Merge tag 'irq-cleanups-2025-05-25' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull irq cleanups from Thomas Gleixner:
 "A set of cleanups for the generic interrupt subsystem:

   - Consolidate on one set of functions for the interrupt domain code
     to get rid of pointlessly duplicated code with only marginal
     different semantics.

   - Update the documentation accordingly and consolidate the coding
     style of the irqdomain header"

* tag 'irq-cleanups-2025-05-25' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (46 commits)
  irqdomain: Consolidate coding style
  irqdomain: Fix kernel-doc and add it to Documentation
  Documentation: irqdomain: Update it
  Documentation: irq-domain.rst: Simple improvements
  Documentation: irq/concepts: Minor improvements
  Documentation: irq/concepts: Add commas and reflow
  irqdomain: Improve kernel-docs of functions
  irqdomain: Make struct irq_domain_info variables const
  irqdomain: Use irq_domain_instantiate()'s return value as initializers
  irqdomain: Drop irq_linear_revmap()
  pinctrl: keembay: Switch to irq_find_mapping()
  irqchip/armada-370-xp: Switch to irq_find_mapping()
  gpu: ipu-v3: Switch to irq_find_mapping()
  gpio: idt3243x: Switch to irq_find_mapping()
  sh: Switch to irq_find_mapping()
  powerpc: Switch to irq_find_mapping()
  irqdomain: Drop irq_domain_add_*() functions
  powerpc: Switch irq_domain_add_nomap() to use fwnode
  thermal: Switch to irq_domain_create_linear()
  soc: Switch to irq_domain_create_*()
  ...

1 files changed, 14 insertions, 13 deletions

diff --git a/Documentation/core-api/irq/concepts.rst b/Documentation/core-api/irq/concepts.rst
index 4273806a606b..7c4564f3cbdf 100644
--- a/Documentation/core-api/irq/concepts.rst
+++ b/Documentation/core-api/irq/concepts.rst
@@ -2,23 +2,24 @@
 What is an IRQ?
 ===============
 
-An IRQ is an interrupt request from a device.
-Currently they can come in over a pin, or over a packet.
-Several devices may be connected to the same pin thus
-sharing an IRQ.
+An IRQ is an interrupt request from a device. Currently, they can come
+in over a pin, or over a packet. Several devices may be connected to
+the same pin thus sharing an IRQ. Such as on legacy PCI bus: All devices
+typically share 4 lanes/pins. Note that each device can request an
+interrupt on each of the lanes.
 
 An IRQ number is a kernel identifier used to talk about a hardware
-interrupt source.  Typically this is an index into the global irq_desc
-array, but except for what linux/interrupt.h implements the details
-are architecture specific.
+interrupt source. Typically, this is an index into the global irq_desc
+array or sparse_irqs tree. But except for what linux/interrupt.h
+implements, the details are architecture specific.
 
 An IRQ number is an enumeration of the possible interrupt sources on a
-machine.  Typically what is enumerated is the number of input pins on
-all of the interrupt controller in the system.  In the case of ISA
-what is enumerated are the 16 input pins on the two i8259 interrupt
-controllers.
+machine. Typically, what is enumerated is the number of input pins on
+all of the interrupt controllers in the system. In the case of ISA,
+what is enumerated are the 8 input pins on each of the two i8259
+interrupt controllers.
 
 Architectures can assign additional meaning to the IRQ numbers, and
-are encouraged to in the case  where there is any manual configuration
-of the hardware involved.  The ISA IRQs are a classic example of
+are encouraged to in the case where there is any manual configuration
+of the hardware involved. The ISA IRQs are a classic example of
 assigning this kind of additional meaning.