopback
  -H --cpha     clock phase
  -O --cpol     clock polarity
  -L --lsb      least significant bit first
  -C --cs-high  chip select active high
  -3 --3wire    SI/SO signals shared
  -v --verbose  Verbose (show tx buffer)
  -p            Send data (e.g. "1234\xde\xad")
  -N --no-cs    no chip select
  -R --ready    slave pulls low to pause
  -2 --dual     dual transfer
  -4 --quad     quad transfer
  -8 --octal    octal transfer
  -S --size     transfer size
  -I --iter     iterations