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

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>

diff --git a/drivers/of/dynamic.c b/drivers/of/dynamic.c
index 661ad2f..6659c39 100644 (file)
--- 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 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)
 {

diff --git a/include/linux/of.h b/include/linux/of.h
index 27635c8..8e3a264 100644 (file)
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -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);