On Mon, Oct 24, 2011 at 11:20 AM, Mike Frysinger vapier.adi@gmail.com wrote:
but the question here is about pinctrl. does userspace really need to manipulate the pinmapping ? if we agree on that, then the question is on the userspace interface.
assuming we want this, i can't see the performance argument being made here for pinctrl. which means doing a sysfs interface here like we already have with GPIO makes the most sense. GPIO deals in "binary" data for the most part (reading/writing 0/1 ints) so the string-based sysfs parsing is a bit weird, but pinctrl deals with strings everywhere for selecting mapping groups, so sysfs is the natural answer.
Hm now I feel I start to agree with you and come back to my original proposition to do pinctrl in sysfs after all.
I wonder how soon we have a practical use case for this. We do have this hacked-up driver in ux500: http://git.linaro.org/gitweb?p=bsp/st-ericsson/linux-3.0-ux500.git%3Ba=tree%...
This controls a lot of SIM card pins from userspace...
Yours, Linus Walleij