On Wed, Jun 13, 2018 at 7:35 AM, Suzuki K Poulose Suzuki.Poulose@arm.com wrote:
Hi Matt,
Thanks for your comments, responses inline.
On 13/06/18 13:49, Matt Sealey wrote:
Suzuki,
Why not use “unit”?
I believe we had this discussion years ago about numbering serial ports and sdhci (i.e. how do you know it’s UART0 or UART1 from just the address? Some SoC’s don’t address sequentially *or* in a forward direction) - I believe it’s not exactly codified in ePAPR, not am I sure where it may be otherwise, but it exists.
We have different situation here. We need to know *the port number* as understood by the hardware, so that we can enable *the specific* port for a given path.
I agree with Rob on the slave-mode nonsense, this is an SPI controller concept weirdly stuffed into a directed graph which implicitly tells you the data direction - it’s a rooted tree (just like DT!).
OF graph is not directional. All links must be bi-directional and in fact dtc checks that now. The parent node should know the numbering and direction of each port.
Btw, the "slave-mode" is not a standard DT graph binding. It is not part of the generic DT graph binding. In fact the generic bindings stay away from the direction aspect and explicitly mentions the same.
I really don't like slave-mode nor coresight,hwid.
I would prefer to see getting rid of both and splitting ports into "in-ports" and "out-ports" nodes instead of a single "ports" node. Then you don't need any of these properties and reg can be used as the hwid.
Rob