| SPI Chip Select behavior: | |
| With the Blackfin on-chip SPI peripheral, there is some logic tied to the CPHA | |
| bit whether the Slave Select Line is controlled by hardware (CPHA=0) or | |
| controlled by software (CPHA=1). However, the Linux SPI bus driver assumes that | |
| the Slave Select is always under software control and being asserted during | |
| the entire SPI transfer. - And not just bits_per_word duration. | |
| In most cases you can utilize SPI MODE_3 instead of MODE_0 to work-around this | |
| behavior. If your SPI slave device in question requires SPI MODE_0 or MODE_2 | |
| timing, you can utilize the GPIO controlled SPI Slave Select option instead. | |
| In this case, you should use GPIO based CS for all of your slaves and not just | |
| the ones using mode 0 or 2 in order to guarantee correct CS toggling behavior. | |
| You can even use the same pin whose peripheral role is a SSEL, | |
| but use it as a GPIO instead. |