mailbox: Fix up error handling in mbox_request_channel()

mbox_request_channel() currently returns EBUSY in the event the controller
is not present or if of_xlate() fails, but in neither case is EBUSY really
appropriate.  Return EPROBE_DEFER if the controller is not yet present
and change of_xlate() to return an ERR_PTR instead of NULL so that the
error can be propagated back to the caller of mbox_request_channel().

Signed-off-by: Benson Leung <bleung@chromium.org>
Signed-off-by: Andrew Bresticker <abrestic@chromium.org>
Acked-by: Suman Anna <s-anna@ti.com>
Reviewed-by: Jon Hunter <jonathanh@nvidia.com>
Tested-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>

1 files changed, 8 insertions, 3 deletions

diff --git a/drivers/mailbox/mailbox.c b/drivers/mailbox/mailbox.c
index 19b491d2964f..c3c42d42d017 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);
@@ -390,7 +395,7 @@ 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];
 }