[PATCH] asm-generic/gpio.h: merge basic gpiolib wrappers

[Mike Frysinger]

On Thu, Oct 27, 2011 at 15:11, Russell King - ARM Linux wrote:
> On Thu, Oct 27, 2011 at 09:01:43AM -0400, Mike Frysinger wrote:
>> diff --git a/include/asm-generic/gpio.h b/include/asm-generic/gpio.h
>> index d494001..622851c 100644
>> --- a/include/asm-generic/gpio.h
>> +++ b/include/asm-generic/gpio.h
>> @@ -170,6 +170,29 @@ extern int __gpio_cansleep(unsigned gpio);
>>
>>  extern int __gpio_to_irq(unsigned gpio);
>>
>> +#ifndef gpio_get_value
>> +#define gpio_get_value(gpio) __gpio_get_value(gpio)
>> +#endif
>> +
>> +#ifndef gpio_set_value
>> +#define gpio_set_value(gpio, value) __gpio_set_value(gpio, value)
>> +#endif
>> +
>> +#ifndef gpio_cansleep
>> +#define gpio_cansleep(gpio) __gpio_cansleep(gpio)
>> +#endif
>> +
>> +#ifndef gpio_to_irq
>> +#define gpio_to_irq(gpio) __gpio_to_irq(gpio)
>> +#endif
>> +
>> +#ifndef irq_to_gpio
>> +static inline int irq_to_gpio(unsigned int irq)
>> +{
>> +     return -EINVAL;
>> +}
>> +#endif
>> +
>
> This is extremely dangerous.  Consider for example this code
> (see ARM mach-davinci's gpio.h):
> ...
> This is why I didn't solve this using the preprocessor method in ARM, but
> instead used __ARM_GPIOLIB_COMPLEX to control whether these definitions
> are required.

i thought the arm mach were defining things already, but i guess i
missed some in my review

easy enough to glue the arm-specific world to the asm-generic world
... a bit ugly, but should work i think:
#ifndef __ARM_GPIOLIB_COMPLEX
/* assume the mach has defined this */
#ifndef gpio_get_value
#define gpio_get_value gpio_get_value
#endif
#ifndef gpio_set_value
#define gpio_set_value gpio_set_value
#endif
#ifndef gpio_cansleep
#define gpio_cansleep gpio_cansleep
#endif
#ifndef gpio_to_irq
#define gpio_to_irq gpio_to_irq
#endif
#ifndef irq_to_gpio
#define irq_to_gpio irq_to_gpio
#endif
...

the next step might be to drill down into the arm mach's and sprinkle
the defines into the parts that need it ...
-mike