Re: [hwmon-next PATCH v6 3/4] hwmon: (adt7470) Expose fan control via PWM framework

Guenter Roeck <[email protected]> Wed, 5 Aug 2026 07:58:42 -0700
Newsgroups org.kernel.vger.linux-hwmon,org.kernel.vger.linux-devicetree,org.kernel.vger.linux-kernel,org.kernel.vger.linux-pwm
Message-ID <[email protected]>
On Wed, Aug 05, 2026 at 10:15:19AM -0300, Luiz Angelo Daros de Luca wrote:
> The ADT7470 features four PWM outputs designed to control fans.
> Previously, these were only accessible through the legacy hwmon
> sysfs interface.
> 
> Expose the ADT7470 fan control lines through the generic PWM framework.
> This allows generic PWM consumers described in Device Tree, such as
> "pwm-fan", to use the device through the "#pwm-cells" property.  This is
> particularly necessary for boards where the ADT7470 external temperature
> sensors are not populated and the chip is used strictly as a fan
> controller (e.g., Edgecore ECS-2100-52T switches). In such setups,
> delegating control to the generic PWM subsystem allows the kernel's
> thermal framework to manage the fans based on unrelated temperature
> zones, such as internal SoC sensors.
> 
> When a PWM consumer applies a new PWM state, the driver automatically
> switches the corresponding PWM channel to manual mode so that the
> requested duty cycle takes effect. The duty cycle specified by the PWM
> framework is internally converted to the 0-255 scale expected by the
> hardware registers.
> 
> To prevent conflicting access, the hwmon PWM sysfs attributes are hidden
> when the device is registered with PWM framework support (i.e. when
> "#pwm-cells" is present in DT and CONFIG_PWM is reachable).
> 
> Signed-off-by: Luiz Angelo Daros de Luca <[email protected]>

Applied.

Thanks,
Guenter