bus: uniphier-system-bus: add UniPhier System Bus driver

Since commit 1517126fdac2 ("ARM: uniphier: select DM_ETH"), DM-based
drivers/net/smc911x.c is compiled, but it is never probed because the
parent node lacks the DM-based driver.

I need a skeleton driver to populate child devices (but the next commit
will move more hardware settings to the this driver).

I put this to drivers/bus/uniphier-system-bus.c because this is the
same path as the driver in Linux kernel.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

1 files changed, 14 insertions, 0 deletions

diff --git a/drivers/bus/uniphier-system-bus.c b/drivers/bus/uniphier-system-bus.c
new file mode 100644
index 0000000..c61d795
--- /dev/null
+++ b/drivers/bus/uniphier-system-bus.c
@@ -0,0 +1,14 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include <dm.h>
+
+static const struct udevice_id uniphier_system_bus_match[] = {
+	{ .compatible = "socionext,uniphier-system-bus" },
+	{ /* sentinel */ }
+};
+
+U_BOOT_DRIVER(uniphier_system_bus_driver) = {
+	.name	= "uniphier-system-bus",
+	.id	= UCLASS_SIMPLE_BUS,
+	.of_match = uniphier_system_bus_match,
+};