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