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From: Tushar Behera <tushar.behera@linaro.org>
To: balbi@ti.com
Cc: Julius Werner <jwerner@chromium.org>,
	LKML <linux-kernel@vger.kernel.org>,
	linux-usb@vger.kernel.org, devicetree-discuss@lists.ozlabs.org,
	linux-samsung-soc <linux-samsung-soc@vger.kernel.org>,
	Vivek Gautam <gautam.vivek@samsung.com>,
	Praveen Paneri <p.paneri@samsung.com>,
	Kukjin Kim <kgene.kim@samsung.com>,
	Doug Anderson <dianders@chromium.org>,
	Olof Johansson <olofj@chromium.org>,
	Vincent Palatin <vpalatin@chromium.org>
Subject: Re: [PATCH] usb: phy: samsung-usb2: Toggle HSIC GPIO from device tree
Date: Wed, 28 Aug 2013 09:25:22 +0530	[thread overview]
Message-ID: <CAHbNUh06Rxd9JRieeXCydB_JwiUOrUXADL6nUGZxONQJmz2-CQ@mail.gmail.com> (raw)
In-Reply-To: <20130827184447.GR3005@radagast>

On 28 August 2013 00:14, Felipe Balbi <balbi@ti.com> wrote:
> On Tue, Aug 13, 2013 at 02:11:27PM +0530, Tushar Behera wrote:
>> On 12 July 2013 12:27, Felipe Balbi <balbi@ti.com> wrote:
>> > Hi,
>> >
>> > On Wed, Jul 10, 2013 at 10:42:27AM -0700, Julius Werner wrote:
>> >> Hi Felipe,
>> >>
>> >> This is intended to pull down a reset signal line, not to switch power
>> >> to the device. I could implement that with the regulator framework
>> >> too, but I think that would just be confusing and harder to understand
>> >> without providing any benefit. It's really just a plain old GPIO.
>> >
>> > alright, in that case how about using drivers/reset/ ?
>> >
>>
>> IIUC, reset-gpio driver only provides APIs for reset controls (reset,
>> assert, deassert). We still need to find out the location from where
>> we would be calling the reset function.
>
> that's fair, but at least you reuse a bunch of boilerplate code to claim
> the GPIO, set proper direction and value. No need to duplicate that in
> your driver.
>

SMSC3503 driver code was recently updated by Mark Brown [1] which
allows the device to work even if it is not connected to I2C bus. The
timing is still an issue though [2]. With this USB works on
linux-next, but surely that [2] is not the solution.

[1] http://comments.gmane.org/gmane.linux.usb.general/92061
[2] https://lkml.org/lkml/2013/8/14/814
-- 
Tushar Behera

WARNING: multiple messages have this Message-ID (diff)
From: Tushar Behera <tushar.behera-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
To: balbi-l0cyMroinI0@public.gmane.org
Cc: Julius Werner <jwerner-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>,
	LKML <linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	linux-usb-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org,
	linux-samsung-soc
	<linux-samsung-soc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	Vivek Gautam
	<gautam.vivek-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>,
	Praveen Paneri <p.paneri-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>,
	Kukjin Kim <kgene.kim-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>,
	Doug Anderson <dianders-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>,
	Olof Johansson <olofj-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>,
	Vincent Palatin
	<vpalatin-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
Subject: Re: [PATCH] usb: phy: samsung-usb2: Toggle HSIC GPIO from device tree
Date: Wed, 28 Aug 2013 09:25:22 +0530	[thread overview]
Message-ID: <CAHbNUh06Rxd9JRieeXCydB_JwiUOrUXADL6nUGZxONQJmz2-CQ@mail.gmail.com> (raw)
In-Reply-To: <20130827184447.GR3005@radagast>

On 28 August 2013 00:14, Felipe Balbi <balbi-l0cyMroinI0@public.gmane.org> wrote:
> On Tue, Aug 13, 2013 at 02:11:27PM +0530, Tushar Behera wrote:
>> On 12 July 2013 12:27, Felipe Balbi <balbi-l0cyMroinI0@public.gmane.org> wrote:
>> > Hi,
>> >
>> > On Wed, Jul 10, 2013 at 10:42:27AM -0700, Julius Werner wrote:
>> >> Hi Felipe,
>> >>
>> >> This is intended to pull down a reset signal line, not to switch power
>> >> to the device. I could implement that with the regulator framework
>> >> too, but I think that would just be confusing and harder to understand
>> >> without providing any benefit. It's really just a plain old GPIO.
>> >
>> > alright, in that case how about using drivers/reset/ ?
>> >
>>
>> IIUC, reset-gpio driver only provides APIs for reset controls (reset,
>> assert, deassert). We still need to find out the location from where
>> we would be calling the reset function.
>
> that's fair, but at least you reuse a bunch of boilerplate code to claim
> the GPIO, set proper direction and value. No need to duplicate that in
> your driver.
>

SMSC3503 driver code was recently updated by Mark Brown [1] which
allows the device to work even if it is not connected to I2C bus. The
timing is still an issue though [2]. With this USB works on
linux-next, but surely that [2] is not the solution.

[1] http://comments.gmane.org/gmane.linux.usb.general/92061
[2] https://lkml.org/lkml/2013/8/14/814
-- 
Tushar Behera
--
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  reply	other threads:[~2013-08-28  3:55 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-07-10  0:34 [PATCH] usb: phy: samsung-usb2: Toggle HSIC GPIO from device tree Julius Werner
2013-07-10  0:34 ` Julius Werner
2013-07-10  5:25 ` Felipe Balbi
2013-07-10  5:25   ` Felipe Balbi
2013-07-10 17:42   ` Julius Werner
2013-07-10 17:42     ` Julius Werner
2013-07-11  0:01     ` Fabio Estevam
2013-07-12  6:57     ` Felipe Balbi
2013-07-12  6:57       ` Felipe Balbi
2013-08-13  8:41       ` Tushar Behera
2013-08-27 18:44         ` Felipe Balbi
2013-08-27 18:44           ` Felipe Balbi
2013-08-28  3:55           ` Tushar Behera [this message]
2013-08-28  3:55             ` Tushar Behera
2013-08-28 18:24             ` Julius Werner
2013-08-28 18:24               ` Julius Werner
2013-07-10 23:52 ` Jingoo Han
2013-07-11 21:46   ` Julius Werner
2013-07-12  0:48     ` Jingoo Han
2013-07-12 10:34       ` Tomasz Figa

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