On 4/24/24 02:04, Peter Korsgaard wrote:
For some use cases defaulting the PWM to full fan speed is not ideal
(noise, power consumption, ..), so support an optional target-pwm
property (0..255) to override the default PWM value.
Signed-off-by: Peter Korsgaard <peter@xxxxxxxxxxxxx>
---
drivers/hwmon/pwm-fan.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/drivers/hwmon/pwm-fan.c b/drivers/hwmon/pwm-fan.c
index b67bc9e833c0..ebdefbd5789c 100644
--- a/drivers/hwmon/pwm-fan.c
+++ b/drivers/hwmon/pwm-fan.c
@@ -482,6 +482,7 @@ static int pwm_fan_probe(struct platform_device *pdev)
const struct hwmon_channel_info **channels;
u32 *fan_channel_config;
int channel_count = 1; /* We always have a PWM channel. */
+ u32 target_pwm = MAX_PWM;
int i;
ctx = devm_kzalloc(dev, sizeof(*ctx), GFP_KERNEL);
@@ -527,11 +528,17 @@ static int pwm_fan_probe(struct platform_device *pdev)
ctx->enable_mode = pwm_disable_reg_enable;
+ of_property_read_u32(dev->of_node, "target-pwm", &target_pwm);
+ if (target_pwm > (u32)MAX_PWM) {
+ dev_err(dev, "Invalid target-pwm: %u > %d\n", target_pwm, MAX_PWM);
+ return -EINVAL;
+ }
+
/*
- * Set duty cycle to maximum allowed and enable PWM output as well as
+ * Set duty cycle to target 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, target_pwm);
if (ret) {
dev_err(dev, "Failed to configure PWM: %d\n", ret);
return ret;
A much better name would be default-pwm for the property name.
target-pwm is misleading and doesn't really make sense because
there is no "target", just a value that is being set.
Guenter
