gpio: Add support for push-pull/open-drain output mode

This attribute is not part of gpio standard attributes
so it's necessary to implement a custom version of this function

Signed-off-by: Nicola Ponte <nicola.ponte@u-blox.com>
Signed-off-by: Brendan Le Foll <brendan.le.foll@intel.com>

api/mraa/gpio.h

@@ -92,6 +92,15 @@ typedef enum {
     MRAA_GPIO_ACTIVE_LOW = 1,  /**< Resistive Low */
 } mraa_gpio_input_mode_t;
 
+
+/**
+ * Gpio output driver modes
+ */
+typedef enum {
+    MRAA_GPIO_OPEN_DRAIN = 0, /**< Open Drain Configuration */
+    MRAA_GPIO_PUSH_PULL = 1,  /**< Push Pull Configuration */
+} mraa_gpio_out_driver_mode_t;
+
 /**
  * Initialise gpio_context, based on board number
  *
@@ -235,6 +244,14 @@ int mraa_gpio_get_pin_raw(mraa_gpio_context dev);
  */
 mraa_result_t mraa_gpio_input_mode(mraa_gpio_context dev, mraa_gpio_input_mode_t);
 
+/**
+ * Set Gpio output driver mode. This is not a standard feature, it needs custom implementation for each board
+ *
+ * @param dev The Gpio context
+ * @param mode Set output driver mode
+ * @return Result of operation
+ */
+mraa_result_t mraa_gpio_out_driver_mode(mraa_gpio_context dev, mraa_gpio_out_driver_mode_t mode);
 
 #ifdef __cplusplus
 }

api/mraa/gpio.hpp

@@ -77,6 +77,14 @@ typedef enum {
     MODE_IN_ACTIVE_LOW = 1,  /**< Resistive Low */
 } InputMode;
 
+/**
+ * Gpio output driver modes
+ */
+typedef enum {
+    MODE_OUT_OPEN_DRAIN = 0, /**< Open Drain Configuration */
+    MODE_OUT_PUSH_PULL = 1,  /**< Push Pull Configuration */
+} OutputMode;
+
 /**
  * @brief API to General Purpose IO
  *
@@ -336,6 +344,17 @@ class Gpio
         return (Result )mraa_gpio_input_mode(m_gpio, (mraa_gpio_input_mode_t) mode);
     }
 
+    /**
+     * Change Gpio output driver mode
+     *
+     * @param mode @param mode Set output driver mode
+     * @return Result of operation
+     */
+    Result
+    outputMode(OutputMode mode)
+    {
+        return (Result) mraa_gpio_out_driver_mode(m_gpio, (mraa_gpio_out_driver_mode_t) mode);
+    }
 
   private:
     mraa_gpio_context m_gpio;

include/mraa_adv_func.h

@@ -59,6 +59,7 @@ typedef struct {
     mraa_result_t (*gpio_wait_interrupt_replace) (mraa_gpio_context dev);
     mraa_result_t (*gpio_isr_replace) (mraa_gpio_context dev, mraa_gpio_edge_t mode, void (*fptr)(void*), void* args);
     mraa_result_t (*gpio_isr_exit_replace) (mraa_gpio_context dev);
+    mraa_result_t (*gpio_out_driver_mode_replace) (mraa_gpio_context dev, mraa_gpio_out_driver_mode_t mode);
 
     mraa_result_t (*i2c_init_pre) (unsigned int bus);
     mraa_result_t (*i2c_init_bus_replace) (mraa_i2c_context dev);

src/gpio/gpio.c

@@ -881,3 +881,20 @@ mraa_gpio_input_mode(mraa_gpio_context dev, mraa_gpio_input_mode_t mode)
 
     return MRAA_SUCCESS;
 }
+
+
+mraa_result_t
+mraa_gpio_out_driver_mode(mraa_gpio_context dev, mraa_gpio_out_driver_mode_t mode)
+{
+    if (dev == NULL) {
+        syslog(LOG_ERR, "gpio: write: context is invalid");
+        return MRAA_ERROR_INVALID_HANDLE;
+    }
+
+    if (IS_FUNC_DEFINED(dev, gpio_out_driver_mode_replace)) {
+        return dev->advance_func->gpio_out_driver_mode_replace(dev, mode);
+    }
+    else {
+        return MRAA_ERROR_FEATURE_NOT_SUPPORTED;
+    }
+}