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: Peter Korsgaard <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
[groeck: Dropped double empty line]
Signed-off-by: Guenter Roeck <[email protected]>

diff --git a/drivers/hwmon/pwm-fan.c b/drivers/hwmon/pwm-fan.c
index 231b3b348263d6c67985842f8c3f3020c44353c5..579d31bb9ac78ce489c1638a79549337fd7a2c72 100644 (file)
--- a/drivers/hwmon/pwm-fan.c
+++ b/drivers/hwmon/pwm-fan.c
@@ -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,