Messages in this thread | | | Date | Tue, 25 Apr 2017 11:31:13 +0100 | From | Mark Brown <> | Subject | Re: [PATCH RFC 0/5] *** SPI Slave mode support *** |
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On Mon, Apr 24, 2017 at 12:55:21PM +0200, Geert Uytterhoeven wrote: > On Fri, Apr 14, 2017 at 7:39 AM, Jiada Wang <jiada_wang@mentor.com> wrote:
> > Our use case is to use spidev as an interface to communicate with external > > SPI master devices. > > meanwhile the SPI bus controller can also act as master device to send data > > to other > > SPI slave devices on the board.
> That sounds a bit hackish to me. SPI was never meant to be a multi-master bus. > While it can be done, you will need external synchronization (signals) to > avoid conflicts between the SPI masters.
> > I found in your implementation, SPI bus controller is limited to either work > > in master mode or > > slave mode, is there any reasoning to not configure SPI mode based on SPI > > devices use case?
> If you really need both master and slave support, you can use 2 subnodes > in DT, the first representing the master, the second the slave.
> Mark, what's your opinion about this?
That sounds like a mess... we *could* put the slave flag on the device rather than the controller I guess but there's also going to need to be something representing whatever avoids collisions on the bus somewhere. [unhandled content-type:application/pgp-signature] | |