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From: David Brownell <david-b@pacbell.net>
To: Anton Vorontsov <avorontsov@ru.mvista.com>
Subject: Re: [PATCH 1/4] gpiolib: make gpio_to_chip() public
Date: Wed, 24 Sep 2008 14:40:43 -0700
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On Wednesday 24 September 2008, Anton Vorontsov wrote:
> We'll need this function to write platform-specific hooks to deal
> with pin's dedicated functions. Quite obviously this will work only
> for the platforms with 1-to-1 GPIO to PIN mapping.
> 
> This is stopgap solution till we think out and implement a proper
> api (pinlib?).
> 
> p.s. This patch actually exports gpio_desc and places gpio_to_chip
> into the asm-generic/gpio.h as `static inline'. This is needed
> to not cause function calls for this trivial translation.
> 
> Also, the patch does not export FLAG_*s... the names are too
> generic, and nobody is using them outside of gpiolib.c.

For the record:  NAK, still.  The concept has problems,
there is no "need" for this.  I sketched a cleaner way
to address the issues of the QE USB driver; I'm sure it
would only take an hour or two to code, using what's
already present.

And if I were to approve something like this it would
be a lot simpler, not exposing internals, and with
appropriate kerneldoc.  Simpler such as

	struct gpio_chip *gpio_to_gpiochip(unsigned gpio)
	{
		return gpio_to_chip(gpio);
	}
	EXPORT_SYMBOL_NOTREALLY(gpio_to_gpiochip);

with a declaration in a header.  It's not like THIS
version would be performance-critical (unlike the one
inside gpiolib).

- Dave