drivers/of/of_mtd.c

   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  */
  19 static 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  */
  35 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 }
  50 EXPORT_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  */
  59 int 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 }
  67 EXPORT_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  */
  76 int 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 }
  84 EXPORT_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  */
  92 int 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 }
 107 EXPORT_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  */
 115 bool of_get_nand_on_flash_bbt(struct device_node *np)
 116 {
 117         return of_property_read_bool(np, "nand-on-flash-bbt");
 118 }
 119 EXPORT_SYMBOL_GPL(of_get_nand_on_flash_bbt);