From: Linus Walleij <linus.walleij@linaro.org>
To: Robert Baldyga <r.baldyga@samsung.com>
Cc: David Cohen <david.a.cohen@linux.intel.com>,
MyungJoo Ham <myungjoo.ham@samsung.com>,
Chanwoo Choi <cw00.choi@samsung.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>,
baolu.lu@linux.intel.com
Subject: Re: [PATCH v2] extcon: otg_gpio: add driver for USB OTG port controlled by GPIO(s)
Date: Fri, 20 Feb 2015 10:53:44 +0100 [thread overview]
Message-ID: <CACRpkdYkcjgvYQBuGtu2-JGvtM+y-zrMD=0xyiZLS=b3gEGMOw@mail.gmail.com> (raw)
In-Reply-To: <54E6D721.9070107@samsung.com>
On Fri, Feb 20, 2015 at 7:41 AM, Robert Baldyga <r.baldyga@samsung.com> wrote:
> Hi David,
>
> On 02/19/2015 08:59 PM, David Cohen wrote:
>> Some Intel platforms have an USB OTG port fully (or partially)
>> controlled by GPIOs:
>>
>> (1) USB ID is connected directly to a pulled up GPIO.
>>
>> Optionally:
>> (2) VBUS is enabled/disabled by a GPIO
>> (3) Platform has 2 USB controllers connected to same port: one for
>> device and one for host role. D+/- are switched between phys.
>> according to this GPIO level.
>>
>> This driver configures USB OTG port for device or host role according to
>> USB ID value.
>> - If USB ID's GPIO level is low, OTG port is configured for host role
>> by sourcing VBUS and switching D+/- to host phy.
>> - If USB ID's GPIO level is high, by standard, the OTG port is
>> configured for device role by not sourcing VBUS and switching D+/- to
>> device controller.
>
> IMO it's not very elegant to handle VBUS power on/off in extcon driver.
> Creating fixed regulator would allow to make VBUS handling more generic.
IMHO it's just layers of abstraction piled on top of each other here.
I would put this adjacent to the phy driver somewhere in drivers/usb/*
and make the actual USB-driver thing handle its GPIOs directly.
But I guess David and Felipe have already discussed that as we're
seeing this patch?
Yours,
Linus Walleij
next prev parent reply other threads:[~2015-02-20 9:53 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-12-22 22:43 [RFC/PATCH] extcon: otg_gpio: add driver for USB OTG port controlled by GPIO(s) David Cohen
2014-12-23 1:25 ` Peter Chen
2014-12-23 19:40 ` David Cohen
2014-12-24 3:08 ` Peter Chen
2014-12-24 22:46 ` David Cohen
2014-12-23 13:10 ` Sergei Shtylyov
2014-12-23 19:57 ` David Cohen
2014-12-23 20:09 ` Sergei Shtylyov
2014-12-23 20:43 ` David Cohen
2014-12-24 0:29 ` Felipe Balbi
2014-12-24 22:43 ` David Cohen
2014-12-26 4:49 ` Felipe Balbi
2015-02-17 19:18 ` David Cohen
2015-02-17 19:25 ` Felipe Balbi
2015-02-17 19:35 ` David Cohen
2015-02-18 10:17 ` Mika Westerberg
2015-02-18 17:53 ` David Cohen
2015-01-08 19:23 ` Linus Walleij
2015-02-17 19:20 ` David Cohen
2015-02-19 19:59 ` [PATCH v2] " David Cohen
2015-02-19 22:39 ` Paul Bolle
2015-02-20 19:02 ` David Cohen
2015-02-20 19:09 ` Felipe Balbi
2015-02-20 19:18 ` David Cohen
2015-02-20 19:10 ` Paul Bolle
2015-02-20 19:18 ` David Cohen
2015-02-20 6:41 ` Robert Baldyga
2015-02-20 9:53 ` Linus Walleij [this message]
2015-02-20 19:17 ` David Cohen
2015-02-20 19:36 ` Felipe Balbi
2015-02-20 19:59 ` David Cohen
2015-02-20 20:00 ` Felipe Balbi
2015-02-20 20:40 ` David Cohen
2015-03-07 20:03 ` Linus Walleij
2015-02-24 19:18 ` David Cohen
2015-03-07 20:06 ` Linus Walleij
2015-03-09 16:16 ` Felipe Balbi
2015-03-09 19:10 ` David Cohen
2015-03-16 16:46 ` David Cohen
2015-03-16 16:46 ` David Cohen
2015-03-19 8:18 ` Linus Walleij
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