+linux-usb ml, Guenter and others. On Sun, Sep 10, 2023 at 09:29:04PM -0400, Douglas Gilbert wrote: > Hi, > The Peak current 2 bit field has been present in the fixed source PDO > since PD 2.0 . It is commented out in typec/pd.c with a note to revisit > as it needs the Operational current field from the active RDO. > > Not sure I agree with that: the 2 bit field is unit-less and could easily > be displayed as such. At the moment the active RDO is not directly > available through sysfs and would certainly be a useful addition for > many reasons. > > So my vote (not that I get one) would be to output peak_current in > sysfs with no unit. Then in the ABI peak_current could be explained > by reference to a table in the spec (e.g. "USB Power Delivery > Specification Revision 3.1, Version 1.8, table 6-10 Fixed Power > Source Peak Current Capability"). Then the issue of what it means > is handed off to the user space :-) > > Also of note is that the Peak current field is B21..B20 which is > below B23 (obviously) so all fixed source PDOs have that field > (and thus those unit-less values could differ), not just > PDO #1 . I agree with you. I don't think it makes sense to try to interpret the peak current value in kernel, so we could just expose the value as-is. But first giving the others heads-up on this, just in case somebody disagrees. thanks, -- heikki
