mtd: nand: denali_dt: add a DT driver

A patch for NAND uclass support was proposed about half a year ago:
https://patchwork.ozlabs.org/patch/722282/

It was not merged and I do not see on-going work for this.

Without DM-based probing, we need to set up pinctrl etc. in an ad-hoc
way and give lots of crappy CONFIG options for base addresses and
properties, which are supposed to be specified by DT.  This is painful.

This commit just provides a probe hook to retrieve "reg" from DT and
allocate private data in a DM manner.  This DT driver is not essentially
a NAND driver, in fact it is (ab)using UCLASS_MISC.  Once UCLASS_NAND is
supported, it would be possible to migrate to it.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

drivers/mtd/nand/Kconfig

@@ -16,6 +16,13 @@ config NAND_DENALI
 	help
 	  Enable support for the Denali NAND controller.
 
+config NAND_DENALI_DT
+	bool "Support Denali NAND controller as a DT device"
+	depends on NAND_DENALI && OF_CONTROL && DM
+	help
+	  Enable the driver for NAND flash on platforms using a Denali NAND
+	  controller as a DT device.
+
 config SYS_NAND_DENALI_64BIT
 	bool "Use 64-bit variant of Denali NAND controller"
 	depends on NAND_DENALI

drivers/mtd/nand/Makefile

@@ -44,6 +44,7 @@ obj-$(CONFIG_NAND_ATMEL) += atmel_nand.o
 obj-$(CONFIG_NAND_ARASAN) += arasan_nfc.o
 obj-$(CONFIG_NAND_DAVINCI) += davinci_nand.o
 obj-$(CONFIG_NAND_DENALI) += denali.o
+obj-$(CONFIG_NAND_DENALI_DT) += denali_dt.o
 obj-$(CONFIG_NAND_FSL_ELBC) += fsl_elbc_nand.o
 obj-$(CONFIG_NAND_FSL_IFC) += fsl_ifc_nand.o
 obj-$(CONFIG_NAND_FSL_UPM) += fsl_upm.o

drivers/mtd/nand/denali.c

@@ -1175,7 +1175,7 @@ static void denali_hw_init(struct denali_nand_info *denali)
 
 static struct nand_ecclayout nand_oob;
 
-static int denali_init(struct denali_nand_info *denali)
+int denali_init(struct denali_nand_info *denali)
 {
 	struct mtd_info *mtd = nand_to_mtd(&denali->nand);
 	int ret;
@@ -1273,6 +1273,7 @@ fail:
 	return ret;
 }
 
+#ifndef CONFIG_NAND_DENALI_DT
 static int __board_nand_init(void)
 {
 	struct denali_nand_info *denali;
@@ -1296,3 +1297,4 @@ void board_nand_init(void)
 	if (__board_nand_init() < 0)
 		pr_warn("Failed to initialize Denali NAND controller.\n");
 }
+#endif

drivers/mtd/nand/denali.h

@@ -464,4 +464,6 @@ struct denali_nand_info {
 	uint32_t max_banks;
 };
 
+int denali_init(struct denali_nand_info *denali);
+
 #endif /* __DENALI_H__ */

drivers/mtd/nand/denali_dt.c

@@ -0,0 +1,68 @@
+/*
+ * Copyright (C) 2017 Socionext Inc.
+ *   Author: Masahiro Yamada <yamada.masahiro@socionext.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <linux/io.h>
+#include <linux/ioport.h>
+
+#include "denali.h"
+
+static const struct udevice_id denali_nand_dt_ids[] = {
+	{
+		.compatible = "altr,socfpga-denali-nand",
+	},
+	{
+		.compatible = "socionext,uniphier-denali-nand-v5a",
+	},
+	{
+		.compatible = "socionext,uniphier-denali-nand-v5b",
+	},
+	{ /* sentinel */ }
+};
+
+static int denali_dt_probe(struct udevice *dev)
+{
+	struct denali_nand_info *denali = dev_get_priv(dev);
+	struct resource res;
+	int ret;
+
+	ret = dev_read_resource_byname(dev, "denali_reg", &res);
+	if (ret)
+		return ret;
+
+	denali->flash_reg = devm_ioremap(dev, res.start, resource_size(&res));
+
+	ret = dev_read_resource_byname(dev, "nand_data", &res);
+	if (ret)
+		return ret;
+
+	denali->flash_mem = devm_ioremap(dev, res.start, resource_size(&res));
+
+	return denali_init(denali);
+}
+
+U_BOOT_DRIVER(denali_nand_dt) = {
+	.name = "denali-nand-dt",
+	.id = UCLASS_MISC,
+	.of_match = denali_nand_dt_ids,
+	.probe = denali_dt_probe,
+	.priv_auto_alloc_size = sizeof(struct denali_nand_info),
+};
+
+void board_nand_init(void)
+{
+	struct udevice *dev;
+	int ret;
+
+	ret = uclass_get_device_by_driver(UCLASS_MISC,
+					  DM_GET_DRIVER(denali_nand_dt),
+					  &dev);
+	if (ret && ret != -ENODEV)
+		printf("Failed to initialize Denali NAND controller. (error %d)\n",
+		       ret);
+}