On 6/29/24 2:04 PM, Marcelo Schmitt wrote: > The behavior of an SPI controller data output line (SDO or MOSI or COPI > (Controller Output Peripheral Input) for disambiguation) is usually not > specified when the controller is not clocking out data on SCLK edges. > However, there do exist SPI peripherals that require specific MOSI line > state when data is not being clocked out of the controller. > > Conventional SPI controllers may set the MOSI line on SCLK edges then bring > it low when no data is going out or leave the line the state of the last > transfer bit. More elaborated controllers are capable to set the MOSI idle > state according to different configurable levels and thus are more suitable > for interfacing with demanding peripherals. > > Add SPI mode bits to allow peripherals to request explicit MOSI idle state > when needed. > > When supporting a particular MOSI idle configuration, the data output line > state is expected to remain at the configured level when the controller is > not clocking out data. When a device that needs a specific MOSI idle state > is identified, its driver should request the MOSI idle configuration by > setting the proper SPI mode bit. > > Acked-by: Nuno Sa <nuno.sa@xxxxxxxxxx> > Signed-off-by: Marcelo Schmitt <marcelo.schmitt@xxxxxxxxxx> > --- Tested both valid and invalid combinations of flags and saw expected behavior/error messages in all cases. Reviewed-by: David Lechner <dlechner@xxxxxxxxxxxx> Tested-by: David Lechner <dlechner@xxxxxxxxxxxx>
