mtd: rawnand: socrates: Move the ECC initialization to ->attach_chip()

The probe function is only supposed to initialize the controller
hardware but not the ECC engine. Indeed, we don't know anything about
the NAND chip(s) at this stage. Let's move the logic initializing the
ECC engine, even pretty simple, to the ->attach_chip() hook which gets
called during nand_scan() routine, after the NAND chip discovery. As
the previously mentioned logic is supposed to parse the DT for us, it
is likely that the chip->ecc.* entries be overwritten. So let's avoid
this by moving these lines to ->attach_chip().

Fixes: d7157ff ("mtd: rawnand: Use the ECC framework user input parsing bits")
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20201113123424.32233-20-miquel.raynal@bootlin.com

drivers/mtd/nand/raw/socrates_nand.c

@@ -22,6 +22,7 @@
 #define FPGA_NAND_DATA_SHIFT		16
 
 struct socrates_nand_host {
+	struct nand_controller	controller;
 	struct nand_chip	nand_chip;
 	void __iomem		*io_base;
 	struct device		*dev;
@@ -116,6 +117,18 @@ static int socrates_nand_device_ready(struct nand_chip *nand_chip)
 	return 1;
 }
 
+static int socrates_attach_chip(struct nand_chip *chip)
+{
+	chip->ecc.engine_type = NAND_ECC_ENGINE_TYPE_SOFT;
+	chip->ecc.algo = NAND_ECC_ALGO_HAMMING;
+
+	return 0;
+}
+
+static const struct nand_controller_ops socrates_ops = {
+	.attach_chip = socrates_attach_chip,
+};
+
 /*
  * Probe for the NAND device.
  */
@@ -141,6 +154,10 @@ static int socrates_nand_probe(struct platform_device *ofdev)
 	mtd = nand_to_mtd(nand_chip);
 	host->dev = &ofdev->dev;
 
+	nand_controller_init(&host->controller);
+	host->controller.ops = &socrates_ops;
+	nand_chip->controller = &host->controller;
+
 	/* link the private data structures */
 	nand_set_controller_data(nand_chip, host);
 	nand_set_flash_node(nand_chip, ofdev->dev.of_node);
@@ -153,10 +170,6 @@ static int socrates_nand_probe(struct platform_device *ofdev)
 	nand_chip->legacy.read_buf = socrates_nand_read_buf;
 	nand_chip->legacy.dev_ready = socrates_nand_device_ready;
 
-	/* enable ECC */
-	nand_chip->ecc.engine_type = NAND_ECC_ENGINE_TYPE_SOFT;
-	nand_chip->ecc.algo = NAND_ECC_ALGO_HAMMING;
-
 	/* TODO: I have no idea what real delay is. */
 	nand_chip->legacy.chip_delay = 20;	/* 20us command delay time */