Messages in this thread | | | Date | Wed, 19 May 2021 08:20:30 +0200 | From | Thomas Bogendoerfer <> | Subject | Re: [PATCH v5 1/2] gpio: Add support for IDT 79RC3243x GPIO controller |
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On Wed, May 19, 2021 at 01:50:39AM +0200, Linus Walleij wrote: > Hi Thomas, > > thanks for your patch! > > I can see this is starting to look really good. > > There is one thing that confuses me: > > On Fri, May 14, 2021 at 2:33 PM Thomas Bogendoerfer > <tsbogend@alpha.franken.de> wrote: > > > IDT 79RC3243x SoCs integrated a gpio controller, which handles up > > to 32 gpios. All gpios could be used as an interrupt source. > > > > Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de> > > --- > > Changes in v5: > (...) > > > +static int idt_gpio_irq_set_type(struct irq_data *d, unsigned int flow_type) > > +{ > (...) > > + /* hardware only supports level triggered */ > > + if (sense == IRQ_TYPE_NONE || (sense & IRQ_TYPE_EDGE_BOTH)) > > + return -EINVAL; > (...) > > + irq_set_handler_locked(d, handle_level_irq); > > But: > > > +static void idt_gpio_ack(struct irq_data *d) > > +{ > > + struct gpio_chip *gc = irq_data_get_irq_chip_data(d); > > + struct idt_gpio_ctrl *ctrl = gpiochip_get_data(gc); > > + > > + writel(~BIT(d->hwirq), ctrl->gpio + IDT_GPIO_ISTAT); > > +} > (...) > > + .irq_ack = idt_gpio_ack, > > Correct me if I'm wrong but I thing .irq_ack() is only called > from handle_edge_irq ... so never in this case.
handle_level_irq() does a mask_ack_irq() and this uses mask_irq() and desc->irq_data.chip->irq_ack(), if there is no irq_mask_ack function.
> Can this ACK just be deleted?
no without it interrupts won't go away.
> The code in the ACK callback also looks really weird: > write all bits except for the current IRQ into the status > register? It's usually the other way around with these > things. That really makes me suspect it is unused.
interrupts are acked by writing a 0 to the bit position. I know it's unusal...
Thomas.
-- Crap can work. Given enough thrust pigs will fly, but it's not necessarily a good idea. [ RFC1925, 2.3 ]
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