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From: Stephen Warren <swarren@nvidia.com>
To: Linus Walleij <linus.walleij@linaro.org>,
        Chanho Park <chanho61.park@samsung.com>
CC: Linus Walleij <linus.walleij@stericsson.com>,
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        Rajendra Nayak <rajendra.nayak@linaro.org>,
        Haojian Zhuang <haojian.zhuang@marvell.com>
Date: Wed, 14 Dec 2011 07:44:26 -0800
Subject: RE: [PATCH v6] pinctrl: add a pin config interface
Thread-Topic: [PATCH v6] pinctrl: add a pin config interface
Thread-Index: Acy6P49Tecgq5cqyQLCVvpUhJaZ5UgANysUQ
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Linus Walleij wrote at Wednesday, December 14, 2011 2:06 AM:
> On Wed, Dec 14, 2011 at 8:04 AM, Chanho Park <chanho61.park@samsung.com> wrote:
> 
> >> ChangeLog v5->v6:
> >> - Change to using a pin name as parameter for the
> >>   [get|set]_config() functions, as suggested by Stephen Warren.
> >>   This is more natural as names will be what a developer has
> >>   access to in written documentation etc.
> >
> > I don't agree with it.
> > Someone doesn't like to assign a pin name individually because a
> > pin number is sufficient to represent each pin.
...
> What turned me around to see things Stephen's way was the fact
> that if someone reads this code and finds:
> 
> pin_config_set(dev, 42, MY_FUNNY_PULLUP_MACRO);
> 
> It is harder to understand than:
> 
> pin_config_set(dev, "I2C0 SCL", MY_FUNNY_PULLUP_MACRO);

You could mitigate the opaqueness of the numbers by having the pinctrl
driver export a header of #defines for the pin numbers, so this could be:

pin_config_set(dev, FOO_PMX_PIN_I2C0_SCL, MY_FUNNY_PULLUP_MACRO);

Still, using strings avoids the need to do this.

Equally, I don't see the disadvantage of using strings here. In earlier
discussions, I thought we already discussed making pin names mandatory,
which seems to avoid most of Chanho's objections?

-- 
nvpublic