Nikita Shubin via B4 Relay <devnull+n.shubin.yadro....@kernel.org>
writes:
> From: Nikita Shubin <n.shu...@yadro.com>
>
> Add GUSE (FUSE based kernel module similiar to CUSE) based backend.
>
> This allows transparent usage of Linux GPIO UAPI based tools like
> in kernel tools/gpio or libgpiod.
>
> libgpiod requires some modification to allow "/sys/class/guse" in
> gpiod_check_gpiochip_device().
>
> It requires guse module to be loaded and providing DEVICE()->id
> for GPIO module, for example:
>
> ```
> DEVICE(&s->gpio)->id = g_strdup("aspeed-gpio0");
> ```
>
> The id should be provided to gpiodev with any `devname` that doesn't
> exists in /dev:
>
> ```
> -gpiodev guse,id=aspeed-gpio0,devname=gpiochip10
> ```
>
> That /dev/gpiochip10 can be used in the same way we usually operate with
> gpiochip's.
>
> Link:
> http://git.maquefel.me/?p=qemu-gpiodev/libgpiod.git;a=shortlog;h=refs/heads/nshubin/guse-fix
> Link: http://git.maquefel.me/?p=qemu-gpiodev/guse.git;a=summary
> Link:
> http://git.maquefel.me/?p=qemu-gpiodev/libfuse.git;a=shortlog;h=refs/heads/nshubin/guse
> Signed-off-by: Nikita Shubin <n.shu...@yadro.com>
[...]
> diff --git a/qapi/gpio.json b/qapi/gpio.json
> index
> 1c2b7af36813ff52cbb3a44e64a2e5a5d8658d62..e3cdca793260212622a30947eaea61bd523e98fb
> 100644
> --- a/qapi/gpio.json
> +++ b/qapi/gpio.json
> @@ -21,12 +21,36 @@
> ##
> # @GpiodevBackendKind:
> #
> -# @chardev: chardevs
> +# @chardev: Gpio dev over chardev backend
> +# @gusedev: Gpio dev over GUSE FUSE module
> #
> # Since: 9.2
10.1
> ##
> { 'enum': 'GpiodevBackendKind',
> - 'data': [ 'chardev' ] }
> + 'data': [ 'chardev',
> + { 'name': 'gusedev', 'if': 'CONFIG_LINUX' } ] }
> +
> +##
> +# @GpiodevGusedev:
> +#
> +# Configuration info for guse gpiodevs.
> +#
> +# @devname: Name of device created in /dev
Existing names for similar things elsewhere:
* @dev in AudiodevAlsaPerDirectionOptions
* @device in ChardevHostdev
* @devname in NetdevNetmapOptions
* @vhostdev in NetdevVhostUserOptions
* @sev-device in SevCommonProperties
* @filename in RngRandomProperties
* @path in BlockdevOptionsNvmeIoUring,
BlockdevOptionsVirtioBlkVhostVdpa, TPMPassthroughOptions
What a mess.
@filename and @path are clearly bad.
I'd prefer @device or @gpio-device, or maybe @dev.
> +#
> +# Since: 9.2
> +##
> + { 'struct': 'GpiodevGusedev',
> + 'data': { 'devname': 'str' } }
> +
> +##
> +# @GpiodevGusedevWrapper:
> +#
> +# @data: Configuration info for chardev gpiodevs
> +#
> +# Since: 9.2
> +##
> +{ 'struct': 'GpiodevGusedevWrapper',
> + 'data': { 'data': 'GpiodevGusedev' } }
Avoid the wrapper?
>
> ##
> # @GpiodevChardev:
> @@ -65,4 +89,5 @@
> { 'union': 'GpiodevBackend',
> 'base': { 'type': 'GpiodevBackendKind' },
> 'discriminator': 'type',
> - 'data': { 'chardev': 'GpiodevChardevWrapper' } }
> \ No newline at end of file
> + 'data': { 'chardev': 'GpiodevChardevWrapper',
> + 'gusedev': { 'type': 'GpiodevGusedevWrapper', 'if':
> 'CONFIG_LINUX' } } }
> \ No newline at end of file
Please add a newline at the end of the file.
