irq/irq_sim: improve the API

From: Bartosz Golaszewski <[email protected]>

The interrupt simulator API exposes a lot of custom data structures and functions and doesn't reuse the interfaces already exposed by the irq subsystem. This series tries to address it.

First, we make irq_domain_reset_irq_data() available to non-V2 domain API users - that'll be used in the subsequent patch. Next we overhaul the public interfaces - we hide all specific data structures and instead rely on the irq_domain struct and virtual interrupt numberspace.

The end effect is that we limit the interrupt simulator API to two functions (plus one device managed variant) and zero new structures.

v1: https://lkml.org/lkml/2019/8/12/558

v1 -> v2:
- instead of just making the new data structures opaque for users, remove them entirely in favor of irq_domain
- call irq_set_handler() & irq_domain_reset_irq_data() when unmapping the simulated interrupt
- fix a memory leak in error path
- make it possible to use irq_find_matching_fwnode() with the simulator domain
- correctly use irq_create_mapping() and irq_find_mapping(): only use the former at init-time and the latter at interrupt-time

v2 -> v3:
- drop the controverial changes to irq_domain code and only leave the changes to irq_sim and its users with the plan to revisit the former at a later time

v3 -> v4:
- add the Ack from Jonathan
- remove redundant parts of patch 1/2

v4 -> v5:
- add the review tags from Linus
- use the irq_set_irqchip_state interface and drop irq_sim_fire() entirely as suggested by Marc

Bartosz Golaszewski (2):
irq: make irq_domain_reset_irq_data() available even for non-V2 users irq/irq_sim: simplify the API

 drivers/gpio/gpio-mockup.c          |  53 ++++--
 drivers/iio/dummy/iio_dummy_evgen.c |  34 ++--
 include/linux/irq_sim.h             |  33 +---
 include/linux/irqdomain.h           |   2 +-
 kernel/irq/Kconfig                  |   1 +
 kernel/irq/irq_sim.c                | 267 +++++++++++++++++-----------
 kernel/irq/irqdomain.c              |  24 +--
 7 files changed, 250 insertions(+), 164 deletions(-)

2.25.0