I took the liberty to format your C code for improved readability.
You write that the clock was not generated. That means that no SPI transaction was started, so I expect an error has occured. I notice in your code that you ignore most return values. That is a very bad idea, and the first thing you should do is to improve your code so that you check all return values using APP_ERROR_CHECK (particularly the return values from nrf_drv_spi_transfer()). Are there any errors here? What else do you see from debugging?
