spark: add volume control for alsa mixer

Makefile.am

@@ -43,9 +43,11 @@ libstb_hal_a_LIBADD += \
 	azbox/video.o
 endif
 if BOXTYPE_SPARK
+libstb_hal_test_LDADD += -lasound
 SUBDIRS += libspark libeplayer3
 libstb_hal_a_LIBADD += \
 	libspark/audio.o \
+	libspark/audio_mixer.o \
 	libspark/dmx.o \
 	libspark/init.o \
 	libspark/irmp.o \

include/audio_td.h

@@ -3,6 +3,9 @@
 #include "../libtriple/audio_td.h"
 #elif HAVE_SPARK_HARDWARE
 #include "../libspark/audio_lib.h"
+#ifdef MARTII
+#include "../libspark/audio_mixer.h"
+#endif
 #elif HAVE_AZBOX_HARDWARE
 #include "../azbox/audio_lib.h"
 #else

libspark/Makefile.am

@@ -5,7 +5,7 @@ INCLUDES = \
 noinst_LIBRARIES = libspark.a
 
 AM_CXXFLAGS = -fno-rtti -fno-exceptions -fno-strict-aliasing
-AM_LDFLAGS = -lpthread
+AM_LDFLAGS = -lpthread -lasound
 
 libspark_a_SOURCES = \
 	irmp.c \
@@ -13,6 +13,7 @@ libspark_a_SOURCES = \
 	dmx.cpp \
 	video.cpp \
 	audio.cpp \
+	audio_mixer.cpp \
 	init.cpp \
 	playback_libeplayer3.cpp \
 	pwrmngr.cpp \

libspark/audio_mixer.cpp

@@ -0,0 +1,70 @@
+/*
+ * audio_mixer.c
+ *
+ * (C) 2012 martii
+ *
+ * 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 2
+ * 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, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <audio_mixer.h>
+
+mixerVolume::mixerVolume(const char *name, const char *card, long volume) {
+	sid = NULL;
+	elem = NULL;
+	handle = NULL;
+	min = 0;
+	max = 100;
+	char cardId[10];
+
+	if (!name || !card)
+		return;
+
+	int cx = snd_card_get_index(card);
+	if (cx < 0 || cx > 31)
+		return;
+	snprintf(cardId, sizeof(cardId), "hw:%i", cx);
+
+	if (0 > snd_mixer_open(&handle, 0))
+		return;
+	if (0 > snd_mixer_attach(handle, cardId))
+		return;
+	if (0 > snd_mixer_selem_register(handle, NULL, NULL))
+		return;
+	if (0 > snd_mixer_load(handle))
+		return;
+	snd_mixer_selem_id_alloca(&sid);
+	if (!sid)
+		return;
+	snd_mixer_selem_id_set_index(sid, 0);
+	snd_mixer_selem_id_set_name(sid, name);
+	elem = snd_mixer_find_selem(handle, sid);
+	if (elem) {
+		snd_mixer_selem_get_playback_volume_range(elem, &min, &max);
+		setVolume(volume);
+	}
+}
+mixerVolume::~mixerVolume()
+{
+	if (handle)
+		snd_mixer_close(handle);
+	if (sid)
+		snd_mixer_selem_id_free(sid);
+}
+
+bool mixerVolume::setVolume(long volume) {
+	return elem
+		&& (volume > -1)
+		&& (volume < 101)
+		&& !snd_mixer_selem_set_playback_volume_all(elem, min + volume * (max - min)/101);
+}

libspark/audio_mixer.h

@@ -0,0 +1,37 @@
+/*
+ * audio_mixer.h
+ *
+ * (C) 2012 martii
+ *
+ * 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 2
+ * 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, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef __AUDIO_MIXER_H__
+#define __AUDIO_MIXER_H__
+#include <alsa/asoundlib.h>
+
+class mixerVolume
+{
+	private:
+		long min, max;
+		snd_mixer_t *handle;
+		snd_mixer_elem_t* elem;
+		snd_mixer_selem_id_t *sid;
+	public:
+		mixerVolume(const char *selem_name, const char *Card, long volume = -1);
+		~mixerVolume(void);
+		bool setVolume(long volume);
+};
+#endif
+