On Wed, Feb 28, 2024 at 03:20:44PM +0100, Krzysztof Kozlowski wrote: > On 28/02/2024 15:02, Sudeep Holla wrote: > > On Wed, Feb 28, 2024 at 02:27:30PM +0100, Ulf Hansson wrote: > >> On Mon, 26 Feb 2024 at 15:24, Nikunj Kela <quic_nkela@xxxxxxxxxxx> wrote: > >>> > >>> Hi Sudeep, > >>> > >>> I would like to conclude on this thread. I was discussing this with Ulf. > >>> He thinks that using the domain names to identify if platform is > >>> abstracting clocks etc. are not scalable and sufficient. Instead he > >>> thinks that the change in the interface to OS(and FW) is a good > >>> candidate for a new compatible(even though HW is same). Even for SCMI, > >>> we do change phandle in DT to SCMI protocol phandle so that is like a > >>> different platform altogether. Could you please let me know if you still > >>> think that using a different compatible in this case is not warranted. > >> > >> My apologies for joining this discussion at this late state. Yet, I > >> just wanted to confirm what Nikunj said above. > >> > >> In the end we are indeed talking about adding a new platform, as > >> changing the FW interface from a QCOM proprietary one into SCMI, > >> simply requires updates to a DTS file(s) that is platform specific. > >> > > > > The way I read this sounds like all this are platform specific and need > > new compatible. > > > >> That said, it also seems reasonable to me to use a compatible string, > >> to allow us to describe the update of HW for various affected devices. > >> > > > > While I agree with the above statement, it depends on what you refer as > > update of HW above. It is all Qcom specific and there is so much turn > > between SoCs that this shouldn't matter but I would like to take example > > and describe what I initially mentioned/argued against. > > > > Lets us assume 2 SoCs: A and B. A is old and didn't use SCMI while B is > > new and migrated to use SCMI. Now let us assume both A and B SoCs have > > exact same version/revision of an IP: X. Now just because B uses SCMI, > > should X have one compatible to be used in A and another in B. That > > doesn't sound right IMO. > > That's trivial to answer, because these are different SoCs. Compatibles > are SoC specific and every SoC-IP-block needs its compatible. Rob was > repeating this many times that versioned compatibles are discouraged. OK I may have confused or derailed the discussion with the mention of "exact same version/revision" of X. This is not related versioned compatibles. Let me try to explain it with some real example. If you look at all the users of "arm,coresight-tpiu", they all have same compatible on all the platforms irrespective of the clock/reset/voltage/power domain providers on these platforms. E.g. on juno it is based on SCMI while on qcom-msm8974/apq8064 or hi3660/hi6220 it is platform specific clock/power domain providers. However all these platform have the same compatible "arm,coresight-tpiu". That was the point I was trying to make and not related to versioned compatible for different versions on an IP. -- Regards, Sudeep
