[PATCH v2 1/2] dt-bindings: gpio: 74x164: Introduce the 'registers-default' property

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



There are cases where a certain default output value in the 74x164
output is needed.

For example: the imx6ul-evk board has the Ethernet PHY reset controlled
by the 74x164 chip.

After enabling the OE pin, the output pins of the 74x164 chip go to
zero by default, which makes the Ethernet PHY not to be detected.

Add a new optional property called 'registers-default' that allows
describing the default output value for each shift register.

Signed-off-by: Fabio Estevam <festevam@xxxxxxxxx>
---
Changes since v1:
- None

 Documentation/devicetree/bindings/gpio/gpio-74x164.txt | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/Documentation/devicetree/bindings/gpio/gpio-74x164.txt b/Documentation/devicetree/bindings/gpio/gpio-74x164.txt
index 2a97553d8d76..bf8f45896018 100644
--- a/Documentation/devicetree/bindings/gpio/gpio-74x164.txt
+++ b/Documentation/devicetree/bindings/gpio/gpio-74x164.txt
@@ -14,6 +14,8 @@ Required properties:
 
 Optional properties:
 - enable-gpios: GPIO connected to the OE (Output Enable) pin.
+- registers-default: An array of 8-bit values describing the default output
+value of each shift registers.
 
 Example:
 
@@ -24,4 +26,5 @@ gpio5: gpio5@0 {
 	#gpio-cells = <2>;
 	registers-number = <4>;
 	spi-max-frequency = <100000>;
+	registers-default = /bits/ 8 <0x57 0xF0 0xFF 0xF0>;
 };
-- 
2.17.1




[Index of Archives]     [Device Tree Compilter]     [Device Tree Spec]     [Linux Driver Backports]     [Video for Linux]     [Linux USB Devel]     [Linux PCI Devel]     [Linux Audio Users]     [Linux Kernel]     [Linux SCSI]     [XFree86]     [Yosemite Backpacking]


  Powered by Linux