Re: [PATCH v4 00/20] gpio: cdev: add uAPI v2

[Bartosz Golaszewski]

On Fri, Aug 14, 2020 at 5:03 AM Kent Gibson <warthog618@xxxxxxxxx> wrote:
>
> This patchset defines and implements adds a new version of the
> GPIO CDEV uAPI to address existing 32/64-bit alignment issues, add
> support for debounce, event sequence numbers, and allowing for requested
> lines with different configurations.
> It provides some future proofing by adding optional configuration fields
> and padding reserved for future use.
>
> The series can be partitioned into two sets; the first eleven
> contain the v2 uAPI implementation, and the final seven port
> the GPIO tools to the v2 uAPI and extend them to use new uAPI features.
>
> The more complicated patches include their own commentary where
> appropriate.
>
> Cheers,
> Kent.
>
> Changes for v4:
>  - bitmap width clarification in gpiod.h (patch 04)
>  - fix info offset initialisation bug (patch 08 and inserting patch 01)
>  - replace strncpy with strscpy to remove compiler warnings
>    (patch 08 and inserting patch 02)
>  - fix mask handling in line_get_values (patch 07)
>
> Changes for v3:
>  - disabling the character device from the build requires EXPERT
>  - uAPI revisions (see patch 02)
>  - replace padding_not_zeroed with calls to memchr_inv
>  - don't use bitops on 64-bit flags as that doesn't work on BE-32
>  - accept first attribute matching a line in gpio_v2_line_config.attrs
>    rather than the last
>  - rework lsgpio port to uAPI v2 as flags reverted to v1 like layout
>    (since patch v2)
>  - swapped patches 17 and 18 to apply debounce to multiple monitored
>    lines
>
> Changes for v2:
>  - split out cleanup patches into a separate series.
>  - split implementation patch into a patch for each ioctl or major feature.
>  - split tool port patch into a patch per tool.
>  - rework uAPI to allow requested lines with different configurations.
>
>
> Kent Gibson (20):
>   gpiolib: cdev: desc_to_lineinfo should set info offset
>   gpiolib: cdev: replace strncpy with strscpy
>   gpio: uapi: define GPIO_MAX_NAME_SIZE for array sizes
>   gpio: uapi: define uAPI v2
>   gpiolib: make cdev a build option
>   gpiolib: add build option for CDEV v1 ABI
>   gpiolib: cdev: support GPIO_V2_GET_LINE_IOCTL and
>     GPIO_V2_LINE_GET_VALUES_IOCTL
>   gpiolib: cdev: support GPIO_V2_GET_LINEINFO_IOCTL and
>     GPIO_V2_GET_LINEINFO_WATCH_IOCTL
>   gpiolib: cdev: support edge detection for uAPI v2
>   gpiolib: cdev: support GPIO_V2_LINE_SET_CONFIG_IOCTL
>   gpiolib: cdev: support GPIO_V2_LINE_SET_VALUES_IOCTL
>   gpiolib: cdev: support setting debounce
>   gpio: uapi: document uAPI v1 as deprecated
>   tools: gpio: port lsgpio to v2 uAPI
>   tools: gpio: port gpio-watch to v2 uAPI
>   tools: gpio: rename nlines to num_lines
>   tools: gpio: port gpio-hammer to v2 uAPI
>   tools: gpio: port gpio-event-mon to v2 uAPI
>   tools: gpio: add multi-line monitoring to gpio-event-mon
>   tools: gpio: add debounce support to gpio-event-mon
>
>  drivers/gpio/Kconfig        |   29 +-
>  drivers/gpio/Makefile       |    2 +-
>  drivers/gpio/gpiolib-cdev.c | 1354 +++++++++++++++++++++++++++++++++--
>  drivers/gpio/gpiolib-cdev.h |   15 +
>  drivers/gpio/gpiolib.c      |    2 +
>  drivers/gpio/gpiolib.h      |    6 +
>  include/uapi/linux/gpio.h   |  316 +++++++-
>  tools/gpio/gpio-event-mon.c |  146 ++--
>  tools/gpio/gpio-hammer.c    |   56 +-
>  tools/gpio/gpio-utils.c     |  127 ++--
>  tools/gpio/gpio-utils.h     |   50 +-
>  tools/gpio/gpio-watch.c     |   16 +-
>  tools/gpio/lsgpio.c         |   60 +-
>  13 files changed, 1949 insertions(+), 230 deletions(-)
>
>
> base-commit: 22cc422070d9a9a399f8a70b89f1b852945444cb
> --
> 2.28.0
>

Hi Kent!

The series looks quite good to me and I think we're on track to get it
in for v5.10. I'd love to have Andy (Cc'd) take a look as well. There
are some nits here and there but as long as we get the ABI right, any
implementation details can be ironed out later.

I need to think about some details a bit more but I really like the
current state of the patches.

Bart