bindings: cxx: add support for bias flags

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@pdp7.com>.

Signed-off-by: Kent Gibson <warthog618@gmail.com>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>

diff --git a/bindings/cxx/gpiod.hpp b/bindings/cxx/gpiod.hpp
index b5a9401d2be4688fcc7099e26f18319dce2e63eb..52c6aaece7b36a9a15b5886ead8ddd7c38f4f618 100644 (file)
--- 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 df6eada274f7843454696760909fd1d830f41fc1..29ea5b26f173e5f52a64e8bca184d99ed0cff900 100644 (file)
--- a/bindings/cxx/line.cpp
+++ b/bindings/cxx/line.cpp
@@ -6,10 +6,22 @@
  */
 
 #include <gpiod.hpp>
+#include <map>
 #include <system_error>
 
 namespace gpiod {
 
+namespace {
+
+const ::std::map<int, int> bias_mapping = {
+       { GPIOD_LINE_BIAS_PULL_UP,      line::BIAS_PULL_UP, },
+       { GPIOD_LINE_BIAS_PULL_DOWN,    line::BIAS_PULL_DOWN, },
+       { GPIOD_LINE_BIAS_DISABLE,      line::BIAS_DISABLE, },
+       { GPIOD_LINE_BIAS_AS_IS,        line::BIAS_AS_IS, },
+};
+
+} /* namespace */
+
 line::line(void)
        : _m_line(nullptr),
          _m_chip()
@@ -67,6 +79,13 @@ 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();
+
+       return bias_mapping.at(::gpiod_line_bias(this->_m_line));
+}
+
 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 c708c8bb2768d7ced2fe809ac6e686e2c571c52e..5f1cac4243fe6ec911e7d3c3a21224c56ad7afe6 100644 (file)
--- 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 */