SPI Chip Select Fine Control

[orangespringlabs]

Hi,
I am trying to interface the ESP32 with the TLC5958 (http://www.ti.com/product/TLC5958). The MOSI and SCK pins are standard, however, the CS pin is not and needs to be held high for ONLY some number of SPI clock cycles. I have attached the timing diagram below.

The SPI_CS_HOLD_DELAY, SPI_CS_DELAY_NUM, and SPI_CS_DELAY_MODE registers look promising, however they are not exposed to the user in the latest ESP32 Tech Reference.

Is there a way to configure the SPI driver to do this? If not, what is the best way to bit-bang this so that the SPI bus can still run at 20Mhz?

Thank you for your help.