2 files changed, 79 insertions, 0 deletions

diff --git a/Documentation/arm/OMAP/DSS b/Documentation/arm/OMAP/DSS
index d0aea9192204..a564ceea9e98 100644
--- a/Documentation/arm/OMAP/DSS
+++ b/Documentation/arm/OMAP/DSS
@@ -47,6 +47,51 @@ flexible way to enable non-common multi-display configuration. In addition to
 modelling the hardware overlays, omapdss supports virtual overlays and overlay
 managers. These can be used when updating a display with CPU or system DMA.
 
+omapdss driver support for audio
+--------------------------------
+There exist several display technologies and standards that support audio as
+well. Hence, it is relevant to update the DSS device driver to provide an audio
+interface that may be used by an audio driver or any other driver interested in
+the functionality.
+
+The audio_enable function is intended to prepare the relevant
+IP for playback (e.g., enabling an audio FIFO, taking in/out of reset
+some IP, enabling companion chips, etc). It is intended to be called before
+audio_start. The audio_disable function performs the reverse operation and is
+intended to be called after audio_stop.
+
+While a given DSS device driver may support audio, it is possible that for
+certain configurations audio is not supported (e.g., an HDMI display using a
+VESA video timing). The audio_supported function is intended to query whether
+the current configuration of the display supports audio.
+
+The audio_config function is intended to configure all the relevant audio
+parameters of the display. In order to make the function independent of any
+specific DSS device driver, a struct omap_dss_audio is defined. Its purpose
+is to contain all the required parameters for audio configuration. At the
+moment, such structure contains pointers to IEC-60958 channel status word
+and CEA-861 audio infoframe structures. This should be enough to support
+HDMI and DisplayPort, as both are based on CEA-861 and IEC-60958.
+
+The audio_enable/disable, audio_config and audio_supported functions could be
+implemented as functions that may sleep. Hence, they should not be called
+while holding a spinlock or a readlock.
+
+The audio_start/audio_stop function is intended to effectively start/stop audio
+playback after the configuration has taken place. These functions are designed
+to be used in an atomic context. Hence, audio_start should return quickly and be
+called only after all the needed resources for audio playback (audio FIFOs,
+DMA channels, companion chips, etc) have been enabled to begin data transfers.
+audio_stop is designed to only stop the audio transfers. The resources used
+for playback are released using audio_disable.
+
+The enum omap_dss_audio_state may be used to help the implementations of
+the interface to keep track of the audio state. The initial state is _DISABLED;
+then, the state transitions to _CONFIGURED, and then, when it is ready to
+play audio, to _ENABLED. The state _PLAYING is used when the audio is being
+rendered.
+
+
 Panel and controller drivers
 ----------------------------
 
diff --git a/include/video/omapdss.h b/include/video/omapdss.h
index 1217df40cb7e..bb30242eeea1 100644
--- a/include/video/omapdss.h
+++ b/include/video/omapdss.h
@@ -51,6 +51,8 @@
 
 struct omap_dss_device;
 struct omap_overlay_manager;
+struct snd_aes_iec958;
+struct snd_cea_861_aud_if;
 
 enum omap_display_type {
         OMAP_DISPLAY_TYPE_NONE          = 0,
@@ -158,6 +160,13 @@ enum omap_dss_display_state {
         OMAP_DSS_DISPLAY_SUSPENDED,
 };
 
+enum omap_dss_audio_state {
+        OMAP_DSS_AUDIO_DISABLED = 0,
+        OMAP_DSS_AUDIO_ENABLED,
+        OMAP_DSS_AUDIO_CONFIGURED,
+        OMAP_DSS_AUDIO_PLAYING,
+};
+
 /* XXX perhaps this should be removed */
 enum omap_dss_overlay_managers {
         OMAP_DSS_OVL_MGR_LCD,
@@ -583,6 +592,8 @@ struct omap_dss_device {
 
         enum omap_dss_display_state state;
 
+        enum omap_dss_audio_state audio_state;
+
         /* platform specific  */
         int (*platform_enable)(struct omap_dss_device *dssdev);
         void (*platform_disable)(struct omap_dss_device *dssdev);
@@ -595,6 +606,11 @@ struct omap_dss_hdmi_data
         int hpd_gpio;
 };
 
+struct omap_dss_audio {
+        struct snd_aes_iec958 *iec;
+        struct snd_cea_861_aud_if *cea;
+};
+
 struct omap_dss_driver {
         struct device_driver driver;
 
@@ -642,6 +658,24 @@ struct omap_dss_driver {
 
         int (*read_edid)(struct omap_dss_device *dssdev, u8 *buf, int len);
         bool (*detect)(struct omap_dss_device *dssdev);
+
+        /*
+         * For display drivers that support audio. This encompasses
+         * HDMI and DisplayPort at the moment.
+         */
+        /*
+         * Note: These functions might sleep. Do not call while
+         * holding a spinlock/readlock.
+         */
+        int (*audio_enable)(struct omap_dss_device *dssdev);
+        void (*audio_disable)(struct omap_dss_device *dssdev);
+        bool (*audio_supported)(struct omap_dss_device *dssdev);
+        int (*audio_config)(struct omap_dss_device *dssdev,
+                struct omap_dss_audio *audio);
+        /* Note: These functions may not sleep */
+        int (*audio_start)(struct omap_dss_device *dssdev);
+        void (*audio_stop)(struct omap_dss_device *dssdev);
+
 };
 
 int omap_dss_register_driver(struct omap_dss_driver *);