On Thu, Feb 22, 2024 at 09:02:30PM +0100, Marco Felsch wrote: > On 24-02-22, Conor Dooley wrote: > > On Wed, Feb 21, 2024 at 08:12:47PM +0100, Marco Felsch wrote: > > > Microchip FPGAs can communicate in different modes, so document them to > > > avoid dt-validate warnings. > > > > Are you sure it can "communicate in different modes"? > > No I'm not but I didn't found an overview within the FPGA datasheet [1] > which modes are supported. What I did found was an note which says: > > """ > 1. Parameters are referenced to the active edge of SCK, which depends on > the configured SPI protocol (for example, Motorola SPI mode uses rising > edge as active edge if SPO = 0) > """ > > Therefore I thought that this can be configured somehow differently. > > [1] https://www.microsemi.com/document-portal/doc_view/136519-ds0141-polarfire-fpga-datasheet > > > The documentation actually says "Motorla SPI Mode 3 is required to > > communicate with M2S, M2GL, and MPF devices using dedicated system > > controller SPI port" with mode 3 being SPO = SPH = 1: > > https://www.microsemi.com/document-portal/doc_view/137543-spi-directc-sp1-v2-0-user-guide > > Thanks for the Pointer, there are plenty documents for the Polarfire > FPGA. > > > I suspect the answer is that it can actually communicate in different > > modes (because I don't recall setting those options), but the binding > > should enforce the correct way of doing it IMO. > > Sure, I will rephrase my commit message to: > > """ > dt-bindings: fpga: microchip,mpf-spi-fpga-mgr: document CPOL/CPHA > > Using the dedicated system controller SPI port requires Motorola SPI > Mode 3 according the SPI-DirectC v2.0 User Guid [1]. So require the > spi-cpol and spi-cpha to be set. > > [1] https://www.microsemi.com/document-portal/doc_view/137543-spi-directc-sp1-v2-0-user-guide > """ You say require here, but don't actually make them required. I think we probably should actually make them required, since the docs say they should be used, but I'd like to look at it a bit more though before that, since it does work on the setup I had without them. I'd say do s/require/allow/ and I'll try to do some testing as to whether we should actually mark the properties as required. Acked-by: Conor Dooley <conor.dooley@xxxxxxxxxxxxx> Cheers, Conor.
Attachment:
signature.asc
Description: PGP signature
