From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 98D8FC433FE for ; Sat, 12 Mar 2022 00:08:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229709AbiCLAKA (ORCPT ); Fri, 11 Mar 2022 19:10:00 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34970 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229448AbiCLAJ5 (ORCPT ); Fri, 11 Mar 2022 19:09:57 -0500 Received: from mail-oo1-f44.google.com (mail-oo1-f44.google.com [209.85.161.44]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 58FF622635A; Fri, 11 Mar 2022 16:08:50 -0800 (PST) Received: by mail-oo1-f44.google.com with SMTP id u30-20020a4a6c5e000000b00320d8dc2438so12373196oof.12; Fri, 11 Mar 2022 16:08:50 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=O+ZowuaGpChH9k7dXrO+pQwCk5UuyOxTNI7OLQVdPlw=; b=HnogdFWeuUfOHy4wp4FG9lhBQrDHhAlNHvBlkQntWIKWP1d7OR41oEThEUnuq8qCkq hoGNrxRs2reFTEynEoAuKk/7UauHhjtGIMGcbCeOWRiLYBGaeV5hroxfTc1qSksIY2QW zW3y3XOOOdB1t7Y3k/ExGUpcTq8Kif1rF7pyTJQXDeGtm2FJxi9MtV+Cxmr0xPcXEue2 WuICvwAWWL9R50QjJi/2PrMJ+J5J0q/mDgq9s4iLMNb3ACgFWpiTNQih+i/FIWVVs57a qwuEoSSDzdiWNjjO6/G7WjG6hsEz7+w0toJmU7/X9hMVsyrppfeZmbKuavxkolCRKph7 POaw== X-Gm-Message-State: AOAM5334pxmx8Oh1VRp/TwDkmdzEp05zfzjjA6PKool13eCe5uDZ/lwy HzkJboHmd2r4t6aWei+voA== X-Google-Smtp-Source: ABdhPJxKJfen2kigP0gnh/8VFptrw0maG5VWC2hBhKLIhJu+QNoF9eXdi5I/avYm4FAyN1IQGZsxTg== X-Received: by 2002:a05:6871:890:b0:da:6895:1b41 with SMTP id r16-20020a056871089000b000da68951b41mr12065172oaq.74.1647043729574; Fri, 11 Mar 2022 16:08:49 -0800 (PST) Received: from robh.at.kernel.org (66-90-144-107.dyn.grandenetworks.net. [66.90.144.107]) by smtp.gmail.com with ESMTPSA id p21-20020a4a2f15000000b00320fca09b74sm4282072oop.1.2022.03.11.16.08.48 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 11 Mar 2022 16:08:48 -0800 (PST) Received: (nullmailer pid 445165 invoked by uid 1000); Sat, 12 Mar 2022 00:08:47 -0000 Date: Fri, 11 Mar 2022 18:08:47 -0600 From: Rob Herring To: Zev Weiss Cc: devicetree@vger.kernel.org, Arnd Bergmann , Greg Kroah-Hartman , openbmc@lists.ozlabs.org, linux-kernel@vger.kernel.org, Liam Girdwood , Mark Brown Subject: Re: [PATCH v2 1/2] dt-bindings: Add power-efuse binding Message-ID: References: <20220308011811.10353-1-zev@bewilderbeest.net> <20220308011811.10353-2-zev@bewilderbeest.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 > > > --- > > > .../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 > > > + > > > +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