mtd: rawnand: mxc: set chip->of_node to nand@0 child node if present

The nand-controller.yaml binding requires a child node (e.g. nand@0) under
the NAND controller. However, the driver currently assigns the controller's
of_node directly to the NAND chip.

Search for the first child node with the "nand" prefix and assign it to
chip->of_node. This filters out properties such as "partition" that may be
placed under the controller node in some older DTS files.

Fall back to using the controller's of_node if no suitable child node is
found to maintain backward compatibility.

This issue went unnoticed because the default behavior works for most NAND
chips.

Signed-off-by: Frank Li <Frank.Li@nxp.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>

Author: nxpfrankli

drivers/mtd/nand/raw/mxc_nand.c

@@ -4,6 +4,7 @@
  * Copyright 2008 Sascha Hauer, kernel@pengutronix.de
  */
 
+#include <linux/cleanup.h>
 #include <linux/delay.h>
 #include <linux/slab.h>
 #include <linux/init.h>
@@ -1714,7 +1715,14 @@ static int mxcnd_probe(struct platform_device *pdev)
 	this->legacy.chip_delay = 5;
 
 	nand_set_controller_data(this, host);
-	nand_set_flash_node(this, pdev->dev.of_node);
+
+	struct device_node *np __free(device_node) =
+		of_get_next_child_with_prefix(pdev->dev.of_node, NULL, "nand");
+
+	if (np)
+		nand_set_flash_node(this, np);
+	else
+		nand_set_flash_node(this, pdev->dev.of_node);
 
 	host->clk = devm_clk_get(&pdev->dev, NULL);
 	if (IS_ERR(host->clk))