mtd: rawnand: denali: decouple controller and NAND chips

Currently, this driver sticks to the legacy NAND model because it was
upstreamed before commit 2d472aba15ff ("mtd: nand: document the NAND
controller/NAND chip DT representation"). However, relying on the
dummy_controller is already deprecated.

Switch over to the new controller/chip representation.

The struct denali_nand_info has been split into denali_controller
and denali_chip, to contain the controller data, per-chip data,
respectively.

One problem is, this commit changes the DT binding. So, as always,
the backward compatibility must be taken into consideration.

In the new binding, the controller node expects

  #address-cells = <1>;
  #size-cells = <0>;

... since the child nodes represent NAND chips.

In the old binding, the controller node may have subnodes, but they
are MTD partitions.

The denali_dt_is_legacy_binding() exploits it to distinguish old/new
platforms.

Going forward, the old binding is only allowed for existing DT files.
I updated the binding document.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>

1 files changed, 94 insertions, 4 deletions

diff --git a/drivers/mtd/nand/raw/denali_dt.c b/drivers/mtd/nand/raw/denali_dt.c
index 0b5ae2418815..5e14836f6bd5 100644
--- a/drivers/mtd/nand/raw/denali_dt.c
+++ b/drivers/mtd/nand/raw/denali_dt.c
@@ -18,7 +18,7 @@
 #include "denali.h"
 
 struct denali_dt {
-	struct denali_nand_info	denali;
+	struct denali_controller controller;
 	struct clk *clk;	/* core clock */
 	struct clk *clk_x;	/* bus interface clock */
 	struct clk *clk_ecc;	/* ECC circuit clock */
@@ -71,19 +71,92 @@ static const struct of_device_id denali_nand_dt_ids[] = {
 };
 MODULE_DEVICE_TABLE(of, denali_nand_dt_ids);
 
+static int denali_dt_chip_init(struct denali_controller *denali,
+			       struct device_node *chip_np)
+{
+	struct denali_chip *dchip;
+	u32 bank;
+	int nsels, i, ret;
+
+	nsels = of_property_count_u32_elems(chip_np, "reg");
+	if (nsels < 0)
+		return nsels;
+
+	dchip = devm_kzalloc(denali->dev, struct_size(dchip, sels, nsels),
+			     GFP_KERNEL);
+	if (!dchip)
+		return -ENOMEM;
+
+	dchip->nsels = nsels;
+
+	for (i = 0; i < nsels; i++) {
+		ret = of_property_read_u32_index(chip_np, "reg", i, &bank);
+		if (ret)
+			return ret;
+
+		dchip->sels[i].bank = bank;
+
+		nand_set_flash_node(&dchip->chip, chip_np);
+	}
+
+	return denali_chip_init(denali, dchip);
+}
+
+/* Backward compatibility for old platforms */
+static int denali_dt_legacy_chip_init(struct denali_controller *denali)
+{
+	struct denali_chip *dchip;
+	int nsels, i;
+
+	nsels = denali->nbanks;
+
+	dchip = devm_kzalloc(denali->dev, struct_size(dchip, sels, nsels),
+			     GFP_KERNEL);
+	if (!dchip)
+		return -ENOMEM;
+
+	dchip->nsels = nsels;
+
+	for (i = 0; i < nsels; i++)
+		dchip->sels[i].bank = i;
+
+	nand_set_flash_node(&dchip->chip, denali->dev->of_node);
+
+	return denali_chip_init(denali, dchip);
+}
+
+/*
+ * Check the DT binding.
+ * The new binding expects chip subnodes in the controller node.
+ * So, #address-cells = <1>; #size-cells = <0>; are required.
+ * Check the #size-cells to distinguish the binding.
+ */
+static bool denali_dt_is_legacy_binding(struct device_node *np)
+{
+	u32 cells;
+	int ret;
+
+	ret = of_property_read_u32(np, "#size-cells", &cells);
+	if (ret)
+		return true;
+
+	return cells != 0;
+}
+
 static int denali_dt_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct resource *res;
 	struct denali_dt *dt;
 	const struct denali_dt_data *data;
-	struct denali_nand_info *denali;
+	struct denali_controller *denali;
+	struct device_node *np;
 	int ret;
 
 	dt = devm_kzalloc(dev, sizeof(*dt), GFP_KERNEL);
 	if (!dt)
 		return -ENOMEM;
-	denali = &dt->denali;
+	denali = &dt->controller;
 
 	data = of_device_get_match_data(dev);
 	if (data) {
@@ -140,9 +213,26 @@ static int denali_dt_probe(struct platform_device *pdev)
 	if (ret)
 		goto out_disable_clk_ecc;
 
+	if (denali_dt_is_legacy_binding(dev->of_node)) {
+		ret = denali_dt_legacy_chip_init(denali);
+		if (ret)
+			goto out_remove_denali;
+	} else {
+		for_each_child_of_node(dev->of_node, np) {
+			ret = denali_dt_chip_init(denali, np);
+			if (ret) {
+				of_node_put(np);
+				goto out_remove_denali;
+			}
+		}
+	}
+
 	platform_set_drvdata(pdev, dt);
+
 	return 0;
 
+out_remove_denali:
+	denali_remove(denali);
 out_disable_clk_ecc:
 	clk_disable_unprepare(dt->clk_ecc);
 out_disable_clk_x:
@@ -157,7 +247,7 @@ static int denali_dt_remove(struct platform_device *pdev)
 {
 	struct denali_dt *dt = platform_get_drvdata(pdev);
 
-	denali_remove(&dt->denali);
+	denali_remove(&dt->controller);
 	clk_disable_unprepare(dt->clk_ecc);
 	clk_disable_unprepare(dt->clk_x);
 	clk_disable_unprepare(dt->clk);