On Mon, Aug 22, 2011 at 02:38:16PM +0200, Linus Walleij wrote:
> On Sun, Aug 21, 2011 at 4:24 PM, Jamie Iles <ja...@jamieiles.com> wrote:
>
> > for device tree, when the gpio
> > controllers are registered, the base is typically dynamically assigned. I
> > suspect that this can be solved in the device tree binding for the
> > controller
> > that references the bindings of the pinctrl, but this would require
> > registering the gpio_ranges at runtime (or at least the bases).
>
> Oh registering ranges at runtime ... crap. But possible I think.
>
> > So perhaps if we had:
> >
> > struct pinctrl_gpio_range {
> > unsigned int pinctrl_base;
> > struct gpio_chip *chip;
> > }
> >
> > and then gpio_request_enable was:
> >
> > int (*gpio_request_enable)(struct pinctrl_dev *pctldev,
> > struct gpio_chip *gc,
> > unsigned offset)
> >
> > Then have pinctrl_register_gpio_chip()?
>
> I'm not following - the struct gpio_chip is opaque outside the gpio
> subsystem, I've proposed patches to make it public but they have
> been NAK:ed.
>
> Which means pinctrl has no use of that pointer.
>
> What is the intended purpose of sending that thing in?
Well even though the gpio_chip is opaque to pinctrl, the pointer can
still be used for searching, which means that gpio_request() doesn't
need to know the integer instance number (which would presumably be
passed with platform_data for non-DT?).
> Right now my range struct looks like this:
>
> /**
> * struct pinctrl_gpio_range - each pin controller can provide subranges of
> * the GPIO number space to be handled by the controller
> * @name: a name for the chip in this range
> * @id: an ID number for the chip in this range
> * @base: base offset of the GPIO range
> * @npins: number of pins in the GPIO range, including the base number
> */
> struct pinctrl_gpio_range {
> const char name[16];
> unsigned int id;
> unsigned int base;
> unsigned int npins;
> };
>
> > For the static devices case then we can require gc->base must match the
> > pinctrl gpio base. For the device tree case we could do some matching of
> > device_nodes from the gpio_chip to the pinctrl definitions?
>
> Can't do that since we can't look into struct gpio_chip intrinsics...
>
> But we can register ranges at runtime, I'll just make the pin controller keep
> a list of GPIO ranges, simple.
OK, I do think it would be nice to use a gpio_chip based request, but I
don't want to create too many obstacles for getting this code merged!
Jamie
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