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@xxxxxxxxxxxxxxxxx> > > > --- > > > .../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@xxxxxxxxxxxxxxxxx> > > > + > > > +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
