From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mout-p-201.mailbox.org (mout-p-201.mailbox.org [80.241.56.171]) (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 0C821198E9B; Sun, 20 Jul 2025 20:08:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=80.241.56.171 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753042085; cv=none; b=WyhztM4FdIF8tFBal7oDgBvhpCxr0/TUqY2XYtQydqBkCkd8vAP9Tk8KjY3OhGll/Ynd2eRWl3yAbRXdFZgPXR2qqrEyM9aByItqwDJB/FcHd2aH9317UtzQG/j2KNP9ujGbGS7O7LrrehY1HoNIUFbo/nB0/L/Tq6KOiceO6+o= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753042085; c=relaxed/simple; bh=HE5XfTbqoBFUbJB80+/8sdW4W7hcnSgLwxV3XXsUcw8=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=oSwr4Qs0iJkApKWRObQlYHZuKWiT2oq0hoPss6dZboODq1P12guRX6c6eBw6zm9JBqRZnFNwSudXHRnqKf4uI61MSzsBvG2NJtWEtvGN7ASpWCOv+21mTzF4vmP3zStzUn12eD+rk2O1PMulvIxyjBwJGgALhe4TiZuEfngpPC8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=mailbox.org; spf=pass smtp.mailfrom=mailbox.org; dkim=pass (2048-bit key) header.d=mailbox.org header.i=@mailbox.org header.b=UvTqpPD1; arc=none smtp.client-ip=80.241.56.171 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=mailbox.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=mailbox.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=mailbox.org header.i=@mailbox.org header.b="UvTqpPD1" Received: from smtp102.mailbox.org (smtp102.mailbox.org [IPv6:2001:67c:2050:b231:465::102]) (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) by mout-p-201.mailbox.org (Postfix) with ESMTPS id 4blZMh3GvHz9sjY; Sun, 20 Jul 2025 22:08:00 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mailbox.org; s=mail20150812; t=1753042080; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=f2mnKQ0A6cmyOjTY4uC1w0qQca4Edbna8BbLEyyk48c=; b=UvTqpPD17fL7QiwSGNffDuWHFM1alqTcV7ulBZJ5x7levFeT5zhMBeVDu1BxlQyPqUM9fd ec3XL+nE7uWwsy9HoSE//tfpSFIXmpCNBUmtAX+yKE4A5NbIDVvF7K/176pgbYvejeUBls O/Rws2O/OqwfdsMgE/xjLgS8o1LQwnqY4PIUkmf8lja+l+6iZFqq9GCmNvH7WMXiUzPCJ2 UIOTNsIXhpdyBTC8fENyPEiPZLr8ROctIsem9uMY0wd0ogKLyzh53VVuUuphft90EqjTzK +94MCqtUMdvnoTFXbZA/JLuI/9c+DSw8SU/pM1Qid8DakkMenS9SBNRU3qo2Hg== Message-ID: <9ba974d7-456d-4255-bb74-cfd1998a43ae@mailbox.org> Date: Sun, 20 Jul 2025 22:07:57 +0200 Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Subject: Re: [PATCH 1/2] dt-bindings: hwmon: pwm-fan: Document after shutdown fan settings To: Rob Herring Cc: linux-hwmon@vger.kernel.org, Conor Dooley , Guenter Roeck , Jean Delvare , Krzysztof Kozlowski , devicetree@vger.kernel.org, linux-renesas-soc@vger.kernel.org References: <20250629220301.935515-1-marek.vasut+renesas@mailbox.org> <20250708155058.GA477029-robh@kernel.org> Content-Language: en-US From: Marek Vasut In-Reply-To: <20250708155058.GA477029-robh@kernel.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-MBO-RS-META: am9qc1c5pjaufgrd1fewytyoucn99ho8 X-MBO-RS-ID: 9153788d8f5d9aa425f On 7/8/25 5:50 PM, Rob Herring wrote: > On Mon, Jun 30, 2025 at 12:02:08AM +0200, Marek Vasut wrote: >> Document fan-shutdown-percent property, used to describe fan RPM in percent >> set during shutdown. This is used to keep the fan running at fixed RPM after >> the kernel shut down, which is useful on hardware that does keep heating >> itself even after the kernel did shut down, for example from some sort of >> management core. > > This sounds more like "don't ever let the fan go below this RPM" or > "don't ever turn off the fan". IOW, it is more than just shutdown. This property is literally only used during/after shutdown , this does not limit or affect fan RPM during runtime in any way. Also, sorry for the late reply. >> diff --git a/Documentation/devicetree/bindings/hwmon/pwm-fan.yaml b/Documentation/devicetree/bindings/hwmon/pwm-fan.yaml >> index 8b4ed5ee962f..a84cc3a4cfdc 100644 >> --- a/Documentation/devicetree/bindings/hwmon/pwm-fan.yaml >> +++ b/Documentation/devicetree/bindings/hwmon/pwm-fan.yaml >> @@ -31,6 +31,15 @@ properties: >> it must be self resetting edge interrupts. >> maxItems: 1 >> >> + fan-shutdown-percent: >> + description: >> + Fan RPM in percent set during shutdown. This is used to keep the fan >> + running at fixed RPM after the kernel shut down, which is useful on >> + hardware that does keep heating itself even after the kernel did shut >> + down, for example from some sort of management core. >> + minimum: 0 >> + maximum: 100 >> + >> fan-stop-to-start-percent: >> description: >> Minimum fan RPM in percent to start when stopped. >> -- >> 2.47.2 >> -- Best regards, Marek Vasut