[AM3358] Increase McSPI chip-select control hold time

Dear TI,

I need a specific design between CS and SPI clock for delay above 20us. But it seems to be too short for the default  McSPI setting.

Here're some method that I want to use

1. Can I add delay time in spi-omap2-mcspi.c ? If yes, where can I add it ?

2. Use additional GPIO pin  as CS pin  to control ?

or Is there any  method to solve ?

Thanks a lot.

BR.