| 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. |
