2 files changed, 27 insertions, 23 deletions

diff --git a/Documentation/devicetree/bindings/gpio/gpio-fan.txt b/Documentation/devicetree/bindings/gpio/gpio-fan.txt
index 2dd457a3469a..f996d428f132 100644
--- a/Documentation/devicetree/bindings/gpio/gpio-fan.txt
+++ b/Documentation/devicetree/bindings/gpio/gpio-fan.txt
@@ -2,16 +2,18 @@ Bindings for fan connected to GPIO lines
 
 Required properties:
 - compatible : "gpio-fan"
+
+Optional properties:
 - gpios: Specifies the pins that map to bits in the control value,
   ordered MSB-->LSB.
 - gpio-fan,speed-map: A mapping of possible fan RPM speeds and the
   control value that should be set to achieve them. This array
   must have the RPM values in ascending order.
-
-Optional properties:
 - alarm-gpios: This pin going active indicates something is wrong with
   the fan, and a udev event will be fired.
 
+Note: At least one the "gpios" or "alarm-gpios" properties must be set.
+
 Examples:
 
         gpio_fan {
diff --git a/drivers/hwmon/gpio-fan.c b/drivers/hwmon/gpio-fan.c
index 36abf814b8c7..c241f5b0b7cf 100644
--- a/drivers/hwmon/gpio-fan.c
+++ b/drivers/hwmon/gpio-fan.c
@@ -404,10 +404,32 @@ static int gpio_fan_get_of_pdata(struct device *dev,
 
         node = dev->of_node;
 
+        /* Alarm GPIO if one exists */
+        if (of_gpio_named_count(node, "alarm-gpios") > 0) {
+                struct gpio_fan_alarm *alarm;
+                int val;
+                enum of_gpio_flags flags;
+
+                alarm = devm_kzalloc(dev, sizeof(struct gpio_fan_alarm),
+                                        GFP_KERNEL);
+                if (!alarm)
+                        return -ENOMEM;
+
+                val = of_get_named_gpio_flags(node, "alarm-gpios", 0, &flags);
+                if (val < 0)
+                        return val;
+                alarm->gpio = val;
+                alarm->active_low = flags & OF_GPIO_ACTIVE_LOW;
+
+                pdata->alarm = alarm;
+        }
+
         /* Fill GPIO pin array */
         pdata->num_ctrl = of_gpio_count(node);
         if (pdata->num_ctrl <= 0) {
-                dev_err(dev, "gpios DT property empty / missing");
+                if (pdata->alarm)
+                        return 0;
+                dev_err(dev, "DT properties empty / missing");
                 return -ENODEV;
         }
         ctrl = devm_kzalloc(dev, pdata->num_ctrl * sizeof(unsigned),
@@ -460,26 +482,6 @@ static int gpio_fan_get_of_pdata(struct device *dev,
         }
         pdata->speed = speed;
 
-        /* Alarm GPIO if one exists */
-        if (of_gpio_named_count(node, "alarm-gpios") > 0) {
-                struct gpio_fan_alarm *alarm;
-                int val;
-                enum of_gpio_flags flags;
-
-                alarm = devm_kzalloc(dev, sizeof(struct gpio_fan_alarm),
-                                        GFP_KERNEL);
-                if (!alarm)
-                        return -ENOMEM;
-
-                val = of_get_named_gpio_flags(node, "alarm-gpios", 0, &flags);
-                if (val < 0)
-                        return val;
-                alarm->gpio = val;
-                alarm->active_low = flags & OF_GPIO_ACTIVE_LOW;
-
-                pdata->alarm = alarm;
-        }
-
         return 0;
 }