Patchwork [v2,02/17] dt-bindings: olpc,xo1.75-ec: Add OLPC XO-1.75 EC bindings

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Submitter Lubomir Rintel
Date Nov. 16, 2018, 4:23 p.m.
Message ID <20181116162403.49854-3-lkundrak@v3.sk>
Download mbox | patch
Permalink /patch/658745/
State New
Headers show

Comments

Lubomir Rintel - Nov. 16, 2018, 4:23 p.m.
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 <lkundrak@v3.sk>
Acked-by: Pavel Machek <pavel@ucw.cz>

---
Changes since v1:
- s/cmd-gpio/cmd-gpios/
- s/ready-gpio/ready-gpios/ in the documentation paragraph
- Remove status = "okay" from the example

 .../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
Rob Herring - Nov. 17, 2018, 4:03 p.m.
On Fri, 16 Nov 2018 17:23:48 +0100, Lubomir Rintel wrote:
> 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 <lkundrak@v3.sk>
> Acked-by: Pavel Machek <pavel@ucw.cz>
> 
> ---
> Changes since v1:
> - s/cmd-gpio/cmd-gpios/
> - s/ready-gpio/ready-gpios/ in the documentation paragraph
> - Remove status = "okay" from the example
> 
>  .../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
> 

Reviewed-by: Rob Herring <robh@kernel.org>

Patch

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:
+<Documentation/devicetree/bindings/spi/spi-pxa2xx.txt>.
+
+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>;
+		};
+	};