From mboxrd@z Thu Jan  1 00:00:00 1970
From: Felipe Balbi <balbi@ti.com>
Subject: Re: OMAP: DSS2: Common IRQ handler for all OMAPs
Date: Tue, 15 Feb 2011 10:05:55 +0200
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To: archit taneja <archit@ti.com>
Cc: "Balbi, Felipe" <balbi@ti.com>, "Valkeinen, Tomi" <tomi.valkeinen@ti.com>, "linux-omap@vger.kernel.org" <linux-omap@vger.kernel.org>

Hi,

On Tue, Feb 15, 2011 at 09:58:24AM +0530, archit taneja wrote:
> >does it make sense to install an irq_chip for that ? I mean, can you
> >mask/unmask dss and or dsi IRQs ? If you can, then it might make sense
> >to take a look into GENIRQ and install an irq_chip for that. Then both
> >dsi and dss would be able to use standard request_irq() API.
> >
> 
> We could disable dsi IRQs by masking all the possible interrupt
> events in DSI_IRQSTATUS. The same goes for dispc. Is this what you
> meant by masking/unmasking irqs?

yes it is. Then it makes sense to have an irq_chip for those two irqs, I
think.

/proc/interrupt will reflect how the hardware works (DSI and DISPC IRQs
being handled by DSS), both dsi and dispc can use normal request_irq()
without setting IRQF_SHARED, etc etc. All you need to do is:

static struct irq_chip dss_irq_chip = {
	.name			= "DSS",
	.irq_bus_lock		= dss_bus_lock,
	.irq_bus_sync_unlock	= dss_bus_sync_unlock,
	.irq_mask		= dss_irq_mask,
	.irq_unmask		= dss_irq_unmask,
	.irq_ack		= dss_irq_ack,
};

then, somewhere during probe() you have to:

for (irq = irq_base; irq < irq_end; irq++) {
#ifdef CONFIG_ARM
	set_irq_flags(irq, IRQF_VALID)
#else
	set_irq_noprobe(irq);
#endif

	set_irq_data(irq, dss_device_structure_pointer);
	set_irq_chip_and_handler(irq, &dss_irq_chip,
		handle_simple_irq);
}

and on exit() you just need to cleanup:

for (irq = irq_base; irq < irq_end; irq++) {
#ifdef CONFIG_ARM
	set_irq_flags(irq, 0)
#endif

	set_irq_chip_and_handler(irq, NULL, NULL);
	set_irq_data(irq, NULL);
}

-- 
balbi