Commit ecf1cf1c authored by Peter Korsgaard's avatar Peter Korsgaard Committed by Guenter Roeck
Browse files

hwmon: (pwm-fan) Default to the Maximum cooling level if provided 



The pwm-fan driver uses full PWM (255) duty cycle at startup, which may not
always be desirable because of noise or power consumption peaks.

The driver optionally accept a list of "cooling-levels" for the thermal
subsystem.  If provided, use the PWM value corresponding to the maximum
cooling level rather than the full level as the initial PWM setting.

Signed-off-by: default avatarPeter Korsgaard <peter@korsgaard.com>
Link: https://lore.kernel.org/r/20250113135118.3994998-1-peter@korsgaard.com


[groeck: Dropped double empty line]
Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
parent 74a2594a

drivers/hwmon/pwm-fan.c

+12 −6
Original line number Diff line number Diff line
@@ -497,7 +497,7 @@ static int pwm_fan_probe(struct platform_device *pdev) 
	struct device *hwmon;

	int ret;

	const struct hwmon_channel_info **channels;

	u32 pwm_min_from_stopped = 0;

	u32 initial_pwm, pwm_min_from_stopped = 0;

	u32 *fan_channel_config;

	int channel_count = 1;	/* We always have a PWM channel. */

	int i;
@@ -545,11 +545,21 @@ static int pwm_fan_probe(struct platform_device *pdev) 


	ctx->enable_mode = pwm_disable_reg_enable;



	ret = pwm_fan_get_cooling_data(dev, ctx);

	if (ret)

		return ret;



	/* use maximum cooling level if provided */

	if (ctx->pwm_fan_cooling_levels)

		initial_pwm = ctx->pwm_fan_cooling_levels[ctx->pwm_fan_max_state];

	else

		initial_pwm = MAX_PWM;



	/*

	 * Set duty cycle to maximum allowed and enable PWM output as well as

	 * the regulator. In case of error nothing is changed

	 */

	ret = set_pwm(ctx, MAX_PWM);

	ret = set_pwm(ctx, initial_pwm);

	if (ret) {

		dev_err(dev, "Failed to configure PWM: %d\n", ret);

		return ret;
@@ -661,10 +671,6 @@ static int pwm_fan_probe(struct platform_device *pdev) 
		return PTR_ERR(hwmon);

	}



	ret = pwm_fan_get_cooling_data(dev, ctx);

	if (ret)

		return ret;



	ctx->pwm_fan_state = ctx->pwm_fan_max_state;

	if (IS_ENABLED(CONFIG_THERMAL)) {

		cdev = devm_thermal_of_cooling_device_register(dev,