SPI4 on stm32mp157f-dk2 SCLK won't run faster than 16MHz

[Acekiller007]

Hi, I am trying to run spidev on the stm32mp157f-dk2 using python and I have set my SPI4 max frequency above 40MHz, but I can't seem to run it more than 16MHz. I have checked the clock tree configurations and the device tree configuration; I seem to have set everything correctly but I can't seem to run it faster. 

[Andrew Neil · Accepted solution]

Please see the Posting Tips for how to properly post source code - not as images:

https://community.st.com/t5/community-guidelines/how-to-write-your-question-to-maximize-your-chances-to-find-a/ta-p/575228

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@Acekiller007 wrote:

 I can't seem to run it more than 16MHz.

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So what does happen when you try >16MHz ?

Do you get an error? Does it just stick at 16MHz? Or what?

Does the Python documentation state any limitations?

[Acekiller007]

Hello Andrew! Thank you for the guidelines. 

Regarding the issue, I do not get any specific error message I just cannot seem to measure the Frequency above 16MHz even though I try to run SPI4 at 40MHz or more. I'm not sure if the python documentation states any limitations and it should be able to run more than 16MHz but if I try to run at 40MHz, my code works but I cannot see the equivalent frequency of the clock when I measure it.