mtd: spi-nor: Bindings for Cadence Quad SPI Flash Controller driver

Add binding document for the Cadence QSPI controller.

Signed-off-by: Graham Moore <grmoore@opensource.altera.com>
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Alan Tull <atull@opensource.altera.com>
Cc: Brian Norris <computersforpeace@gmail.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Dinh Nguyen <dinguyen@opensource.altera.com>
Cc: Graham Moore <grmoore@opensource.altera.com>
Cc: Vignesh R <vigneshr@ti.com>
Cc: Yves Vandervennet <yvanderv@opensource.altera.com>
Cc: devicetree@vger.kernel.org
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

diff --git a/Documentation/devicetree/bindings/mtd/cadence-quadspi.txt b/Documentation/devicetree/bindings/mtd/cadence-quadspi.txt
new file mode 100644 (file)
index 0000000..f248056
--- /dev/null
+++ b/Documentation/devicetree/bindings/mtd/cadence-quadspi.txt
@@ -0,0 +1,56 @@
+* Cadence Quad SPI controller
+
+Required properties:
+- compatible : Should be "cdns,qspi-nor".
+- reg : Contains two entries, each of which is a tuple consisting of a
+       physical address and length. The first entry is the address and
+       length of the controller register set. The second entry is the
+       address and length of the QSPI Controller data area.
+- interrupts : Unit interrupt specifier for the controller interrupt.
+- clocks : phandle to the Quad SPI clock.
+- cdns,fifo-depth : Size of the data FIFO in words.
+- cdns,fifo-width : Bus width of the data FIFO in bytes.
+- cdns,trigger-address : 32-bit indirect AHB trigger address.
+
+Optional properties:
+- cdns,is-decoded-cs : Flag to indicate whether decoder is used or not.
+
+Optional subnodes:
+Subnodes of the Cadence Quad SPI controller are spi slave nodes with additional
+custom properties:
+- cdns,read-delay : Delay for read capture logic, in clock cycles
+- cdns,tshsl-ns : Delay in nanoseconds for the length that the master
+                  mode chip select outputs are de-asserted between
+                 transactions.
+- cdns,tsd2d-ns : Delay in nanoseconds between one chip select being
+                  de-activated and the activation of another.
+- cdns,tchsh-ns : Delay in nanoseconds between last bit of current
+                  transaction and deasserting the device chip select
+                 (qspi_n_ss_out).
+- cdns,tslch-ns : Delay in nanoseconds between setting qspi_n_ss_out low
+                  and first bit transfer.
+
+Example:
+
+       qspi: spi@ff705000 {
+               compatible = "cdns,qspi-nor";
+               #address-cells = <1>;
+               #size-cells = <0>;
+               reg = <0xff705000 0x1000>,
+                     <0xffa00000 0x1000>;
+               interrupts = <0 151 4>;
+               clocks = <&qspi_clk>;
+               cdns,is-decoded-cs;
+               cdns,fifo-depth = <128>;
+               cdns,fifo-width = <4>;
+               cdns,trigger-address = <0x00000000>;
+
+               flash0: n25q00@0 {
+                       ...
+                       cdns,read-delay = <4>;
+                       cdns,tshsl-ns = <50>;
+                       cdns,tsd2d-ns = <50>;
+                       cdns,tchsh-ns = <4>;
+                       cdns,tslch-ns = <4>;
+               };
+       };