Subject: ARCH=powerpc: IRQ numbers change mysteriously

From: Fredrik Roubert <[email-masked]>
Date: Mon, 23 Oct 2006 18:41:16 +0200

Hi!

On my MPC8439 based board, running Linux 2.6.18 with ARCH=powerpc, the
IRQ's for the I2C behave in a for me mysterious way.

In my DTS file, I have the following:

i2c@3000 {
	device_type = "i2c";
	compatible = "fsl-i2c";
	reg = <3000 100>;
	interrupts = <e 8>;
	interrupt-parent = <&/soc8349@ff400000/pic@700>;
	dfsrr;
};

i2c@3100 {
	device_type = "i2c";
	compatible = "fsl-i2c";
	reg = <3000 100>;
	interrupts = <f 8>;
	interrupt-parent = <&/soc8349@ff400000/pic@700>;
	dfsrr;
};

But when I boot the system and cat /proc/interrupts, the output says:

18:         61   IPIC   Level     i2c-mpc
19:          0   IPIC   Level     i2c-mpc

This doesn't make sense to me. Why are the IRQ numbers changed? They are
still adjacent, so it seems to be some logic to the change. Does anyone
know what this is?

Cheers // Fredrik Roubert

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