[PATCH v4 3/5] DT: Add binding for Altera FPGAs in passive-serial mode

[Steffen Trumtrar]

From: Sascha Hauer <s.hauer at pengutronix.de>

Altera FPGAs that are programmed via SPI use the passive serial protocol.
Add a simple binding that describes the setup for this usecase.

Cc: devicetree at vger.kernel.org
Signed-off-by: Sascha Hauer <s.hauer at pengutronix.de>
Signed-off-by: Steffen Trumtrar <s.trumtrar at pengutronix.de>
---
 .../bindings/firmware/altr,passive-serial.txt      | 24 ++++++++++++++++++++++
 1 file changed, 24 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/firmware/altr,passive-serial.txt

diff --git a/Documentation/devicetree/bindings/firmware/altr,passive-serial.txt b/Documentation/devicetree/bindings/firmware/altr,passive-serial.txt
new file mode 100644
index 000000000000..d357dd39cf67
--- /dev/null
+++ b/Documentation/devicetree/bindings/firmware/altr,passive-serial.txt
@@ -0,0 +1,24 @@
+Altera FPGAs in passive serial mode
+-----------------------------------
+
+This binding defines the control interface to Altera FPGAs in
+passive serial mode. This is used to upload the firmware and
+to start the FPGA.
+
+Required properties:
+- compatible: shall be "altr,fpga-passive-serial"
+- reg: SPI chip select
+- nstat-gpios: Specify GPIO for controlling the nstat pin
+- confd-gpios: Specify GPIO for controlling the confd pin
+- nconfig-gpios: Specify GPIO for controlling the nconfig pin
+
+Example:
+
+	fpga at 0 {
+		compatible = "altr,fpga-passive-serial";
+		nstat-gpios = <&gpio4 18 0>;
+		confd-gpios = <&gpio4 19 0>;
+		nconfig-gpios = <&gpio4 20 0>;
+		spi-max-frequency = <10000000>;
+		reg = <0>;
+	};
-- 
2.1.0