[v2,2/2] hwmon: (pwm-fan): support default-pwm property to set default PWM value

Commit Message

Peter Korsgaard April 24, 2024, 8:24 p.m. UTC

For some use cases defaulting the PWM to full fan speed is not ideal
(noise, power consumption, ..), so support an optional default-pwm
property (0..255) to override the default PWM value.

Signed-off-by: Peter Korsgaard <[e-mail]>
---
Changes since v1:
- Rename property to default-pwm
- Drop u32 cast

 drivers/hwmon/pwm-fan.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

Patch

diff --git a/drivers/hwmon/pwm-fan.c b/drivers/hwmon/pwm-fan.c
index b67bc9e833c0..a2a309f8e3ee 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 default_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, "default-pwm", &default_pwm);
+	if (default_pwm > MAX_PWM) {
+		dev_err(dev, "Invalid default-pwm: %u > %d\n", default_pwm, MAX_PWM);
+		return -EINVAL;
+	}
+
 	/*
-	 * Set duty cycle to maximum allowed and enable PWM output as well as
+	 * Set duty cycle to default 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, default_pwm);
 	if (ret) {
 		dev_err(dev, "Failed to configure PWM: %d\n", ret);
 		return ret;