Re: [PATCH v10 02/18] counter: Documentation: Add Generic Counter sysfs documentation

Pavel Machek
2019-04-08T21:55:38Z

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On Tue 2019-04-02 15:30:37, William Breathitt Gray wrote:
> This patch adds standard documentation for the userspace sysfs
> attributes of the Generic Counter interface.
>
> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
> ---
> Documentation/ABI/testing/sysfs-bus-counter | 230 ++++++++++++++++++++
> MAINTAINERS | 1 +
> 2 files changed, 231 insertions(+)
> create mode 100644 Documentation/ABI/testing/sysfs-bus-counter
>
> diff --git a/Documentation/ABI/testing/sysfs-bus-counter b/Documentation/ABI/testing/sysfs-bus-counter
> new file mode 100644
> index 000000000000..566bd99fe0a5
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-bus-counter
> @@ -0,0 +1,230 @@
> +What: /sys/bus/counter/devices/counterX/countY/count
> +KernelVersion: 5.2
> +Contact: linux-iio@vger.kernel.org
> +Description:
> + Count data of Count Y represented as a string.
> +
> +What: /sys/bus/counter/devices/counterX/countY/ceiling
> +KernelVersion: 5.2
> +Contact: linux-iio@vger.kernel.org
> +Description:
> + Count value ceiling for Count Y. This is the upper limit for the
> + respective counter.
> +
> +What: /sys/bus/counter/devices/counterX/countY/floor
> +KernelVersion: 5.2
> +Contact: linux-iio@vger.kernel.org
> +Description:
> + Count value floor for Count Y. This is the lower limit for the
> + respective counter.
> +
> +What: /sys/bus/counter/devices/counterX/countY/count_mode
> +KernelVersion: 5.2
> +Contact: linux-iio@vger.kernel.org
> +Description:
> + Count mode for channel Y. The ceiling and floor values for
> + Count Y are used by the count mode where required. The following
> + count modes are available:
> +
> + normal:
> + Counting is continuous in either direction.
> +
> + range limit:
> + An upper or lower limit is set, mimicking limit switches
> + in the mechanical counterpart. The upper limit is set to
> + the Count Y ceiling value, while the lower limit is set
> + to the Count Y floor value. The counter freezes at
> + count = ceiling when counting up, and at count = floor
> + when counting down. At either of these limits, the
> + counting is resumed only when the count direction is
> + reversed.
> +
> + non-recycle:
> + The counter is disabled whenever a counter overflow or
> + underflow takes place. The counter is re-enabled when a
> + new count value is loaded to the counter via a preset
> + operation or direct write.
> +
> + modulo-n:
> + A count value boundary is set between the Count Y floor
> + value and the Count Y ceiling value. The counter is
> + reset to the Count Y floor value at count = ceiling when
> + counting up, while the counter is set to the Count Y
> + ceiling value at count = floor when counting down; the
> + counter does not freeze at the boundary points, but
> + counts continuously throughout.
> +
> +What: /sys/bus/counter/devices/counterX/countY/count_mode_available
> +What: /sys/bus/counter/devices/counterX/countY/error_noise_available
> +What: /sys/bus/counter/devices/counterX/countY/function_available
> +What: /sys/bus/counter/devices/counterX/countY/signalZ_action_available
> +KernelVersion: 5.2
> +Contact: linux-iio@vger.kernel.org
> +Description:
> + Discrete set of available values for the respective Count Y
> + configuration are listed in this file. Values are delimited by
> + newline characters.

Elsewhere in sysfs we do space-separated:

pavel@amd:~$ cat /sys/power/state
freeze mem disk

And we use [] to mark current selection:

pavel@amd:~$ cat /sys/class/leds/tpacpi\:\:thinkvantage/trigger
[none] bluetooth-power rfkill-any rfkill-none kbd-scrolllock
kbd-numlock kbd-capslock kbd-kanalock kbd-shiftlock kbd-altgrlock
kbd-ctrllock kbd-altlock kbd-shiftllock kbd-shiftrlock kbd-ctrlllock
kbd-ctrlrlock AC-online BAT0-charging-or-full BAT0-charging BAT0-full
BAT0-charging-blink-full-solid rfkill0 phy0rx phy0tx phy0assoc
phy0radio phy0tpt mmc0 timer heartbeat audio-mute audio-micmute
rfkill1

Note this only works if you have less than PAGE_SIZE of entries... and
will never have more.

Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

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