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Merge branch 'omapdss-hdmi-audio'
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Merge OMAP DSS HDMI audio patches from Ricardo Neri
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Tomi Valkeinen committed May 11, 2012
2 parents 38137c8 + f3a9749 commit 037983e
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45 changes: 45 additions & 0 deletions Documentation/arm/OMAP/DSS
Original file line number Diff line number Diff line change
Expand Up @@ -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
----------------------------

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4 changes: 4 additions & 0 deletions drivers/video/omap2/dss/Kconfig
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Expand Up @@ -68,6 +68,10 @@ config OMAP4_DSS_HDMI
HDMI Interface. This adds the High Definition Multimedia Interface.
See http://www.hdmi.org/ for HDMI specification.

config OMAP4_DSS_HDMI_AUDIO
bool
depends on OMAP4_DSS_HDMI

config OMAP2_DSS_SDI
bool "SDI support"
depends on ARCH_OMAP3
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8 changes: 8 additions & 0 deletions drivers/video/omap2/dss/dss.h
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Expand Up @@ -464,6 +464,14 @@ int omapdss_hdmi_read_edid(u8 *buf, int len);
bool omapdss_hdmi_detect(void);
int hdmi_panel_init(void);
void hdmi_panel_exit(void);
#ifdef CONFIG_OMAP4_DSS_HDMI_AUDIO
int hdmi_audio_enable(void);
void hdmi_audio_disable(void);
int hdmi_audio_start(void);
void hdmi_audio_stop(void);
bool hdmi_mode_has_audio(void);
int hdmi_audio_config(struct omap_dss_audio *audio);
#endif

/* RFBI */
int rfbi_init_platform_driver(void) __init;
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8 changes: 6 additions & 2 deletions drivers/video/omap2/dss/dss_features.c
Original file line number Diff line number Diff line change
Expand Up @@ -568,13 +568,17 @@ static const struct ti_hdmi_ip_ops omap4_hdmi_functions = {
.pll_enable = ti_hdmi_4xxx_pll_enable,
.pll_disable = ti_hdmi_4xxx_pll_disable,
.video_enable = ti_hdmi_4xxx_wp_video_start,
.video_disable = ti_hdmi_4xxx_wp_video_stop,
.dump_wrapper = ti_hdmi_4xxx_wp_dump,
.dump_core = ti_hdmi_4xxx_core_dump,
.dump_pll = ti_hdmi_4xxx_pll_dump,
.dump_phy = ti_hdmi_4xxx_phy_dump,
#if defined(CONFIG_SND_OMAP_SOC_OMAP4_HDMI) || \
defined(CONFIG_SND_OMAP_SOC_OMAP4_HDMI_MODULE)
#if defined(CONFIG_OMAP4_DSS_HDMI_AUDIO)
.audio_enable = ti_hdmi_4xxx_wp_audio_enable,
.audio_disable = ti_hdmi_4xxx_wp_audio_disable,
.audio_start = ti_hdmi_4xxx_audio_start,
.audio_stop = ti_hdmi_4xxx_audio_stop,
.audio_config = ti_hdmi_4xxx_audio_config,
#endif

};
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