ASoC: hdmi-codec: Fix hdmi_of_xlate_dai_name when #sound-dai-cells = <0>

If a DAI specifies "#sound-dai-cells = <0>" in device-tree then hdmi_of_xlate_dai_name() will be called with zero args, which it isn't implemented to cope with. The resulting use of an uninitialised variable for the id will usually result in an error like:

asoc-simple-card sound: parse error -11
asoc-simple-card: probe of sound failed with error -11

Fix this by using and id of zero if no arg is provided.

---

Jyri, FYI, I believe this issue broke your commit df0bd1e8f3c508 ("ARM: dts:
am335x-boneblack: Add HDMI audio support")

 sound/soc/codecs/hdmi-codec.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

index b904492..6661ace 100644
@@ -364,7 +364,7 @@ static int hdmi_of_xlate_dai_name(struct snd_soc_component *component,
 				  struct of_phandle_args *args,
 				  const char **dai_name)
 {
-	int id = args->args[0];
+	int id = args->args_count ? args->args[0] : 0;
 
 	if (id < ARRAY_SIZE(hdmi_dai_name)) {
 		*dai_name = hdmi_dai_name[id];

2.1.4

If a DAI specifies "#sound-dai-cells = <0>" in device-tree then hdmi_of_xlate_dai_name() will be called with zero args, which it isn't implemented to cope with. The resulting use of an uninitialised variable for the id will usually result in an error like:

asoc-simple-card sound: parse error -11
asoc-simple-card: probe of sound failed with error -11

Fix this by using and id of zero if no arg is provided.

---

Changes since v1
- Replace ternary ?: operator with if/else

 sound/soc/codecs/hdmi-codec.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

index b904492..90b5948 100644
@@ -364,7 +364,12 @@ static int hdmi_of_xlate_dai_name(struct snd_soc_component *component,
 				  struct of_phandle_args *args,
 				  const char **dai_name)
 {
-	int id = args->args[0];
+	int id;
+
+	if (args->args_count)
+		id = args->args[0];
+	else
+		id = 0;
 
 	if (id < ARRAY_SIZE(hdmi_dai_name)) {
 		*dai_name = hdmi_dai_name[id];

2.1.4