On Wed, 28 Feb 2024 at 17:09, Sudeep Holla <sudeep.holla@xxxxxxx> wrote: > > 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. That's perfectly fine, if that is sufficient. It would also be perfectly fine to extend it with a platform/soc specific compatible, when needed. An example could be: compatible = "qcom,sm8450-coresight-tpiu", "arm,coresight-tpiu"; Krzysztof, please correct me if I am wrong. Kind regards Uffe
