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driver core: platform_bus: allow runtime override of dev_pm_ops 

Currently, the platform_bus allows customization of several of the
busses dev_pm_ops methods by using weak symbols so that platform code
can override them.  The weak-symbol approach is not scalable when
wanting to support multiple platforms in a single kernel binary.

Instead, provide __init methods for platform code to customize the
dev_pm_ops methods at runtime.

NOTE: after these dynamic methods are merged, the weak symbols should
      be removed from drivers/base/platform.c.  AFAIK, this will only
      affect SH and sh-mobile which should be converted to use this
      runtime approach instead of the weak symbols.  After SH &
      sh-mobile are converted, the weak symobols could be removed.

Tested on OMAP3.

Cc: Magnus Damm <magnus.damm@gmail.com>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Kevin Hilman 2010-08-25 12:50:00 -07:00 committed by Greg Kroah-Hartman
parent 1037246cac
commit c64a092671
2 changed files with 38 additions and 0 deletions
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35
drivers/base/platform.c
View File

@ -976,6 +976,41 @@ struct bus_type platform_bus_type = {
};
EXPORT_SYMBOL_GPL(platform_bus_type);
/**
* platform_bus_get_pm_ops() - return pointer to busses dev_pm_ops
*
* This function can be used by platform code to get the current
* set of dev_pm_ops functions used by the platform_bus_type.
*/
const struct dev_pm_ops * __init platform_bus_get_pm_ops(void)
{
return platform_bus_type.pm;
}
/**
* platform_bus_set_pm_ops() - update dev_pm_ops for the platform_bus_type
*
* @pm: pointer to new dev_pm_ops struct to be used for platform_bus_type
*
* Platform code can override the dev_pm_ops methods of
* platform_bus_type by using this function. It is expected that
* platform code will first do a platform_bus_get_pm_ops(), then
* kmemdup it, then customize selected methods and pass a pointer to
* the new struct dev_pm_ops to this function.
*
* Since platform-specific code is customizing methods for *all*
* devices (not just platform-specific devices) it is expected that
* any custom overrides of these functions will keep existing behavior
* and simply extend it. For example, any customization of the
* runtime PM methods should continue to call the pm_generic_*
* functions as the default ones do in addition to the
* platform-specific behavior.
*/
void __init platform_bus_set_pm_ops(const struct dev_pm_ops *pm)
{
platform_bus_type.pm = pm;
}
int __init platform_bus_init(void)
{
int error;

3
include/linux/platform_device.h
View File

@ -138,6 +138,9 @@ extern struct platform_device *platform_create_bundle(struct platform_driver *dr
struct resource *res, unsigned int n_res,
const void *data, size_t size);
extern const struct dev_pm_ops * platform_bus_get_pm_ops(void);
extern void platform_bus_set_pm_ops(const struct dev_pm_ops *pm);
/* early platform driver interface */
struct early_platform_driver {
const char *class_str;