Development SPI driver, found that continuous send multi-byte choose it was not always lower signal, each byte is lower then up in this way, whether it's written in function of the SPI driver, or directly in the source code inside has some SPI driver from the device, with the oscilloscope is the amount of this phenomenon, see online have a solution is to put the selected signal into a general IO, their control, but ask why not using Linux with SPI function directly, there is no bug is Linux source code, I tried a version 4.9 and 5.3 is the problem, please guide the great god!!!!! Be very grateful!

CodePudding user response:

It has to do with SPI controller, is the SPI master drive related, not SPI device drivers,
Some SPI master, it is straight hair, and CS has been low, as for your situation over there, looking at how SPI configuration, the SoC in theory, there should be a configuration item, look at how to say the SoC specification,

CodePudding user response:

The source code to check the spi controller implementation, take a look at how is set up,

CodePudding user response:

You are wrong, you use the oscilloscope measurement?
There is no doubt that the Linux, either you put the SCK line as the cs line, or you don't have a test for,