Re: [RFC 01/19] extcon: add extcon-odroid-usbotg driver

From: Chanwoo Choi
Date: Thu Mar 19 2015 - 16:50:46 EST

Hi Roger,

On Thu, Mar 19, 2015 at 11:45 PM, Roger Quadros <rogerq@xxxxxx> wrote:
> On 19/03/15 14:19, George Cherian wrote:
>> Hi Robert,
>> +Roger
>> On Thu, Mar 19, 2015 at 5:37 PM, Robert Baldyga <r.baldyga@xxxxxxxxxxx> wrote:
>>> Hi George,
>>> On 03/19/2015 09:50 AM, George Cherian wrote:
>>>> Hi Robert,
>>>> This looks like a extcon driver based on gpio for USB.
>>>> Roger posted a generic one a while back.
>>>> Doesn't this serve the purpose rather than adding this driver?
>>> Roger's driver doesn't support VBUS state detection so it cannot handle
>> I feel Roger's driver could be extended for supporting VBUS.
>> Also I think Roger's driver is about to get merged.
>> Probably, Roger or Chanwoo can better tell that
> It is already queued for 4.1 and is available in linux-next.
>>> situation when USB cable is unpluged. In addition some of Odroid boards
>>> has only VBUS detection (without ID pin), so this driver cannot handle
>>> them at all.
> why not?
> x15-beagleboard also gets VBUS event over GPIO and I was planning to extent it
> to support VBUS detection.

Sounds good to me to extent extcon-usb-gpio.c.
I'd like to hold only one extcon driver to support both USB and
USB-HOST with gpio .

There are one more extcon-gpio driver in mailing list as following:
- extcon-usb-gpio.c (will be merged to Linux 4.1)
- extcon-odroid-usbotg.c
- extcon-otg_gpio.c [1]

The each extcon gpio driver support both USB/USB-HOST cable by using
different way,
Because some board which detect USB/USB-HOST by gpio have a little
different pin composition

I think only one extcon driver can support all cases with optional properties.

I'd like you to share your plan to extent the extcon-usb-gpio.c for
removing duplicate work.


Chanwoo Choi
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