On Mon, Aug 22, 2011 at 02:38:16PM +0200, Linus Walleij wrote:
On Sun, Aug 21, 2011 at 4:24 PM, Jamie Iles jamie@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