devicetree: add APIs to get interrupt priority

We have `DT_IRQN` to get a node's (only) interrupt number
(at index 0), and `DT_IRQN_BY_IDX` to get a node's interrupt
number at a given index. It probably makes sense to have a
priority equivalent of that, so add:
- `DT_IRQP`, and
- `DT_IRQP_BY_IDX`

Signed-off-by: Yong Cong Sin <[email protected]>

include/zephyr/devicetree.h

@@ -2409,6 +2409,29 @@
  */
 #define DT_IRQ(node_id, cell) DT_IRQ_BY_IDX(node_id, 0, cell)
 
+/**
+ * @brief Get a node's (only) irq priority
+ *
+ * Equivalent to DT_IRQ(node_id, priority). This is provided as a convenience
+ * for the common case where a node generates exactly one interrupt,
+ * and the IRQ priority is in a cell named `priority`.
+ *
+ * @param node_id node identifier
+ * @return the interrupt priority for the node's only interrupt
+ */
+#define DT_IRQP(node_id) DT_IRQ(node_id, priority)
+
+/**
+ * @brief Get a node's irq priority at index
+ *
+ * Equivalent to DT_IRQ_BY_IDX(node_id, idx, priority).
+ *
+ * @param node_id node identifier
+ * @param idx node identifier
+ * @return the interrupt priority for the node's interrupt by the index
+ */
+#define DT_IRQP_BY_IDX(node_id, idx) DT_IRQ_BY_IDX(node_id, idx, priority)
+
 /* DT helper macro to get interrupt-parent node  */
 #define Z_DT_PARENT_INTC(node_id) DT_PROP(node_id, interrupt_parent)
 /* DT helper macro to get the node's interrupt grandparent node  */
@@ -3891,6 +3914,13 @@
  */
 #define DT_INST_IRQN(inst) DT_IRQN(DT_DRV_INST(inst))
 
+/**
+ * @brief Get a `DT_DRV_COMPAT`'s (only) irq priority
+ * @param inst instance number
+ * @return the interrupt priority for the node's only interrupt
+ */
+#define DT_INST_IRQP(inst) DT_IRQP(DT_DRV_INST(inst))
+
 /**
  * @brief Get a `DT_DRV_COMPAT`'s bus node identifier
  * @param inst instance number