mailbox: Add ability for clients to request channels by name

This patch supplies a new framework API; mbox_request_channel_byname().

It works by supplying the usual client pointer as the first argument and
a string as the second.  The API will search the client's node for a
'mbox-names' property then request a channel in the normal way using the
requested string's index as the expected second 'index' argument.

Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>

1 files changed, 29 insertions, 0 deletions

diff --git a/drivers/mailbox/mailbox.c b/drivers/mailbox/mailbox.c
index c3c42d42d017..c7fdb57fd166 100644
--- a/drivers/mailbox/mailbox.c
+++ b/drivers/mailbox/mailbox.c
@@ -362,6 +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.