android-things: Prep for peripheralmanager support

Signed-off-by: Brendan Le Foll <brendan.le.foll@intel.com>

include/peripheralmanager/gpio.h

@@ -0,0 +1,107 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef SYSTEM_PERIPHERALMANAGER_GPIO_H_
+#define SYSTEM_PERIPHERALMANAGER_GPIO_H_
+
+#include <sys/cdefs.h>
+#include <sys/types.h>
+
+__BEGIN_DECLS
+
+/// @defgroup Gpio Gpio Interface
+/// @brief Functions to control GPIO pins.
+///
+/// These functions can be used to control GPIO.
+/// @{
+
+/// Edge trigger types.
+enum {
+  NONE_EDGE,  /**<  None */
+  RISING_EDGE,  /**<  Rising edge */
+  FALLING_EDGE,  /**<  Falling edge */
+  BOTH_EDGE  /**<  Both edges */
+};
+
+/// GPIO direction types.
+enum {
+  DIRECTION_IN,  /**<  Input mode */
+  DIRECTION_OUT_INITIALLY_HIGH,  /**<  Output mode, initially set to high */
+  DIRECTION_OUT_INITIALLY_LOW  /**<  Output mode, initially set to low */
+};
+
+/// Possible active types.
+enum {
+  ACTIVE_LOW,  /**<  Active Low */
+  ACTIVE_HIGH  /**<  Active High */
+};
+
+typedef struct BGpio BGpio;
+
+/// Sets the GPIO direction to output.
+/// @param gpio Pointer to the BGpio struct
+/// @param direction One of DIRECTION_IN,
+/// DIRECTION_OUT_INITIALLY_HIGH, DIRECTION_OUT_INITIALLY_LOW.
+/// @return 0 on success, errno on error.
+int BGpio_setDirection(const BGpio* gpio, int direction);
+
+/// Sets the interrupt edge trigger type.
+/// @param gpio Pointer to the BGpio struct
+/// @param type One of NONE_EDGE, RISING_EDGE, FALLING_EDGE or BOTH_EDGE.
+/// @return 0 on success, errno on error.
+int BGpio_setEdgeTriggerType(const BGpio* gpio, int type);
+
+/// Sets the GPIO’s active low/high status.
+/// @param gpio Pointer to the BGpio struct.
+/// @param type One of ACTIVE_HIGH, ACTIVE_LOW.
+/// @return 0 on success, errno on error.
+int BGpio_setActiveType(const BGpio* gpio, int type);
+
+/// Sets the GPIO value (for output GPIO only).
+/// @param gpio Pointer to the BGpio struct.
+/// @param value Value to set.
+/// @return 0 on success, errno on error.
+int BGpio_setValue(const BGpio* gpio, int value);
+
+/// Gets the GPIO value (for input GPIO only).
+/// @param gpio Pointer to the BGpio struct.
+/// @param value Output pointer to the value of the GPIO.
+/// @return 0 on success, errno on error.
+int BGpio_getValue(const BGpio* gpio, int* value);
+
+/// Returns a file descriptor that can be used to poll on new data.
+/// Can be passed to select/epoll to wait for data to become available.
+/// @param gpio Pointer to the BGpio struct.
+/// @param fd Output pointer to the file descriptor number.
+/// @return 0 on success, errno on error.
+int BGpio_getPollingFd(const BGpio* gpio, int* fd);
+
+/// Acknowledges the interrupt and resets the file descriptor.
+/// This must be called after each event triggers in order to be able to
+/// poll/select for another event.
+/// @param fd Polling file descriptor to reset.
+/// @return 0 on success, errno on error.
+int BGpio_ackInterruptEvent(int fd);
+
+/// Destroys a BGpio struct.
+/// @param gpio Pointer to the BGpio struct.
+void BGpio_delete(BGpio* gpio);
+
+/// @}
+
+__END_DECLS
+
+#endif  // SYSTEM_PERIPHERALMANAGER_GPIO_H_