From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2F6213FF89E; Tue, 28 Apr 2026 10:42:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777372939; cv=none; b=V2szyYv3v/iJVD+whniUXJ3bzEtsTQ58hKckqsTSx2jFxWV40q8Ed+XNpB031YVFhjpfsWbUOgUFqunUahROzrfYmpP3FL03/BQ1KEwPUw0okBlOKQo6V3bLj8NgkO5o91up35t9bJD8jY4OPqYec+yrFPyAbDJYzynswz3n0S8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777372939; c=relaxed/simple; bh=kPur6jWe6BvdHYe0RM6/hM1TWbrq+uMmPOxcVVn7tU8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=HizMNN8eFDt63VRZQiHTvHu2/PepbXL81MTlSVXnte4hEIZXHe+cLMqp/Jg2xp2TCp1vkWrBT32Vowm1nurs5Pr8IoEMre/3tEzYN1aSlrUTp7h6cDgBE6PvQHK4tSAlSNNYEFCzQeLchqyzp3fao0Wva3s5V4IW0EdvqiUuihk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=gB8fmX51; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="gB8fmX51" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6877DC2BCC7; Tue, 28 Apr 2026 10:42:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1777372938; bh=kPur6jWe6BvdHYe0RM6/hM1TWbrq+uMmPOxcVVn7tU8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=gB8fmX51C8i5Ld1o9Znvh0MfxonevAAxXjt1pNUB3xl/GGspzEhc1z27L/POXfn+9 2ARwlrv4Zf1lYOiWMji1RyKduiTD6nH+KsX5HWc55WPmFDZpsHlCo9bmLtkfCymH7I KpbzuSq/WLe0rc8rcFziU6kooIi6rjgCyGNkOtcaL+C3Zi9ZKUVUW/Btht+XXMmD0G u9/MC9xyz17RWZuaiNQ2TWBo1cxy+5jdlsVeKMakvIdQvdkMoYY3mX+TNutn3k/zH/ Blnc4AhsFvci2EAiJKYVdigaD9leMIF422NdfVI63e5mKDpPzJwAB892eKwOGmvEHW VGzk6a+toOF5g== From: Sasha Levin To: patches@lists.linux.dev, stable@vger.kernel.org Cc: Frieder Schrempf , Krzysztof Kozlowski , Alexandre Belloni , Sasha Levin , a.zummo@towertech.it, robh+dt@kernel.org, krzysztof.kozlowski+dt@linaro.org, conor+dt@kernel.org, linux-rtc@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH AUTOSEL 7.0-6.6] dt-bindings: rtc: microcrystal,rv3028: Allow to specify vdd-supply Date: Tue, 28 Apr 2026 06:40:43 -0400 Message-ID: <20260428104133.2858589-32-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260428104133.2858589-1-sashal@kernel.org> References: <20260428104133.2858589-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 7.0.2 Content-Transfer-Encoding: 8bit From: Frieder Schrempf [ Upstream commit 10663044bee592ba049a2aa37f4431fbdf93b739 ] In case the VDD supply voltage regulator of the RTC needs to be specified explicitly, allow to set vdd-supply. Signed-off-by: Frieder Schrempf Reviewed-by: Krzysztof Kozlowski Link: https://patch.msgid.link/20260309085749.25747-2-frieder@fris.de Signed-off-by: Alexandre Belloni Signed-off-by: Sasha Levin --- LLM Generated explanations, may be completely bogus: ## Decision Summary Backport this **with the companion DTS fix**. By itself it is a schema- only change, but the mailing-list history verifies it was added because the runtime DTS fix for Kontron i.MX8MP OSM RTC boot hangs was dropped due to `dtb_check` warning: `'vdd-supply' is not allowed`. This patch is a 2-line DT binding addition for existing hardware, reviewed by a DT maintainer, and has essentially no runtime regression risk. ## Phase Walkthrough 1.1 Record: Subsystem `dt-bindings: rtc: microcrystal,rv3028`; action verb `Allow`; intent is to permit `vdd-supply` in the RV3028 RTC binding. 1.2 Record: Tags found: `Signed-off-by: Frieder Schrempf`, `Reviewed-by: Krzysztof Kozlowski`, `Link: https://patch.msgid.link/20260309085749.25747-2-frieder@fris.de`, `Signed-off-by: Alexandre Belloni`. No `Fixes`, `Reported-by`, `Tested- by`, or `Cc: stable`. 1.3 Record: Commit body says only that explicit VDD regulator specification should be allowed. The series and v2 discussion verify the concrete issue: the companion DTS fix adds `vdd-supply` so fw_devlink orders PMIC before RTC, avoiding sporadic boot hangs. 1.4 Record: Hidden bug-fix context exists, but not in this patch alone. This patch fixes a DT schema gap that blocked a real DTS boot-hang fix. 2.1 Record: One file changed, `Documentation/devicetree/bindings/rtc/microcrystal,rv3028.yaml`; 2 lines added; no functions; single-file schema change. 2.2 Record: Before, `unevaluatedProperties: false` rejected `vdd- supply`. After, `vdd-supply: true` permits the regulator phandle. 2.3 Record: Bug category is DT schema/build-validation fix and prerequisite for hardware dependency expression. Not memory safety, locking, or runtime driver logic. 2.4 Record: Fix is obviously correct and minimal. Regression risk is very low because it only relaxes schema validation for one standard supply property. 3.1 Record: Blame shows the binding file was introduced by `c690048ed59b5` in `v6.3-rc1`; `#clock-cells` was added by `4015580e983da` in `v6.12-rc1`. 3.2 Record: Candidate has no `Fixes:` tag. Companion DTS patch fixes `946ab10e3f40f`, introduced in `v6.13-rc1`. 3.3 Record: Recent binding history only shows the file creation and `#clock-cells` addition. The patch is standalone, but its stable value is tied to the companion DTS fix. 3.4 Record: Author has multiple Kontron DTS fixes in local history; not the RTC maintainer, but the patch was reviewed by Krzysztof Kozlowski and applied by Alexandre Belloni. 