Re: [RFI] pinmux: pin group ownership

[Linus Walleij <linus.walleij@xxxxxxxxxx>]

On Fri, May 8, 2015 at 5:01 PM, Jon Hunter <jonathanh@xxxxxxxxxx> wrote:

> Looking at this change, if pinmux_enable_setting() is called but
> .get_group_pins() is not defined, then num_pins will be 0. If this is
> the case then pin_request() is not called to allocate the pins in the
> group (because no pins are defined for the group). So that makes sense.
>
> However, I am trying to understand then, if the pinmux driver will
> protect against another device attempting to use the same group for a
> different function when already in-use?
>
> For example, if you have the two functions i2c0 and uart0 mapped to pin
> group A, but no pins are defined for group A, will pinmux prevent
> someone attempting to configure both functions on the same group at the
> same time?
>
> I did not see anywhere that sets a usecount for a group (ie. allocates
> the group) but only for a pin.

The usecount are done on individual pins, not groups.

In the devel tree you can even set the pinmux_ops.strict to disallow
GPIOs and other functions to share a pin.

Yours,
Linus Walleij
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