Messages in this thread | | | Subject | Re: "compatible" and "model" properties in .dts for ARC boards | From | Vineet Gupta <> | Date | Tue, 17 Nov 2015 17:48:48 +0530 |
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On Friday 06 November 2015 04:27 PM, Jonas Gorski wrote: > On 06.11.2015 09:59, Arnd Bergmann wrote: >> On Friday 06 November 2015 04:45:24 Vineet Gupta wrote: >>>> >>>> During OpenWRT upsreaming process one interesting topic was raised. >>>> See in the middle of https://lists.openwrt.org/pipermail/openwrt-devel/2015-November/036959.html >>>> >>>> In Device Tree descriptions for our boards we don't use "model" property >>>> even though it is a required one as specified by ePAPR, see >>>> http://free-electrons.com/~thomas/pub/Power_ePAPR_APPROVED_v1.0.pdf, >>>> page 39 "Table 3-1 Root node properties". >>>> >>>> Instead we put 2 items in "compatible" property. >>>> >>>> For example: >>>> ------------------->8---------------- >>>> compatible = "snps,axs101", "snps,arc-sdp"; >>>> ------------------->8---------------- >>>> >>>> And from ePAPR standpoint it makes sense to split contents of that "compatible" >>>> property in 2: >>>> ------------------->8---------------- >>>> compatible = "snps,arc-sdp"; >>>> model = "snps,axs101"; >>>> ------------------->8---------------- >>> >>> It seems model is just a descriptive label and we can surely add them to existing DT. >>> compatible on the other hand is more fundamental used for exact comparisons etc >>> and follows the vendor,device convention. >>> It is pretty common for compatible to have multiple strings for exactly the same >>> reason as I have them here. Both axs101 and axs103 are based on sdp thus we want >>> the ability to have both pieces of information and use as needed. >> >> Correct. >> >> The model should also be a human readable name of the machine, just one >> string like "Synapsys AXS101 Development Board" (or whatever that is called). > > This contradicts ePAPR, which says the model's recommended* format is the same as > the compatible one's (<vendor>,<model>). Most PowerPC and some MIPS dts files > follow that, while ARM(64) uses the free text form. > > To me it looks like the intended usage was > model = <actual_model>; compatible = <platform>; > but the actual usage in arm is > model = <human readable string>; compatible = <actual_model>, <platform>; > > Of course for changing this in the existing dts files it might be a bit late, but it > would be good to decide which of these two is the actually expected format. > > It also is a required property, and we have a few boards not having a model property, > including the example in Documentation/devicetree/usage-model.txt. > > > Jonas > > * compatible strings are also only "recommended" to be in that format. >
Alexey, can u please rework the DT files per Jonas' suggestion above.
Thx, -Vineet
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