[PATCH 2/4] genirq: Document interaction between <linux/irq.h> and DT binding defs

[Geert Uytterhoeven]

Document that the DT binding definitions in
<dt-bindings/interrupt-controller/irq.h> shadow the first six IRQ_TYPE_*
definitions in <linux/irq.h>.  The values must be the same anyway, so
this is harmless (as long as the latter is included first when both are
included), but it is good to document this explicitly.

Signed-off-by: Geert Uytterhoeven <geert+renesas at glider.be>
---
 include/linux/irq.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/include/linux/irq.h b/include/linux/irq.h
index 951acbdb9f8457de..efa514ee562fcf91 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -35,6 +35,10 @@ enum irqchip_irq_state;
  *
  * Bits 0-7 are the same as the IRQF_* bits in linux/interrupt.h
  *
+ * Note that the first 6 definitions are shadowed by C preprocessor definitions
+ * in include/dt-bindings/interrupt-controller/irq.h.  This is not an issue, as
+ * the actual values must be the same, due to being part of the stable DT ABI.
+ *
  * IRQ_TYPE_NONE		- default, unspecified type
  * IRQ_TYPE_EDGE_RISING		- rising edge triggered
  * IRQ_TYPE_EDGE_FALLING	- falling edge triggered
-- 
2.43.0