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 5a64775..4bea53f 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