driver core: move platform_data into platform_device

This patch moves platform_data from struct device into
struct platform_device, based on the two ideas:

1. Now all platform_driver is registered by platform_driver_register,
   which makes probe()/release()/... of platform_driver passed parameter
   of platform_device *, so platform driver can get platform_data from
   platform_device;

2. Other kind of devices do not need to use platform_data, we can
   decrease size of device if moving it to platform_device.

Taking into consideration of thousands of files to be fixed and they
can't be finished in one night(maybe it will take a long time), so we
keep platform_data in device to allow two kind of cases coexist until
all platform devices pass its platfrom data from
platform_device->platform_data.

All patches to do this kind of conversion are welcome.

Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 7 insertions, 2 deletions

diff --git a/include/linux/device.h b/include/linux/device.h
index 5a64775e68e4..4bea53fe8f4c 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -385,8 +385,13 @@ struct device {
         struct device_driver *driver;   /* which driver has allocated this
                                            device */
         void            *driver_data;   /* data private to the driver */
-        void            *platform_data; /* Platform specific data, device
-                                           core doesn't touch it */
+
+        void            *platform_data; /* We will remove platform_data
+                                           field if all platform devices
+                                           pass its platform specific data
+                                           from platform_device->platform_data,
+                                           other kind of devices should not
+                                           use platform_data. */
         struct dev_pm_info      power;
 
 #ifdef CONFIG_NUMA