From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 70F663BC68E; Wed, 30 Sep 2026 18:59:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790794780; cv=none; b=NMCTEAYtTCaVFcadY+iV1tmLPXjX77xmnA9dxhJdiansyeqLxFMc8XCoixK3iDnnfgn4YbsXSvFeXGf8hmuylS5buYd5eyTpaAUGVUKekUY0KBel2xt5bogLeKHQeqeqOiY1G4SMBZvYr+ceWS29A+icIPK5cgES8WehbJtXybs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790794780; c=relaxed/simple; bh=g8Kv9MKYXdnEPARGuTOs9k9Kz3js14jKd6tDdq+EXfs=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=jma8Z0/pKMYnqbx97Iq5pszEhhZZBUe+Gq3PsBz+O5N/jfgyMpQGiNZjtfoIiaAOMh4zgerImhPvxkgd5MX7jL5gLZkceBmGaJ+SRQpnm1sjSENpgxzkOvvJt4HsrpQsw7DlDR1WpLBg+j/Jqfwfhlb7mL7Ai3kk6/lnC+HIBQY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=2MtnCKhj; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="2MtnCKhj" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CDC951F000FF; Wed, 30 Sep 2026 18:59:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1790794779; bh=f84KDxX0rOOAz1UpQTTHrgOPUPFKaLGnwtcsZrqUKIA=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=2MtnCKhj4YuxlkyB/Z0cot/yegjImsOXIc8qZcrI7FwblSv9VabZfgobI4leh0mmp Sg4rSK1n1UUVcDh3kJKMcRhynUL6P5WjnKLmY0d26R+NKAvhuftL1XP+y38Qewh1oh Kr4esHIUpjJQa8Xu4PcLa+O9y6x7CVJ8f5mHw2VE= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Kamal Wadhwa , Mark Brown , Sasha Levin Subject: [PATCH 6.6 0324/1193] regulator: core: clamp voltage constraints before applying apply_uV Date: Wed, 30 Sep 2026 17:16:48 +0200 Message-ID: <20260930152441.337546407@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260930152434.301151190@linuxfoundation.org> References: <20260930152434.301151190@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Kamal Wadhwa [ Upstream commit a45cc646a3aa83eb4ab4c7ed2685785ea51dc5e6 ] machine_constraints_voltage() currently applies apply_uV against the machine-supplied [min_uV, max_uV] range, and only afterwards clamps that range down to what the regulator can actually supply (via ops->list_voltage()). If the machine-supplied range is wider than the regulator's actual range, apply_uV's rounding can pick a selector outside the (correct) clamped range, so the regulator ends up programmed outside its clamped min/max. At bring-up this shows up as a voltage read-back outside the clamped range. Fix this by moving the clamping block ahead of the apply_uV block, so apply_uV always targets an already-clamped range. Whether apply_uV should run is decided from the unclamped constraints beforehand and stored in a local bool, since clamping must not itself change whether apply_uV fires. No functional change to the clamping logic itself, only its position relative to apply_uV. Its early return 0 exits become fallthroughs since the apply_uV logic now follows it. Assisted-by: Claude:claude-sonnet-5 Signed-off-by: Kamal Wadhwa Link: https://patch.msgid.link/20260720-b4-regulator-core-clamp-voltage-v1-1-8e5eec076a8e@oss.qualcomm.com Signed-off-by: Mark Brown Signed-off-by: Sasha Levin --- drivers/regulator/core.c | 163 +++++++++++++++++++++------------------ 1 file changed, 90 insertions(+), 73 deletions(-) diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c index 35729234c375d..ce69d37cfaa90 100644 --- a/drivers/regulator/core.c +++ b/drivers/regulator/core.c @@ -1242,10 +1242,98 @@ static int machine_constraints_voltage(struct regulator_dev *rdev, { const struct regulator_ops *ops = rdev->desc->ops; int ret; + bool apply_uV; + + /* + * Decide up front, from the constraints as handed to us, whether + * apply_uV needs to run below. The clamping pass right after this + * may rewrite constraints->min_uV/max_uV (e.g. the fixed-voltage + * autoconfigure case), and we don't want that to change whether + * apply_uV fires. + */ + apply_uV = rdev->constraints->apply_uV && + rdev->constraints->min_uV && rdev->constraints->max_uV; + + /* + * Constrain machine-level voltage specs to fit the actual range + * supported by this regulator before apply_uV (below) tries to + * force hardware to a value from that range: otherwise apply_uV + * can target a constraint value that doesn't correspond to any + * real voltage