The 01/29/2019 18:21, Boris Brezillon wrote:
+Optional properties:
+Driver calculates controller timings base on NAND flash memory timings and
+the following delays in picoseconds.
+ - cdns,if-skew : Skew value of the output signals of the NAND Flash interface
+ - cdns,nand2-delay : Delay value of one NAND2 gate from which
+ the delay element is build
+ - cdns,board-delay : Estimated Board delay. The value includes the total
+ round trip delay for the signals and is used for deciding on values
+ associated with data read capture. The example formula for SDR mode is
+ the following:
+ board_delay = RE#PAD_delay + PCB trace to device + PCB trace from device
+ + DQ PAD delay
The unit of those props is not defined, and if possible I'd like to
avoid specifying custom timing adjustment values in the DT. Looks like
some of these values are SoC specific (depends on the integration of
this IP in a SoC) and others are board specific. For SoC specific
values, this should be attached to the SoC specific compatible at the
driver level. For board-specific values, I'd prefer to have a generic
way to describe boards constraints.
Moving SoC specific delays from DTS to the driver data is clear for me. I do not know how to handle a board delay. Could you give me an example how it may be implemented? Where this board related stuff could be placed?
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Regards
Piotr Sroka
