[DRIVER MODEL] Improved dynamically allocated platform_device interface

Re-jig the simple platform device support to allow private data
to be attached to a platform device, as well as allowing the
parent device to be set.

Example usage:

	pdev = platform_device_alloc("mydev", id);
	if (pdev) {
		err = platform_device_add_resources(pdev, &resources,
						    ARRAY_SIZE(resources));
		if (err == 0)
			err = platform_device_add_data(pdev, &platform_data,
						       sizeof(platform_data));
		if (err == 0)
			err = platform_device_add(pdev);
	} else {
		err = -ENOMEM;
	}
	if (err)
		platform_device_put(pdev);

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/base/platform.c b/drivers/base/platform.c
index d597c92..6d4736e 100644 (file)
--- a/drivers/base/platform.c
+++ b/drivers/base/platform.c
@@ -116,12 +116,115 @@ int platform_add_devices(struct platform_device **devs, int num)
        return ret;
 }
 
+struct platform_object {
+       struct platform_device pdev;
+       char name[1];
+};
+
 /**
- *     platform_device_register - add a platform-level device
+ *     platform_device_put
+ *     @pdev:  platform device to free
+ *
+ *     Free all memory associated with a platform device.  This function
+ *     must _only_ be externally called in error cases.  All other usage
+ *     is a bug.
+ */
+void platform_device_put(struct platform_device *pdev)
+{
+       if (pdev)
+               put_device(&pdev->dev);
+}
+EXPORT_SYMBOL_GPL(platform_device_put);
+
+static void platform_device_release(struct device *dev)
+{
+       struct platform_object *pa = container_of(dev, struct platform_object, pdev.dev);
+
+       kfree(pa->pdev.dev.platform_data);
+       kfree(pa->pdev.resource);
+       kfree(pa);
+}
+
+/**
+ *     platform_device_alloc
+ *     @name:  base name of the device we're adding
+ *     @id:    instance id
+ *
+ *     Create a platform device object which can have other objects attached
+ *     to it, and which will have attached objects freed when it is released.
+ */
+struct platform_device *platform_device_alloc(const char *name, unsigned int id)
+{
+       struct platform_object *pa;
+
+       pa = kzalloc(sizeof(struct platform_object) + strlen(name), GFP_KERNEL);
+       if (pa) {
+               strcpy(pa->name, name);
+               pa->pdev.name = pa->name;
+               pa->pdev.id = id;
+               device_initialize(&pa->pdev.dev);
+               pa->pdev.dev.release = platform_device_release;
+       }
+
+       return pa ? &pa->pdev : NULL;   
+}
+EXPORT_SYMBOL_GPL(platform_device_alloc);
+
+/**
+ *     platform_device_add_resources
+ *     @pdev:  platform device allocated by platform_device_alloc to add resources to
+ *     @res:   set of resources that needs to be allocated for the device
+ *     @num:   number of resources
+ *
+ *     Add a copy of the resources to the platform device.  The memory
+ *     associated with the resources will be freed when the platform
+ *     device is released.
+ */
+int platform_device_add_resources(struct platform_device *pdev, struct resource *res, unsigned int num)
+{
+       struct resource *r;
+
+       r = kmalloc(sizeof(struct resource) * num, GFP_KERNEL);
+       if (r) {
+               memcpy(r, res, sizeof(struct resource) * num);
+               pdev->resource = r;
+               pdev->num_resources = num;
+       }
+       return r ? 0 : -ENOMEM;
+}
+EXPORT_SYMBOL_GPL(platform_device_add_resources);
+
+/**
+ *     platform_device_add_data
+ *     @pdev:  platform device allocated by platform_device_alloc to add resources to
+ *     @data:  platform specific data for this platform device
+ *     @size:  size of platform specific data
+ *
+ *     Add a copy of platform specific data to the platform device's platform_data
+ *     pointer.  The memory associated with the platform data will be freed
+ *     when the platform device is released.
+ */
+int platform_device_add_data(struct platform_device *pdev, void *data, size_t size)
+{
+       void *d;
+
+       d = kmalloc(size, GFP_KERNEL);
+       if (d) {
+               memcpy(d, data, size);
+               pdev->dev.platform_data = d;
+       }
+       return d ? 0 : -ENOMEM;
+}
+EXPORT_SYMBOL_GPL(platform_device_add_data);
+
+/**
+ *     platform_device_add - add a platform device to device hierarchy
  *     @pdev:  platform device we're adding
  *
+ *     This is part 2 of platform_device_register(), though may be called
+ *     separately _iff_ pdev was allocated by platform_device_alloc().
  */
-int platform_device_register(struct platform_device * pdev)
+int platform_device_add(struct platform_device *pdev)
 {
        int i, ret = 0;
 
