On Wed, Jul 13, 2016 at 10:06:45AM +0800, Peter Chen wrote:
> Add binding doc for generic power sequence library.
I'd written a review on last version, but forgot to send it out. Anyway,
I mostly had the same comments as Philipp and Joshua. A couple of things
they missed...
>
> Signed-off-by: Peter Chen <peter.chen@xxxxxxx>
> ---
> .../bindings/power/pwrseq/pwrseq-generic.txt | 53 ++++++++++++++++++++++
> 1 file changed, 53 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..186c58c
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/power/pwrseq/pwrseq-generic.txt
> @@ -0,0 +1,53 @@
> +The generic power sequence library
> +
> +Some hard-wired USB/MMC devices need to do power sequence to let the
> +device work normally, the typical power sequence like: enable USB
> +PHY clock, toggle reset pin, etc. But current Linux USB driver
> +lacks of such code to do it, it may cause some hard-wired USB 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 USB
> +bus.
> +
> +The power sequence properties is under the device node.
> +
> +Required properties:
> +- power-sequence: this device needs to do power sequence before enumeration
> +
> +Optional properties:
> +- clocks: the input clock 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>;
> + hub: genesys@1 {
genesys: hub@1
> + compatible = "usb5e3,608";
> + reg = <1>;
> +
> + power-sequence;
> + 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>;
> + ethernet: asix@1 {
asix: ethernet@1
> + compatible = "usbb95,1708";
> + reg = <1>;
> +
> + power-sequence;
> + clocks = <&clks IMX6SX_CLK_IPG>;
> + reset-gpios = <&gpio4 6 GPIO_ACTIVE_LOW>; /* ethernet_rst */
> + reset-duration-us = <15>;
> + };
> + };
> +};
> --
> 1.9.1
>
>
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