[PATCH 0/3] Add Intel 8254 Counter support

[William Breathitt Gray <william.gray@linaro.org>]

The Intel 8254 PIT first appeared in the early 1980s and was used
initially in IBM PC compatibles. The popularity of the original Intel
825x family of chips led to many subsequent variants and clones of the
interface in various chips and integrated circuits. Although still
popular, interfaces compatible with the Intel 8254 PIT are nowdays
typically found embedded in larger VLSI processing chips and FPGA
components rather than as discrete ICs.

This patch series introduces a library to provide support for interfaces
compatible with the venerable Intel 8254 Programmable Interval Timer
(PIT). Modules wanting access to the i8254 library should select the
newly introduced CONFIG_I8254 Kconfig option, and import the I8254
symbol namespace.

Support for the i8254 is added in respective follow-up patches for the
104-dio-48e driver and stx104 driver whose devices feature i8254
compatible interfaces. Several additional dependencies are necessary for
the 104-dio-48e [0][1][2] and stx104 [3][4].

Due to the dependency requirements, I can take the i8254 introduction
patch through the Counter tree and provide an immutable branch that can
be merged to the GPIO and IIO trees; the 104-dio-48e patch and stx104
patch could then be picked up separately by the respective subsystem
maintainers.

[0] https://lore.kernel.org/all/05a878d340251b781387db4b6490f288e41a651c.1680543810.git.william.gray@linaro.org/
[1] https://lore.kernel.org/all/20230208105542.9459-1-william.gray@linaro.org/
[2] https://lore.kernel.org/all/cover.1679323449.git.william.gray@linaro.org/
[3] https://lore.kernel.org/all/20230318185503.341914-1-william.gray@linaro.org/
[4] https://lore.kernel.org/all/cover.1680790580.git.william.gray@linaro.org/

William Breathitt Gray (3):
  counter: i8254: Introduce the Intel 8254 interface library module
  gpio: 104-dio-48e: Add Counter/Timer support
  iio: addac: stx104: Add 8254 Counter/Timer support

 Documentation/ABI/testing/sysfs-bus-counter |  54 +++
 MAINTAINERS                                 |   7 +
 drivers/counter/Kconfig                     |  15 +
 drivers/counter/Makefile                    |   1 +
 drivers/counter/counter-sysfs.c             |   8 +-
 drivers/counter/i8254.c                     | 447 ++++++++++++++++++++
 drivers/gpio/Kconfig                        |   1 +
 drivers/gpio/gpio-104-dio-48e.c             | 127 +++++-
 drivers/iio/addac/Kconfig                   |   1 +
 drivers/iio/addac/stx104.c                  |  61 ++-
 include/linux/i8254.h                       |  21 +
 include/uapi/linux/counter.h                |   6 +
 12 files changed, 730 insertions(+), 19 deletions(-)
 create mode 100644 drivers/counter/i8254.c
 create mode 100644 include/linux/i8254.h


base-commit: 09a9639e56c01c7a00d6c0ca63f4c7c41abe075d
prerequisite-patch-id: 934c63dd47cb47e19739af076b95d3d55f5604f1
prerequisite-patch-id: 02aafdd535091da6a4ed6abbb20fb661f74af9fb
prerequisite-patch-id: cd19046150b7cff1be4ac7152198777aa960a3df
prerequisite-patch-id: bd3e3830d9ce4f3876a77483364d7190b7fdffa7
prerequisite-patch-id: 1e091c1f8f945a56cac59070221c4284306ba087
prerequisite-patch-id: c6f681fcbf7495c5ed6a596872dc4f762f22d977
prerequisite-patch-id: 239b016817624d56a4a2bddea1fda95282cb3d81
prerequisite-patch-id: 5fbfe7df44dcf5a629cd82ba8383480cb05b52d1
prerequisite-patch-id: 25a89f7312f225aaca11ef192e8d1f903a8b20e8
prerequisite-patch-id: 899b556161f417e20db8e957c5099b92c3dcb673
prerequisite-patch-id: eb09641cfb9e7caf7641ae6cb8e84e33cbb665a6
-- 
2.39.2