rcvr: add generic driver API for receivers

Will be used to collapse PWM, PPM, Spektrum and SBUS so we
can choose between them at boot time instead of at compile time.

flight/PiOS/Common/pios_rcvr.c

@@ -0,0 +1,88 @@
+/* Project Includes */
+#include "pios.h"
+
+#if defined(PIOS_INCLUDE_RCVR)
+
+#include <pios_rcvr_priv.h>
+
+static bool PIOS_RCVR_validate(struct pios_rcvr_dev * rcvr_dev)
+{
+  return (rcvr_dev->magic == PIOS_RCVR_DEV_MAGIC);
+}
+
+#if defined(PIOS_INCLUDE_FREERTOS) && 0
+static struct pios_rcvr_dev * PIOS_RCVR_alloc(void)
+{
+  struct pios_rcvr_dev * rcvr_dev;
+
+  rcvr_dev = (struct pios_rcvr_dev *)malloc(sizeof(*rcvr_dev));
+  if (!rcvr_dev) return (NULL);
+
+  rcvr_dev->magic = PIOS_RCVR_DEV_MAGIC;
+  return(rcvr_dev);
+}
+#else
+static struct pios_rcvr_dev pios_rcvr_devs[PIOS_RCVR_MAX_DEVS];
+static uint8_t pios_rcvr_num_devs;
+static struct pios_rcvr_dev * PIOS_RCVR_alloc(void)
+{
+  struct pios_rcvr_dev * rcvr_dev;
+
+  if (pios_rcvr_num_devs >= PIOS_RCVR_MAX_DEVS) {
+    return (NULL);
+  }
+
+  rcvr_dev = &pios_rcvr_devs[pios_rcvr_num_devs++];
+  rcvr_dev->magic = PIOS_RCVR_DEV_MAGIC;
+
+  return (rcvr_dev);
+}
+#endif
+
+/**
+  * Initialises RCVR layer
+  * \param[out] handle
+  * \param[in] driver
+  * \param[in] id
+  * \return < 0 if initialisation failed
+  */
+int32_t PIOS_RCVR_Init(uint32_t * rcvr_id, const struct pios_rcvr_driver * driver, const uint32_t lower_id)
+{
+  PIOS_DEBUG_Assert(rcvr_id);
+  PIOS_DEBUG_Assert(driver);
+
+  struct pios_rcvr_dev * rcvr_dev;
+
+  rcvr_dev = (struct pios_rcvr_dev *) PIOS_RCVR_alloc();
+  if (!rcvr_dev) goto out_fail;
+
+  rcvr_dev->driver = driver;
+  rcvr_dev->id     = lower_id;
+
+  *rcvr_id = (uint32_t)rcvr_dev;
+  return(0);
+
+out_fail:
+  return(-1);
+}
+
+int32_t PIOS_RCVR_Read(uint32_t rcvr_id)
+{
+  struct pios_rcvr_dev * rcvr_dev = (struct pios_rcvr_dev *)rcvr_id;
+
+  if (!PIOS_RCVR_validate(rcvr_dev)) {
+    /* Undefined RCVR port for this board (see pios_board.c) */
+    PIOS_DEBUG_Assert(0);
+  }
+
+  PIOS_DEBUG_Assert(rcvr_dev->driver->read);
+
+  return rcvr_dev->driver->read(rcvr_dev->id);
+}
+
+#endif
+
+/**
+ * @}
+ * @}
+ */

flight/PiOS/inc/pios_rcvr.h

@@ -0,0 +1,50 @@
+/**
+ ******************************************************************************
+ * @addtogroup PIOS PIOS Core hardware abstraction layer
+ * @{
+ * @addtogroup PIOS_RCVR RCVR layer functions
+ * @brief Hardware communication layer
+ * @{
+ *
+ * @file       pios_rcvr.h  
+ * @author     The OpenPilot Team, http://www.openpilot.org Copyright (C) 2010.
+ * 	       Parts by Thorsten Klose (tk@midibox.org)
+ * @brief      COM layer functions header
+ * @see        The GNU Public License (GPL) Version 3
+ *
+ *****************************************************************************/
+/* 
+ * This program is free software; you can redistribute it and/or modify 
+ * it under the terms of the GNU General Public License as published by 
+ * the Free Software Foundation; either version 3 of the License, or 
+ * (at your option) any later version.
+ * 
+ * This program is distributed in the hope that it will be useful, but 
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 
+ * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 
+ * for more details.
+ * 
+ * You should have received a copy of the GNU General Public License along 
+ * with this program; if not, write to the Free Software Foundation, Inc., 
+ * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#ifndef PIOS_RCVR_H
+#define PIOS_RCVR_H
+
+extern uint32_t pios_rcvr_channel_to_id_map[];
+
+struct pios_rcvr_driver {
+  void    (*init)(uint32_t id);
+  int32_t (*read)(uint32_t id);
+};
+
+/* Public Functions */
+extern int32_t PIOS_RCVR_Read(uint32_t rcvr_id);
+
+#endif /* PIOS_RCVR_H */
+
+/**
+  * @}
+  * @}
+  */

flight/PiOS/inc/pios_rcvr_priv.h

@@ -0,0 +1,58 @@
+/**
+ ******************************************************************************
+ * @addtogroup PIOS PIOS Core hardware abstraction layer
+ * @{
+ * @addtogroup   PIOS_RCVR RCVR Functions
+ * @brief PIOS interface for RCVR drivers
+ * @{
+ *
+ * @file       pios_rcvr_priv.h
+ * @author     The OpenPilot Team, http://www.openpilot.org Copyright (C) 2010.
+ * 	       Parts by Thorsten Klose (tk@midibox.org)
+ * @brief      USART private definitions.
+ * @see        The GNU Public License (GPL) Version 3
+ *
+ *****************************************************************************/
+/*
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#ifndef PIOS_RCVR_PRIV_H
+#define PIOS_RCVR_PRIV_H
+
+#include <pios.h>
+
+extern uint32_t pios_rcvr_max_channel;
+
+enum pios_rcvr_dev_magic {
+  PIOS_RCVR_DEV_MAGIC = 0x99aabbcc,
+};
+
+struct pios_rcvr_dev {
+  enum pios_rcvr_dev_magic        magic;
+  uint32_t                        id;
+  const struct pios_rcvr_driver * driver;
+};
+
+extern int32_t PIOS_RCVR_Init(uint32_t * rcvr_id, const struct pios_rcvr_driver * driver, const uint32_t lower_id);
+
+extern void PIOS_RCVR_IRQ_Handler(uint32_t rcvr_id);
+
+#endif /* PIOS_RCVR_PRIV_H */
+
+/**
+  * @}
+  * @}
+  */

flight/PiOS/pios.h

@@ -78,6 +78,7 @@
 #include <pios_spi.h>
 #include <pios_ppm.h>
 #include <pios_pwm.h>
+#include <pios_rcvr.h>
 #include <pios_spektrum.h>
 #include <pios_sbus.h>
 #include <pios_usb_hid.h>