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Message-Id: <20170614153635.2763-5-atull@kernel.org>
Date: Wed, 14 Jun 2017 10:36:28 -0500
From: Alan Tull <atull@...nel.org>
To: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc: Moritz Fischer <moritz.fischer@...us.com>,
Alan Tull <atull@...nel.org>, linux-kernel@...r.kernel.org,
linux-fpga@...r.kernel.org,
Joshua Clayton <stillcompiling@...il.com>
Subject: [PATCH v2 04/11] doc: dt: document altera-passive-serial binding
From: Joshua Clayton <stillcompiling@...il.com>
Describe an altera-passive-serial devicetree entry, required features
Signed-off-by: Joshua Clayton <stillcompiling@...il.com>
Acked-by: Rob Herring <robh@...nel.org>
Signed-off-by: Alan Tull <atull@...nel.org>
---
.../bindings/fpga/altera-passive-serial.txt | 29 ++++++++++++++++++++++
1 file changed, 29 insertions(+)
create mode 100644 Documentation/devicetree/bindings/fpga/altera-passive-serial.txt
diff --git a/Documentation/devicetree/bindings/fpga/altera-passive-serial.txt b/Documentation/devicetree/bindings/fpga/altera-passive-serial.txt
new file mode 100644
index 0000000..48478bc
--- /dev/null
+++ b/Documentation/devicetree/bindings/fpga/altera-passive-serial.txt
@@ -0,0 +1,29 @@
+Altera Passive Serial SPI FPGA Manager
+
+Altera FPGAs support a method of loading the bitstream over what is
+referred to as "passive serial".
+The passive serial link is not technically SPI, and might require extra
+circuits in order to play nicely with other SPI slaves on the same bus.
+
+See https://www.altera.com/literature/hb/cyc/cyc_c51013.pdf
+
+Required properties:
+- compatible: Must be one of the following:
+ "altr,fpga-passive-serial",
+ "altr,fpga-arria10-passive-serial"
+- reg: SPI chip select of the FPGA
+- nconfig-gpios: config pin (referred to as nCONFIG in the manual)
+- nstat-gpios: status pin (referred to as nSTATUS in the manual)
+
+Optional properties:
+- confd-gpios: confd pin (referred to as CONF_DONE in the manual)
+
+Example:
+ fpga: fpga@0 {
+ compatible = "altr,fpga-passive-serial";
+ spi-max-frequency = <20000000>;
+ reg = <0>;
+ nconfig-gpios = <&gpio4 9 GPIO_ACTIVE_LOW>;
+ nstat-gpios = <&gpio4 11 GPIO_ACTIVE_LOW>;
+ confd-gpios = <&gpio4 12 GPIO_ACTIVE_LOW>;
+ };
--
2.7.4
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