[PATCH 08/12] doc: binding: pwrseq-usb-generic: add binding doc for generic usb power sequence driver

Peter Chen
2016-06-21T02:14:28Z

On Mon, Jun 20, 2016 at 08:29:55PM +0800, Chen-Yu Tsai wrote:
> Hi,
>
> On Mon, Jun 20, 2016 at 7:26 PM, Peter Chen <hzpeterchen@gmail.com> wrote:
> > On Fri, Jun 17, 2016 at 12:16:48PM -0500, Rob Herring wrote:
> >> On Fri, Jun 17, 2016 at 5:09 AM, Peter Chen <peter.chen@nxp.com> wrote:
> >> > Add binding doc for generic usb power sequence driver, and update
> >> > generic usb device binding-doc accordingly.
> >> >
> >> > Signed-off-by: Peter Chen <peter.chen@nxp.com>
> >> > ---
> >> > .../bindings/power/pwrseq/pwrseq-usb-generic.txt | 31 ++++++++++++++++++++++
> >> > .../devicetree/bindings/usb/usb-device.txt | 2 ++
> >> > 2 files changed, 33 insertions(+)
> >> > create mode 100644 Documentation/devicetree/bindings/power/pwrseq/pwrseq-usb-generic.txt
> >> >
> >> > diff --git a/Documentation/devicetree/bindings/power/pwrseq/pwrseq-usb-generic.txt b/Documentation/devicetree/bindings/power/pwrseq/pwrseq-usb-generic.txt
> >> > new file mode 100644
> >> > index 0000000..8ad98382
> >> > --- /dev/null
> >> > +++ b/Documentation/devicetree/bindings/power/pwrseq/pwrseq-usb-generic.txt
> >> > @@ -0,0 +1,31 @@
> >> > +The power sequence for generic USB Devices
> >> > +
> >> > +Some hard-wired USB 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.
> >> > +
> >> > +Required properties:
> >> > +- compatible : contains "usb-pwrseq-generic".
> >>
> >> In case I have not been clear, no.
> >>
> >> I am not going to accept anything along the lines of the current mmc
> >> pwrseq. I am basically okay with Krzysztof's proposal as it is *only*
> >> an added property and not a duplication of information. I'd suggest
> >> you figure out how to make the kernel work with that rather than
> >> trying to work-around whatever kernel limitations there are.
> >>
> >
> > I see.
> >
> > Would you agree with below:
> >
> > &usbotg1 {
> > vbus-supply = <&reg_usb_otg1_vbus>;
> > pinctrl-names = "default";
> > pinctrl-0 = <&pinctrl_usb_otg1_id>;
> > status = "okay";
> >
> > #address-cells = <1>;
> > #size-cells = <0>;
> > hub: genesys at 1 {
> > compatible = "usb5e3,608";
> > reg = <1>;
> >
> > power-sequence;
> > reset-gpios = <&gpio4 5 GPIO_ACTIVE_LOW>; /* hub reset pin */
> > reset-duration-us = <10>;
> > clocks = <&clks IMX6SX_CLK_CKO>;
> >
> > #address-cells = <1>;
> > #size-cells = <0>;
> > ethernet: asix at 1 {
> > compatible = "usbb95,1708";
> > reg = <1>;
> >
> > power-sequence;
> > reset-gpios = <&gpio4 6 GPIO_ACTIVE_LOW>; /* ethernet_rst */
> > reset-duration-us = <15>;
> > clocks = <&clks IMX6SX_CLK_IPG>;
> > };
> > };
> > };
> >
> > If the node has property "power-sequence", the pwrseq core will create
> > related platform device, and the driver under pwrseq driver will handle
> > power sequence stuffs. The property below "power-sequence" will be
> > handled at pwrseq driver.
>
> Isn't this binding what Krzysztof proposed? His series also provides example
> code for enabling USB device power sequencing. Does it not work for you?
>

In this series, I just change RFC to formal patch, and finished his
example code. USB power sequence should be described on USB bus, not
platform bus.

--

Best Regards,
Peter Chen