Hi Robert, On 04/09/2015 04:57 PM, Robert Baldyga wrote: > Hi Chanwoo, > > On 04/09/2015 04:12 AM, Chanwoo Choi wrote: >> Hi Robert, >> [snip] >> But, I have one question about case[3] >> >> If id is low and vbus is high, this patch will update the state of both USB and USB-HOST cable as attached state. >> Is it possible that two different cables (both USB and USB-HOST) are connected to one port simultaneously? >> > > It's because state of single USB cable connection cannot be completely > described using single extcon cable. USB cable state has two bits (VBUS > and ID), so we need to use two cables for single cable connection. We > use following convention: > cable "USB" = VBUS > cable "USB-HOST" = !ID. I think that extcon provider driver have to update the only one cable state of either USB or USB-HOST because USB and USB-HOST feature can not be used at the same time through one h/w port. If extcon-usb-gpio.c update two connected event of both USB and USB-HOST cable at the same time, the extcon consumer driver can not decide what handle either USB or USB-HOST. > In fact it would be better to have cables named "USB-VBUS" and "USB-ID" > - in this convention it would be more clear. Thanks, Chanwoo Choi -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
