[PATCH 2/7] mailbox: Allow #mbox-cells = <0> without specifying a custom xlate

[Douglas Anderson]

If a mailbox is only providing one channel, there is no reason to
require any extra mbox-cells. Allow specifying 0.

Signed-off-by: Douglas Anderson <dianders@xxxxxxxxxxxx>
---

 drivers/mailbox/mailbox.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/mailbox/mailbox.c b/drivers/mailbox/mailbox.c
index efacd24a085d..6c9d426f4e58 100644
--- a/drivers/mailbox/mailbox.c
+++ b/drivers/mailbox/mailbox.c
@@ -524,7 +524,13 @@ EXPORT_SYMBOL_GPL(mbox_free_channel);
 static struct mbox_chan *fw_mbox_index_xlate(struct mbox_controller *mbox,
 					     const struct fwnode_reference_args *sp)
 {
-	if (sp->nargs < 1 || sp->args[0] >= mbox->num_chans)
+	if (!sp->nargs) {
+		if (mbox->num_chans == 1)
+			return &mbox->chans[0];
+		return ERR_PTR(-EINVAL);
+	}
+
+	if (sp->args[0] >= mbox->num_chans)
 		return ERR_PTR(-EINVAL);
 
 	return &mbox->chans[sp->args[0]];
-- 
2.55.0.141.g00534a21ce-goog