Re: [PATCH 2/3] gpio: lpc32xx: enable interrupt lookup for port 3
From: Linus Walleij
Date: Thu Apr 11 2019 - 09:55:45 EST
On Wed, Apr 10, 2019 at 12:39 PM Alexandre Belloni
> Interrupt support was disabled "temporarily" in commit 320a6480ef24 ("gpio:
> lpc32xx: disable broken to_irq support").
> Reenable to_irq for port 3 as they are directly connected to an interrupt
> controller and a simple lookup is working.
> Signed-off-by: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxx>
Unfortunately this seems to be one of these hacks for
hierarchical interrupts that does not quite cut it.
> +static int lpc32xx_gpio_to_irq_p3(struct gpio_chip *chip, unsigned int offset)
> + return of_irq_get_byname(chip->of_node, chip->names[offset]);
This works as long as consuming drivers pick a GPIO first
using gpiod_get() (and variants) and then convert it to an
IRQ using gpiod_to_irq().
But it doesn't work when some consumer is just picking an
IRQ off of the node without picking the GPIO first.
And in DT that is OK, this DT node is definately an interrupt
controller. (Leaving out the attribute for interrupt controller
as is currently the case doesn't really fix the issue, it is
Look at Brian Masney's series for the qualcomm pin controller
chips for inspiration on how to do things right, see:
Especially note how he removes the kind of hack you are
adding in e.g.