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of/reconfig: Add of_reconfig_get_state_change() of notifier helper.

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Introduce of_reconfig_get_state_change() which allows an of notifier
to query about device state changes.

Signed-off-by: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
Signed-off-by: Grant Likely <grant.likely@linaro.org>
This commit is contained in:
Pantelis Antoniou 2014-10-28 22:33:53 +02:00 committed by Grant Likely
parent da56d04c80
commit b53a2340d0
2 changed files with 103 additions and 0 deletions
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96
drivers/of/dynamic.c
View File

@ -85,6 +85,102 @@ int of_reconfig_notify(unsigned long action, void *p)
return notifier_to_errno(rc);
}
/*
* of_reconfig_get_state_change() - Returns new state of device
* @action - action of the of notifier
* @arg - argument of the of notifier
*
* Returns the new state of a device based on the notifier used.
* Returns 0 on device going from enabled to disabled, 1 on device
* going from disabled to enabled and -1 on no change.
*/
int of_reconfig_get_state_change(unsigned long action, void *arg)
{
struct device_node *dn;
struct property *prop, *old_prop;
struct of_prop_reconfig *pr;
int is_status, status_state, old_status_state, prev_state, new_state;
/* figure out if a device should be created or destroyed */
dn = NULL;
prop = old_prop = NULL;
switch (action) {
case OF_RECONFIG_ATTACH_NODE:
case OF_RECONFIG_DETACH_NODE:
dn = arg;
prop = of_find_property(dn, "status", NULL);
break;
case OF_RECONFIG_ADD_PROPERTY:
case OF_RECONFIG_REMOVE_PROPERTY:
pr = arg;
dn = pr->dn;
prop = pr->prop;
break;
case OF_RECONFIG_UPDATE_PROPERTY:
pr = arg;
dn = pr->dn;
prop = pr->prop;
old_prop = pr->old_prop;
break;
default:
return OF_RECONFIG_NO_CHANGE;
}
is_status = 0;
status_state = -1;
old_status_state = -1;
prev_state = -1;
new_state = -1;
if (prop && !strcmp(prop->name, "status")) {
is_status = 1;
status_state = !strcmp(prop->value, "okay") ||
!strcmp(prop->value, "ok");
if (old_prop)
old_status_state = !strcmp(old_prop->value, "okay") ||
!strcmp(old_prop->value, "ok");
}
switch (action) {
case OF_RECONFIG_ATTACH_NODE:
prev_state = 0;
/* -1 & 0 status either missing or okay */
new_state = status_state != 0;
break;
case OF_RECONFIG_DETACH_NODE:
/* -1 & 0 status either missing or okay */
prev_state = status_state != 0;
new_state = 0;
break;
case OF_RECONFIG_ADD_PROPERTY:
if (is_status) {
/* no status property -> enabled (legacy) */
prev_state = 1;
new_state = status_state;
}
break;
case OF_RECONFIG_REMOVE_PROPERTY:
if (is_status) {
prev_state = status_state;
/* no status property -> enabled (legacy) */
new_state = 1;
}
break;
case OF_RECONFIG_UPDATE_PROPERTY:
if (is_status) {
prev_state = old_status_state != 0;
new_state = status_state != 0;
}
break;
}
if (prev_state == new_state)
return OF_RECONFIG_NO_CHANGE;
return new_state ? OF_RECONFIG_CHANGE_ADD : OF_RECONFIG_CHANGE_REMOVE;
}
EXPORT_SYMBOL_GPL(of_reconfig_get_state_change);
int of_property_notify(int action, struct device_node *np,
struct property *prop, struct property *oldprop)
{

7
include/linux/of.h
View File

@ -327,6 +327,7 @@ struct of_prop_reconfig {
extern int of_reconfig_notifier_register(struct notifier_block *);
extern int of_reconfig_notifier_unregister(struct notifier_block *);
extern int of_reconfig_notify(unsigned long, void *);
extern int of_reconfig_get_state_change(unsigned long action, void *arg);
extern int of_attach_node(struct device_node *);
extern int of_detach_node(struct device_node *);
@ -887,6 +888,12 @@ struct of_changeset {
struct list_head entries;
};
enum of_reconfig_change {
OF_RECONFIG_NO_CHANGE = 0,
OF_RECONFIG_CHANGE_ADD,
OF_RECONFIG_CHANGE_REMOVE,
};
#ifdef CONFIG_OF_DYNAMIC
extern void of_changeset_init(struct of_changeset *ocs);
extern void of_changeset_destroy(struct of_changeset *ocs);