clk: ti: omap4: add clock manager driver

This minimal driver is only used to bind child devices.

For DT binding details see Linux doc:
- Documentation/devicetree/bindings/arm/omap/prcm.txt

Signed-off-by: Dario Binacchi <dariobin@libero.it>

drivers/clk/ti/Makefile

@@ -3,7 +3,7 @@
 # Copyright (C) 2020 Dario Binacchi <dariobin@libero.it>
 #
 
-obj-$(CONFIG_ARCH_OMAP2PLUS) += clk.o
+obj-$(CONFIG_ARCH_OMAP2PLUS) += clk.o omap4-cm.o
 
 obj-$(CONFIG_CLK_TI_AM3_DPLL) += clk-am3-dpll.o clk-am3-dpll-x2.o
 obj-$(CONFIG_CLK_TI_CTRL) += clk-ctrl.o

drivers/clk/ti/omap4-cm.c

@@ -0,0 +1,22 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * OMAP4 clock manager (cm)
+ *
+ * Copyright (C) 2020 Dario Binacchi <dariobin@libero.it>
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <dm/lists.h>
+
+static const struct udevice_id ti_omap4_cm_ids[] = {
+	{.compatible = "ti,omap4-cm"},
+	{}
+};
+
+U_BOOT_DRIVER(ti_omap4_cm) = {
+	.name = "ti_omap4_cm",
+	.id = UCLASS_SIMPLE_BUS,
+	.of_match = ti_omap4_cm_ids,
+	.bind = dm_scan_fdt_dev,
+};