Re: [libgpiod][PATCH v2 7/7] core: add the kernel uapi header to the repository

[Kent Gibson <warthog618@gmail.com>]

On Fri, Jan 15, 2021 at 11:30:18AM +0100, Bartosz Golaszewski wrote:
> From: Bartosz Golaszewski <bgolaszewski@baylibre.com>
> 
> In order to avoid any problems with symbols missing from the host linux
> kernel headers (for example: if current version of libgpiod supports
> features that were added recently to the kernel but the host headers are
> outdated and don't export required symbols) let's add the uapi header to
> the repository and include it instead of the one in /usr/include/linux.
> 
> Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
> ---
>  configure.ac    |  12 +-
>  lib/Makefile.am |   2 +-
>  lib/core.c      |   3 +-
>  lib/uapi/gpio.h | 522 ++++++++++++++++++++++++++++++++++++++++++++++++
>  4 files changed, 528 insertions(+), 11 deletions(-)
>  create mode 100644 lib/uapi/gpio.h
> 

[snip]
> +enum gpio_v2_line_flag {
> +	GPIO_V2_LINE_FLAG_USED			= _BITULL(0),
> +	GPIO_V2_LINE_FLAG_ACTIVE_LOW		= _BITULL(1),
> +	GPIO_V2_LINE_FLAG_INPUT			= _BITULL(2),
> +	GPIO_V2_LINE_FLAG_OUTPUT		= _BITULL(3),
> +	GPIO_V2_LINE_FLAG_EDGE_RISING		= _BITULL(4),
> +	GPIO_V2_LINE_FLAG_EDGE_FALLING		= _BITULL(5),
> +	GPIO_V2_LINE_FLAG_OPEN_DRAIN		= _BITULL(6),
> +	GPIO_V2_LINE_FLAG_OPEN_SOURCE		= _BITULL(7),
> +	GPIO_V2_LINE_FLAG_BIAS_PULL_UP		= _BITULL(8),
> +	GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN	= _BITULL(9),
> +	GPIO_V2_LINE_FLAG_BIAS_DISABLED		= _BITULL(10),
> +};

Perhaps include the header from v5.11-rc3 that includes the
GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME flag?

Unless your intent is for the next libgpiod release to explicitly target
v5.10?

+1 for including the header, btw.  Targetting a specific kernel header
simplifies the build.  We are always going to have to deal with current
apps being run on old kernels, either way, and anyone that cares to use
current features has to ensure they have a current kernel, either way.

Cheers,
Kent.