[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>

2 files changed, 132 insertions, 27 deletions

diff --git a/drivers/base/platform.c b/drivers/base/platform.c
index d597c922af11..6d4736e89f1a 100644
--- 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 a726225e0afe..1a165b7ae01b 100644
--- 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_ */