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Subject[PATCH] [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>

diff -up -x BitKeeper -x ChangeSet -x SCCS -x _xlk -x *.orig -x *.rej -x .git linus/drivers/base/platform.c linux/drivers/base/platform.c
--- linus/drivers/base/platform.c Fri Oct 28 21:31:47 2005
+++ linux/drivers/base/platform.c Sun Oct 30 16:23:09 2005
@@ -116,12 +116,115 @@ int platform_add_devices(struct platform
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->dev.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 plat
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_init(&pdev->dev);
+ return platform_device_add(pdev);
+}

/**
* platform_device_unregister - remove a platform-level device
@@ -197,18 +312,6 @@ void platform_device_unregister(struct p
}
}

-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_simp
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 -u b/include/linux/platform_device.h b/include/linux/platform_device.h
--- b/include/linux/platform_device.h
+++ b/include/linux/platform_device.h
@@ -37,4 +37,10 @@

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_ */

--
Russell King
Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/
maintainer of: 2.6 Serial core
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