[PATCH v10 1/3] doc: dt: add altera-ps-spi binding document

From: Anatolij Gustschin
Date: Wed May 17 2017 - 14:23:58 EST


From: Joshua Clayton <stillcompiling@xxxxxxxxx>

Describe an altera-ps-spi devicetree entry, required features

Signed-off-by: Joshua Clayton <stillcompiling@xxxxxxxxx>
Acked-by: Rob Herring <robh@xxxxxxxxxx>
Signed-off-by: Anatolij Gustschin <agust@xxxxxxx>
---
Changes in v10:
- fix compatible string in example
- add Arria 10 compatible
- s/spi/SPI/
- reword to remove entries mentioning cyclone, since it
can be used with other FPGAs now (Arria 10, Stratix V)

.../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..3e240b2
--- /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_spi: evi-fpga-spi@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