On Monday 15 August 2016 02:43 PM, Peter Chen wrote:
Add binding doc for generic power sequence library.
Signed-off-by: Peter Chen <peter.chen@xxxxxxx>
Acked-by: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx>
Acked-by: Rob Herring <robh@xxxxxxxxxx>
---
.../bindings/power/pwrseq/pwrseq-generic.txt | 48 ++++++++++++++++++++++
1 file changed, 48 insertions(+)
create mode 100644 Documentation/devicetree/bindings/power/pwrseq/pwrseq-generic.txt
diff --git a/Documentation/devicetree/bindings/power/pwrseq/pwrseq-generic.txt b/Documentation/devicetree/bindings/power/pwrseq/pwrseq-generic.txt
new file mode 100644
index 0000000..ebf0d47
--- /dev/null
+++ b/Documentation/devicetree/bindings/power/pwrseq/pwrseq-generic.txt
@@ -0,0 +1,48 @@
+The generic power sequence library
+
+Some hard-wired devices (eg USB/MMC) need to do power sequence before
+the device can be enumerated on the bus, the typical power sequence
+like: enable USB PHY clock, toggle reset pin, etc. But current
+Linux device driver lacks of such code to do it, it may cause some
+hard-wired devices works abnormal or can't be recognized by
+controller at all. The power sequence will be done before this device
+can be found at the bus.
+
+The power sequence properties is under the device node.
+
+Optional properties:
+- clocks: the input clocks for device.
+- reset-gpios: Should specify the GPIO for reset.
+- reset-duration-us: the duration in microsecond for assert reset signal.
+
+Below is the example of USB power sequence properties on USB device
+nodes which have two level USB hubs.
+
+&usbotg1 {
+ vbus-supply = <®_usb_otg1_vbus>;
+ pinctrl-names = "default";
+ pinctrl-0 = <&pinctrl_usb_otg1_id>;
+ status = "okay";
+
+ #address-cells = <1>;
+ #size-cells = <0>;
+ genesys: hub@1 {
+ compatible = "usb5e3,608";
+ reg = <1>;
+
+ clocks = <&clks IMX6SX_CLK_CKO>;
+ reset-gpios = <&gpio4 5 GPIO_ACTIVE_LOW>; /* hub reset pin */
+ reset-duration-us = <10>;
+
+ #address-cells = <1>;
+ #size-cells = <0>;
+ asix: ethernet@1 {
+ compatible = "usbb95,1708";
So I assume, with our recent discussion and the change
we are proposing, the library would have some knowledge
about this compatible string, right?
what I was asking on other email was, how are you connecting
multiple power sequence libraries to their respective consumers ?
Thanks,
Vaibhav
+ reg = <1>;
+
+ clocks = <&clks IMX6SX_CLK_IPG>;
+ reset-gpios = <&gpio4 6 GPIO_ACTIVE_LOW>; /* ethernet_rst */
+ reset-duration-us = <15>;
+ };
+ };
+};
--
Thanks,
Vaibhav
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