Re: [patch/rfc 2.6.19-rc5] arch-neutral GPIO calls

Bill Gatliff
2006-11-13T20:27:27Z

David Brownell wrote:

>On Monday 13 November 2006 11:43 am, Bill Gatliff wrote:
>
>
>>Maybe we should codify an approach for that now, i.e. add to the
>>reference implementation some code that hands off out-of-range GPIO
>>lines to a function in the machine descriptor:
>>
>>
>>+static inline int gpio_direction_input(unsigned gpio)
>>+ { if (gpio < OMAP_MAX_ARCH_GPIO) return __gpio_set_direction(gpio, 1);
>>+ else if(mdesc->platform_gpio_set_direction) platform_gpio_set_direction(gpio, 1); }
>>
>>
>>... conveniently neglecting the way you find mdesc. :)
>>
>>
>
>Nah; look at arch/arm/plat-omap/gpio.c and ignore the mess, but observe
>that what you see there is essentially a bunch of "gpio controller"
>classes using the ugly "switch(type)" dispatch scheme instead of the
>prettier "type->op()" dispatch scheme. All that stuff needs to be
>cleaner, but for now it'd suffice to add a new FPGA typecode.
>
>

Agreed. But if we add to the machine descriptor, then not only do you
not need to touch arch-omap/gpio.c, but you can take that switch
statement out, too. Just one less chunk of code to tweak when a new
platform is supported.

b.g.

--
Bill Gatliff
bgat@billgatliff.com