It is strange that this spi clk frequency can only be increased but not decreased. For example, the clk configuration is not available if it is lower than 150khz, but it is available if it is higher than 150khz, for example, it can be configured as 200khz.
I can not config the SPI2’s CLK to low frequency, like 80khz. seems it need to config the SPI clock source ? How to do it?
For lower SPI frequncy, you may need to use another parent clock for SPI2.
Please refer to the following steps:
Step 1. Check current parent clock
$ sudo su
# cat /sys/kernel/debug/bpmp/debug/clk/spi2/parent
Step 2. Use pll_c instead
# echo pll_c > /sys/kernel/debug/bpmp/debug/clk/spi2/parent
Step 3. Check its rate
# cat /sys/kernel/debug/bpmp/debug/clk/spi2/rate
Step 4. Check if SPI2 could work with 80KHz in your case