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-rw-r--r--Documentation/arm/OMAP/DSS45
-rw-r--r--include/video/omapdss.h34
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 *);