ARM: OMAP4: PRM: use PRCM interrupt handler

Use the new PRCM interrupt handler code on OMAP4 systems.

The OMAP code will need to be converted to use sparse IRQs for this
to work.  Until that time, the following message will appear on boot:

PRCM: failed to allocate irq descs: -12
Signed-off-by: Tero Kristo <t-kristo@ti.com>
Tested-by: Kevin Hilman <khilman@ti.com>
Reviewed-by: Kevin Hilman <khilman@ti.com>
[paul@pwsan.com: split this from a previous patch to this patch; call
 omap4xxx_prcm_init() during init; write trivial commit log]
Signed-off-by: Paul Walmsley <paul@pwsan.com>

arch/arm/mach-omap2/prm44xx.c

@@ -27,6 +27,24 @@
 #include "prcm44xx.h"
 #include "prminst44xx.h"
 
+static const struct omap_prcm_irq omap4_prcm_irqs[] = {
+	OMAP_PRCM_IRQ("wkup",   0,      0),
+	OMAP_PRCM_IRQ("io",     9,      1),
+};
+
+static struct omap_prcm_irq_setup omap4_prcm_irq_setup = {
+	.ack			= OMAP4_PRM_IRQSTATUS_MPU_OFFSET,
+	.mask			= OMAP4_PRM_IRQENABLE_MPU_OFFSET,
+	.nr_regs		= 2,
+	.irqs			= omap4_prcm_irqs,
+	.nr_irqs		= ARRAY_SIZE(omap4_prcm_irqs),
+	.irq			= OMAP44XX_IRQ_PRCM,
+	.read_pending_irqs	= &omap44xx_prm_read_pending_irqs,
+	.ocp_barrier		= &omap44xx_prm_ocp_barrier,
+	.save_and_clear_irqen	= &omap44xx_prm_save_and_clear_irqen,
+	.restore_irqen		= &omap44xx_prm_restore_irqen,
+};
+
 /* PRM low-level functions */
 
 /* Read a register in a CM/PRM instance in the PRM module */
@@ -211,3 +229,11 @@ void omap44xx_prm_restore_irqen(u32 *saved_mask)
 	omap4_prm_write_inst_reg(saved_mask[1], OMAP4430_PRM_DEVICE_INST,
 				 OMAP4_PRM_IRQENABLE_MPU_2_OFFSET);
 }
+
+static int __init omap4xxx_prcm_init(void)
+{
+	if (cpu_is_omap44xx())
+		return omap_prcm_register_chain_handler(&omap4_prcm_irq_setup);
+	return 0;
+}
+subsys_initcall(omap4xxx_prcm_init);