Hi, On DRA7 EVMs the USB ID pin is connected to a GPIO line. The USB drivers (dwc3 + dwc3-omap) depend on extcon framework to get the USB cable state (USB or USB-Host) to put the controller in the right mode. There were earlier attempts [1] to get this working by trying to patch up the existing GPIO extcon driver. This series attemts to take a different approach by introducing a new USB specific extcon driver to handle the USB ID GPIO pin and interpret a right USB cable state. The reasoning to introduce this new driver is: 1) The existing GPIO extcon driver doesn't understand USB cable states and it can't handle more than one cable per instance. For the USB case we need to handle at least 2 cable states. a) USB (attach/detach) b) USB-Host (attach/detach) and could possible include more states like c) Fast-charger (attach/detach) d) Slow-charger (attach/detach) 2) This USB specific driver can be easily updated in the future to handle VBUS events, or charger detect events, in case it happens to be available on GPIO for any platform. 3) The DT implementation is very easy. You just need one extcon node per USB instead of one extcon node per cable state as in case of [1]. 4) The cable state string doesn't need to be encoded in the device tree as in case of [1]. 5) With only ID event available, you can simulate a USB-peripheral attach when USB-Host is detacted instead of hacking the USB driver to do the same. Tested on DRA7-evm and DRA72-evm. cheers, -roger [1] - https://lkml.org/lkml/2014/11/3/513 Roger Quadros (5): extcon: gpio-usb: Introduce gpio usb extcon driver usb: extcon: Fix USB-Host cable name ARM: dts: dra7-evm: Add extcon nodes for USB ARM: dts: dra72-evm: Add extcon nodes for USB ARM: omap2plus_defconfig: Enable PCF857X and EXTCON_GPIO_USB .../devicetree/bindings/extcon/extcon-usb.txt | 20 ++ arch/arm/boot/dts/dra7-evm.dts | 31 +++ arch/arm/boot/dts/dra72-evm.dts | 31 +++ arch/arm/configs/omap2plus_defconfig | 2 + drivers/extcon/Kconfig | 7 + drivers/extcon/Makefile | 1 + drivers/extcon/extcon-gpio-usb.c | 225 +++++++++++++++++++++ drivers/extcon/extcon-palmas.c | 18 +- drivers/usb/dwc3/dwc3-omap.c | 6 +- drivers/usb/phy/phy-omap-otg.c | 4 +- drivers/usb/phy/phy-tahvo.c | 8 +- 11 files changed, 335 insertions(+), 18 deletions(-) create mode 100644 Documentation/devicetree/bindings/extcon/extcon-usb.txt create mode 100644 drivers/extcon/extcon-gpio-usb.c -- 2.1.0 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html