Add documentation for gpio-addr-flash. This binding allow creating
flash devices that are paged using GPIOs.

Cc: devicet...@vger.kernel.org
Signed-off-by: Ricardo Ribalda Delgado <ricardo.riba...@gmail.com>
---
 .../bindings/mtd/gpio-addr-flash.txt          | 46 +++++++++++++++++++
 1 file changed, 46 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/mtd/gpio-addr-flash.txt

diff --git a/Documentation/devicetree/bindings/mtd/gpio-addr-flash.txt 
b/Documentation/devicetree/bindings/mtd/gpio-addr-flash.txt
new file mode 100644
index 000000000000..4279e8cad09b
--- /dev/null
+++ b/Documentation/devicetree/bindings/mtd/gpio-addr-flash.txt
@@ -0,0 +1,46 @@
+Memory Mapped flash with some address lines addressed using GPIOs
+
+Handle the case where a flash device is mostly addressed using physical
+line and supplemented by GPIOs.  This way you can hook up say a 8MiB flash
+to a 2MiB memory range and use the GPIOs to select a particular range.
+
+ - compatible : "cfi-gpio-addr-flash"
+ - reg : Address range of the mtd chip that is memory mapped, this is,
+   on the previous example 2MiB.
+ - bank-width : Width (in bytes) of the bank.  Equal to the
+   device width times the number of interleaved chips.
+ - probe-type : (optional) "cfi_probe", "jedec_probe". How the mtd chip
+   is going to be probed. If omitted, assumed to be equal to "cfi_probe".
+ - #address-cells, #size-cells : Must be present if the device has
+   sub-nodes representing partitions (see below).  In this case
+   both #address-cells and #size-cells must be equal to 1.
+
+The device tree may optionally contain sub-nodes describing partitions of the
+address space. See partition.txt for more detail.
+
+Example:
+
+       cfi_flash_0: cfi_flash {
+               #address-cells = <1>;
+               #size-cells = <1>;
+               compatible = "cfi-gpio-addr-flash";
+               bank-width = <2>;
+               reg = < 0x00300000 0x00200000 >;
+               gpios = <&gpio_0 3 0>, <&gpio_0 4 0>;
+               partition@0 {
+                       reg = < 0x0 0x200000 >;
+                       label = "Golden Bitstream";
+               };
+               partition@200000 {
+                       reg = < 0x200000 0x200000 >;
+                       label = "User Bitstream";
+               };
+               partition@400000 {
+                       reg = < 0x400000 0x200000 >;
+                       label = "V4L Controls";
+               };
+               partition@600000 {
+                       reg = < 0x600000 0x200000 >;
+                       label = "Production Data";
+               };
+       } ;
-- 
2.18.0

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