[PATCH RESEND 2/5] pinctrl: berlin: add a pinctrl driver for Marvell Berlin SoCs

[linus.walleij@linaro.org (Linus Walleij)]

On Tue, Apr 22, 2014 at 5:56 PM, Antoine T?nart
<antoine.tenart@free-electrons.com> wrote:
> On Tue, Apr 22, 2014 at 02:52:10PM +0200, Linus Walleij wrote:
>> On Fri, Apr 11, 2014 at 3:35 PM, Sebastian Hesselbarth
>> <sebastian.hesselbarth@gmail.com> wrote:
>> > On 04/11/2014 02:37 PM, Antoine T?nart wrote:
>> >> On Fri, Apr 11, 2014 at 11:03:48AM +0200, Sebastian Hesselbarth wrote:
>> >>> On 04/10/2014 03:07 PM, Antoine T?nart wrote:
>>
>> >>> Having said that, the above assumes that each function is unique
>> >>> but IIRC the idea of the function table was to group pins/groups
>> >>> with the same function, e.g. function "gpio", groups 1,7,25,...
>> >>
>> >> Most of the functions you can use on the Berlin they will be unique and
>> >> would
>> >> only be used in one group, except for the 'gpio' one.
>> >
>> > Yeah, I had a similar discussion about it back then for mvebu. IIRC, the
>> > correct answer is: Have a list of functions with groups assigned to it
>> > no matter if there is only one group per function (or 40 per function as
>> > it will be for gpio).
>> >
>> > Maybe Linus can give an update on how to deal with it?
>>
>> Have you considered implementing pinmux_ops
>> .gpio_request_enable(), .gpio_set_direction() and
>> .gpio_disable_free() instead of defining groups for each
>> and every GPIO?
>
> The function 'gpio' can be found on different groups. But the Berlin pin muxing
> does not allow to configure a pin individually. It is then not possible to mux
> GPIO pins individually. For example the 'gpio' function of group 'GSM2' on the
> BG2Q will mux GPIOs 17 *and* 18.
>
> Groups does not have more than a single 'gpio' function.
>
> Since the gpio_request_enable() comment says 'Implement this only if you can mux
> every pin individually as GPIO', I did not considered implementing these
> functions.

OK makes perfect sense.

Then I guess the current implementation is the best alternative,
but I may need to look closer.

Yours,
Linus Walleij