Re: [PATCH] s3c/s3c24xx: arm: leds: Make s3c24xx LEDS driver usegpiolib

From: Denis Kuzmenko
Date: Mon Nov 21 2011 - 19:26:16 EST


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.
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