From f22558d701755f2f9cfdbd4a0862a58ef5fb1dbb Mon Sep 17 00:00:00 2001 From: Lubomir Rintel Date: Mon, 13 May 2019 09:56:32 +0200 Subject: dt-bindings: olpc,xo1.75-ec: Add OLPC XO-1.75 EC bindings The OLPC XO-1.75 Embedded Controller is a SPI master that uses extra signals for handshaking. It needs to know when is the slave (Linux) side's TX FIFO ready for transfer (the ready-gpio signal on the SPI controller node) and when does it wish to respond with a command (the cmd-gpio property). Signed-off-by: Lubomir Rintel Acked-by: Pavel Machek Reviewed-by: Rob Herring Signed-off-by: Andy Shevchenko --- .../devicetree/bindings/misc/olpc,xo1.75-ec.txt | 23 ++++++++++++++++++++++ 1 file changed, 23 insertions(+) create mode 100644 Documentation/devicetree/bindings/misc/olpc,xo1.75-ec.txt (limited to 'Documentation/devicetree/bindings/misc') diff --git a/Documentation/devicetree/bindings/misc/olpc,xo1.75-ec.txt b/Documentation/devicetree/bindings/misc/olpc,xo1.75-ec.txt new file mode 100644 index 000000000000..8c4d649cdd8f --- /dev/null +++ b/Documentation/devicetree/bindings/misc/olpc,xo1.75-ec.txt @@ -0,0 +1,23 @@ +OLPC XO-1.75 Embedded Controller + +Required properties: +- compatible: Should be "olpc,xo1.75-ec". +- cmd-gpios: gpio specifier of the CMD pin + +The embedded controller requires the SPI controller driver to signal readiness +to receive a transfer (that is, when TX FIFO contains the response data) by +strobing the ACK pin with the ready signal. See the "ready-gpios" property of the +SSP binding as documented in: +. + +Example: + &ssp3 { + spi-slave; + ready-gpios = <&gpio 125 GPIO_ACTIVE_HIGH>; + + slave { + compatible = "olpc,xo1.75-ec"; + spi-cpha; + cmd-gpios = <&gpio 155 GPIO_ACTIVE_HIGH>; + }; + }; -- cgit v1.2.3