genirq: Document interaction between <linux/irq.h> and DT binding defines

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@glider.be>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Link: https://patch.msgid.link/fbcc65dcee6c5437fab5ef18d21766bb4effb7cb.1772644406.git.geert+renesas@glider.be

diff --git a/include/linux/irq.h b/include/linux/irq.h
index 951acbdb9f8457dec84ce813c83df1728e046c64..efa514ee562fcf9137f8b047db32e1807283b07b 100644 (file)
--- 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