IRQ3 seems to work now for SH7709

[Kristoffer Ericson <kristoffer.ericson@gmail.com>]

Greetings,

IRQ0->IRQ5 needs to be silenced by first setting priority 0 and then mask out the affected bit in IRR0. This was done previously in 2.6.17 in the ipr handler. This is also according to SH7709 manual.

This can be found inside 2.6.17 with linuxsh patches applied :

static void mask_and_ack_ipr(unsigned int irq)

  89 {
  90         disable_ipr_irq(irq);
  91 
  92 #if defined(CONFIG_CPU_SUBTYPE_SH7707) || defined(CONFIG_CPU_SUBTYPE_SH7709) || \
  93     defined(CONFIG_CPU_SUBTYPE_SH7300) || defined(CONFIG_CPU_SUBTYPE_SH7705)
  94         /* This is needed when we use edge triggered setting */
  95         /* XXX: Is it really needed? */
  96         if (IRQ0_IRQ <= irq && irq <= IRQ5_IRQ) {
  97                 /* Clear external interrupt request */
  98                 int a = ctrl_inb(INTC_IRR0);
  99                 a &= ~(1 << (irq - IRQ0_IRQ));
 100                 ctrl_outb(a, INTC_IRR0);
 101         }
 102 #endif
 103 }

(you can access entire file at http://www.jlime.org/gitweb?p=jlime-stable.git;a=blob;f=arch/sh/kernel/cpu/irq/ipr.c;hå5150ed085619d5962e039e1ebb2a4fdc2e9b15;hb?3554525f5c300a6e41d0aae01673c45e9098c3)

I added minor code to intc_disable() just to test it

#ifdef CONFIG_CPU_SUBTYPE_SH7709
	if (irq = 35) {                <--- my touchscreen IRQ
		int a = inb(IRR0);
		a &= ~(1 << 3);
		outb(a, IRR0);
	}
#endif

And the result was that the interrupt no longer keeps feeding data instead only when touchscreen is actually touched, so seems valid.

Best wishes
Kristoffer