@@ -174,6 +277,18 @@ int platform_device_register(struct platform_device * pdev)
                        release_resource(&pdev->resource[i]);
        return ret;
 }
+EXPORT_SYMBOL_GPL(platform_device_add);
+
+/**
+ *     platform_device_register - add a platform-level device
+ *     @pdev:  platform device we're adding
+ *
+ */
+int platform_device_register(struct platform_device * pdev)
+{
+       device_initialize(&pdev->dev);
+       return platform_device_add(pdev);
+}
 
 /**
  *     platform_device_unregister - remove a platform-level device
@@ -197,18 +312,6 @@ void platform_device_unregister(struct platform_device * pdev)
        }
 }
 
-struct platform_object {
-        struct platform_device pdev;
-        struct resource resources[0];
-};
-
-static void platform_device_release_simple(struct device *dev)
-{
-       struct platform_device *pdev = to_platform_device(dev);
-
-       kfree(container_of(pdev, struct platform_object, pdev));
-}
-
 /**
  *     platform_device_register_simple
  *     @name:  base name of the device we're adding
@@ -225,33 +328,29 @@ static void platform_device_release_simple(struct device *dev)
 struct platform_device *platform_device_register_simple(char *name, unsigned int id,
                                                        struct resource *res, unsigned int num)
 {
-       struct platform_object *pobj;
+       struct platform_device *pdev;
        int retval;
 
-       pobj = kzalloc(sizeof(*pobj) + sizeof(struct resource) * num, GFP_KERNEL);
-       if (!pobj) {
+       pdev = platform_device_alloc(name, id);
+       if (!pdev) {
                retval = -ENOMEM;
                goto error;
        }
 
-       pobj->pdev.name = name;
-       pobj->pdev.id = id;
-       pobj->pdev.dev.release = platform_device_release_simple;
-
        if (num) {
-               memcpy(pobj->resources, res, sizeof(struct resource) * num);
-               pobj->pdev.resource = pobj->resources;
-               pobj->pdev.num_resources = num;
+               retval = platform_device_add_resources(pdev, res, num);
+               if (retval)
+                       goto error;
        }
 
-       retval = platform_device_register(&pobj->pdev);
+       retval = platform_device_add(pdev);
        if (retval)
                goto error;
 
-       return &pobj->pdev;
+       return pdev;
 
 error:
-       kfree(pobj);
+       platform_device_put(pdev);
        return ERR_PTR(retval);
 }
 

diff --git a/include/linux/platform_device.h b/include/linux/platform_device.h
index a726225..1a165b7 100644 (file)
--- a/include/linux/platform_device.h
+++ b/include/linux/platform_device.h
@@ -37,4 +37,10 @@ extern int platform_add_devices(struct platform_device **, int);
 
 extern struct platform_device *platform_device_register_simple(char *, unsigned int, struct resource *, unsigned int);
 
+extern struct platform_device *platform_device_alloc(const char *name, unsigned int id);
+extern int platform_device_add_resources(struct platform_device *pdev, struct resource *res, unsigned int num);
+extern int platform_device_add_data(struct platform_device *pdev, void *data, size_t size);
+extern int platform_device_add(struct platform_device *pdev);
+extern void platform_device_put(struct platform_device *pdev);
+
 #endif /* _PLATFORM_DEVICE_H_ */