Hello,
As there was no response to my question I assume that I see it correctly
that at the moment the only 2 options for setting up GPIO configurations
is either via platform-specific code by eg. platform_data or via userspace?
Would there be a common use of defining GPIO configurations via a device
tree and applying those settings via a generic, platform-unaware driver?
Regards,
Christian
On Fri, 13 Jul 2012 10:04:40 +0200
Christian Engelmayer <christian.engelma...@frequentis.com> wrote:
> Hello,
>
> I am looking for a way to configure GPIO initial settings and exports to the
> userspace via Sysfs in a generic way via a device tree.
>
> The purpose would be to have the same features as when initializing and
> exporting pins via platform code, eg.
>
> static struct gpio leds_gpios[] = {
> { 32, GPIOF_OUT_INIT_HIGH, "Power LED" }, /* default to ON */
> { 33, GPIOF_OUT_INIT_LOW, "Green LED" }, /* default to OFF */
> { 34, GPIOF_OUT_INIT_LOW, "Red LED" }, /* default to OFF */
> { 35, GPIOF_OUT_INIT_LOW, "Blue LED" }, /* default to OFF */
> { ... },
> };
>
> ,however, with no need for the kernel to know anything more about those pins
> and their later handling by simple userpsace drivers than the setup
> information
> provided in the device tree.
>
> This should also attack the problem of unstable GPIO numbers in the case of
> daughtercards on different base boards and would help provide a defined API
> to the userspace based on pin labels with the board specifics hidden in one
> place in the device tree.
>
> Is there already a way for realizing such a scenario ?
>
> Regards,
> Christian
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