lkml.org 
[lkml]   [2022]   [Mar]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v2 1/2] dt-bindings: Add power-efuse binding
On Fri, Mar 11, 2022 at 01:48:22PM -0800, Zev Weiss wrote:
> On Fri, Mar 11, 2022 at 07:24:41AM PST, Rob Herring wrote:
> > On Mon, Mar 07, 2022 at 05:18:09PM -0800, Zev Weiss wrote:
> > > This can be used to describe a power output supplied by a regulator
> > > device that the system controls.
> > >
> > > Signed-off-by: Zev Weiss <zev@bewilderbeest.net>
> > > ---
> > > .../devicetree/bindings/misc/power-efuse.yaml | 49 +++++++++++++++++++
> > > 1 file changed, 49 insertions(+)
> > > create mode 100644 Documentation/devicetree/bindings/misc/power-efuse.yaml
> > >
> > > diff --git a/Documentation/devicetree/bindings/misc/power-efuse.yaml b/Documentation/devicetree/bindings/misc/power-efuse.yaml
> > > new file mode 100644
> > > index 000000000000..5f8f0b21af0e
> > > --- /dev/null
> > > +++ b/Documentation/devicetree/bindings/misc/power-efuse.yaml
> > > @@ -0,0 +1,49 @@
> > > +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> > > +%YAML 1.2
> > > +---
> > > +$id: http://devicetree.org/schemas/misc/power-efuse.yaml#
> > > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > > +
> > > +title: Generic power efuse device
> > > +
> > > +maintainers:
> > > + - Zev Weiss <zev@bewilderbeest.net>
> > > +
> > > +description: |
> > > + This binding describes a physical power output supplied by a
> > > + regulator providing efuse functionality (manual on/off control, and
> > > + auto-shutoff if current, voltage, or thermal limits are exceeded).
> > > +
> > > + These may be found on systems such as "smart" network PDUs, and
> > > + typically supply power to devices entirely separate from the system
> > > + described by the device-tree by way of an external connector such as
> > > + an Open19 power cable:
> > > +
> > > + https://www.open19.org/marketplace/coolpower-cable-assembly-8ru/
> >
> > Not really a helpful link...
> >
> > I still don't understand what the h/w looks like here. At least I now
> > understand we're talking a fuse on power rail, not efuses in an SoC
> > used as OTP bits or feature disables.
> >
>
> The systems this would actually be used for would be things like these:
> - https://www.open19.org/marketplace/delta-16kw-power-shelf/
> - https://www.open19.org/marketplace/inspur-open19-power-shelf-ob19200l1/

Those still don't help show me what the h/w looks like. High level
schematics is what I'm looking for.


> The rightmost pictures on those pages show the four black connectors where
> the cable assembly linked in the patch plugs in, each of which provides the
> outputs from 12 such efuses, on 12 pairs of ground and +12VDC pins. (There
> are also two more single outputs off to the side.)
>
> It essentially just amounts to an external power output supplied by a
> regulator, with the regulator providing an on/off switch, overcurrent
> protection, etc.
>
> And yes, the ambiguity of the "efuse" terminology is unfortunate (the
> "power-" prefix was an attempt to clarify it slightly). That's the term
> used in the documentation for the hardware and hence is what I've called it
> here, but I'd be open to using a different name if that would help.
>
> > > +
> > > +properties:
> > > + compatible:
> > > + const: power-efuse
> > > +
> > > + vout-supply:
> > > + description:
> > > + phandle to the regulator providing power for the efuse
> >
> > Vout is a supply to the efuse and not the rail being fused?
>
> Yeah, that was a fairly muddled description -- it's really the latter.
> Perhaps:
>
> phandle to the regulator providing power for the output rail
> controlled by the efuse
>
> ?
>
> >
> > Sorry, I know nothing about how an efuse is implemented so you are going
> > to have to explain or draw it.
> >
> > > +
> > > + error-flags-cache-ttl-ms:
> > > + description:
> > > + The number of milliseconds the vout-supply regulator's error
> > > + flags should be cached before re-fetching them.
> >
> > How does one fetch/read? the error flags?
> >
>
> In the specific case I'm dealing with, via PMBus STATUS_* commands, though I
> was aiming to keep this more generic so it could potentially be used to
> describe non-PMBus arrangements (in the Linux case, via whatever mechanism
> the implementation of the regulator's .get_error_flags() function uses).

PMBus is I2C (subset). What device(s) is on the PMBus?

Here's what I've got for connections so far:

Vout(regulator)-->|efuse|-->12V

Host-->PMbus--->????

Rob

\
 
 \ /
  Last update: 2022-03-12 01:09    [W:0.038 / U:0.272 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site