Commit c64a0926 authored by Kevin Hilman's avatar Kevin Hilman Committed by Greg Kroah-Hartman
Browse files

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: default avatarGrant Likely <grant.likely@secretlab.ca>
Signed-off-by: default avatarKevin Hilman <khilman@deeprootsystems.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 1037246c

drivers/base/platform.c

+35 −0
Original line number Diff line number Diff line
@@ -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;

include/linux/platform_device.h

+3 −0
Original line number Diff line number Diff line
@@ -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;

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