ALSA: sh: add SuperH DAC audio driver for ALSA V4

This is a port of the sound/oss/sh_dac_audio.c driver.
The driver uses an on-chip 8-bit D/A converter, which has a speaker connected
to one of its channels, found in several ancient HP machines.
For interrupts it uses a high-resolution timer (hrtimer).
Tested on SH7709 based hp6xx (HP Jornada 680/690 and HP Palmtop 620lx/660lx).

Also, since OSS Emulation works, the old OSS sound/oss/sh_dac_audio.c driver
would be obsolete soon, and it could be removed.

Signed-off-by: Rafael Ignacio Zurita <rizurita@yahoo.com>
Acked-by: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/include/sound/sh_dac_audio.h b/include/sound/sh_dac_audio.h
new file mode 100644
index 0000000..f5deaf1
--- /dev/null
+++ b/include/sound/sh_dac_audio.h
@@ -0,0 +1,21 @@
+/*
+ * SH_DAC specific configuration, for the dac_audio platform_device
+ *
+ * Copyright (C) 2009 Rafael Ignacio Zurita <rizurita@yahoo.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation.
+ */
+
+#ifndef __INCLUDE_SH_DAC_AUDIO_H
+#define __INCLUDE_SH_DAC_AUDIO_H
+
+struct dac_audio_pdata {
+	int buffer_size;
+	int channel;
+	void (*start)(struct dac_audio_pdata *pd);
+	void (*stop)(struct dac_audio_pdata *pd);
+};
+
+#endif /* __INCLUDE_SH_DAC_AUDIO_H */