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

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Message-Id: <20230309011009.2109696-1-lorenz@brun.one>
Date:   Thu,  9 Mar 2023 02:10:08 +0100
From:   Lorenz Brun <lorenz@...n.one>
To:     Jean Delvare <jdelvare@...e.com>,
        Guenter Roeck <linux@...ck-us.net>
Cc:     linux-hwmon@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH] hwmon: pwm-fan: set usage_power on 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.

Signed-off-by: Lorenz Brun <lorenz@...n.one>
---
 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
-- 
2.39.2