1 files changed, 37 insertions, 3 deletions

diff --git a/drivers/mailbox/mailbox.c b/drivers/mailbox/mailbox.c
index 19b491d2964f..c7fdb57fd166 100644
--- a/drivers/mailbox/mailbox.c
+++ b/drivers/mailbox/mailbox.c
@@ -318,7 +318,7 @@ struct mbox_chan *mbox_request_channel(struct mbox_client *cl, int index)
                 return ERR_PTR(-ENODEV);
         }
 
-        chan = NULL;
+        chan = ERR_PTR(-EPROBE_DEFER);
         list_for_each_entry(mbox, &mbox_cons, node)
                 if (mbox->dev->of_node == spec.np) {
                         chan = mbox->of_xlate(mbox, &spec);
@@ -327,7 +327,12 @@ struct mbox_chan *mbox_request_channel(struct mbox_client *cl, int index)
 
         of_node_put(spec.np);
 
-        if (!chan || chan->cl || !try_module_get(mbox->dev->driver->owner)) {
+        if (IS_ERR(chan)) {
+                mutex_unlock(&con_mutex);
+                return chan;
+        }
+
+        if (chan->cl || !try_module_get(mbox->dev->driver->owner)) {
                 dev_dbg(dev, "%s: mailbox not free\n", __func__);
                 mutex_unlock(&con_mutex);
                 return ERR_PTR(-EBUSY);
@@ -357,6 +362,35 @@ struct mbox_chan *mbox_request_channel(struct mbox_client *cl, int index)
 }
 EXPORT_SYMBOL_GPL(mbox_request_channel);
 
+struct mbox_chan *mbox_request_channel_byname(struct mbox_client *cl,
+                                              const char *name)
+{
+        struct device_node *np = cl->dev->of_node;
+        struct property *prop;
+        const char *mbox_name;
+        int index = 0;
+
+        if (!np) {
+                dev_err(cl->dev, "%s() currently only supports DT\n", __func__);
+                return ERR_PTR(-ENOSYS);
+        }
+
+        if (!of_get_property(np, "mbox-names", NULL)) {
+                dev_err(cl->dev,
+                        "%s() requires an \"mbox-names\" property\n", __func__);
+                return ERR_PTR(-ENOSYS);
+        }
+
+        of_property_for_each_string(np, "mbox-names", prop, mbox_name) {
+                if (!strncmp(name, mbox_name, strlen(name)))
+                        break;
+                index++;
+        }
+
+        return mbox_request_channel(cl, index);
+}
+EXPORT_SYMBOL_GPL(mbox_request_channel_byname);
+
 /**
  * mbox_free_channel - The client relinquishes control of a mailbox
  *                      channel by this call.
@@ -390,7 +424,7 @@ of_mbox_index_xlate(struct mbox_controller *mbox,
         int ind = sp->args[0];
 
         if (ind >= mbox->num_chans)
-                return NULL;
+                return ERR_PTR(-EINVAL);
 
         return &mbox->chans[ind];
 }