linux-kernel - Re: [PATCH] hwmon: pwm-fan: set usage

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Date:   Tue, 21 Mar 2023 08:03:31 -0700
From:   Guenter Roeck <linux@...ck-us.net>
To:     Lorenz Brun <lorenz@...n.one>
Cc:     Jean Delvare <jdelvare@...e.com>, linux-hwmon@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] hwmon: pwm-fan: set usage_power on PWM state

On Thu, Mar 09, 2023 at 02:10:08AM +0100, Lorenz Brun wrote:
> PWM fans are controlled solely by the duty cycle of the PWM signal, they
> do not care about the exact timing. Thus set usage_power to true to
> allow less flexible hardware to work as a PWM source for fan control.
> 
> Signed-off-by: Lorenz Brun <lorenz@...n.one>

Applied to hwmon-next.

Thanks,
Guenter

> ---
>  drivers/hwmon/pwm-fan.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/drivers/hwmon/pwm-fan.c b/drivers/hwmon/pwm-fan.c
> index 83a347ca35da..aa746c2bde39 100644
> --- a/drivers/hwmon/pwm-fan.c
> +++ b/drivers/hwmon/pwm-fan.c
> @@ -507,6 +507,14 @@ static int pwm_fan_probe(struct platform_device *pdev)
>  
>  	pwm_init_state(ctx->pwm, &ctx->pwm_state);
>  
> +	/*
> +	 * PWM fans are controlled solely by the duty cycle of the PWM signal,
> +	 * they do not care about the exact timing. Thus set usage_power to true
> +	 * to allow less flexible hardware to work as a PWM source for fan
> +	 * control.
> +	 */
> +	ctx->pwm_state.usage_power = true;
> +
>  	/*
>  	 * set_pwm assumes that MAX_PWM * (period - 1) fits into an unsigned
>  	 * long. Check this here to prevent the fan running at a too low