Re: [PATCH v12 00/17] Introduce the Counter character device interface

[William Breathitt Gray]

On Sun, Jul 11, 2021 at 02:48:28PM +0100, Jonathan Cameron wrote:
> On Mon,  5 Jul 2021 17:18:48 +0900
> William Breathitt Gray <vilhelm.gray@xxxxxxxxx> wrote:
> 
> > Changes in v12:
> >  - Move unlock to after register set in quad8_count_ceiling_write()
> >  - Add locking protection to counter_set_event_node()
> >  - Fix sparse warning by using {} instead of {0}
> >  - Clean up and organize comments for clarity
> >  - Reduce boilerplate by utilizing devm_add_action_or_reset()
> >  - Use switch statements in ti_eqep_action_read() to make possible cases
> >    more obvious
> > 
> > I pulled out a lot of bits and pieces to their own patches; hopefully
> > that makes reviewing this patchset much simpler than before. This
> > patchset is also available on my personal git repo for convenience:
> > https://gitlab.com/vilhelmgray/iio/-/tree/counter_chrdev_v12
> > 
> > The patches preceding "counter: Internalize sysfs interface code" are
> > primarily cleanup and fixes that can be picked up and applied now to the
> > IIO tree if so desired. The "counter: Internalize sysfs interface code"
> > patch as well may be considered for pickup because it is relatively safe
> > and makes no changes to the userspace interface.
> > 
> > To summarize the main points of this patchset: there are no changes to
> > the existing Counter sysfs userspace interface; a Counter character
> > device interface is introduced that allows Counter events and associated
> > data to be read() by userspace; the events_configure() and
> > watch_validate() driver callbacks are introduced to support Counter
> > events; and IRQ support is added to the 104-QUAD-8 driver, serving as an
> > example of how to support the new Counter events functionality.
> > 
> > Something that should still be discussed: should the struct
> > counter_event "status" member be 8 bits or 32 bits wide? This member
> > will provide the return status (system error number) of an event
> > operation.
> 
> Hi william,
> 
> I've looked through the lot and where I haven't commented, I had nothing
> much to add to David's comments.
> 
> I'm not planning to go through the whole thing again unless major changes
> occur. Fingers crossed for v13.
> 
> If it looks like there are still some unresolved issues after that, perhaps
> applying up to patch 8 or so makes sense to reduced the volume of code you
> are carrying.  Let me know if you'd like me to do that.
> 
> Thanks,
> 
> Jonathan

Yes, much of the code has remained stable for some months now so I think
we're pretty close. If we do need a v14, then applying up to patch 8
would help me a lot (most of the merge conflicts I encounter when I
rebase are due to the large subsystem refactor in patch 06).

William Breathitt Gray

> > 
> > William Breathitt Gray (17):
> >   counter: 104-quad-8: Return error when invalid mode during
> >     ceiling_write
> >   counter: Return error code on invalid modes
> >   counter: Standardize to ERANGE for limit exceeded errors
> >   counter: Rename counter_signal_value to counter_signal_level
> >   counter: Rename counter_count_function to counter_function
> >   counter: Internalize sysfs interface code
> >   counter: Update counter.h comments to reflect sysfs internalization
> >   docs: counter: Update to reflect sysfs internalization
> >   counter: Move counter enums to uapi header
> >   counter: Add character device interface
> >   docs: counter: Document character device interface
> >   tools/counter: Create Counter tools
> >   counter: Implement signalZ_action_component_id sysfs attribute
> >   counter: Implement *_component_id sysfs attributes
> >   counter: Implement events_queue_size sysfs attribute
> >   counter: 104-quad-8: Replace mutex with spinlock
> >   counter: 104-quad-8: Add IRQ support for the ACCES 104-QUAD-8
> > 
> >  Documentation/ABI/testing/sysfs-bus-counter   |   38 +-
> >  Documentation/driver-api/generic-counter.rst  |  366 +++-
> >  .../userspace-api/ioctl/ioctl-number.rst      |    1 +
> >  MAINTAINERS                                   |    3 +-
> >  drivers/counter/104-quad-8.c                  |  728 ++++----
> >  drivers/counter/Kconfig                       |    6 +-
> >  drivers/counter/Makefile                      |    1 +
> >  drivers/counter/counter-chrdev.c              |  498 ++++++
> >  drivers/counter/counter-chrdev.h              |   14 +
> >  drivers/counter/counter-core.c                |  182 ++
> >  drivers/counter/counter-sysfs.c               |  953 +++++++++++
> >  drivers/counter/counter-sysfs.h               |   13 +
> >  drivers/counter/counter.c                     | 1496 -----------------
> >  drivers/counter/ftm-quaddec.c                 |   59 +-
> >  drivers/counter/intel-qep.c                   |  150 +-
> >  drivers/counter/interrupt-cnt.c               |   73 +-
> >  drivers/counter/microchip-tcb-capture.c       |  103 +-
> >  drivers/counter/stm32-lptimer-cnt.c           |  176 +-
> >  drivers/counter/stm32-timer-cnt.c             |  147 +-
> >  drivers/counter/ti-eqep.c                     |  205 ++-
> >  include/linux/counter.h                       |  716 ++++----
> >  include/linux/counter_enum.h                  |   45 -
> >  include/uapi/linux/counter.h                  |  133 ++
> >  tools/Makefile                                |   13 +-
> >  tools/counter/Build                           |    1 +
> >  tools/counter/Makefile                        |   53 +
> >  tools/counter/counter_example.c               |   95 ++
> >  27 files changed, 3501 insertions(+), 2767 deletions(-)
> >  create mode 100644 drivers/counter/counter-chrdev.c
> >  create mode 100644 drivers/counter/counter-chrdev.h
> >  create mode 100644 drivers/counter/counter-core.c
> >  create mode 100644 drivers/counter/counter-sysfs.c
> >  create mode 100644 drivers/counter/counter-sysfs.h
> >  delete mode 100644 drivers/counter/counter.c
> >  delete mode 100644 include/linux/counter_enum.h
> >  create mode 100644 include/uapi/linux/counter.h
> >  create mode 100644 tools/counter/Build
> >  create mode 100644 tools/counter/Makefile
> >  create mode 100644 tools/counter/counter_example.c
> > 
> > 
> > base-commit: 6cbb3aa0f9d5d23221df787cf36f74d3866fdb78
>

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