hwmon: Introduce hwmon_device_register_for_thermal

The thermal subsystem registers a hwmon driver without providing
chip or sysfs group information. This is for legacy reasons and
would be difficult to change. At the same time, we want to enforce
that chip information is provided when registering a hwmon device
using hwmon_device_register_with_info(). To enable this, introduce
a special API for use only by the thermal subsystem.

Acked-by: Rafael J . Wysocki <rafael@kernel.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

drivers/hwmon/hwmon.c

@@ -916,6 +916,31 @@ hwmon_device_register_with_info(struct device *dev, const char *name,
 }
 EXPORT_SYMBOL_GPL(hwmon_device_register_with_info);
 
+/**
+ * hwmon_device_register_for_thermal - register hwmon device for thermal subsystem
+ * @dev: the parent device
+ * @name: hwmon name attribute
+ * @drvdata: driver data to attach to created device
+ *
+ * The use of this function is restricted. It is provided for legacy reasons
+ * and must only be called from the thermal subsystem.
+ *
+ * hwmon_device_unregister() must be called when the device is no
+ * longer needed.
+ *
+ * Returns the pointer to the new device.
+ */
+struct device *
+hwmon_device_register_for_thermal(struct device *dev, const char *name,
+				  void *drvdata)
+{
+	if (!name || !dev)
+		return ERR_PTR(-EINVAL);
+
+	return __hwmon_device_register(dev, name, drvdata, NULL, NULL);
+}
+EXPORT_SYMBOL_NS_GPL(hwmon_device_register_for_thermal, HWMON_THERMAL);
+
 /**
  * hwmon_device_register - register w/ hwmon
  * @dev: the device to register

include/linux/hwmon.h

@@ -450,6 +450,9 @@ hwmon_device_register_with_info(struct device *dev,
 				const struct hwmon_chip_info *info,
 				const struct attribute_group **extra_groups);
 struct device *
+hwmon_device_register_for_thermal(struct device *dev, const char *name,
+				  void *drvdata);
+struct device *
 devm_hwmon_device_register_with_info(struct device *dev,
 				const char *name, void *drvdata,
 				const struct hwmon_chip_info *info,