linux/drivers/of/of_mtd.c
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   1/*
   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 */
  35int 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);
  86
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