common: Add new clk command

Command provides just dump subcommand for showing clock
frequencies in a soc.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Acked-by: Stefano Babic <sbabic@denx.de>

common/cmd_clk.c

@@ -0,0 +1,51 @@
+/*
+ * Copyright (C) 2013 Xilinx, Inc.
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+#include <common.h>
+#include <command.h>
+#include <clk.h>
+
+int __weak soc_clk_dump(void)
+{
+	puts("Not implemented\n");
+	return 1;
+}
+
+static int do_clk_dump(cmd_tbl_t *cmdtp, int flag, int argc,
+		       char *const argv[])
+{
+	return soc_clk_dump();
+}
+
+static cmd_tbl_t cmd_clk_sub[] = {
+	U_BOOT_CMD_MKENT(dump, 1, 1, do_clk_dump, "", ""),
+};
+
+static int do_clk(cmd_tbl_t *cmdtp, int flag, int argc,
+		  char *const argv[])
+{
+	cmd_tbl_t *c;
+
+	if (argc < 2)
+		return CMD_RET_USAGE;
+
+	/* Strip off leading 'clk' command argument */
+	argc--;
+	argv++;
+
+	c = find_cmd_tbl(argv[0], &cmd_clk_sub[0], ARRAY_SIZE(cmd_clk_sub));
+
+	if (c)
+		return c->cmd(cmdtp, flag, argc, argv);
+	else
+		return CMD_RET_USAGE;
+}
+
+#ifdef CONFIG_SYS_LONGHELP
+static char clk_help_text[] =
+	"dump - Print clock frequencies";
+#endif
+
+U_BOOT_CMD(clk, 2, 1, do_clk, "CLK sub-system", clk_help_text);