RE: [PATCH 02/12] usb: typec: add basic typec properties

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 




Hi,

> -----Original Message-----
> From: Heikki Krogerus [mailto:heikki.krogerus@xxxxxxxxxxxxxxx]
> Sent: Tuesday, September 26, 2017 4:23 PM
> To: Jun Li <jun.li@xxxxxxx>
> Cc: gregkh@xxxxxxxxxxxxxxxxxxx; linux@xxxxxxxxxxxx; robh+dt@xxxxxxxxxx;
> mark.rutland@xxxxxxx; yueyao@xxxxxxxxxx; o_leveque@xxxxxxxxx; Peter
> Chen <peter.chen@xxxxxxx>; A.s. Dong <aisheng.dong@xxxxxxx>; linux-
> usb@xxxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH 02/12] usb: typec: add basic typec properties
> 
> On Tue, Sep 26, 2017 at 08:45:17AM +0800, Li Jun wrote:
> > port-type is required for any typec port; default-role is only
> > required for drp; power source capable needs src-pdos; power sink
> > capable needs snk-pdos, max-snk-mv, max-snk-ma, op-snk-mw.
> >
> > Signed-off-by: Li Jun <jun.li@xxxxxxx>
> > ---
> >  Documentation/devicetree/bindings/usb/typec.txt | 46
> > +++++++++++++++++++++++++
> >  1 file changed, 46 insertions(+)
> >
> > diff --git a/Documentation/devicetree/bindings/usb/typec.txt
> > b/Documentation/devicetree/bindings/usb/typec.txt
> > new file mode 100644
> > index 0000000..36d4467
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/usb/typec.txt
> > @@ -0,0 +1,46 @@
> > +Generic typec and power delivery properties
> > +-------------------------------------------
> > +
> > +Required properties:
> > +- port-type:    should be one of "source", "sink" or "dual".
> > +- default-role: preferred power role if drp, should be "sink" or "source".
> > +- src-pdos:     An array of u32 with each entry providing supported power
> > +                source data object(PDO), the detailed bit definitions of
> > +                PDO can be found in "Universal Serial Bus Power Delivery
> > +                Specification" chapter 6.4.1.2 Source_Capabilities Message,
> > +                the order of each entry(PDO) should follow the PD spec chapter
> > +                6.4.1. Required only for power source and power dual role with
> > +                power delivery support.
> > +- snk-pdos:     An array of u32 with each entry providing supported power
> > +                sink data object(PDO), the detailed bit definitions of PDO
> > +                can be found in "Universal Serial Bus Power Delivery
> > +                Specification" chapter 6.4.1.3 Sink Capabilities Message,
> > +                the order of each entry(PDO) should follow the PD spec chapter
> > +                6.4.1. Required only for power sink and power dual role with
> > +                power delivery support.
> 
> Wouldn't it be better to supply a property per detail and let the drivers construct
> the pdos as needed?

This is my original idea, but different kind of PDOs have so many detail attributes for
different config, we will have a very long properties list, for simple, maybe it's easier
for user to check the standard PD spec and construct it by hand in this case.

> 
> > +- max-snk-mv:   The max voltage the sink can support in millivoltage, required
> > +                only for power sink and power dual role with power delivery
> > +                support.
> > +- max-snk-ma:   The max current the sink can support in milliampere, required
> > +                only for power sink and power dual role with power delivery
> > +                support.
> > +- op-snk-mw:    Sink required operating power in milliwatts, if source offered
> > +                power is less then it, Capability Mismatch is set, required
> > +                only for power sink and power dual role with power delivery
> > +                support.
> 
> I'm a little bit concerned about these. Has any OF/DT guys reviewed them?
> 
> We should also keep in mind that the same properties should also be possible to
> use with ACPI. That may not be a problem as such, but we should consult the
> ACPI guys as well.
> 

Ok, let's wait DT guys comments.

Li Jun
> 
> Thanks,
> 
> --
> heikki
--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html




[Index of Archives]     [Device Tree Compilter]     [Device Tree Spec]     [Linux Driver Backports]     [Video for Linux]     [Linux USB Devel]     [Linux PCI Devel]     [Linux Audio Users]     [Linux Kernel]     [Linux SCSI]     [XFree86]     [Yosemite Backpacking]


  Powered by Linux