From: Florin Leotescu <florin.leotescu@nxp.com>

This series adds support for configuring the fan PWM duty cycle applied
during system shutdown for the EMC2305 fan controller.

Some platforms require fans to transition to a predefined safe state
during shutdown or reboot handoff until firmware or the next boot stage
reconfigures the controller.

The new optional Device Tree property "fan-shutdown-percent" allows the
shutdown PWM duty cycle to be configured per fan output.

Changes in v3:
- Rebased on current upstream
- Dropped already upstreamed of_node_put(child) fix
Changes in v2:
- Address feedback from Guenter Roeck
- Make shutdown behavior configurable via Device Tree
- Add optional fan-shutdown-percent property
- Apply shutdown PWM only for channels defining the property

Florin Leotescu (2):
  dt-bindings: hwmon: emc2305: Add fan-shutdown-percent property
  hwmon: emc2305: Support configurable fan PWM at shutdown

 .../bindings/hwmon/microchip,emc2305.yaml     |  8 +++++
 drivers/hwmon/emc2305.c                       | 34 +++++++++++++++++++
 2 files changed, 42 insertions(+)

-- 
2.34.1

On 3/12/26 07:43, florin.leotescu@oss.nxp.com wrote:
> From: Florin Leotescu <florin.leotescu@nxp.com>
> 
> This series adds support for configuring the fan PWM duty cycle applied
> during system shutdown for the EMC2305 fan controller.
> 
> Some platforms require fans to transition to a predefined safe state
> during shutdown or reboot handoff until firmware or the next boot stage
> reconfigures the controller.
> 
> The new optional Device Tree property "fan-shutdown-percent" allows the
> shutdown PWM duty cycle to be configured per fan output.
> 
> Changes in v3:
> - Rebased on current upstream
> - Dropped already upstreamed of_node_put(child) fix
> Changes in v2:
> - Address feedback from Guenter Roeck
> - Make shutdown behavior configurable via Device Tree
> - Add optional fan-shutdown-percent property
> - Apply shutdown PWM only for channels defining the property
> 
> Florin Leotescu (2):
>    dt-bindings: hwmon: emc2305: Add fan-shutdown-percent property
>    hwmon: emc2305: Support configurable fan PWM at shutdown
> 
>   .../bindings/hwmon/microchip,emc2305.yaml     |  8 +++++
>   drivers/hwmon/emc2305.c                       | 34 +++++++++++++++++++
>   2 files changed, 42 insertions(+)
> 
AI review of series is here:

https://sashiko.dev/#/patchset/20260312144325.1311314-1-florin.leotescu%40oss.nxp.com

Please take a look.

Thanks,
Guenter

On Tue, Mar 17, 2026 at 09:17:21AM -0700, Guenter Roeck wrote:
> On 3/12/26 07:43, florin.leotescu@oss.nxp.com wrote:
> > From: Florin Leotescu <florin.leotescu@nxp.com>
> > 
> > This series adds support for configuring the fan PWM duty cycle applied
> > during system shutdown for the EMC2305 fan controller.
> > 
> > Some platforms require fans to transition to a predefined safe state
> > during shutdown or reboot handoff until firmware or the next boot stage
> > reconfigures the controller.
> > 
> > The new optional Device Tree property "fan-shutdown-percent" allows the
> > shutdown PWM duty cycle to be configured per fan output.
> > 
> > Changes in v3:
> > - Rebased on current upstream
> > - Dropped already upstreamed of_node_put(child) fix
> > Changes in v2:
> > - Address feedback from Guenter Roeck
> > - Make shutdown behavior configurable via Device Tree
> > - Add optional fan-shutdown-percent property
> > - Apply shutdown PWM only for channels defining the property
> > 
> > Florin Leotescu (2):
> >    dt-bindings: hwmon: emc2305: Add fan-shutdown-percent property
> >    hwmon: emc2305: Support configurable fan PWM at shutdown
> > 
> >   .../bindings/hwmon/microchip,emc2305.yaml     |  8 +++++
> >   drivers/hwmon/emc2305.c                       | 34 +++++++++++++++++++
> >   2 files changed, 42 insertions(+)
> > 
> AI review of series is here:
> 
> https://sashiko.dev/#/patchset/20260312144325.1311314-1-florin.leotescu%40oss.nxp.com
> 
> Please take a look.
>
Hi Guenter,

Thanks for pointing this out.
You're right, since the pwm_shutdown array is zero-initialized by devm_kzalloc,
the channels that are not explicitly configured, will be treated as valid
and written as 0 during shutdown. I'll fix it in next revision.

> Thanks,
> Guenter
>