[PATCH 1/3] ARM: at91: move at91 aic driver to drivers/irqchip

[Thomas Petazzoni]

Dear Russell King - ARM Linux,

On Thu, 23 May 2013 11:18:25 +0100, Russell King - ARM Linux wrote:

> I notice arch/arm/mach-at91/pm.c makes use of some of the register
> definitions:
> 
>         at91_irq_suspend();
> 
>         pr_debug("AT91: PM - wake mask %08x, pm state %d\n",
>                         /* remember all the always-wake irqs */
>                         (at91_pmc_read(AT91_PMC_PCSR)
>                                         | (1 << AT91_ID_FIQ)
>                                         | (1 << AT91_ID_SYS)
>                                         | (at91_extern_irq))
>                                 & at91_aic_read(AT91_AIC_IMR),
>                         state);
> 
> at91_irq_suspend() is in arch/arm/mach-at91/irq.c already, so there's no
> reason that fragment can't be moved there.

The problem is that the goal of the patch set is to move
arch/arm/mach-at91/irq.c into drivers/irqchip/.

However, if you move that chunk of code to drivers/irqchip/irq-at91.c,
you are using at91_pmc_read() which is defined in
arch/arm/mach-at91/include/mach/at91_pmc.h. So,
drivers/irqchip/irq-at91.c would have to include such an header file,
which is something we want to avoid since drivers/ code should not
include something in <mach/...>, as it breaks multiplatform kernels.

So, I'm afraid, simply moving this chunk of code in at91_irq_suspend()
doesn't make the thing any better.

Best regards,

Thomas
-- 
Thomas Petazzoni, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com