Re: [libgpiod] [PATCH 18/19] tools: add support for bias flags

[Kent Gibson <warthog618@xxxxxxxxx>]

On Fri, Nov 15, 2019 at 10:43:54PM +0800, Kent Gibson wrote:
> Add support for bias flags to applicable tools - gpioget, gpioset, and
> gpiomon.
> 
> Signed-off-by: Kent Gibson <warthog618@xxxxxxxxx>
> ---
>  tools/gpioget.c | 24 ++++++++++++++++++++----
>  tools/gpiomon.c | 28 ++++++++++++++++++++++------
>  tools/gpioset.c | 26 +++++++++++++++++++++-----
>  3 files changed, 63 insertions(+), 15 deletions(-)
> 
> diff --git a/tools/gpioget.c b/tools/gpioget.c
> index 196ebeb..025811a 100644
> --- a/tools/gpioget.c
> +++ b/tools/gpioget.c
> @@ -17,10 +17,13 @@ static const struct option longopts[] = {
>  	{ "help",	no_argument,	NULL,	'h' },
>  	{ "version",	no_argument,	NULL,	'v' },
>  	{ "active-low",	no_argument,	NULL,	'l' },
> +	{ "pull-down",	no_argument,	NULL,	'D' },
> +	{ "pull-up",	no_argument,	NULL,	'U' },
> +	{ "bias-disable", no_argument,	NULL,	'B' },
>  	{ GETOPT_NULL_LONGOPT },
>  };
>  
> -static const char *const shortopts = "+hvl";
> +static const char *const shortopts = "+hvlDUB";
>  
>  static void print_help(void)
>  {
> @@ -32,6 +35,9 @@ static void print_help(void)
>  	printf("  -h, --help:\t\tdisplay this message and exit\n");
>  	printf("  -v, --version:\tdisplay the version and exit\n");
>  	printf("  -l, --active-low:\tset the line active state to low\n");
> +	printf("  -D, --pull-down:\tenable internal pull-down\n");
> +	printf("  -U, --pull-up:\tenable internal pull-up\n");
> +	printf("  -B, --bias-disable:\tdisable internal bias\n");
>  }
>  
>  int main(int argc, char **argv)
> @@ -39,6 +45,7 @@ int main(int argc, char **argv)
>  	unsigned int *offsets, i, num_lines;
>  	int *values, optc, opti, rv;
>  	bool active_low = false;
> +	int flags = 0;
>  	char *device, *end;
>  
>  	for (;;) {
> @@ -56,6 +63,15 @@ int main(int argc, char **argv)
>  		case 'l':
>  			active_low = true;
>  			break;
> +		case 'D':
> +			flags |= GPIOD_LINE_REQUEST_FLAG_BIAS_PULL_DOWN;
> +			break;
> +		case 'U':
> +			flags |= GPIOD_LINE_REQUEST_FLAG_BIAS_PULL_UP;
> +			break;
> +		case 'B':
> +			flags |= GPIOD_LINE_REQUEST_FLAG_BIAS_DISABLE;
> +			break;
>  		case '?':
>  			die("try %s --help", get_progname());
>  		default:
> @@ -86,9 +102,9 @@ int main(int argc, char **argv)
>  			die("invalid GPIO offset: %s", argv[i + 1]);
>  	}
>  

Nuts - this is wrong - it should be using the CTXLESS flags, not the 
LINE_REQUEST flags.  That applies to all three of the tools changed.
I forgot to propagate the last minute CTXLESS changes to the tools.
And unfortunately we don't have test cases for the tools :-(.
I've got a fix in my github branch that I will incorporate into v2.

I'm also wondering if it would be preferable to replace the individual
bias command line flags with a single bias parameter, e.g. --bias=pull-up
I've coded that in my github branch as well, if you would care to
compare.

Let me know if you'd like a v2, otherwise I'll hold off for a few days
in case something else crops up.

Cheers,
Kent.