LXR linux/drivers/of/of

   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_ecc_step_size - Get ECC step size associated to
  54 * the required ECC strength (see below).
  55 * @np: Pointer to the given device_node
  56 *
  57 * return the ECC step size, or errno in error case.
  58 */
  59int of_get_nand_ecc_step_size(struct device_node *np)
  60{
  61        int ret;
  62        u32 val;
  63
  64        ret = of_property_read_u32(np, "nand-ecc-step-size", &val);
  65        return ret ? ret : val;
  66}
  67EXPORT_SYMBOL_GPL(of_get_nand_ecc_step_size);
  68
  69/**
  70 * of_get_nand_ecc_strength - Get required ECC strength over the
  71 * correspnding step size as defined by 'nand-ecc-size'
  72 * @np: Pointer to the given device_node
  73 *
  74 * return the ECC strength, or errno in error case.
  75 */
  76int of_get_nand_ecc_strength(struct device_node *np)
  77{
  78        int ret;
  79        u32 val;
  80
  81        ret = of_property_read_u32(np, "nand-ecc-strength", &val);
  82        return ret ? ret : val;
  83}
  84EXPORT_SYMBOL_GPL(of_get_nand_ecc_strength);
  85
  86/**
  87 * of_get_nand_bus_width - Get nand bus witdh for given device_node
  88 * @np: Pointer to the given device_node
  89 *
  90 * return bus width option, or errno in error case.
  91 */
  92int of_get_nand_bus_width(struct device_node *np)
  93{
  94        u32 val;
  95
  96        if (of_property_read_u32(np, "nand-bus-width", &val))
  97                return 8;
  98
  99        switch(val) {
 100        case 8:
 101        case 16:
 102                return val;
 103        default:
 104                return -EIO;
 105        }
 106}
 107EXPORT_SYMBOL_GPL(of_get_nand_bus_width);
 108
 109/**
 110 * of_get_nand_on_flash_bbt - Get nand on flash bbt for given device_node
 111 * @np: Pointer to the given device_node
 112 *
 113 * return true if present false other wise
 114 */
 115bool of_get_nand_on_flash_bbt(struct device_node *np)
 116{
 117        return of_property_read_bool(np, "nand-on-flash-bbt");
 118}
 119EXPORT_SYMBOL_GPL(of_get_nand_on_flash_bbt);
 120