Messages in this thread | | | Subject | Re: [RFC PATCH 0/1] Portable Device Tree Connector -- conceptual | From | Frank Rowand <> | Date | Mon, 4 Jul 2016 11:15:44 -0700 |
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On 07/04/16 08:22, Mark Brown wrote: > On Sat, Jul 02, 2016 at 04:55:49PM -0700, frowand.list@gmail.com wrote: > >> This is an extremely simple example to illustrate the concepts. It is not >> meant to represent the complexity of a real board. >> >> To start with, assume that the device that will eventually be on a daughter >> board is first soldered onto the mother board. The mother board contains >> two devices connected via bus spi_1. One device is described in the .dts >> file, the other is described in an included .dtsi file. >> Then the device tree files will look like: > > Can I suggest not using SPI as an example here? It's particularly > messy since addresses are essentially just a random signal that can be > totally separate to the controller hardware which might be adding more > complexity early on in building up your model than is really desirable. > It will need to be dealt with but perhaps not right now. I2C might be > easier. > > The initial issue with SPI is that you really need to do something like > bring out individual slots on the bus rather than the bus as a whole > since you're going to need a remapping layer to map chip selects on the > module to chip selects on the host board. >
Yes, thank you for pointing that out.
For the purposes of the mental model, when thinking about what I wrote, just change SPI to I2C everywhere.
-Frank
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