Re: [libgpiod][PATCH v3 03/14] bindings: cxx: add support for bias flags

[Bartosz Golaszewski <bgolaszewski@xxxxxxxxxxxx>]

pon., 25 lis 2019 o 15:32 Kent Gibson <warthog618@xxxxxxxxx> napisał(a):
>
> Add support for bias flags in line requests and returning the line bias
> setting via a bias accessor.
>
> Based on initial work by Drew Fustini <drew@xxxxxxxx>.
>
> Signed-off-by: Kent Gibson <warthog618@xxxxxxxxx>
> ---
>  bindings/cxx/gpiod.hpp     | 26 ++++++++++++++++++++++++++
>  bindings/cxx/line.cpp      | 19 +++++++++++++++++++
>  bindings/cxx/line_bulk.cpp |  6 ++++++
>  3 files changed, 51 insertions(+)
>
> diff --git a/bindings/cxx/gpiod.hpp b/bindings/cxx/gpiod.hpp
> index b5a9401..2b1a6ab 100644
> --- a/bindings/cxx/gpiod.hpp
> +++ b/bindings/cxx/gpiod.hpp
> @@ -233,6 +233,12 @@ struct line_request
>         /**< The line is an open-source port. */
>         GPIOD_API static const ::std::bitset<32> FLAG_OPEN_DRAIN;
>         /**< The line is an open-drain port. */
> +       GPIOD_API static const ::std::bitset<32> FLAG_BIAS_DISABLE;
> +       /**< The line has neither pull-up nor pull-down resistor enabled */
> +       GPIOD_API static const ::std::bitset<32> FLAG_BIAS_PULL_DOWN;
> +       /**< The line has a configurable pull-down resistor enabled */
> +       GPIOD_API static const ::std::bitset<32> FLAG_BIAS_PULL_UP;
> +       /**< The line has a configurable pull-up resistor enabled */
>
>         ::std::string consumer;
>         /**< Consumer name to pass to the request. */
> @@ -320,6 +326,12 @@ public:
>          */
>         GPIOD_API int active_state(void) const;
>
> +       /**
> +        * @brief Get current bias of this line.
> +        * @return Current bias setting.
> +        */
> +       GPIOD_API int bias(void) const;
> +
>         /**
>          * @brief Check if this line is used by the kernel or other user space
>          *        process.
> @@ -456,6 +468,20 @@ public:
>                 /**< Line's active state is high. */
>         };
>
> +       /**
> +        * @brief Possible bias settings.
> +        */
> +       enum : int {
> +               BIAS_AS_IS = 1,
> +               /**< Line's bias state is unknown. */
> +               BIAS_DISABLE,
> +               /**< Line's internal bias is disabled. */
> +               BIAS_PULL_UP,
> +               /**< Line's internal pull-up bias is enabled. */
> +               BIAS_PULL_DOWN,
> +               /**< Line's internal pull-down bias is enabled. */
> +       };
> +
>  private:
>
>         line(::gpiod_line* line, const chip& owner);
> diff --git a/bindings/cxx/line.cpp b/bindings/cxx/line.cpp
> index df6eada..dd6bb6a 100644
> --- a/bindings/cxx/line.cpp
> +++ b/bindings/cxx/line.cpp
> @@ -67,6 +67,25 @@ int line::active_state(void) const
>         return active == GPIOD_LINE_ACTIVE_STATE_HIGH ? ACTIVE_HIGH : ACTIVE_LOW;
>  }
>
> +int line::bias(void) const
> +{
> +       this->throw_if_null();
> +
> +       int bias = ::gpiod_line_bias(this->_m_line);
> +
> +       switch (bias) {
> +       case GPIOD_LINE_BIAS_PULL_UP:
> +               return BIAS_PULL_UP;
> +       case GPIOD_LINE_BIAS_PULL_DOWN:
> +               return BIAS_PULL_DOWN;
> +       case GPIOD_LINE_BIAS_DISABLE:
> +               return BIAS_DISABLE;
> +       case GPIOD_LINE_BIAS_AS_IS:
> +       default:
> +               return BIAS_AS_IS;
> +       }

I think that for consistency with other mappings, this can be made
shorter by using std::map - please see line_bulk.cpp.

Bart


> +}
> +
>  bool line::is_used(void) const
>  {
>         this->throw_if_null();
> diff --git a/bindings/cxx/line_bulk.cpp b/bindings/cxx/line_bulk.cpp
> index c708c8b..5f1cac4 100644
> --- a/bindings/cxx/line_bulk.cpp
> +++ b/bindings/cxx/line_bulk.cpp
> @@ -14,6 +14,9 @@ namespace gpiod {
>  const ::std::bitset<32> line_request::FLAG_ACTIVE_LOW(GPIOD_BIT(0));
>  const ::std::bitset<32> line_request::FLAG_OPEN_SOURCE(GPIOD_BIT(1));
>  const ::std::bitset<32> line_request::FLAG_OPEN_DRAIN(GPIOD_BIT(2));
> +const ::std::bitset<32> line_request::FLAG_BIAS_DISABLE(GPIOD_BIT(3));
> +const ::std::bitset<32> line_request::FLAG_BIAS_PULL_DOWN(GPIOD_BIT(4));
> +const ::std::bitset<32> line_request::FLAG_BIAS_PULL_UP(GPIOD_BIT(5));
>
>  namespace {
>
> @@ -38,6 +41,9 @@ const ::std::map<::std::bitset<32>, int, bitset_cmp> reqflag_mapping = {
>         { line_request::FLAG_ACTIVE_LOW,        GPIOD_LINE_REQUEST_FLAG_ACTIVE_LOW, },
>         { line_request::FLAG_OPEN_DRAIN,        GPIOD_LINE_REQUEST_FLAG_OPEN_DRAIN, },
>         { line_request::FLAG_OPEN_SOURCE,       GPIOD_LINE_REQUEST_FLAG_OPEN_SOURCE, },
> +       { line_request::FLAG_BIAS_DISABLE,      GPIOD_LINE_REQUEST_FLAG_BIAS_DISABLE, },
> +       { line_request::FLAG_BIAS_PULL_DOWN,    GPIOD_LINE_REQUEST_FLAG_BIAS_PULL_DOWN, },
> +       { line_request::FLAG_BIAS_PULL_UP,      GPIOD_LINE_REQUEST_FLAG_BIAS_PULL_UP, },
>  };
>
>  } /* namespace */
> --
> 2.24.0
>