mmc: Probe DM based mmc devices in u-boot

During mmc initialize probe all devices with the MMC Uclass if build
with CONFIG_DM_MMC

Signed-off-by: Sjoerd Simons <sjoerd.simons@collabora.co.uk>
Acked-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Simon Glass <sjg@chromium.org>

drivers/mmc/mmc.c

@@ -10,6 +10,8 @@
 #include <config.h>
 #include <common.h>
 #include <command.h>
+#include <dm.h>
+#include <dm/device-internal.h>
 #include <errno.h>
 #include <mmc.h>
 #include <part.h>
@@ -1759,10 +1761,44 @@ static void do_preinit(void)
 	}
 }
 
+#if defined(CONFIG_DM_MMC) && defined(CONFIG_SPL_BUILD)
+static int mmc_probe(bd_t *bis)
+{
+	return 0;
+}
+#elif defined(CONFIG_DM_MMC)
+static int mmc_probe(bd_t *bis)
+{
+	int ret;
+	struct uclass *uc;
+	struct udevice *m;
+
+	ret = uclass_get(UCLASS_MMC, &uc);
+	if (ret)
+		return ret;
+
+	uclass_foreach_dev(m, uc) {
+		ret = device_probe(m);
+		if (ret)
+			printf("%s - probe failed: %d\n", m->name, ret);
+	}
+
+	return 0;
+}
+#else
+static int mmc_probe(bd_t *bis)
+{
+	if (board_mmc_init(bis) < 0)
+		cpu_mmc_init(bis);
+
+	return 0;
+}
+#endif
 
 int mmc_initialize(bd_t *bis)
 {
 	static int initialized = 0;
+	int ret;
 	if (initialized)	/* Avoid initializing mmc multiple times */
 		return 0;
 	initialized = 1;
@@ -1770,10 +1806,9 @@ int mmc_initialize(bd_t *bis)
 	INIT_LIST_HEAD (&mmc_devices);
 	cur_dev_num = 0;
 
-#ifndef CONFIG_DM_MMC
-	if (board_mmc_init(bis) < 0)
-		cpu_mmc_init(bis);
-#endif
+	ret = mmc_probe(bis);
+	if (ret)
+		return ret;
 
 #ifndef CONFIG_SPL_BUILD
 	print_mmc_devices(',');