hwmon: Provide managed hwmon registration

Drivers using the new hwmon_device_register_with_groups API often have a
remove function which consists solely of a call hwmon_device_unregister().

Provide support for devm_hwmon_device_register_with_groups and
devm_hwmon_device_unregister to allow this repeated code to be removed
and help eliminate error handling code.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>

2 files changed, 68 insertions, 0 deletions

diff --git a/drivers/hwmon/hwmon.c b/drivers/hwmon/hwmon.c
index a982528293ea..e176a43af63d 100644
--- a/drivers/hwmon/hwmon.c
+++ b/drivers/hwmon/hwmon.c
@@ -163,6 +163,69 @@ void hwmon_device_unregister(struct device *dev)
 }
 EXPORT_SYMBOL_GPL(hwmon_device_unregister);
 
+static void devm_hwmon_release(struct device *dev, void *res)
+{
+        struct device *hwdev = *(struct device **)res;
+
+        hwmon_device_unregister(hwdev);
+}
+
+/**
+ * devm_hwmon_device_register_with_groups - register w/ hwmon
+ * @dev: the parent device
+ * @name: hwmon name attribute
+ * @drvdata: driver data to attach to created device
+ * @groups: List of attribute groups to create
+ *
+ * Returns the pointer to the new device. The new device is automatically
+ * unregistered with the parent device.
+ */
+struct device *
+devm_hwmon_device_register_with_groups(struct device *dev, const char *name,
+                                       void *drvdata,
+                                       const struct attribute_group **groups)
+{
+        struct device **ptr, *hwdev;
+
+        if (!dev)
+                return ERR_PTR(-EINVAL);
+
+        ptr = devres_alloc(devm_hwmon_release, sizeof(*ptr), GFP_KERNEL);
+        if (!ptr)
+                return ERR_PTR(-ENOMEM);
+
+        hwdev = hwmon_device_register_with_groups(dev, name, drvdata, groups);
+        if (IS_ERR(hwdev))
+                goto error;
+
+        *ptr = hwdev;
+        devres_add(dev, ptr);
+        return hwdev;
+
+error:
+        devres_free(ptr);
+        return hwdev;
+}
+EXPORT_SYMBOL_GPL(devm_hwmon_device_register_with_groups);
+
+static int devm_hwmon_match(struct device *dev, void *res, void *data)
+{
+        struct device **hwdev = res;
+
+        return *hwdev == data;
+}
+
+/**
+ * devm_hwmon_device_unregister - removes a previously registered hwmon device
+ *
+ * @dev: the parent device of the device to unregister
+ */
+void devm_hwmon_device_unregister(struct device *dev)
+{
+        WARN_ON(devres_release(dev, devm_hwmon_release, devm_hwmon_match, dev));
+}
+EXPORT_SYMBOL_GPL(devm_hwmon_device_unregister);
+
 static void __init hwmon_pci_quirks(void)
 {
 #if defined CONFIG_X86 && defined CONFIG_PCI
diff --git a/include/linux/hwmon.h b/include/linux/hwmon.h
index 6d02ff77ae1a..09354f6c1d63 100644
--- a/include/linux/hwmon.h
+++ b/include/linux/hwmon.h
@@ -22,7 +22,12 @@ struct device *
 hwmon_device_register_with_groups(struct device *dev, const char *name,
                                   void *drvdata,
                                   const struct attribute_group **groups);
+struct device *
+devm_hwmon_device_register_with_groups(struct device *dev, const char *name,
+                                       void *drvdata,
+                                       const struct attribute_group **groups);
 
 void hwmon_device_unregister(struct device *dev);
+void devm_hwmon_device_unregister(struct device *dev);
 
 #endif