From 45f4155b6de85a607b1c0f9a590c196e9aef13cb Mon Sep 17 00:00:00 2001
From: Christos Choutouridis <hoo2@hoo2.net>
Date: Mon, 4 Oct 2021 21:18:01 +0300
Subject: [PATCH] WIP: add gpio device to utl

---
 include/utl/dev/gpio_dev.h | 107 +++++++++++++++++++++++++++++++++++++
 1 file changed, 107 insertions(+)
 create mode 100644 include/utl/dev/gpio_dev.h

diff --git a/include/utl/dev/gpio_dev.h b/include/utl/dev/gpio_dev.h
new file mode 100644
index 0000000..0deb4f7
--- /dev/null
+++ b/include/utl/dev/gpio_dev.h
@@ -0,0 +1,107 @@
+/*!
+ * \file dev/gpio_dev.h
+ * \brief
+ *      A STM32 gpio wrapper class
+ *
+ * \copyright Copyright (C) 2021 Christos Choutouridis <christos@choutouridis.net>
+ *
+ * <dl class=\"section copyright\"><dt>License</dt><dd>
+ * The MIT License (MIT)
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ * </dd></dl>
+ */
+
+#ifndef utl_dev_gpio_dev_h__
+#define utl_dev_gpio_dev_h__
+
+#include <utl/core/impl.h>
+
+namespace utl {
+
+    /*!
+     * CRTP class for gpio digital input-output.
+     *
+     * The derived class requirements are:
+     *  - bool read_impl ()
+     *  - void write_impl(bool)
+     *
+     * \tparam  Impl_t  The type of derived class
+     */
+    template <typename Impl_t>
+    class DigitalInOut {
+    public:
+            _CRTP_IMPL(Impl_t);
+
+        /*!
+         * \name Object lifetime
+         */
+        //! @{
+        protected:
+            DigitalInOut() noexcept = default;
+            ~DigitalInOut() = default;
+            DigitalInOut(const DigitalInOut&)             = delete;   //!< No copy constructions
+            DigitalInOut operator=(const DigitalInOut&)   = delete;   //!< No copies
+
+        //! @}
+
+        //! \name Public interface
+        //! @{
+        public:
+            //! Reads the state of the pin. This is true for both input and output pins.
+            //! \return     The state of the pin
+            bool read () noexcept { return impl().read_impl (); }
+            //! Write a new state to pin. If the pin is set for output, otherwise this state will remain
+            //! to pin registers and reflect to the pin state if we select output mode
+            void write (bool state) noexcept { impl().write_impl(state); }
+
+            //! Implicit conversion to bool for reading operations
+            operator bool () noexcept {
+                return read();
+            }
+            //! Stream from bool for write operations
+            DigitalInOut& operator<< (bool state) noexcept {
+                write(state);
+                return *this;
+            }
+            //! Right stream to bool for read operations
+            DigitalInOut& operator>> (bool& state) noexcept {
+                state = read();
+                return *this;
+            }
+        //! @}
+    };
+
+    /*!
+     * This definition enables the "data << pin" syntax for read operation
+     *
+     * \tparam Impl_t   The derived class type of the DigitalInOut
+     *
+     * \param lhs   Left hand site operand
+     * \param rhs   Right hand site operand
+     * \return      The read value
+     */
+    template<typename Impl_t>
+    bool operator<<(bool& lhs, DigitalInOut<Impl_t>& rhs) noexcept {
+        lhs = rhs.read();
+        return lhs;
+    }
+}
+
+#endif //#ifndef utl_dev_gpio_dev_h__