drivers/audio: Add Audio Tone Generator for NuttX

drivers/audio/Kconfig

@@ -33,7 +33,18 @@ config AUDIO_I2SCHAR_TXTIMEOUT
 		transfers.  This is in units of system clock ticks (configurable).
 		The special value of zero disables RX timeouts.  Default: 0
 
-endif #AUDIO_I2SCHAR
+endif # AUDIO_I2SCHAR
+
+config AUDIO_TONE
+        bool "Audio Tone Generator using PWM"
+        default n
+        depends on PWM && AUDIO_DEVICES
+        ---help---
+                This driver enables the Audio Tone Generator for NuttX.
+
+if AUDIO_TONE
+
+endif # AUDIO_TONE
 
 config VS1053
 	bool "VS1053 codec chip"

drivers/audio/Make.defs

@@ -62,6 +62,10 @@ ifeq ($(CONFIG_AUDIO_I2SCHAR),y)
 CSRCS += i2schar.c
 endif
 
+ifeq ($(CONFIG_AUDIO_TONE),y)
+CSRCS += tone.c
+endif
+
 # Include Audio driver support
 
 DEPPATH += --dep-path audio

include/nuttx/audio/tone.h

@@ -0,0 +1,97 @@
+/****************************************************************************
+ * include/nuttx/audio/tone.h
+ *
+ *   Copyright (C) 2016 Gregory Nutt. All rights reserved.
+ *   Author: Alan Carvalho de Assis <acassis@gmail.com>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+#ifndef __INCLUDE_NUTTX_AUDIO_TONE_H
+#define __INCLUDE_NUTTX_AUDIO_TONE_H
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+#include <nuttx/compiler.h>
+
+#include <fixedmath.h>
+
+#include <nuttx/drivers/pwm.h>
+#include <nuttx/fs/ioctl.h>
+
+#ifdef CONFIG_AUDIO_TONE
+
+/****************************************************************************
+ * Public Function Prototypes
+ ****************************************************************************/
+
+#ifdef __cplusplus
+#define EXTERN extern "C"
+extern "C"
+{
+#else
+#define EXTERN extern
+#endif
+
+/****************************************************************************
+ * Name: tone_register
+ *
+ * Description:
+ *   This function binds an instance of a "lower half" PWM driver with
+ *   the "upper half" Audio Tone device and registers that device so that can
+ *   be used by application code.
+ *
+ *
+ * Input parameters:
+ *   path - The full path to the driver to be registers in the NuttX pseudo-
+ *     filesystem.  The recommended convention is to name all PWM drivers
+ *     as "/dev/tone0", "/dev/tone1", etc.  where the driver path
+ *     differs only in the "minor" number at the end of the device name.
+ *   tone - A pointer to an instance of lower half PWM driver tone. This
+ *     instance will be bound to the Audio Tone driver and must persists as
+ *     long as that driver persists.
+ *
+ * Returned Value:
+ *   Zero on success; a negated errno value on failure.
+ *
+ ****************************************************************************/
+
+int tone_register(FAR const char *path, FAR struct pwm_lowerhalf_s *tone,
+                  FAR struct oneshot_lowerhalf_s *oneshot);
+
+#undef EXTERN
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* CONFIG_AUDIO_TONE */
+#endif /* __INCLUDE_NUTTX_AUDIO_TONE_H */