mailbox: implement a sandbox test
This adds a sandbox mailbox implementation (provider), a test client
device, instantiates them both from Sandbox's DT, and adds a DM test
that excercises everything.
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Acked-by: Simon Glass <sjg@chromium.org> # v1
diff --git a/configs/sandbox_defconfig b/configs/sandbox_defconfig
index 6e30c5d..4eb3c22 100644
--- a/configs/sandbox_defconfig
+++ b/configs/sandbox_defconfig
@@ -170,3 +170,6 @@
CONFIG_UT_TIME=y
CONFIG_UT_DM=y
CONFIG_UT_ENV=y
+CONFIG_MISC=y
+CONFIG_DM_MAILBOX=y
+CONFIG_SANDBOX_MBOX=y