is there a shell command can change SPI clock for raspberry pi zero?

Question

I would like to write a bash file to light up an OLED screen with SSD1306 driver, with below code I can send the SPI commands to the screen but seems the CLK is supper fast so the SSD1306 doesn't work, is there a way to change the SCLK for SPI interface(like set to 4Mhz) in the shell? I am using Raspberry Pi Zero W.

echo -ne $cmd > /dev/spidev0.0

Answer 1

You can try the following for 3.9MHz:

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

Table for different speed deviders you can find here