On Mon, Aug 03, 2015 at 11:13:55AM -0500, Rob Herring wrote: > On Mon, Aug 3, 2015 at 1:59 AM, Sagar Dharia <sdharia@xxxxxxxxxxxxxx> wrote: > > +Optional: > > +- compatible - Slave devices can use compatible field to have a name. > > + If this field is missing, name of the device will be > > + determined using slave's enumeration address. > > + (e.g. in the example below, slave's name will be: > > + 0x217:0x60:0x1:0x0) > Are devices discoverable and uniquely identifiable? This would be > something like a VID/PID which can be read in a generic way. It looks > like the address contains this info, but can you discover the > addresses of devices on the bus? If not compatible should not be > optional. Yes, the bus is enumerable. However in essentially all implementations devices won't enumerate without some additional non-standard work being done to power them on since applications tend to be extremely power sensitive relative to the basic operating cost of the bus. Which is entertaining. This probably means that the binding needs to say that the compatible is optional but that for all practical purposes Linux requires it until such time as someone decides it's worth supporting systems that can usefully enumerate.
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