Re: [PATCH] mfd: cottula: add cottula board

From: Arnd Bergmann
Date: Sat Dec 20 2014 - 15:12:13 EST


On Saturday 20 December 2014 10:43:48 Robert Jarzmik wrote:
> Robert Jarzmik <robert.jarzmik@xxxxxxx> writes:
> > Arnd Bergmann <arnd@xxxxxxxx> writes:
> >> This looks a bit ambiguous: You get a GPIO line for the purpose of the
> >> IRQ nesting but don't use the GPIO otherwise, and you pass the device's
> >> own irq domain start as an IORESOURCE_IRQ resource.
> >>
> >> For consistency between DT and ATAGS based uses, and with similar DT
> >> based drivers, I would instead recommend passing the parent irq (from
> >> the GPIO) as an IORESOURCE_IRQ resource instead of a gpio lookup,
> >> and passing the base_irq as platform_data for the ATAGS case.
>
> Hi Arnd,
>
> I thought again about the GPIO.
>
> I put in the "gpiod_get()" call to ensure proper ordering between the gpio
> probing and this driver probing. It ensured that this driver's probe will be
> defered until the gpio driver is probed, which is the main purpose of this
> patch (commit message).
>
> If I pass an irq from the machine code, I loose this guarantee, don't I ?

Not sure, my guess is that it could still work the same way because
the irq is not registered yet and request_irq or similar will fail.

Arnd
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