From: David Lechner <david@lechnology.com>
To: William Breathitt Gray <vilhelm.gray@gmail.com>,
gregkh@linuxfoundation.org
Cc: jic23@kernel.org, linux-arm-kernel@lists.infradead.org,
devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-iio@vger.kernel.org, fabrice.gasnier@st.com,
benjamin.gaignard@st.com, robh+dt@kernel.org, knaack.h@gmx.de,
lars@metafoo.de, pmeerw@pmeerw.net, mark.rutland@arm.com
Subject: Re: [v7,03/10] docs: Add Generic Counter interface documentation
Date: Mon, 2 Jul 2018 14:37:53 -0500 [thread overview]
Message-ID: <b7c690eb-274e-3377-cf8a-2f9ab836677e@lechnology.com> (raw)
In-Reply-To: <7606bdc53c26c332b2bbff0f865380fb0e874b56.1529607879.git.vilhelm.gray@gmail.com>
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
next prev parent reply other threads:[~2018-07-02 19:38 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-21 21:06 [PATCH v7 00/10] Introduce the Counter subsystem William Breathitt Gray
2018-06-21 21:07 ` [PATCH v7 01/10] counter: Introduce the Generic Counter interface William Breathitt Gray
2018-07-07 15:16 ` Greg KH
2018-07-09 17:40 ` William Breathitt Gray
2018-07-09 18:54 ` Greg KH
2018-07-09 18:56 ` William Breathitt Gray
2018-07-18 3:49 ` Andrew Morton
2018-07-21 16:26 ` William Breathitt Gray
2018-07-22 5:41 ` Andrew Morton
2018-06-21 21:07 ` [PATCH v7 02/10] counter: Documentation: Add Generic Counter sysfs documentation William Breathitt Gray
2018-07-02 19:11 ` [v7, " David Lechner
2018-07-03 14:04 ` William Breathitt Gray
2018-06-21 21:07 ` [PATCH v7 03/10] docs: Add Generic Counter interface documentation William Breathitt Gray
2018-06-22 16:51 ` Jonathan Cameron
2018-07-02 19:37 ` David Lechner [this message]
2018-07-03 14:16 ` [v7,03/10] " William Breathitt Gray
2018-07-04 17:23 ` Linus Walleij
2018-07-06 17:15 ` Jonathan Cameron
2018-07-06 18:25 ` David Lechner
2018-07-02 19:42 ` David Lechner
2018-07-03 14:21 ` William Breathitt Gray
2018-06-21 21:07 ` [PATCH v7 04/10] counter: 104-quad-8: Add Generic Counter interface support William Breathitt Gray
2018-06-22 16:57 ` Jonathan Cameron
2018-06-21 21:08 ` [PATCH v7 05/10] counter: 104-quad-8: Documentation: Add Generic Counter sysfs documentation William Breathitt Gray
2018-06-22 16:59 ` Jonathan Cameron
2018-06-21 21:08 ` [PATCH v7 06/10] counter: Add STM32 Timer quadrature encoder William Breathitt Gray
2018-06-22 17:03 ` Jonathan Cameron
2018-06-21 21:08 ` [PATCH v7 07/10] dt-bindings: counter: Document stm32 " William Breathitt Gray
2018-07-02 19:56 ` [v7,07/10] " David Lechner
2018-07-05 21:13 ` [PATCH v7 07/10] " Rob Herring
2018-06-21 21:08 ` [PATCH v7 08/10] counter: stm32-lptimer: add counter device William Breathitt Gray
2018-06-22 17:06 ` Jonathan Cameron
2018-06-21 21:08 ` [PATCH v7 09/10] dt-bindings: counter: Adjust dt-bindings for STM32 lptimer move William Breathitt Gray
2018-07-05 21:13 ` Rob Herring
2018-06-21 21:09 ` [PATCH v7 10/10] iio: counter: Add deprecation markings for IIO Counter attributes William Breathitt Gray
2018-06-22 17:10 ` [PATCH v7 00/10] Introduce the Counter subsystem Jonathan Cameron
2018-07-02 18:13 ` David Lechner
2018-07-03 2:48 ` William Breathitt Gray
2018-07-06 17:21 ` Jonathan Cameron
2018-07-06 18:22 ` David Lechner
2018-07-06 19:20 ` William Breathitt Gray
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