Re: [PATCH v3 1/2] irqchip: Add driver for Loongson-1 interrupt controller

On Fri, 25 Jan 2019 10:56:33 +0000,
Jiaxun Yang [off-list ref] wrote:

Hi Marc

Thanks for your suggestions, I'm working on v4 and I would like to
ask if it is better to have a driver for only one irqchip and create
dt nodes for each chip, or just register all the chips in a single
driver with only one dt node.

It would make more sense to have a node per chip, meaning that you
end-up with one instance per chip as well. It won't make the driver
much more complicated.

[...]

quoted

quoted

+	domain = irq_domain_add_legacy(node, num_chips * 32, LS1X_IRQ_BASE, 0,
+		&irq_domain_simple_ops, NULL);

Why a legacy domain? This is usually reserved to old drivers that are
converted to a new infrastructure, while needing some form of platform
hacks. I don't see this being the case here.

It is also worrying that although you have up to 5 irqchips, they all
share a single domain. What does this mean? each irqchip is expected
to have its own domain.

Yes, I do like this for backward compatible reason. I'm turning
a legacy platform device mach(arch/mips/loongson32) in to
dt based generic mach and I would like to do it step by step rather
than one time.

So I use legacy domain in order to keep IRQ same with the
old driver exist on arch/mips/loongson32/common/irq.c

OK, it would have been good to make a note of that in the cover
letter, which is a bit empty at the moment.

Thanks,

	M.

-- 
Jazz is not dead, it just smell funny.