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From: Denis Kuzmenko <linux@solonet.org.ua>
To: Stephen Warren <swarren@nvidia.com>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Grant Likely <grant.likely@secretlab.ca>,
	Linus Walleij <linus.walleij@linaro.org>,
	Richard Purdie <rpurdie@rpsys.net>,
	Wolfram Sang <w.sang@pengutronix.de>
Subject: Re: [PATCH] s3c/s3c24xx: arm: leds: Make s3c24xx LEDS driver use gpiolib
Date: Tue, 22 Nov 2011 02:28:22 +0200	[thread overview]
Message-ID: <4ECAECA6.7090109@solonet.org.ua> (raw)
In-Reply-To: <74CDBE0F657A3D45AFBB94109FB122FF174F08C2B4@HQMAIL01.nvidia.com>

On 11/22/2011 01:39 AM, Stephen Warren wrote:
> Denis Kuzmenko wrote at Monday, November 21, 2011 3:52 PM:
> ...
>>> I don't see any pulls being configured in the original code at all,
>>> unless some of the s3c2410_* function have unexpected side-effect. The
>>> only related thing is in probe:
>>>
>>>         /* no point in having a pull-up if we are always driving */
>>>
>>>         if (pdata->flags & S3C24XX_LEDF_TRISTATE) {
>>> ..
>>>         } else {
>>>                 s3c2410_gpio_pullup(pdata->gpio, 0);
>>>
>>> which I assume disables an pull in the case where the pin is always driven.
>>>
>>> So, yes, I'd say submit v3 without any pull manipulation at all.
>>>
>>
>> Actually, "s3c2410_gpio_pullup(pdata->gpio, 0);" enables pull in the
>> same way I've done that. Here is it's code:
> 
> So it does. That's extremely non-obvious if not broken.
> 
> Anyway, I guess that means that your patch V1 is at least a pure conversion
> of the code from custom functions to gpiolib, even if what it was and still
> is doing doesn't make much sense to me.
> 

So what do you suggest? Leave original behavior?
I'd like to remove pull-related actions at all considering:
 - power consumption
 - we are both not able to find any sense in that code
 - s3c2410_gpio_pullup looks like deprecated
 - can't imagine situation where this change will break functionality
(of course when this code used to drive actually LED and not something else)

-- 
Best regards, Denis Kuzmenko.

  reply	other threads:[~2011-11-22  0:26 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-11-17 20:47 [PATCH] s3c/s3c24xx: arm: leds: Make s3c24xx LEDS driver use gpiolib Denis Kuzmenko
2011-11-18 17:08 ` Stephen Warren
2011-11-18 21:00   ` Denis Kuzmenko
2011-11-18 21:44     ` Denis Kuzmenko
2011-11-18 21:59       ` Stephen Warren
2011-11-18 22:34         ` Denis Kuzmenko
2011-11-18 22:39           ` [PATCH v2] " Denis Kuzmenko
2011-11-18 22:44           ` [PATCH] " Stephen Warren
2011-11-18 23:16             ` Denis Kuzmenko
2011-11-21 18:07               ` Stephen Warren
2011-11-21 19:37                 ` Denis Kuzmenko
2011-11-21 22:03                   ` Stephen Warren
2011-11-21 22:52                     ` Denis Kuzmenko
2011-11-21 23:39                       ` Stephen Warren
2011-11-22  0:28                         ` Denis Kuzmenko [this message]
2011-11-22  0:40                           ` Stephen Warren
2011-11-18 21:47     ` Stephen Warren

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