On Tue, Oct 8, 2024 at 5:40 PM Krzysztof Kozlowski <krzk@xxxxxxxxxx> wrote: > > On 08/10/2024 13:59, Joy Chakraborty wrote: > >>> > >>>> > >>>>> + description: When set core will set Tx de-emphasis for USB Gen2 > >>>> > >>>> And why it cannot be implied by compatible? > >>> > >>> As per my understanding these are tuning coefficients for de-emphasis > >>> particular to a platform and not the dwc3 controller, hence should not > >>> be a controller compatible. > >> > >> Platforms must have specific compatible, so this should be implied by > >> compatible. > > > > Maybe I am using the word "platform" incorrectly here, what I > > understand is that the same controller(in a chip) when used on 2 > > different physical form factors might need different deemphasis > > You mean boards? This is board-level property? Yes, the USB controller can be paired with different phys in a SoC and used on different board layouts where we should be able to drive different de-emphasis coefficients to the phy as per the link equalization requirements is my understanding. > > > coefficient values to be passed to its Phy. Someone could correct me > > from the USB link stand point if I am mistaken here. > > > > Then please point me to the upstream DTS boards using these properties. > Lore link is enough, if board or DTS change is being upstreamed. > The DTS change is not being upstreamed currently. But this change would help bring up a new or development board where USB compliance is being run and this parameter needs tuning, hence being able to upstream this would help. > Best regards, > Krzysztof >
