Re: OMAP: DSS2: Common IRQ handler for all OMAPs

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Hi,

On Tuesday 15 February 2011 02:07 PM, Valkeinen, Tomi wrote:
On Tue, 2011-02-15 at 02:30 -0600, Taneja, Archit wrote:
Hi,

On Tuesday 15 February 2011 12:57 PM, Valkeinen, Tomi wrote:

<snip>

I meant something like this:

dispc.c:

dispc_init()
{
	/* did we have a pdev for dispc? if not, this needs to be dss.pdev */
	request_irq(platform_get_irq(dispc.pdev, 0), irq_handler, IRQF_SHARED, "dispc irq", foo);
}

irq_handler()
{
	if (irq_can_be_shared) {
		check if the irq is for us. exit if not;
	}

	handle;
}

dsi.c:

dsi_init()
{
	request_irq(platform_get_irq(dsi.pdev, 0), irq_handler, IRQF_SHARED, "dsi irq", foo);
}

irq_handler()
{
	if (irq_can_be_shared) {
		check if the irq is for us. exit if not;
	}

	handle;
}


This approach looks clean, but isn't IRQF_SHARED used the other way
around. One irq line and multiple handlers?

That is the case here, isn't it (on omap3)? One interrupt line (the DSS
irq, the same returned both from dsi.pdev and dispc.pdev), and two
handlers, one in dispc and one in dsi? Or what do you mean?

Okay, so for OMAP3 we should populate dsi.pdev and dispc.pdev in such a way that they return the single irq line number for DSS. And for OMAP4,
the separate line numbers will go for the modules anyway.

How do differentiate with the common handler now? It will be dirty if we have checks on the irq_line. Could we pass the pdev as the arg to differentiate the source?


On omap2 there's no dsi code ran, so dispc is the only one requesting
the irq, and thus IRQF_SHARED is extra. In omap4 there are separate irq
lines (dsi.pdev and dispc.pdev return different irqs), and so
IRQF_SHARED is again extra. But I don't see any harm in IRQF_SHARED even
in omap2/4.

  Tomi



Regards,
Archit
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