On 28 November 2017 01:38, Badhri Jagan Sridharan wrote: > > examples in the kernel where this happens. Where are these functions likely > > to > > be called from, as wherever that is it will need a reference to the port? > > Actually should we be adding DT bindings to set supported src/snk PDOs from > > FW, > > if you're taking this approach to PDO selection? > > > > This patch also seemingly leaves 'max_snk_mv', 'max_snk_ma' and 'max_snk_mv' > > redundant, although those values can be configured from a PD controller > > driver > > (e.g. fusb302 actually supports DT bindings which allow these to be set > > through > > FW). Now these DT bindings are basically made redundant by your change as > > they > > have no impact. Are we expecting these to be used again in the future, or > > should > > Yes, I think 'max_snk_mv', 'max_snk_ma' and 'max_snk_mw' etc should be > removed. > The problem here is that maintaining these values implies that tcpm is > not going to > request pdo based on the sink_caps that are published. All these > values can be derived from > the sink_pdo objects that were declared, hence, they are redundant, > I will update the patch to remove this.
I have no problem really with this approach, other than right now with your patch there's no way to actually set the PDOs other than the 2 functions to update source and sink capabilities. Previously you had the option, at least through the fusb302 driver, to configure the max_snk_* values from DT, but your patch obviously changes this behaviour. I think we need a FW based method of configuring these at startup at least, as with your current patch the values being used are hard coded. As this is generic for TCPM I would guess DT bindings (and maybe equivalent ACPI properties as well I guess) would be a sensible approach. > > these be removed? FYI, as part of my PPS patch set I have been using them as > > part of the PPS APDO selection criteria, based on TCPM code prior to your > > modifications, as for PPS we're interested in a wide range of voltages and > > currents but want to stay within the platforms limits. > > Arent you defining a new PDO type similar to PDO_FIXED, PDO_VARIABLE etc ? > If so values such as " 'max_snk_mv', 'max_snk_ma' and > 'max_snk_mw' " should be part of the APDO object right ? So why would > you still need > 'max_snk_mv', 'max_snk_ma' and 'max_snk_mw' ? My initial implementation was based on the approach before your changes, and actually for PPS this to me made sense, at least from the sink side. We are dealing with a range of voltages and currents so the important points are the maximum values. However, if we're now making decisions based on sink PDOs then I can look at adapting.
