Hi Linus,
On Fri, May 09, 2014 at 09:38:02AM +0200, Linus Walleij wrote:
> This switches the sunxi pinctrl driver over to using the generic
> gpiolib irqchip helpers for its chained irqs.
>
> As the .to_irq() callback on the gpiochip was doing some function
> indexing this was moved over to the .irq_startup callback on the
> irqchip (where it belongs, since it is perfectly legal to request
> an irq from an irqchip without calling gpio_to_irq() first).
>
> The gpio_chip was converted into a true member of the pinctrl
> struct instead of being a pointer to a separately allocated
> object, avoiding an unnecessary allocation and making it possible
> to use container_of() to get from the struct gpio_chip * back to
> the sunxi pinctrl state container.
>
> Signed-off-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
> ---
> Maxime, can you test this thing? And if it doesn't work, can you
> figure out what it is that I want you to do and do it ;-)
> This is done on top of your recently pulled sunxi series.
I've been quite late at testing this, I'm sorry, but I finally gave it
a try.
Besides the minor glitches here and there that were expected, I think
that it can't really work now given the state of gpiolib_irqchip.
The way this controller works depends on two cases:
- On the older (the one on which we support interrupts) SoC:
+ we have 8 pin banks, almost all of them being at least able to
be muxed to gpio in and out functions.
+ 32 of these 256 pins are actually muxable to another function
that is the one to generate interrupts
+ The interrupt controller is a single 32 bits register, each bit
being about one of these 32 pins, that are pretty much spread
across the banks.
+ There's a single parent interrupt.
- On the newer code (that is not supported yet) would be a bit
easier to support, since the interrupt sources are grouped by
banks. That means that we still have our 8 banks, but this time, 4
banks are interrupt controllers. These banks support as much
interrupts as there is pins in the banks, with a 1:1 mapping
between the pin number and the interrupt number.
This is not something that looks to be well supported at the moment in
gpiolib_irqchip wrapper, especially since it seems to be making the
assumption that there's as much gpio than there is interrupts.
But I guess some of these changes are still useful, especially the
ones on the callbacks.
Thanks,
Maxime
--
Maxime Ripard, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
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