From patchwork Thu Feb 17 10:44:40 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Zev Weiss X-Patchwork-Id: 12749748 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 BC0E9C433F5 for ; Thu, 17 Feb 2022 10:46:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239275AbiBQKq0 (ORCPT ); Thu, 17 Feb 2022 05:46:26 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:60380 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237461AbiBQKqZ (ORCPT ); Thu, 17 Feb 2022 05:46:25 -0500 Received: from thorn.bewilderbeest.net (thorn.bewilderbeest.net [IPv6:2605:2700:0:5::4713:9cab]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 97BE2294105; Thu, 17 Feb 2022 02:46:11 -0800 (PST) Received: from hatter.bewilderbeest.net (174-21-187-98.tukw.qwest.net [174.21.187.98]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: zev) by thorn.bewilderbeest.net (Postfix) with ESMTPSA id 76045461; Thu, 17 Feb 2022 02:46:09 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bewilderbeest.net; s=thorn; t=1645094769; bh=FlSQwzHbM/dm7ihzl/D1hs0n0mSNJjDHh9U0M7jfQIE=; h=From:To:Cc:Subject:Date:From; b=n5WX/GH076Iwu6gmIk+RreldVcm2JdHFvzMzZQ75ipleGhFmWoGrrPk5hr6RuKrK6 UriL9lAVcJRIYaAG0q79ZiAqJ9DOsHolkEonu2PhUubNtLygi1qDIHSt5sHE1GDwLq bkd3kcs7p/pTchNHOdK09foDsUXph9gA0CBBJG80= From: Zev Weiss To: linux-kernel@vger.kernel.org, Greg Kroah-Hartman , Arnd Bergmann Cc: Zev Weiss , openbmc@lists.ozlabs.org, Rob Herring , Guenter Roeck , Jean Delvare , devicetree@vger.kernel.org, linux-hwmon@vger.kernel.org, Mark Brown , Liam Girdwood Subject: [PATCH 0/4] misc: Add power-efuse driver Date: Thu, 17 Feb 2022 02:44:40 -0800 Message-Id: <20220217104444.7695-1-zev@bewilderbeest.net> X-Mailer: git-send-email 2.35.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-hwmon@vger.kernel.org Hello, This patch series is another incarnation of some previous efforts [0] at enabling userspace access to the OPERATION state (and now status flags) of PMBus devices, specifically with respect to efuses protecting general-purpose power outputs. This functionality is an important component enabling a port of OpenBMC to the Delta AHE-50DC Open19 power shelf [1]. The first patch extends the pmbus core's regulator support with an implementation of the .get_error_flags() operation, mapping PMBus status flags to REGULATOR_ERROR_* flags where possible, and the second patch adds regulator support for the lm25066 driver. These two patches are essentially independent of the power-efuse driver (and each other) and could potentially be applicable individually, but are necessary for the power-efuse driver to be useful on the AHE-50DC. The third and fourth patches add dt-bindings and the implementation of the power-efuse driver, respectively. The driver is fairly simple; it merely provides a sysfs interface to enable, disable, and retrieve error flags from an underlying regulator. There is one aspect of its usage of the regulator API I'm a bit uncertain about, however: this driver seems like a case where an exclusive 'get' of the regulator (i.e. devm_regulator_get_exclusive() instead of devm_regulator_get() in efuse_probe()) would be appropriate, since in the intended usage no other device should be using an efuse's regulator. With an exclusive get though, the regulator's use_count and the consumer's enable_count don't balance out properly to allow the enable/disable operations to work properly (the former ending up one more than the latter, leading to enable_count underflows on attempts to disable the regulator). So at least for now it's using a non-exclusive get -- I'd be happy to hear any pointers on a way to allow an exclusive get to work here, though. Thanks, Zev [0] https://lore.kernel.org/openbmc/YGLepYLvtlO6Ikzs@hatter.bewilderbeest.net/ [1] https://www.open19.org/marketplace/delta-16kw-power-shelf/ Zev Weiss (4): hwmon: (pmbus) Add get_error_flags support to regulator ops hwmon: (pmbus) lm25066: Add regulator support dt-bindings: Add power-efuse binding misc: Add power-efuse driver .../devicetree/bindings/misc/power-efuse.yaml | 37 +++ MAINTAINERS | 5 + drivers/hwmon/pmbus/Kconfig | 7 + drivers/hwmon/pmbus/lm25066.c | 14 ++ drivers/hwmon/pmbus/pmbus_core.c | 97 ++++++++ drivers/misc/Kconfig | 15 ++ drivers/misc/Makefile | 1 + drivers/misc/power-efuse.c | 221 ++++++++++++++++++ 8 files changed, 397 insertions(+) create mode 100644 Documentation/devicetree/bindings/misc/power-efuse.yaml create mode 100644 drivers/misc/power-efuse.c