mtd: rawnand: ams-delta: Support custom driver initialisation

In preparation for extending the driver with custom I/O support, try to
obtain device specific initialisation routine from a matching device
table entry and run it as an additional step of device probe.
Signed-off-by: Janusz Krzysztofik <jmkrzyszt@gmail.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20200212003929.6682-12-jmkrzyszt@gmail.com

drivers/mtd/nand/raw/ams-delta.c

@@ -22,6 +22,7 @@
 #include <linux/mtd/nand-gpio.h>
 #include <linux/mtd/rawnand.h>
 #include <linux/mtd/partitions.h>
+#include <linux/of_device.h>
 #include <linux/platform_device.h>
 #include <linux/sizes.h>
 
@@ -230,6 +231,7 @@ static int ams_delta_init(struct platform_device *pdev)
 	struct nand_chip *this;
 	struct mtd_info *mtd;
 	struct gpio_descs *data_gpiods;
+	int (*probe)(struct platform_device *pdev, struct ams_delta_nand *priv);
 	int err = 0;
 
 	if (pdata) {
@@ -319,6 +321,15 @@ static int ams_delta_init(struct platform_device *pdev)
 	priv->data_gpiods = data_gpiods;
 	priv->data_in = true;
 
+	if (pdev->id_entry)
+		probe = (void *) pdev->id_entry->driver_data;
+	else
+		probe = of_device_get_match_data(&pdev->dev);
+	if (probe)
+		err = probe(pdev, priv);
+	if (err)
+		return err;
+
 	/* Initialize the NAND controller object embedded in ams_delta_nand. */
 	priv->base.ops = &ams_delta_ops;
 	nand_controller_init(&priv->base);