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 <peter@xxxxxxxxxxxxx>
---
Changes since v4:
- Dropped custom property, use highest cooling level
Changes since v3:
- Readded validation code from v2, reworded commit message
Changes since v2:
- Recreated/resent
Changes since v1:
- Rename property to default-pwm
- Drop u32 cast
drivers/hwmon/pwm-fan.c | 19 +++++++++++++------
1 file changed, 13 insertions(+), 6 deletions(-)
diff --git a/drivers/hwmon/pwm-fan.c b/drivers/hwmon/pwm-fan.c
index 53a1a968d00d..f8282050a4dd 100644
--- 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 +545,22 @@ 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 +672,6 @@ 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,
--
2.39.5
