cmd: clk: Add trivial implementation of clock dump for DM

Add trivial implementation of the clk dump in case DM is enabled.
This implementation just iterates over all the clock registered
with the CLK uclass and prints their rate.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Chin Liang See <chin.liang.see@intel.com>
Cc: Dinh Nguyen <dinguyen@kernel.org>
Cc: Ley Foon Tan <ley.foon.tan@intel.com>
Cc: Simon Glass <sjg@chromium.org>
Cc: Tom Rini <trini@konsulko.com>
Reviewed-by: Ley Foon Tan <ley.foon.tan@intel.com>

cmd/clk.c

@@ -5,11 +5,48 @@
 #include <common.h>
 #include <command.h>
 #include <clk.h>
+#if defined(CONFIG_DM) && defined(CONFIG_CLK)
+#include <dm.h>
+#include <dm/device-internal.h>
+#endif
 
 int __weak soc_clk_dump(void)
 {
+#if defined(CONFIG_DM) && defined(CONFIG_CLK)
+	struct udevice *dev;
+	struct uclass *uc;
+	struct clk clk;
+	int ret;
+
+	/* Device addresses start at 1 */
+	ret = uclass_get(UCLASS_CLK, &uc);
+	if (ret)
+		return ret;
+
+	uclass_foreach_dev(dev, uc) {
+		memset(&clk, 0, sizeof(clk));
+		ret = device_probe(dev);
+		if (ret) {
+			printf("%-30.30s : ? Hz\n", dev->name);
+			continue;
+		}
+
+		ret = clk_request(dev, &clk);
+		if (ret) {
+			printf("%-30.30s : ? Hz\n", dev->name);
+			continue;
+		}
+
+		printf("%-30.30s : %lu Hz\n", dev->name, clk_get_rate(&clk));
+
+		clk_free(&clk);
+	}
+
+	return 0;
+#else
 	puts("Not implemented\n");
 	return 1;
+#endif
 }
 
 static int do_clk_dump(cmd_tbl_t *cmdtp, int flag, int argc,