From 1bd580fcba8f8dc4587d5d8c42edd85857b11b65 Mon Sep 17 00:00:00 2001
From: Simon Wilson <simonwilson@google.com>
Date: Thu, 2 Jun 2011 15:58:41 -0700
Subject: Support multiple cards and devices

---
 include/tinyalsa/asoundlib.h |  5 +++--
 mixer.c                      |  6 ++++--
 pcm.c                        | 16 +++++++---------
 3 files changed, 14 insertions(+), 13 deletions(-)

diff --git a/include/tinyalsa/asoundlib.h b/include/tinyalsa/asoundlib.h
index 38d3af1..f9920ce 100644
--- a/include/tinyalsa/asoundlib.h
+++ b/include/tinyalsa/asoundlib.h
@@ -57,7 +57,8 @@ struct pcm_config {
 };
 
 /* Open and close a stream */
-struct pcm *pcm_open(unsigned int device, unsigned int flags, struct pcm_config *config);
+struct pcm *pcm_open(unsigned int card, unsigned int device,
+                     unsigned int flags, struct pcm_config *config);
 int pcm_close(struct pcm *pcm);
 int pcm_is_ready(struct pcm *pcm);
 
@@ -92,7 +93,7 @@ struct mixer;
 struct mixer_ctl;
 
 /* Open and close a mixer */
-struct mixer *mixer_open(unsigned int device);
+struct mixer *mixer_open(unsigned int card);
 void mixer_close(struct mixer *mixer);
 
 /* Obtain mixer controls */
diff --git a/mixer.c b/mixer.c
index dc01e99..97f4beb 100644
--- a/mixer.c
+++ b/mixer.c
@@ -111,7 +111,7 @@ void mixer_close(struct mixer *mixer)
     /* TODO: verify frees */
 }
 
-struct mixer *mixer_open(unsigned int device)
+struct mixer *mixer_open(unsigned int card)
 {
     struct snd_ctl_elem_list elist;
     struct snd_ctl_elem_info tmp;
@@ -119,8 +119,10 @@ struct mixer *mixer_open(unsigned int device)
     struct mixer *mixer = NULL;
     unsigned int n, m;
     int fd;
+    char fn[256];
 
-    fd = open("/dev/snd/controlC0", O_RDWR);
+    snprintf(fn, sizeof(fn), "/dev/snd/controlC%u", card);
+    fd = open(fn, O_RDWR);
     if (fd < 0)
         return 0;
 
diff --git a/pcm.c b/pcm.c
index eab306f..2933dec 100644
--- a/pcm.c
+++ b/pcm.c
@@ -266,13 +266,14 @@ static unsigned int pcm_format_to_bits(enum pcm_format format)
     };
 }
 
-struct pcm *pcm_open(unsigned int device, unsigned int flags, struct pcm_config *config)
+struct pcm *pcm_open(unsigned int card, unsigned int device,
+                     unsigned int flags, struct pcm_config *config)
 {
-    const char *dname;
     struct pcm *pcm;
     struct snd_pcm_info info;
     struct snd_pcm_hw_params params;
     struct snd_pcm_sw_params sparams;
+    char fn[256];
 
     pcm = calloc(1, sizeof(struct pcm));
     if (!pcm || !config)
@@ -280,16 +281,13 @@ struct pcm *pcm_open(unsigned int device, unsigned int flags, struct pcm_config
 
     pcm->config = *config;
 
-    if (flags & PCM_IN) {
-        dname = "/dev/snd/pcmC0D0c";
-    } else {
-        dname = "/dev/snd/pcmC0D0p";
-    }
+    snprintf(fn, sizeof(fn), "/dev/snd/pcmC%uD%u%c", card, device,
+             flags & PCM_IN ? 'c' : 'p');
 
     pcm->flags = flags;
-    pcm->fd = open(dname, O_RDWR);
+    pcm->fd = open(fn, O_RDWR);
     if (pcm->fd < 0) {
-        oops(pcm, errno, "cannot open device '%s'", dname);
+        oops(pcm, errno, "cannot open device '%s'", fn);
         return pcm;
     }
 
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