On Mon, Aug 20, 2012 at 4:22 PM, Rob Herring <robherring2@xxxxxxxxx> wrote: > On 08/20/2012 06:39 AM, Alexandre Pereira da Silva wrote: >> +- pl022,hierarchy : master or slave interface > > Is attaching a master and using the pl022 as a slave really a supported > use case? No not currently. People doing this crazy stuff need to have the kernel with the hard real-time patches and lightening response first. But it's in the platform data because it's a feature supported by the hardware. > The DT spi bindings are really designed for a master node with > N slave nodes. So there is more general question of how to describe a > spi controller as a slave. It's not really one I care to answer as the > Linux spi framework isn't designed to act as a slave. Currently the code should hardwire this to master and not define a binding for it I think. >> +- pl022,slave-tx-disable : disconnect tx line in slave mode Applies also to this, then. >> +- pl022,com-mode : polling, interrupt or dma >> +- pl022,rx-level-trig : Rx FIFO watermark level >> +- pl022,tx-level-trig : Tx FIFO watermark level >> +- pl022,ctrl-len : Microwire interface: Control length >> +- pl022,wait-state : Microwire interface: Wait state >> +- pl022,duplex : Microwire interface: Full/Half duplex > > Most of these properties aren't used anywhere in the kernel other than > u300 and I'm not sure what to purpose of dummy_chip_info is. It is used for loopback-testing of the PL022. They're probably not necessary there either. > Perhaps > Linus has some input? I think either they can be decided by the spi > controller (com-mode, fifo watermark) or should be standard properties > (microwire settings). I would argue they should be removed if the spi > framework doesn't have support in a standard way. Uncertain about this, others would need to comment. At some point there has been a chip needing these to be set to some magic values. Yours, Linus Walleij -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
