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    SubjectRe: [v7,03/10] docs: Add Generic Counter interface documentation
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    On 06/21/2018 04:07 PM, William Breathitt Gray wrote:
    > +Userspace Interface
    > +===================
    > +
    > +Several sysfs attributes are generated by the Generic Counter interface,
    > +and reside under the /sys/bus/counter/devices/counterX directory, where
    > +counterX refers to the respective counter device. Please see
    > +Documentation/ABI/testing/sys-bus-counter-generic-sysfs for detailed
    > +information on each Generic Counter interface sysfs attribute.
    > +
    > +Through these sysfs attributes, programs and scripts may interact with
    > +the Generic Counter paradigm Counts, Signals, and Synapses of respective
    > +counter devices.
    > +

    Have you considered a character device in addition to the sysfs interface?

    I basically have many of the same concerns that resulted in a char dev for
    gpio[1].

    - With sysfs, you *can* technically poll for events, but then you have to
    seek and read or re-open the file.
    - File permissions are annoying if you want a non root user to be able to
    use the device.
    - A single program can't claim exclusive access to a device.
    - There is no automatic cleanup if a userspace program accessing the device
    crashes.

    [1]: https://www.elinux.org/images/7/74/Elce2017_new_GPIO_interface.pdf

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