gpiolib, irqs and error returns

From: Jon Smirl
Date: Mon Sep 01 2008 - 00:17:37 EST


>From Documentation/gpio.txt

/* map GPIO numbers to IRQ numbers */
int gpio_to_irq(unsigned gpio);

/* map IRQ numbers to GPIO numbers */
int irq_to_gpio(unsigned irq);

Those return either the corresponding number in the other namespace, or
else a negative errno code if the mapping can't be done. (For example,
some GPIOs can't be used as IRQs.) It is an unchecked error to use a GPIO
number that wasn't set up as an input using gpio_direction_input(), or
to use an IRQ number that didn't originally come from gpio_to_irq().

------------------------------------------------------------

Isn't an irq now an unsigned int? And the only possible error return
is NO_IRQ (ie 0).

--
Jon Smirl
jonsmirl@xxxxxxxxx
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