[PATCH v7 0/5] Introduce the Counter character device interface

[David Lechner]

On 12/25/20 6:15 PM, William Breathitt Gray wrote:
> Changes in v7:
>   - Implemented u32 enums; enum types can now be used directly for
>     callbacks and values
>   - Fixed refcount underflow bug
>   - Refactored all err check to check for err < 0; this should help
>     prevent future oversights on valid positive return valids
>   - Use mutex instead of raw_spin_lock in counter_chrdev_read();
>     kifo_to_user() can now safely sleep
>   - Renamed COUNTER_COMPONENT_DUMMY to COUNTER_COMPONENT_NONE to make
>     purpose more obvious
>   - Introduced a watch_validate() callback
>   - Consolidated the functionality to clear the watches to the
>     counter_clear_watches() function
>   - Reimplemented counter_push_event() as a void function; on error,
>     errno is returned via struct counter_event so that it can be handled
>     by userspace (because interrupt handlers can't do much for this)
>   - Renamed the events_config() callback to events_configure();
>     "events_config" could be confused as a read callback when this is
>     actually intended to configure the device for the requested events
>   - Reimplemented 104-QUAD-8 driver to use events_configure() and
>     watch_validate() callbacks; irq_trigger_enable sysfs attribute
>     removed because events_configure() now serves this purpose
> 
> The changes for this revision were much simpler compared to the previous
> revisions. I don't have any further questions for this patchset, so it's
> really just a search for possible bugs or regressions now. Please test
> and verify this patchset on your systems, and ACK appropriately.
> 

I'll wait for the next round to give my Reviewed-By, Tested-By but I've
rebased my WIP TI eQEP changes[1] on this and I haven't ran into any
problems yet.

[1]: https://github.com/dlech/linux/commits/bone-counter