linux/Documentation/devicetree/bindings/mtd/mtd-physmap.txt
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   1CFI or JEDEC memory-mapped NOR flash, MTD-RAM (NVRAM...)
   2
   3Flash chips (Memory Technology Devices) are often used for solid state
   4file systems on embedded devices.
   5
   6 - compatible : should contain the specific model of mtd chip(s)
   7   used, if known, followed by either "cfi-flash", "jedec-flash"
   8   or "mtd-ram".
   9 - reg : Address range(s) of the mtd chip(s)
  10   It's possible to (optionally) define multiple "reg" tuples so that
  11   non-identical chips can be described in one node.
  12 - bank-width : Width (in bytes) of the bank.  Equal to the
  13   device width times the number of interleaved chips.
  14 - device-width : (optional) Width of a single mtd chip.  If
  15   omitted, assumed to be equal to 'bank-width'.
  16 - #address-cells, #size-cells : Must be present if the device has
  17   sub-nodes representing partitions (see below).  In this case
  18   both #address-cells and #size-cells must be equal to 1.
  19 - no-unaligned-direct-access: boolean to disable the default direct
  20   mapping of the flash.
  21   On some platforms (e.g. MPC5200) a direct 1:1 mapping may cause
  22   problems with JFFS2 usage, as the local bus (LPB) doesn't support
  23   unaligned accesses as implemented in the JFFS2 code via memcpy().
  24   By defining "no-unaligned-direct-access", the flash will not be
  25   exposed directly to the MTD users (e.g. JFFS2) any more.
  26 - linux,mtd-name: allow to specify the mtd name for retro capability with
  27   physmap-flash drivers as boot loader pass the mtd partition via the old
  28   device name physmap-flash.
  29 - use-advanced-sector-protection: boolean to enable support for the
  30   advanced sector protection (Spansion: PPB - Persistent Protection
  31   Bits) locking.
  32
  33For JEDEC compatible devices, the following additional properties
  34are defined:
  35
  36 - vendor-id : Contains the flash chip's vendor id (1 byte).
  37 - device-id : Contains the flash chip's device id (1 byte).
  38
  39The device tree may optionally contain sub-nodes describing partitions of the
  40address space. See partition.txt for more detail.
  41
  42Example:
  43
  44        flash@ff000000 {
  45                compatible = "amd,am29lv128ml", "cfi-flash";
  46                reg = <ff000000 01000000>;
  47                bank-width = <4>;
  48                device-width = <1>;
  49                #address-cells = <1>;
  50                #size-cells = <1>;
  51                fs@0 {
  52                        label = "fs";
  53                        reg = <0 f80000>;
  54                };
  55                firmware@f80000 {
  56                        label ="firmware";
  57                        reg = <f80000 80000>;
  58                        read-only;
  59                };
  60        };
  61
  62Here an example with multiple "reg" tuples:
  63
  64        flash@f0000000,0 {
  65                #address-cells = <1>;
  66                #size-cells = <1>;
  67                compatible = "intel,PC48F4400P0VB", "cfi-flash";
  68                reg = <0 0x00000000 0x02000000
  69                       0 0x02000000 0x02000000>;
  70                bank-width = <2>;
  71                partition@0 {
  72                        label = "test-part1";
  73                        reg = <0 0x04000000>;
  74                };
  75        };
  76
  77An example using SRAM:
  78
  79        sram@2,0 {
  80                compatible = "samsung,k6f1616u6a", "mtd-ram";
  81                reg = <2 0 0x00200000>;
  82                bank-width = <2>;
  83        };
  84
  85