hwmon: (pwm-fan) Fix suspend/resume behavior

The state of a PWM output is not clearly defined after resume. Some PWM drivers do not restore the duty cycle upon resume, thus it is necessary to manually restore the correct value. Signed-off-by: Kamil Debski <[email protected]> Signed-off-by: Guenter Roeck <[email protected]>
josf · Nov 11, 2014 · 48b9d5b · 48b9d5b
1 parent aab18da
commit 48b9d5b
Showing 1 changed file with 10 additions and 3 deletions.
diff --git a/drivers/hwmon/pwm-fan.c b/drivers/hwmon/pwm-fan.c
@@ -161,10 +161,17 @@ static int pwm_fan_suspend(struct device *dev)
 static int pwm_fan_resume(struct device *dev)
 {
 	struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
+	unsigned long duty;
+	int ret;
 
-	if (ctx->pwm_value)
-		return pwm_enable(ctx->pwm);
-	return 0;
+	if (ctx->pwm_value == 0)
+		return 0;
+
+	duty = DIV_ROUND_UP(ctx->pwm_value * (ctx->pwm->period - 1), MAX_PWM);
+	ret = pwm_config(ctx->pwm, duty, ctx->pwm->period);
+	if (ret)
+		return ret;
+	return pwm_enable(ctx->pwm);
 }
 #endif