ASoC: OMAP4: HDMI: add mixer control to get LPCM channels

Also fix a potential race condition where the state
could have changed during the sleep.

Change-Id: I189d0cd17ea56f5e0c2315061ab18acfcff2c91c
Signed-off-by: Simon Wilson <simonwilson@google.com>

1 files changed, 71 insertions, 6 deletions

diff --git a/sound/soc/omap/omap4-hdmi-card.c b/sound/soc/omap/omap4-hdmi-card.c
index 9024735..7a0e749 100644
--- a/sound/soc/omap/omap4-hdmi-card.c
+++ b/sound/soc/omap/omap4-hdmi-card.c
@@ -29,12 +29,10 @@
 
 #define DRV_NAME "omap4-hdmi-audio"
 
-static int omap4_hdmi_dai_hw_params(struct snd_pcm_substream *substream,
-		struct snd_pcm_hw_params *params)
+static struct omap_overlay_manager *omap4_hdmi_get_overlay_mgr(void)
 {
-	int i, count = 0;
+	int i;
 	struct omap_overlay_manager *mgr = NULL;
-	struct device *dev = substream->pcm->card->dev;
 
 	/* Find DSS HDMI device */
 	for (i = 0; i < omap_dss_get_num_overlay_managers(); i++) {
@@ -44,7 +42,21 @@ static int omap4_hdmi_dai_hw_params(struct snd_pcm_substream *substream,
 			break;
 	}
 
-	if (i == omap_dss_get_num_overlay_managers()) {
+	if (i == omap_dss_get_num_overlay_managers())
+		mgr = NULL;
+
+	return mgr;
+}
+
+static int omap4_hdmi_dai_hw_params(struct snd_pcm_substream *substream,
+		struct snd_pcm_hw_params *params)
+{
+	int count = 0;
+	struct omap_overlay_manager *mgr;
+	struct device *dev = substream->pcm->card->dev;
+
+	mgr = omap4_hdmi_get_overlay_mgr();
+	if (mgr == NULL) {
 		dev_err(dev, "HDMI display device not found!\n");
 		return -ENODEV;
 	}
@@ -52,7 +64,9 @@ static int omap4_hdmi_dai_hw_params(struct snd_pcm_substream *substream,
 	/* Make sure HDMI is power-on to avoid L3 interconnect errors */
 	while (mgr->device->state != OMAP_DSS_DISPLAY_ACTIVE) {
 		msleep(50);
-		if (count > 5)
+		if (mgr->device->state == OMAP_DSS_DISPLAY_ACTIVE)
+			break;
+		else if (count > 5)
 			return -EIO;
 		dev_err(dev, "HDMI display is not active!\n");
 		count++;
@@ -75,10 +89,61 @@ static struct snd_soc_dai_link omap4_hdmi_dai = {
 	.ops = &omap4_hdmi_dai_ops,
 };
 
+static int hdmi_max_chan_ctl_info(struct snd_kcontrol *kcontrol,
+					struct snd_ctl_elem_info *uinfo)
+{
+	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
+	uinfo->count = 1;
+	uinfo->value.integer.min = 0;
+	uinfo->value.integer.max = 8;
+
+	return 0;
+}
+
+static int hdmi_max_chan_ctl_get(struct snd_kcontrol *kcontrol,
+					struct snd_ctl_elem_value *ucontrol)
+{
+	struct omap_overlay_manager *mgr;
+	struct fb_monspecs *monspecs;
+	int i;
+	int max = 0;
+
+	mgr = omap4_hdmi_get_overlay_mgr();
+	if (mgr == NULL) {
+		/* HDMI audio not supported */
+		goto out;
+	}
+
+	monspecs = &mgr->device->panel.monspecs;
+	for (i = 0; i < monspecs->audiodb_len; i++) {
+		if (monspecs->audiodb[i].format != FB_AUDIO_LPCM)
+			continue;
+
+		if (max < monspecs->audiodb[i].channel_count)
+			max = monspecs->audiodb[i].channel_count;
+	}
+
+out:
+	ucontrol->value.integer.value[0] = max;
+
+	return 0;
+}
+
+static struct snd_kcontrol_new hdmi_max_chan_ctl = {
+	.access = SNDRV_CTL_ELEM_ACCESS_READ | SNDRV_CTL_ELEM_ACCESS_VOLATILE,
+	.iface = SNDRV_CTL_ELEM_IFACE_PCM,
+	.name = "Maximum LPCM channels",
+	.info = hdmi_max_chan_ctl_info,
+	.get = hdmi_max_chan_ctl_get,
+};
+
 static struct snd_soc_card snd_soc_omap4_hdmi = {
 	.name = "OMAP4HDMI",
 	.dai_link = &omap4_hdmi_dai,
 	.num_links = 1,
+
+	.controls = &hdmi_max_chan_ctl,
+	.num_controls = 1,
 };
 
 static __devinit int omap4_hdmi_probe(struct platform_device *pdev)