[power] Move suspend()/resume() methods.

Instead of putting them in struct device_driver (which few, if any drivers
use directly), put them in the controlling bus_type of the device (which
are currently responsible for claiming the methods and forwarding the calls
to the bus-specific driver anyway).

This will save 8 bytes per driver instance, which isn't that much, but it's
something. It also makes it more obvious to the reader what is going on. 
And, it makes for easier bus-level defaults in the case the device has no
driver attached. 

The old calls remain until all instances have been fixed up.

drivers/base/power/resume.c

@@ -22,10 +22,8 @@ extern int sysdev_resume(void);
 
 int resume_device(struct device * dev)
 {
-	struct device_driver * drv = dev->driver;
-
-	if (drv && drv->resume)
-		return drv->resume(dev,RESUME_RESTORE_STATE);
+	if (dev->bus && dev->bus->resume)
+		return dev->bus->resume(dev);
 	return 0;
 }
 
@@ -49,19 +47,6 @@ void device_pm_resume(void)
 }
 
 
-/**
- *	power_up_device - Power one device on.
- *	@dev:	Device.
- */
-
-void power_up_device(struct device * dev)
-{
-	struct device_driver * drv = dev->driver;
-	if (drv && drv->resume)
-		drv->resume(dev,RESUME_POWER_ON);
-}
-
-
 /**
  *	device_power_up_irq - Power on some devices. 
  *
@@ -78,7 +63,7 @@ void dpm_power_up(void)
 	while(!list_empty(&dpm_off_irq)) {
 		struct list_head * entry = dpm_off_irq.next;
 		list_del_init(entry);
-		power_up_device(to_device(entry));
+		resume_device(to_device(entry));
 		list_add_tail(entry,&dpm_active);
 	}
 }

drivers/base/power/suspend.c

@@ -37,11 +37,10 @@ extern int sysdev_suspend(u32 state);
 
 int suspend_device(struct device * dev, u32 state)
 {
-	struct device_driver * drv = dev->driver;
 	int error = 0;
 
-	if (drv && drv->suspend) 
-		error = drv->suspend(dev,state,SUSPEND_SAVE_STATE);
+	if (dev->bus && dev->bus->suspend)
+		error = dev->bus->suspend(dev,state);
 
 	if (!error) {
 		list_del(&dev->power.entry);
@@ -96,23 +95,6 @@ int device_pm_suspend(u32 state)
 }
 
 
-/**
- *	dpm_power_down - Power down devices without interrupts.
- *	@state:	State to enter.
- *
- *	Walk the dpm_off_irq list (built by device_pm_suspend) and power
- *	down each device that requires the call to be made with interrupts
- *	disabled. 
- */
-
-static int dpm_power_down(u32 state)
-{
-	int error = 0;
-
-	return error;
-}
-
-
 /**
  *	device_pm_power_down - Shut down special devices.
  *	@state:		Power state to enter.

include/linux/device.h

@@ -58,7 +58,8 @@ struct bus_type {
 	struct device * (*add)	(struct device * parent, char * bus_id);
 	int		(*hotplug) (struct device *dev, char **envp, 
 				    int num_envp, char *buffer, int buffer_size);
-
+	int		(*suspend)(struct device * dev, u32 state);
+	int		(*resume)(struct device * dev);
 };
 
 extern int bus_register(struct bus_type * bus);

kernel/power/main.c

@@ -118,7 +118,7 @@ static int power_down(u32 mode)
 	int error = 0;
 
 	local_irq_save(flags);
-	device_pm_power_down();
+	device_pm_power_down(PM_SUSPEND_DISK);
 	switch(mode) {
 	case PM_DISK_PLATFORM:
 		error = pm_ops->enter(PM_SUSPEND_DISK);