On Wed, Jun 08, 2016 at 03:48:00PM +0200, Krzysztof Kozlowski wrote:
> From: Robert Baldyga <r.baldyga@xxxxxxxxxxx>
>
> Add information about VBUS pin detection support, 'debounce' property
> and some other details.
The extcon bindings are a complete mess if you've seen my recent
comments. I'm inclined to NAK anything that amends broken bindings. This
one is headed in the right direction though...
> Signed-off-by: Robert Baldyga <r.baldyga@xxxxxxxxxxx>
> Acked-by: Roger Quadros <rogerq@xxxxxx>
> Signed-off-by: Krzysztof Kozlowski <k.kozlowski@xxxxxxxxxxx>
> ---
> .../devicetree/bindings/extcon/extcon-usb-gpio.txt | 28 ++++++++++++++++++++--
> 1 file changed, 26 insertions(+), 2 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/extcon/extcon-usb-gpio.txt b/Documentation/devicetree/bindings/extcon/extcon-usb-gpio.txt
> index af0b903de293..7096f399b771 100644
> --- a/Documentation/devicetree/bindings/extcon/extcon-usb-gpio.txt
> +++ b/Documentation/devicetree/bindings/extcon/extcon-usb-gpio.txt
> @@ -1,16 +1,40 @@
> USB GPIO Extcon device
>
> -This is a virtual device used to generate USB cable states from the USB ID pin
> -connected to a GPIO pin.
> +This is a virtual device used to generate USB cable states from the USB
> +ID and VBUS signals connected to GPIO pins.
It is not a virtual device, but a connector and connector states.
> +
> +The extcon cable states USB and USB_HOST are actually VBUS and !ID
> +pin states and do not indicate what mode the USB needs to operate in.
> +That decision is done by the USB stack.
> +
> +Some devices have only one of these GPIO pins, so we support cases when
> +only one of them is present. Hence properties 'id-gpio' and 'vbus-gpio'
> +are described as optional, but at least one of them has to be present
> +in extcon-usb-gpio node.
> +
> +In general we have three cases:
> +1. If VBUS and ID gpios are present we pass them as is
> + USB-HOST = !ID, USB = VBUS
> +2. If only VBUS gpio is present we assume that ID pin is always High.
> + USB-HOST = false, USB = VBUS.
> +3. If only ID pin is available we infer the VBUS pin states based on ID.
> + USB-HOST = !ID, USB = ID
USB and USB-HOST look like driver details. Shouldn't this just be in
terms of host and device?
>
> Required properties:
> - compatible: Should be "linux,extcon-usb-gpio"
I'd prefer to see this deprecated in favor of a string that defines the
type of connector (usb-a-connector, usb-microab-connector, etc.)
> +
> +Optional properties
> - id-gpio: gpio for USB ID pin. See gpio binding.
> +- vbus-gpio: gpio for USB VBUS pin. See gpio binding.
vbus-gpios
> +- debounce: gpio debounce time in milliseconds (u32).
debounce of which gpio? Needs a unit suffix.
> +
>
> Example: Examples of extcon-usb-gpio node in dra7-evm.dts as listed below:
> extcon_usb1 {
> compatible = "linux,extcon-usb-gpio";
> id-gpio = <&gpio6 1 GPIO_ACTIVE_HIGH>;
> + vbus-gpio = <&gpio6 2 GPIO_ACTIVE_HIGH>;
> + debounce = <25>;
> }
>
> &omap_dwc3_1 {
> --
> 1.9.1
>
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