tegra: hdmi: audio: sysfs node for max audio channel info

Provide max_pcm_channels from the EDID audio info
to HAL before the EDID audio info gets copied to
the HDA codec driver. This is done since HAL requires
prior channel information in order to open the pcm
device

Bug 200009194

Change-Id: I2dd365a095705950901ec2228b94c8a3a63b1abd
Signed-off-by: Anshuman Nath Kar <anshumank@nvidia.com>
(cherry picked from commit 19a30e527133d06eea3dabc9f3b15011c2c1ad9a)
Reviewed-on: http://git-master/r/426354
Reviewed-by: Mitch Luban <mluban@nvidia.com>
GVS: Gerrit_Virtual_Submit

diff --git a/drivers/video/tegra/dc/hdmi.c b/drivers/video/tegra/dc/hdmi.c
index 41a54b212deb73c17e936e21f324c7a090c09777..7478ceea63d2106054eca7e0767f6f584f95a965 100644 (file)
--- a/drivers/video/tegra/dc/hdmi.c
+++ b/drivers/video/tegra/dc/hdmi.c
@@ -57,6 +57,13 @@
 
 #define HDMI_REKEY_DEFAULT             56
 
+/* According to HDMI EDID specs for Short Audio
+ * Descriptor, format type LPCM is 1 (this is required
+ * by HAL before EDL is copied to hda codec driver
+ */
+#define AUDIO_CODING_TYPE_LPCM         1
+#define AUDIO_SAD_BYTE_SIZE            3
+
 #define HDMI_ELD_VER_INDEX                     0
 #define HDMI_ELD_RESERVED1_INDEX               1
 #define HDMI_ELD_BASELINE_LEN_INDEX            2
@@ -84,6 +91,14 @@
 
 struct tegra_dc_hdmi_data *dc_hdmi;
 
+static ssize_t hdmi_audio_get_max_channel(struct kobject *kobj,
+       struct kobj_attribute *attr, char *buf);
+
+static struct kobj_attribute hdmi_audio_channel_config =
+       __ATTR(config, 0640, hdmi_audio_get_max_channel, NULL);
+
+static struct kobject *hdmi_audio;
+
 #if defined(CONFIG_ARCH_TEGRA_3x_SOC)
 const struct tmds_config tmds_config[] = {
        { /* 480p modes */
@@ -962,6 +977,37 @@ static int tegra_dc_hdmi_i2c_xfer(struct tegra_dc *dc, struct i2c_msg *msgs,
        return i2c_transfer(hdmi->i2c_info.client->adapter, msgs, num);
 }
 
+/* This is needed to obtain audio channel info before HAL
+ * opens pcm stream and copies edid audio data */
+static int tegra_hdmi_get_max_channels(void)
+{
+       struct tegra_dc_hdmi_data *hdmi = dc_hdmi;
+       u8 sad_channels;
+       u8 sad_format;
+       u8 max_channels = 0;
+       int i;
+
+       if (!hdmi)
+               return 0;
+
+       if (!hdmi->eld_retrieved)
+               return 0;
+
+       if (!hdmi->dc->enabled)
+               return 0;
+
+       for (i = 0; i < hdmi->eld.sad_count; i++) {
+               sad_channels = max(((hdmi->eld.sad[AUDIO_SAD_BYTE_SIZE*i]
+                       & 0x7) + 1), 2);
+               sad_format = ((hdmi->eld.sad[AUDIO_SAD_BYTE_SIZE*i]
+                       & 0x78) >> 3);
+               if (sad_format == AUDIO_CODING_TYPE_LPCM)
+                       max_channels =  max_channels > sad_channels ?
+                               max_channels : sad_channels;
+       }
+       return max_channels;
+}
+
 static int tegra_dc_hdmi_init(struct tegra_dc *dc)
 {
        struct tegra_dc_hdmi_data *hdmi;
@@ -1177,6 +1223,18 @@ static int tegra_dc_hdmi_init(struct tegra_dc *dc)
                goto err_gpio_free;
        }
 
+       /*Add sysfs node to query hdmi audio channels on startup*/
+       hdmi_audio = kobject_create_and_add("hdmi_audio_channels", kernel_kobj);
+       if (!hdmi_audio) {
+               pr_warn("kobject create_and_add hdmi_audio_channels failed\n");
+               return 0;
+       }
+       ret = sysfs_create_file(hdmi_audio, &hdmi_audio_channel_config.attr);
+       if (ret) {
+               pr_warn("sysfs create file hdmi_audio_channels failed\n");
+               return 0;
+       }
+
        return 0;
 
 err_gpio_free:
@@ -2230,3 +2288,9 @@ struct tegra_dc *tegra_dc_hdmi_get_dc(struct tegra_dc_hdmi_data *hdmi)
 {
        return hdmi ? hdmi->dc : NULL;
 }
+
+static ssize_t hdmi_audio_get_max_channel(struct kobject *kobj,
+       struct kobj_attribute *attr, char *buf)
+{
+       return sprintf(buf, "%d\n", tegra_hdmi_get_max_channels());
+}