+/*
+ * To avoid cluttering sysfs (and memory) with useless state, only
+ * create attributes that can be meaningfully displayed.
+ */
+static int add_regulator_attributes(struct regulator_dev *rdev)
+{
+ struct device *dev = &rdev->dev;
+ struct regulator_ops *ops = rdev->desc->ops;
+ int status = 0;
+
+ /* some attributes need specific methods to be displayed */
+ if (ops->get_voltage) {
+ status = device_create_file(dev, &dev_attr_microvolts);
+ if (status < 0)
+ return status;
+ }
+ if (ops->get_current_limit) {
+ status = device_create_file(dev, &dev_attr_microamps);
+ if (status < 0)
+ return status;
+ }
+ if (ops->get_mode) {
+ status = device_create_file(dev, &dev_attr_opmode);
+ if (status < 0)
+ return status;
+ }
+ if (ops->is_enabled) {
+ status = device_create_file(dev, &dev_attr_state);
+ if (status < 0)
+ return status;
+ }
+
+ /* some attributes are type-specific */
+ if (rdev->desc->type == REGULATOR_CURRENT) {
+ status = device_create_file(dev, &dev_attr_requested_microamps);
+ if (status < 0)
+ return status;
+ }
+
+ /* all the other attributes exist to support constraints;
+ * don't show them if there are no constraints, or if the
+ * relevant supporting methods are missing.
+ */
+ if (!rdev->constraints)
+ return status;
+
+ /* constraints need specific supporting methods */
+ if (ops->set_voltage) {
+ status = device_create_file(dev, &dev_attr_min_microvolts);
+ if (status < 0)
+ return status;
+ status = device_create_file(dev, &dev_attr_max_microvolts);
+ if (status < 0)
+ return status;
+ }
+ if (ops->set_current_limit) {
+ status = device_create_file(dev, &dev_attr_min_microamps);
+ if (status < 0)
+ return status;
+ status = device_create_file(dev, &dev_attr_max_microamps);
+ if (status < 0)
+ return status;
+ }
+
+ /* suspend mode constraints need multiple supporting methods */
+ if (!(ops->set_suspend_enable && ops->set_suspend_disable))
+ return status;
+
+ status = device_create_file(dev, &dev_attr_suspend_standby_state);
+ if (status < 0)
+ return status;
+ status = device_create_file(dev, &dev_attr_suspend_mem_state);
+ if (status < 0)
+ return status;
+ status = device_create_file(dev, &dev_attr_suspend_disk_state);
+ if (status < 0)
+ return status;
+
+ if (ops->set_suspend_voltage) {
+ status = device_create_file(dev,
+ &dev_attr_suspend_standby_microvolts);
+ if (status < 0)
+ return status;
+ status = device_create_file(dev,
+ &dev_attr_suspend_mem_microvolts);
+ if (status < 0)
+ return status;
+ status = device_create_file(dev,
+ &dev_attr_suspend_disk_microvolts);
+ if (status < 0)
+ return status;
+ }
+
+ if (ops->set_suspend_mode) {
+ status = device_create_file(dev,
+ &dev_attr_suspend_standby_mode);
+ if (status < 0)
+ return status;
+ status = device_create_file(dev,
+ &dev_attr_suspend_mem_mode);
+ if (status < 0)
+ return status;
+ status = device_create_file(dev,
+ &dev_attr_suspend_disk_mode);
+ if (status < 0)
+ return status;
+ }
+
+ return status;
+}
+