Introduce of_reconfig_get_state_change() which allows an of notifier
to query about device state changes.
Signed-off-by: Pantelis Antoniou <pantelis.antoniou@xxxxxxxxxxxx>
---
drivers/of/dynamic.c | 96 ++++++++++++++++++++++++++++++++++++++++++++++++++++
include/linux/of.h | 1 +
2 files changed, 97 insertions(+)
diff --git a/drivers/of/dynamic.c b/drivers/of/dynamic.c
index 9eb8528..303a59b 100644
--- a/drivers/of/dynamic.c
+++ b/drivers/of/dynamic.c
@@ -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 -1; /* don't care */
+ }
+
+ 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 -1;
+
+ return new_state;
+}
+EXPORT_SYMBOL_GPL(of_reconfig_get_state_change);
+
int of_property_notify(int action, struct device_node *np,
struct property *prop, struct property *oldprop)
{
diff --git a/include/linux/of.h b/include/linux/of.h
index 71d25aa..9ff1ec5 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -328,6 +328,7 @@ 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 *);
--
1.7.12
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