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Jean-Christophe PLAGNIOL-VILLARD770d7c32012-01-28 12:12:36 +08001/*
2 * Copyright 2012 Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
3 *
4 * OF helpers for mtd.
5 *
6 * This file is released under the GPLv2
7 *
8 */
9#include <linux/kernel.h>
10#include <linux/of_mtd.h>
11#include <linux/mtd/nand.h>
12#include <linux/export.h>
13
14/**
15 * It maps 'enum nand_ecc_modes_t' found in include/linux/mtd/nand.h
16 * into the device tree binding of 'nand-ecc', so that MTD
17 * device driver can get nand ecc from device tree.
18 */
19static const char *nand_ecc_modes[] = {
20 [NAND_ECC_NONE] = "none",
21 [NAND_ECC_SOFT] = "soft",
22 [NAND_ECC_HW] = "hw",
23 [NAND_ECC_HW_SYNDROME] = "hw_syndrome",
24 [NAND_ECC_HW_OOB_FIRST] = "hw_oob_first",
25 [NAND_ECC_SOFT_BCH] = "soft_bch",
26};
27
28/**
29 * of_get_nand_ecc_mode - Get nand ecc mode for given device_node
30 * @np: Pointer to the given device_node
31 *
32 * The function gets ecc mode string from property 'nand-ecc-mode',
33 * and return its index in nand_ecc_modes table, or errno in error case.
34 */
35const int of_get_nand_ecc_mode(struct device_node *np)
36{
37 const char *pm;
38 int err, i;
39
40 err = of_property_read_string(np, "nand-ecc-mode", &pm);
41 if (err < 0)
42 return err;
43
44 for (i = 0; i < ARRAY_SIZE(nand_ecc_modes); i++)
45 if (!strcasecmp(pm, nand_ecc_modes[i]))
46 return i;
47
48 return -ENODEV;
49}
50EXPORT_SYMBOL_GPL(of_get_nand_ecc_mode);
51
52/**
53 * of_get_nand_bus_width - Get nand bus witdh for given device_node
54 * @np: Pointer to the given device_node
55 *
56 * return bus width option, or errno in error case.
57 */
58int of_get_nand_bus_width(struct device_node *np)
59{
60 u32 val;
61
62 if (of_property_read_u32(np, "nand-bus-width", &val))
63 return 8;
64
65 switch(val) {
66 case 8:
67 case 16:
68 return val;
69 default:
70 return -EIO;
71 }
72}
73EXPORT_SYMBOL_GPL(of_get_nand_bus_width);
74
75/**
76 * of_get_nand_on_flash_bbt - Get nand on flash bbt for given device_node
77 * @np: Pointer to the given device_node
78 *
79 * return true if present false other wise
80 */
81bool of_get_nand_on_flash_bbt(struct device_node *np)
82{
83 return of_property_read_bool(np, "nand-on-flash-bbt");
84}
85EXPORT_SYMBOL_GPL(of_get_nand_on_flash_bbt);