SPI0 bus of C6748LCDK

i use API function: void SPIClkConfigure(unsigned int baseAdd,  unsigned int moduleClk, unsigned int spiClk,  unsigned int dataFormat) to declare SPI0 bus.

 I input values that baseAdd = SOC_SPI_0_REGS, moduleClk = 187500000 and spiClk = 2000000, dataFormat =  SPI_DATA_FORMAT0. As a result, SPI0 bus =2MHZ. Is it true? and Do i have to use PLL to configure SPI0 bus ?