Messages in this thread | | | Date | Tue, 2 Jun 2015 15:33:41 +0200 | Subject | Re: [PATCH v2 2/6] gpio: brcmstb: Add interrupt support | From | Linus Walleij <> |
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On Fri, May 29, 2015 at 4:14 AM, Gregory Fong <gregory.0xf0@gmail.com> wrote:
> Create an irq_chip for each GIO block. Uses chained IRQ handling since > known uses of this block have a BCM7120 L2 interrupt controller as a > parent. Supports interrupts for all GPIOs. > > In the IRQ handler, we check for raised IRQs for invalid GPIOs and warn > (ratelimited) if they're encountered. > > Signed-off-by: Gregory Fong <gregory.0xf0@gmail.com> > --- > v2: > - since imask member of bank struct was removed, just read and write from mask > reg and don't maintain a shadow > - warn on invalid IRQs > - move some irq setup to a separate function since probe is getting unwieldy
This patch basically painfully reimplements GPIOLIB_IRQCHIP.
Is there a reason for not using that generic mechanism?
> +static int brcmstb_gpio_to_irq(struct gpio_chip *gc, unsigned gc_offset) > +{ > + struct brcmstb_gpio_priv *priv = brcmstb_gpio_gc_to_priv(gc); > + /* gc_offset is relative to this gpio_chip; want real offset */ > + int offset = gc_offset + (gc->base - priv->gpio_base); > + > + if (offset >= priv->num_gpios) > + return -ENXIO; > + return irq_create_mapping(priv->irq_domain, offset);
It is a no-no to rely on .to_irq() to be called before using an IRQ from a GPIO chip.
The gpiochip and irq_chip APIs are orthogonal, and a user may request an interrupt from the irqchip without calling .to_irq() on any GPIO line first.
This should only use irq_find_mapping().
irq_create_mapping() needs to be called on all available offsets during probe.
If the module is removable or at error path it also needs to call irq_dispose_mapping() on all lines. Also this is handled by GPIOLIB_IRQCHIP, and that is why it should always be used, if possible.
Yours, Linus Walleij
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