selector and fail registration outright, even + * though the clamping pass would have narrowed it to a value + * the regulator can actually hit. + */ + if (ops->list_voltage && rdev->desc->n_voltages) { + int count = rdev->desc->n_voltages; + int i; + int min_uV = INT_MAX; + int max_uV = INT_MIN; + int cmin = constraints->min_uV; + int cmax = constraints->max_uV; + + /* it's safe to autoconfigure fixed-voltage supplies + * and the constraints are used by list_voltage. + */ + if (count == 1 && !cmin) { + cmin = 1; + cmax = INT_MAX; + constraints->min_uV = cmin; + constraints->max_uV = cmax; + } + + /* voltage constraints are optional */ + if ((cmin == 0) && (cmax == 0)) { + /* nothing more to do */ + + /* else require explicit machine-level constraints */ + } else if (cmin <= 0 || cmax <= 0 || cmax < cmin) { + rdev_err(rdev, "invalid voltage constraints\n"); + return -EINVAL; + + /* no need to loop voltages if range is continuous */ + } else if (rdev->desc->continuous_voltage_range) { + /* nothing more to do */ + + } else { + /* initial: [cmin..cmax] valid, [min_uV..max_uV] not */ + for (i = 0; i < count; i++) { + int value; + + value = ops->list_voltage(rdev, i); + if (value <= 0) + continue; + + /* maybe adjust [min_uV..max_uV] */ + if (value >= cmin && value < min_uV) + min_uV = value; + if (value <= cmax && value > max_uV) + max_uV = value; + } + + /* final: [min_uV..max_uV] valid iff constraints valid */ + if (max_uV < min_uV) { + rdev_err(rdev, + "unsupportable voltage constraints %u-%uuV\n", + min_uV, max_uV); + return -EINVAL; + } + + /* use regulator's subset of machine constraints */ + if (constraints->min_uV < min_uV) { + rdev_dbg(rdev, "override min_uV, %d -> %d\n", + constraints->min_uV, min_uV); + constraints->min_uV = min_uV; + } + if (constraints->max_uV > max_uV) { + rdev_dbg(rdev, "override max_uV, %d -> %d\n", + constraints->max_uV, max_uV); + constraints->max_uV = max_uV; + } + } + } /* do we need to apply the constraint voltage */ - if (rdev->constraints->apply_uV && - rdev->constraints->min_uV && rdev->constraints->max_uV) { + if (apply_uV) { int target_min, target_max; int current_uV = regulator_get_voltage_rdev(rdev); @@ -1300,77 +1388,6 @@ static int machine_constraints_voltage(struct regulator_dev *rdev, } } - /* constrain machine-level voltage specs to fit - * the actual range supported by this regulator. - */ - if (ops->list_voltage && rdev->desc->n_voltages) { - int count = rdev->desc->n_voltages; - int i; - int min_uV = INT_MAX; - int max_uV = INT_MIN; - int cmin = constraints->min_uV; - int cmax = constraints->max_uV; - - /* it's safe to autoconfigure fixed-voltage supplies - * and the constraints are used by list_voltage. - */ - if (count == 1 && !cmin) { - cmin = 1; - cmax = INT_MAX; - constraints->min_uV = cmin; - constraints->max_uV = cmax; - } - - /* voltage constraints are optional */ - if ((cmin == 0) && (cmax == 0)) - return 0; - - /* else require explicit machine-level constraints */ - if (cmin <= 0 || cmax <= 0 || cmax < cmin) { - rdev_err(rdev, "invalid voltage constraints\n"); - return -EINVAL; - } - - /* no need to loop voltages if range is continuous */ - if (rdev->desc->continuous_voltage_range) - return 0; - - /* initial: [cmin..cmax] valid, [min_uV..max_uV] not */ - for (i = 0; i < count; i++) { - int value; - - value = ops->list_voltage(rdev, i); - if (value <= 0) - continue; - - /* maybe adjust [min_uV..max_uV] */ - if (value >= cmin && value < min_uV) - min_uV = value; - if (value <= cmax && value > max_uV) - max_uV = value; - } - - /* final: [min_uV..max_uV] valid iff constraints valid */ - if (max_uV < min_uV) { - rdev_err(rdev, - "unsupportable voltage constraints %u-%uuV\n", - min_uV, max_uV); - return -EINVAL; - } - - /* use regulator's subset of machine constraints */ - if (constraints->min_uV < min_uV) { - rdev_dbg(rdev, "override min_uV, %d -> %d\n", - constraints->min_uV, min_uV); - constraints->min_uV = min_uV; - } - if (constraints->max_uV > max_uV) { - rdev_dbg(rdev, "override max_uV, %d -> %d\n", - constraints->max_uV, max_uV); - constraints->max_uV = max_uV; - } - } - return 0; } -- 2.53.0