From: Rob Herring <robh@kernel.org>
To: florin.leotescu@oss.nxp.com
Cc: Guenter Roeck <linux@roeck-us.net>,
Krzysztof Kozlowski <krzk+dt@kernel.org>,
Conor Dooley <conor+dt@kernel.org>,
Michael Shych <michaelsh@nvidia.com>,
linux-hwmon@vger.kernel.org, devicetree@vger.kernel.org,
linux-kernel@vger.kernel.org, daniel.baluta@nxp.com,
viorel.suman@nxp.com, linux-arm-kernel@lists.infradead.org,
imx@lists.linux.dev, festevam@gmail.com,
Florin Leotescu <florin.leotescu@nxp.com>
Subject: Re: [PATCH v4 1/2] dt-bindings: hwmon: emc2305: Add fan-shutdown-percent property
Date: Wed, 25 Mar 2026 16:56:30 -0500 [thread overview]
Message-ID: <20260325215630.GA6513-robh@kernel.org> (raw)
In-Reply-To: <20260320152959.1575978-2-florin.leotescu@oss.nxp.com>
On Fri, Mar 20, 2026 at 05:29:58PM +0200, florin.leotescu@oss.nxp.com wrote:
> From: Florin Leotescu <florin.leotescu@nxp.com>
>
> The EMC2305 fan controller supports multiple independent PWM fan
> outputs. Some systems require fans to enter a defined safe state
> during system shutdown or reboot handoff, until firmware or the next
> boot stage reconfigures the controller.
>
> Add an optional "fan-shutdown-percent" property to fan child nodes
> allowing the shutdown fan speed to be configured per fan output.
Why not a common fan property in fan-common.yaml?
We generally specify fan speeds in RPM (and then map RPMs to duty cycle
for PWM).
Also, we have (or can have) cooling levels defined. Perhaps we should
define the cooling level for shutdown? Maybe other things with cooling
levels need a shutdown level too?
Rob
next prev parent reply other threads:[~2026-03-25 21:56 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-20 15:29 [PATCH v4 0/2] hwmon: emc2305: Support configurable fan PWM at shutdown florin.leotescu
2026-03-20 15:29 ` [PATCH v4 1/2] dt-bindings: hwmon: emc2305: Add fan-shutdown-percent property florin.leotescu
2026-03-23 9:10 ` Daniel Baluta
2026-03-23 14:43 ` Guenter Roeck
2026-03-25 21:56 ` Rob Herring [this message]
2026-03-25 22:33 ` Guenter Roeck
2026-03-20 15:29 ` [PATCH v4 2/2] hwmon: emc2305: Support configurable fan PWM at shutdown florin.leotescu
2026-03-20 20:06 ` [PATCH v4 0/2] " Guenter Roeck
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