[PATCH 30/47] Driver core: create devices/virtual/ tree

Greg KH
2006-09-26T05:45:13Z

From: Greg Kroah-Hartman <gregkh@suse.de>

This change creates a devices/virtual/CLASS_NAME tree for struct devices
that belong to a class, yet do not have a "real" struct device for a
parent. It automatically creates the directories on the fly as needed.

Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
drivers/base/class.c | 17 +++++++++++++++++
drivers/base/core.c | 7 +++++++
include/linux/device.h | 5 ++++-
3 files changed, 28 insertions(+), 1 deletions(-)

diff --git a/drivers/base/class.c b/drivers/base/class.c
index e078bc2..cbdf47c 100644
--- a/drivers/base/class.c
+++ b/drivers/base/class.c
@@ -19,6 +19,8 @@ #include <linux/err.h>
#include <linux/slab.h>
#include "base.h"

+extern struct subsystem devices_subsys;
+
#define to_class_attr(_attr) container_of(_attr, struct class_attribute, attr)
#define to_class(obj) container_of(obj, struct class, subsys.kset.kobj)

@@ -878,7 +880,22 @@ void class_interface_unregister(struct c
class_put(parent);
}

+int virtual_device_parent(struct device *dev)
+{
+ if (!dev->class)
+ return -ENODEV;
+
+ if (!dev->class->virtual_dir) {
+ static struct kobject *virtual_dir = NULL;

+ if (!virtual_dir)
+ virtual_dir = kobject_add_dir(&devices_subsys.kset.kobj, "virtual");
+ dev->class->virtual_dir = kobject_add_dir(virtual_dir, dev->class->name);
+ }
+
+ dev->kobj.parent = dev->class->virtual_dir;
+ return 0;
+}

int __init classes_init(void)
{
diff --git a/drivers/base/core.c b/drivers/base/core.c
index 0db4756..e21a65f 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -378,6 +378,13 @@ int device_add(struct device *dev)
if (!dev || !strlen(dev->bus_id))
goto Error;

+ /* if this is a class device, and has no parent, create one */
+ if ((dev->class) && (dev->parent == NULL)) {
+ error = virtual_device_parent(dev);
+ if (error)
+ goto Error;
+ }
+
parent = get_device(dev->parent);

pr_debug("DEV: registering device: ID = '%s'\n", dev->bus_id);
diff --git a/include/linux/device.h b/include/linux/device.h
index 3400e09..bbb0d6b 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -149,6 +149,8 @@ struct class {
struct list_head interfaces;
struct semaphore sem; /* locks both the children and interfaces lists */

+ struct kobject *virtual_dir;
+
struct class_attribute * class_attrs;
struct class_device_attribute * class_dev_attrs;
struct device_attribute * dev_attrs;
@@ -291,7 +293,6 @@ extern struct class_device *class_device
__attribute__((format(printf,5,6)));
extern void class_device_destroy(struct class *cls, dev_t devt);

-
/* interface for exporting device attributes */
struct device_attribute {
struct attribute attr;
@@ -400,6 +401,8 @@ extern struct device *device_create(stru
__attribute__((format(printf,4,5)));
extern void device_destroy(struct class *cls, dev_t devt);

+extern int virtual_device_parent(struct device *dev);
+
/*
* Platform "fixup" functions - allow the platform to have their say
* about devices and actions that the general device layer doesn't
--
1.4.2.1