diff options
| -rw-r--r-- | Documentation/arm/OMAP/DSS | 45 | ||||
| -rw-r--r-- | include/video/omapdss.h | 34 |
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 *); |