[ARM] ecard: add helper function for setting ecard irq ops

Rather than having every driver fiddle about setting its private
IRQ operations and data, provide a helper function to contain
this functionality in one place.

Arrange to remove the driver-private IRQ operations and data when
the device is removed from the driver, and remove the driver
private code to do this.

This fixes potential problems caused by drivers forgetting to
remove these hooks.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/kernel/ecard.c b/arch/arm/kernel/ecard.c
index bdbd7da..65f1398 100644
--- a/arch/arm/kernel/ecard.c
+++ b/arch/arm/kernel/ecard.c
@@ -958,6 +958,14 @@
 }
 EXPORT_SYMBOL(ecard_release_resources);
 
+void ecard_setirq(struct expansion_card *ec, const struct expansion_card_ops *ops, void *irq_data)
+{
+	ec->irq_data = irq_data;
+	barrier();
+	ec->ops = ops;
+}
+EXPORT_SYMBOL(ecard_setirq);
+
 /*
  * Probe for an expansion card.
  *
@@ -1133,6 +1141,14 @@
 	drv->remove(ec);
 	ecard_release(ec);
 
+	/*
+	 * Restore the default operations.  We ensure that the
+	 * ops are set before we change the data.
+	 */
+	ec->ops = &ecard_default_ops;
+	barrier();
+	ec->irq_data = NULL;
+
 	return 0;
 }