powerpc: Add i8042 keyboard and mouse irq parsing

Currently the irqs for the i8042, which historically provides keyboard and
mouse (aux) support, is hardwired in the driver rather than parsing the
dts. This patch modifies the powerpc legacy IO code to attempt to parse
the device tree for this information, failing back to the hardcoded values
if it fails.

Signed-off-by: Martyn Welch <[e-mail]>
Signed-off-by: Benjamin Herrenschmidt <[e-mail]>

arch/powerpc/kernel/setup-common.c

···
 	.orig_video_points = 16
 };
 
+/* Variables required to store legacy IO irq routing */
+int of_i8042_kbd_irq;
+int of_i8042_aux_irq;
+
 #ifdef __DO_IRQ_CANON
 /* XXX should go elsewhere eventually */
 int ppc_do_canonicalize_irqs;
···
 			np = of_find_compatible_node(NULL, NULL, "pnpPNP,f03");
 		if (np) {
 			parent = of_get_parent(np);
+
+			of_i8042_kbd_irq = irq_of_parse_and_map(parent, 0);
+			if (!of_i8042_kbd_irq)
+				of_i8042_kbd_irq = 1;
+
+			of_i8042_aux_irq = irq_of_parse_and_map(parent, 1);
+			if (!of_i8042_aux_irq)
+				of_i8042_aux_irq = 12;
+
 			of_node_put(np);
 			np = parent;
 			break;

drivers/input/serio/i8042-io.h

···
 #include <asm/irq.h>
 #elif defined(CONFIG_SH_CAYMAN)
 #include <asm/irq.h>
+#elif defined(CONFIG_PPC)
+extern int of_i8042_kbd_irq;
+extern int of_i8042_aux_irq;
+# define I8042_KBD_IRQ  of_i8042_kbd_irq
+# define I8042_AUX_IRQ  of_i8042_aux_irq
 #else
 # define I8042_KBD_IRQ	1
 # define I8042_AUX_IRQ	12