3.5 Record: No code dependencies. For meaningful runtime benefit, backport with `arm64: dts: imx8mp-kontron: Fix boot order for PMIC and RTC`. 4.1 Record: `b4 dig -c 10663044bee5` found the original v3 patch at the supplied lore/msgid URL. `b4 dig -a` found v1 and v3 series history; v3 added the missing binding patch. 4.2 Record: `b4 dig -w` showed relevant DT/RTC maintainers and lists were included. 4.3 Record: v2 discussion verified Frank Li dropped the DTS fix because it caused `dtb_check` warning: `'vdd-supply' is not allowed`; Frieder replied that v3 adds the binding patch. 4.4 Record: Series context is 2 patches in v3: this binding patch and the DTS boot-order fix. Binding was applied by Alexandre Belloni; DTS fix later applied by Frank Li. 4.5 Record: I found no stable-specific discussion or explicit stable nomination. 5.1 Record: No functions modified. 5.2 Record: No callers. Semantic impact is DT schema validation. 5.3 Record: Verified runtime relevance through OF supplier parsing: `drivers/of/property.c` has `DEFINE_SUFFIX_PROP(regulators, "-supply", NULL)` and includes `parse_regulators` in supplier bindings. 5.4 Record: Companion DTS path is reachable during device probing on Kontron i.MX8MP OSM. PMIC driver enables the I2C level translator when `nxp,i2c-lt-enable` is present; RTC node sits on the same I2C bus. 5.5 Record: Similar `vdd-supply: true` properties exist in many bindings, including another RTC binding, `amlogic,meson6-rtc.yaml`. 6.1 Record: Binding exists from `v6.3+`; Kontron OSM DTS exists from `v6.13+`. `v6.1` lacks the binding file. 6.2 Record: `git apply --check` succeeded on existing `v6.6` and `v6.12` worktrees and current `v7.0.1`; `v6.1` fails because the file does not exist. A separate v6.19 temporary worktree attempt ran out of space before testing, so direct v6.19 apply was not verified. 6.3 Record: No related stable fix already found in local history. 7.1 Record: Subsystem is DT binding documentation for RTC hardware; criticality is peripheral, but it supports a board boot-hang fix. 7.2 Record: Subsystem/file is low churn: only binding creation and `#clock-cells` addition before this patch. 8.1 Record: Affected population is users/builders of RV3028 DTs, especially Kontron i.MX8MP OSM users when paired with the DTS fix. 8.2 Record: Trigger for the companion bug is boot/probe ordering where RTC is accessed before PMIC enables the I2C level shifter. Trigger for this patch alone is DT schema validation with `vdd-supply`. 8.3 Record: Candidate alone fixes a build/validation warning. Companion failure mode is sporadic boot hang, which is critical for affected hardware. 8.4 Record: Benefit is high when paired with the companion DTS fix, low if isolated. Risk is very low: two schema lines, no runtime code. 9.1 Record: For backporting: tiny, reviewed, applies cleanly to relevant trees, enables a verified hardware boot-hang fix, standard DT supply property. Against: schema-only and no standalone runtime fix. 9.2 Record: Stable rules: obviously correct yes; real user bug indirectly yes via companion DTS fix; important issue yes when paired, boot hang; small yes; no runtime API/new driver yes; applies to v6.6/v6.12/current, not v6.1. 9.3 Record: Exception category applies: DT binding addition for existing hardware / build-validation support. 9.4 Record: Decision is YES, but it should be treated as a prerequisite/companion to the DTS boot-order fix, not as a standalone runtime fix. ## Verification - Phase 1: Parsed supplied commit message and local b4 mbox; confirmed tags and absence of `Fixes`/stable tags. - Phase 2: Read diff and current binding file; confirmed only `vdd- supply: true` is added. - Phase 3: Used `git blame`, `git describe --contains`, and file history; confirmed binding introduction in `v6.3-rc1`, `#clock-cells` in `v6.12-rc1`, board DTS in `v6.13-rc1`. - Phase 4: Used `b4 am`, `b4 mbox`, `b4 diff`, `b4 dig -a`, and `b4 dig -w`; verified v2 rejection due dtb_check warning and v3 addition of this binding patch. - Phase 5: Searched/read OF supplier parsing and PCA9450 code; verified `*-supply` creates supplier links and PMIC `nxp,i2c-lt-enable` enables the I2C level translator. - Phase 6: Checked stable tags/worktrees; apply check passes on v6.6, v6.12, and current tree; v6.1 lacks the file. - Phase 7/8: Verified affected paths in Kontron DTS and binding; no runtime code touched. - Unverified: Direct apply check on v6.19 due temporary worktree checkout failure, though v6.19 file contents were inspected and match the expected context. **YES** Documentation/devicetree/bindings/rtc/microcrystal,rv3028.yaml | 2 ++ 1 file changed, 2 insertions(+) diff --git a/Documentation/devicetree/bindings/rtc/microcrystal,rv3028.yaml b/Documentation/devicetree/bindings/rtc/microcrystal,rv3028.yaml index cda8ad7c12037..2ea3b40419530 100644 --- a/Documentation/devicetree/bindings/rtc/microcrystal,rv3028.yaml +++ b/Documentation/devicetree/bindings/rtc/microcrystal,rv3028.yaml @@ -32,6 +32,8 @@ properties: - 9000 - 15000 + vdd-supply: true + required: - compatible - reg -- 2.53.0