drivers/audio: Move the I2S character driver to a dedicated folder.

drivers/Kconfig

@@ -137,6 +137,7 @@ menuconfig I2S
 		See include/nuttx/audio/i2s.h for further I2S driver information.
 
 if I2S
+source drivers/i2s/Kconfig
 endif # I2S
 
 source drivers/timers/Kconfig

drivers/Makefile

@@ -55,6 +55,7 @@ include bch$(DELIM)Make.defs
 include can$(DELIM)Make.defs
 include crypto$(DELIM)Make.defs
 include i2c$(DELIM)Make.defs
+include i2s$(DELIM)Make.defs
 include input$(DELIM)Make.defs
 include ioexpander$(DELIM)Make.defs
 include lcd$(DELIM)Make.defs

drivers/README.txt

@@ -75,6 +75,9 @@ eeprom/
 i2c/
   I2C drivers and support logic.  See include/nuttx/i2c/i2c_master.h
 
+i2s/
+  I2S drivers and support logic.  See include/nuttx/audio/i2s.h
+
 input/
   This directory holds implementations of human input device (HID)
   drivers.  This includes such things as mouse, touchscreen, joystick,

drivers/audio/Kconfig

@@ -3,38 +3,6 @@
 # see the file kconfig-language.txt in the NuttX tools repository.
 #
 
-config AUDIO_I2SCHAR
-	bool "I2S character driver (for testing only)"
-	default n
-	depends on I2S && AUDIO
-	---help---
-		This selection enables a simple character driver that supports I2S
-		transfers via a read() and write().  The intent of this driver is to
-		support I2S testing.  It is not an audio driver but does conform to
-		some of the buffer management heuristics of an audio driver.  It is
-		not suitable for use in any real driver application in its current
-		form.
-
-if AUDIO_I2SCHAR
-
-config AUDIO_I2SCHAR_RXTIMEOUT
-	int "RX timeout"
-	default 0
-	---help---
-		This is a fixed timeout value that will be used for all receiver
-		transfers.  This is in units of system clock ticks (configurable).
-		The special value of zero disables RX timeouts.  Default: 0
-
-config AUDIO_I2SCHAR_TXTIMEOUT
-	int "TX timeout"
-	default 0
-	---help---
-		This is a fixed timeout value that will be used for all transmitter
-		transfers.  This is in units of system clock ticks (configurable).
-		The special value of zero disables RX timeouts.  Default: 0
-
-endif # AUDIO_I2SCHAR
-
 config AUDIO_TONE
 	bool "Audio Tone Generator using PWM"
 	default n

drivers/audio/Make.defs

@@ -73,10 +73,6 @@ ifeq ($(CONFIG_AUDIO_NULL),y)
 CSRCS += audio_null.c
 endif
 
-ifeq ($(CONFIG_AUDIO_I2SCHAR),y)
-CSRCS += i2schar.c
-endif
-
 ifeq ($(CONFIG_AUDIO_TONE),y)
 CSRCS += tone.c
 endif

drivers/i2s/Kconfig

@@ -0,0 +1,35 @@
+#
+# For a description of the syntax of this configuration file,
+# see the file kconfig-language.txt in the NuttX tools repository.
+#
+
+config AUDIO_I2SCHAR
+	bool "I2S character driver (for testing only)"
+	default n
+	---help---
+		This selection enables a simple character driver that supports I2S
+		transfers via a read() and write().  The intent of this driver is to
+		support I2S testing.  It is not an audio driver but does conform to
+		some of the buffer management heuristics of an audio driver.  It is
+		not suitable for use in any real driver application in its current
+		form.
+
+if AUDIO_I2SCHAR
+
+config AUDIO_I2SCHAR_RXTIMEOUT
+	int "RX timeout"
+	default 0
+	---help---
+		This is a fixed timeout value that will be used for all receiver
+		transfers.  This is in units of system clock ticks (configurable).
+		The special value of zero disables RX timeouts.  Default: 0
+
+config AUDIO_I2SCHAR_TXTIMEOUT
+	int "TX timeout"
+	default 0
+	---help---
+		This is a fixed timeout value that will be used for all transmitter
+		transfers.  This is in units of system clock ticks (configurable).
+		The special value of zero disables RX timeouts.  Default: 0
+
+endif # AUDIO_I2SCHAR

drivers/i2s/Make.defs

@@ -0,0 +1,45 @@
+############################################################################
+# drivers/i2s/Make.defs
+#
+#   Copyright (C) 2018 Pinecone Inc. All rights reserved.
+#   Author: Xiang Xiao <xiaoxiang@pinecone.net>
+#
+# 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.
+#
+############################################################################
+
+ifeq ($(CONFIG_I2S),y)
+
+ifeq ($(CONFIG_AUDIO_I2SCHAR),y)
+CSRCS += i2schar.c
+endif
+
+DEPPATH += --dep-path i2s
+VPATH += :i2s
+
+endif

drivers/i2s/i2schar.c

@@ -1,5 +1,5 @@
 /****************************************************************************
- * drivers/audio/i2schar.c
+ * drivers/i2s/i2schar.c
  *
  * This is a simple character driver for testing I2C.  It is not an audio
  * driver but does conform to some of the buffer management heuristics of an