Re: [libgpiod][PATCH 4/6] treewide: make drive settings an enum

[Kent Gibson <warthog618@gmail.com>]

On Mon, Jan 11, 2021 at 02:34:24PM +0100, Bartosz Golaszewski wrote:
> From: Bartosz Golaszewski <bgolaszewski@baylibre.com>
> 
> Open-source and open-drain drive settings are mutually exclusive just like
> the bias settings. Make them into an enum so that becomes clear.
> 
> Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
> ---
>  bindings/cxx/gpiod.hpp                 | 24 +++++----
>  bindings/cxx/line.cpp                  | 18 +++----
>  bindings/cxx/tests/tests-line.cpp      | 45 ++++++----------
>  bindings/python/gpiodmodule.c          | 73 ++++++++++++++------------
>  bindings/python/tests/gpiod_py_test.py | 18 +++----
>  include/gpiod.h                        | 26 +++++----
>  lib/core.c                             | 12 ++---
>  tests/tests-line.c                     | 36 ++++++-------
>  tools/gpioinfo.c                       | 14 ++++-
>  9 files changed, 134 insertions(+), 132 deletions(-)
> 
> diff --git a/bindings/cxx/gpiod.hpp b/bindings/cxx/gpiod.hpp
> index fb675fc..f9c341d 100644
> --- a/bindings/cxx/gpiod.hpp
> +++ b/bindings/cxx/gpiod.hpp
> @@ -332,16 +332,10 @@ public:
>  	GPIOD_API bool is_used(void) const;
>  
>  	/**
> -	 * @brief Check if this line represents an open-drain GPIO.
> -	 * @return True if the line is an open-drain GPIO, false otherwise.
> +	 * @brief Get current drive setting of this line.
> +	 * @return Current drive setting.
>  	 */
> -	GPIOD_API bool is_open_drain(void) const;
> -
> -	/**
> -	 * @brief Check if this line represents an open-source GPIO.
> -	 * @return True if the line is an open-source GPIO, false otherwise.
> -	 */
> -	GPIOD_API bool is_open_source(void) const;
> +	GPIOD_API int drive(void) const;
>  
>  	/**
>  	 * @brief Request this line.
> @@ -482,6 +476,18 @@ public:
>  		/**< Line's direction setting is output. */
>  	};
>  
> +	/**
> +	 * @brief Possible drive settings.
> +	 */
> +	enum : int {
> +		DRIVE_NONE = 1,
> +		/**< Drive setting is unknown. */

Unlike bias, the drive setting is never unknown - if zero the pin is
assumed push-pull.

And to me DRIVE_NONE implies a high impedance state.

Cheers,
Kent.