From mboxrd@z Thu Jan 1 00:00:00 1970 From: Krzysztof Kozlowski Subject: [RFC v4 1/7] Documentation: extcon: usb-gpio: update usb-gpio binding description Date: Wed, 08 Jun 2016 15:48:00 +0200 Message-ID: <1465393686-16644-2-git-send-email-k.kozlowski@samsung.com> References: <1465393686-16644-1-git-send-email-k.kozlowski@samsung.com> Return-path: In-reply-to: <1465393686-16644-1-git-send-email-k.kozlowski@samsung.com> Sender: linux-kernel-owner@vger.kernel.org To: MyungJoo Ham , Chanwoo Choi , Rob Herring , Mark Rutland , Kukjin Kim , Krzysztof Kozlowski , Marek Szyprowski , linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-samsung-soc@vger.kernel.org Cc: rogerq@ti.com, Peter Chen , "Ivan T. Ivanov" , balbi@ti.com, kishon@ti.com, Bartlomiej Zolnierkiewicz List-Id: devicetree@vger.kernel.org From: Robert Baldyga Add information about VBUS pin detection support, 'debounce' property and some other details. Signed-off-by: Robert Baldyga Acked-by: Roger Quadros Signed-off-by: Krzysztof Kozlowski --- .../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. + +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 Required properties: - compatible: Should be "linux,extcon-usb-gpio" + +Optional properties - id-gpio: gpio for USB ID pin. See gpio binding. +- vbus-gpio: gpio for USB VBUS pin. See gpio binding. +- debounce: gpio debounce time in milliseconds (u32). + 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