dm: implement a MTD uclass

Implement a Memory Technology Device (MTD) uclass. It should
include most flash drivers in the future. Though no uclass ops
are defined yet, the MTD ops could be used.

The NAND flash driver is based on MTD. The CFI flash and SPI
flash support MTD, too. It should make sense to convert them
to MTD uclass.

Signed-off-by: Thomas Chou <thomas@wytron.com.tw>

drivers/mtd/Kconfig

@@ -1,3 +1,15 @@
+menu "MTD Support"
+
+config MTD
+	bool "Enable Driver Model for MTD drivers"
+	depends on DM
+	help
+	  Enable driver model for Memory Technology Devices (MTD), such as
+	  flash, RAM and similar chips, often used for solid state file
+	  systems on embedded devices.
+
+endmenu
+
 source "drivers/mtd/nand/Kconfig"
 
 source "drivers/mtd/spi/Kconfig"

drivers/mtd/Makefile

@@ -8,6 +8,7 @@
 ifneq (,$(findstring y,$(CONFIG_MTD_DEVICE)$(CONFIG_CMD_NAND)$(CONFIG_CMD_ONENAND)$(CONFIG_CMD_SF)))
 obj-y += mtdcore.o mtd_uboot.o
 endif
+obj-$(CONFIG_MTD) += mtd-uclass.o
 obj-$(CONFIG_MTD_PARTITIONS) += mtdpart.o
 obj-$(CONFIG_MTD_CONCAT) += mtdconcat.o
 obj-$(CONFIG_HAS_DATAFLASH) += at45.o

drivers/mtd/mtd-uclass.c

@@ -0,0 +1,21 @@
+/*
+ * Copyright (C) 2015 Thomas Chou <thomas@wytron.com.tw>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <errno.h>
+#include <mtd.h>
+
+/*
+ * Implement a MTD uclass which should include most flash drivers.
+ * The uclass private is pointed to mtd_info.
+ */
+
+UCLASS_DRIVER(mtd) = {
+	.id		= UCLASS_MTD,
+	.name		= "mtd",
+	.per_device_auto_alloc_size = sizeof(struct mtd_info),
+};

include/dm/uclass-id.h

@@ -43,6 +43,7 @@ enum uclass_id {
 	UCLASS_MISC,		/* Miscellaneous device */
 	UCLASS_MMC,		/* SD / MMC card or chip */
 	UCLASS_MOD_EXP,		/* RSA Mod Exp device */
+	UCLASS_MTD,		/* Memory Technology Device (MTD) device */
 	UCLASS_PCH,		/* x86 platform controller hub */
 	UCLASS_PCI,		/* PCI bus */
 	UCLASS_PCI_GENERIC,	/* Generic PCI bus device */

include/flash.h

@@ -41,6 +41,9 @@ typedef struct {
 	ulong   addr_unlock2;		/* unlock address 2 for AMD flash roms  */
 	const char *name;		/* human-readable name	                */
 #endif
+#ifdef CONFIG_MTD
+	struct mtd_info *mtd;
+#endif
 } flash_info_t;
 
 extern flash_info_t flash_info[]; /* info for FLASH chips	*/

include/linux/mtd/mtd.h

@@ -272,6 +272,8 @@ struct mtd_info {
 	struct module *owner;
 #ifndef __UBOOT__
 	struct device dev;
+#else
+	struct udevice *dev;
 #endif
 	int usecount;
 };

include/mtd.h

@@ -0,0 +1,23 @@
+/*
+ * Copyright (C) 2015 Thomas Chou <thomas@wytron.com.tw>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#ifndef _MTD_H_
+#define _MTD_H_
+
+#include <linux/mtd/mtd.h>
+
+/*
+ * Get mtd_info structure of the dev, which is stored as uclass private.
+ *
+ * @dev: The MTD device
+ * @return: pointer to mtd_info, NULL on error
+ */
+static inline struct mtd_info *mtd_get_info(struct udevice *dev)
+{
+	return dev_get_uclass_priv(dev);
+}
+
+#endif	/* _MTD_H_ */