On 06/19, Mark Brown wrote: > On Wed, Jun 19, 2024 at 03:58:00PM -0300, Marcelo Schmitt wrote: > > On 06/19, David Lechner wrote: > > > On 6/18/24 6:10 PM, Marcelo Schmitt wrote: > > > > > +In this extension to the usual SPI protocol, the MOSI line state is specified to > > > > +be kept high when CS is active but the controller is not clocking out data to > > > > I think it would be less ambiguous to say "asserted" instead of "active". ack, replaced "active" by "asserted" when describing CS state for v5. > > > I'm not sure. IMHO, it looks less ambiguous to say a CS is active. > > I think the most common for CS lines is to have a CS that is active low (i.e. > > the line is at a low voltage level when the controller is selecting the device). > > To me, "assert" sounds closer to the idea o setting something (like a bit to 1), > > which is the opposite of active low CS. > > Though, no strong opinion about it. > > I go with what the maintainers prefer. > > I think they're synonyms but asserted is the more common term for chip > selects. > > > > > > +#define SPI_CONTROLLER_MOSI_IDLE_LOW BIT(8) /* Can idle MOSI low */ > > > > +#define SPI_CONTROLLER_MOSI_IDLE_HIGH BIT(9) /* Can idle MOSI high */ > > > > I don't see where these are used anywhere else in the series. They > > > seem redundant with SPI_MOSI_IDLE_LOW and SPI_MOSI_IDLE_HIGH. > > > Good point. > > They are currently not being used. > > Comparing with what we have for SPI_CONTROLLER_MULTI_CS, I'm thinking it may be > > handy to have dt properties to indicate controller MOSI idle capabilities. > > Does that sound reasonable? > > We shouldn't need DT properties, we should just know if the controller > supports this based on knowing what controller is, and I'd not expect it > to depend on board wiring. Okay, though, I fail to see the need for #define SPI_CONTROLLER_MOSI_IDLE_LOW BIT(8) /* Can idle MOSI low */ #define SPI_CONTROLLER_MOSI_IDLE_HIGH BIT(9) /* Can idle MOSI high */ It looks like SPI_CONTROLLER bits are used to tweak controller operation in various ways. Right now, I'm not aware of any additional tweak needed to support the MOSI idle feature. I have tested that on Raspberry Pi with bitbang/gpio controller and on CoraZ7 with spi-engine and it did work fine in those setups. Anyway, I'm prone to implement any additional changes to make this set better. Thanks, Marcelo
