[PATCH 2/4 v6] pinmux: add a driver for the U300 pinmux

[Linus Walleij]

On Fri, Sep 2, 2011 at 6:04 PM, Stephen Warren <swarren at nvidia.com> wrote:
> Linus Walleij wrote at Friday, September 02, 2011 2:12 AM:
>> On Thu, Sep 1, 2011 at 11:33 PM, Stephen Warren <swarren at nvidia.com> wrote:
>>
>> >> +static const struct u300_pmx_func u300_pmx_functions[] = {
>> >> +     {
>> >> +             .name = "power",
>> >> +             .groups = { POWERGRP_INDEX },
>> >> +             /* Mask is N/A */
>> >> +     },
>> >
>> > Hmmm. That's a lot of _INDEX defines that'd need to be set up, at least
>> > to fully represent a chip like Tegra. Can the pinmux core be modified
>> > such that the group list is an array of names (char*) rather than the
>> > actual numeric IDs of the groups? Still, perhaps we could use the enum
>> > we already have for this, so perhaps it isn't a big deal...
>>
>> Well I could think about a lot of ways to do this, but it's basically up
>> to the driver, the U300 is just some simple example of what you can
>> do, it's just trying to satisfy the API.
>>
>> Maybe as part of writing the nVidia driver you find a clever
>> mechanism for doing this, if it's looking generally useful at that
>> point then let's move it to the core I'd say.
>
> The reason I asked about the pinmux core handling this is because the
> driver op get_function_groups:
>
> +       int (*get_function_groups) (struct pinctrl_dev *pctldev,
> +                                 unsigned selector,
> +                                 unsigned ** const groups,
> +                                 unsigned * const num_groups);
>
> returns an array of integer indexes. I think the only way to get rid of
> the index definitions in the drivers is to allow get_function_groups to
> return an array of strings instead.

OK good idea, I reworked this interface to get an array of strings
instead, I've been told several times to use strings rather than numbers
when possible, so I think this is the right thing to do.

Check it out in v7!

Yours,
Linus Walleij