Driver Core: add nodename callbacks

This adds the nodename callback for struct class, struct device_type and
struct device, to allow drivers to send userspace hints on the device
name and subdirectory that should be used for it.

Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Jan Blunck <jblunck@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/base/core.c b/drivers/base/core.c
index 4d59975..7ecb193 100644 (file)
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -162,10 +162,18 @@ static int dev_uevent(struct kset *kset, struct kobject *kobj,
        struct device *dev = to_dev(kobj);
        int retval = 0;
 
-       /* add the major/minor if present */
+       /* add device node properties if present */
        if (MAJOR(dev->devt)) {
+               const char *tmp;
+               const char *name;
+
                add_uevent_var(env, "MAJOR=%u", MAJOR(dev->devt));
                add_uevent_var(env, "MINOR=%u", MINOR(dev->devt));
+               name = device_get_nodename(dev, &tmp);
+               if (name) {
+                       add_uevent_var(env, "DEVNAME=%s", name);
+                       kfree(tmp);
+               }
        }
 
        if (dev->type && dev->type->name)
@@ -1129,6 +1137,47 @@ static struct device *next_device(struct klist_iter *i)
 }
 
 /**
+ * device_get_nodename - path of device node file
+ * @dev: device
+ * @tmp: possibly allocated string
+ *
+ * Return the relative path of a possible device node.
+ * Non-default names may need to allocate a memory to compose
+ * a name. This memory is returned in tmp and needs to be
+ * freed by the caller.
+ */
+const char *device_get_nodename(struct device *dev, const char **tmp)
+{
+       char *s;
+
+       *tmp = NULL;
+
+       /* the device type may provide a specific name */
+       if (dev->type && dev->type->nodename)
+               *tmp = dev->type->nodename(dev);
+       if (*tmp)
+               return *tmp;
+
+       /* the class may provide a specific name */
+       if (dev->class && dev->class->nodename)
+               *tmp = dev->class->nodename(dev);
+       if (*tmp)
+               return *tmp;
+
+       /* return name without allocation, tmp == NULL */
+       if (strchr(dev_name(dev), '!') == NULL)
+               return dev_name(dev);
+
+       /* replace '!' in the name with '/' */
+       *tmp = kstrdup(dev_name(dev), GFP_KERNEL);
+       if (!*tmp)
+               return NULL;
+       while ((s = strchr(*tmp, '!')))
+               s[0] = '/';
+       return *tmp;
+}
+
+/**
  * device_for_each_child - device child iterator.
  * @parent: parent struct device.
  * @data: data for the callback.

diff --git a/include/linux/device.h b/include/linux/device.h
index 4410464..ed4e39f 100644 (file)
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -194,6 +194,7 @@ struct class {
        struct kobject                  *dev_kobj;
 
        int (*dev_uevent)(struct device *dev, struct kobj_uevent_env *env);
+       char *(*nodename)(struct device *dev);
 
        void (*class_release)(struct class *class);
        void (*dev_release)(struct device *dev);
@@ -289,6 +290,7 @@ struct device_type {
        const char *name;
        struct attribute_group **groups;
        int (*uevent)(struct device *dev, struct kobj_uevent_env *env);
+       char *(*nodename)(struct device *dev);
        void (*release)(struct device *dev);
 
        struct dev_pm_ops *pm;
@@ -488,6 +490,7 @@ extern struct device *device_find_child(struct device *dev, void *data,
 extern int device_rename(struct device *dev, char *new_name);
 extern int device_move(struct device *dev, struct device *new_parent,
                       enum dpm_order dpm_order);
+extern const char *device_get_nodename(struct device *dev, const char **tmp);
 
 /*
  * Root device objects for grouping under /sys/devices