linux-kernel - Re: [PATCH v6 03/10] usb: dwc3: omap: Pass VBUS and ID events transparently

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Date:	Mon, 11 Apr 2016 16:51:54 +0300
From:	Roger Quadros <rogerq@...com>
To:	Felipe Balbi <balbi@...nel.org>
CC:	<tony@...mide.com>, <Joao.Pinto@...opsys.com>,
	<sergei.shtylyov@...entembedded.com>, <peter.chen@...escale.com>,
	<jun.li@...escale.com>, <grygorii.strashko@...com>,
	<yoshihiro.shimoda.uh@...esas.com>, <nsekhar@...com>,
	<linux-usb@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	<linux-omap@...r.kernel.org>
Subject: Re: [PATCH v6 03/10] usb: dwc3: omap: Pass VBUS and ID events
 transparently

On 11/04/16 16:26, Felipe Balbi wrote:
> 
> Hi,
> 
> Roger Quadros <rogerq@...com> writes:
>> On 11/04/16 15:18, Felipe Balbi wrote:
>>>
>>> Hi,
>>>
>>> Roger Quadros <rogerq@...com> writes:
>>>> Don't make any decisions regarding VBUS session based on ID
>>>> status. That is best left to the OTG core.
>>>
>>> what about builds who don't want OTG and/or dual-role ?
>>>
>>>> Pass ID and VBUS events independent of each other so that OTG
>>>> core knows exactly what to do.
>>>>
>>>> This makes dual-role with extcon work with OTG irq on OMAP platforms.
>>>>
>>>> Signed-off-by: Roger Quadros <rogerq@...com>
>>>> ---
>>>>  drivers/usb/dwc3/dwc3-omap.c | 15 ++++++---------
>>>>  1 file changed, 6 insertions(+), 9 deletions(-)
>>>>
>>>> diff --git a/drivers/usb/dwc3/dwc3-omap.c b/drivers/usb/dwc3/dwc3-omap.c
>>>> index 51ca098..c9b918d 100644
>>>> --- a/drivers/usb/dwc3/dwc3-omap.c
>>>> +++ b/drivers/usb/dwc3/dwc3-omap.c
>>>> @@ -233,19 +233,14 @@ static void dwc3_omap_set_mailbox(struct dwc3_omap *omap,
>>>>  		}
>>>>  
>>>>  		val = dwc3_omap_read_utmi_ctrl(omap);
>>>> -		val &= ~(USBOTGSS_UTMI_OTG_CTRL_IDDIG
>>>> -				| USBOTGSS_UTMI_OTG_CTRL_VBUSVALID
>>>> -				| USBOTGSS_UTMI_OTG_CTRL_SESSEND);
>>>> -		val |= USBOTGSS_UTMI_OTG_CTRL_SESSVALID
>>>> -				| USBOTGSS_UTMI_OTG_CTRL_POWERPRESENT;
>>>> +		val &= ~USBOTGSS_UTMI_OTG_CTRL_IDDIG;
>>>
>>> this creates the possibility of having a USB peripheral with VBUS_VALID,
>>> right 
>>
>> Sorry, I didn't get what you meant.
> 
> if you're touching these bits independently from each other, won't you
> have a situation where you notify IDFLOAT but don't notify that VBUS is
> off ?
> 
We're setting the mailbox state for both ID and VBUS in dwc3_omap_extcon_register()
depending on the initial extcon state. After that, ID and VBUS will be signalled
only when they change.

cheers,
-roger