linux/drivers/gpu/drm/bridge/synopsys
Neil Armstrong fdbdcc83ff drm/bridge: dw-hdmi: Use automatic CTS generation mode when using non-AHB audio
When using an I2S source using a different clock source (usually the I2S
audio HW uses dedicated PLLs, different from the HDMI PHY PLL), fixed
CTS values will cause some frequent audio drop-out and glitches as
reported on Amlogic, Allwinner and Rockchip SoCs setups.

Setting the CTS in automatic mode will let the HDMI controller generate
automatically the CTS value to match the input audio clock.

The DesignWare DW-HDMI User Guide explains:
  For Automatic CTS generation
  Write "0" on the bit field "CTS_manual", Register 0x3205: AUD_CTS3

The DesignWare DW-HDMI Databook explains :
  If "CTS_manual" bit equals 0b this registers contains "audCTS[19:0]"
  generated by the Cycle time counter according to specified timing.

Cc: Jernej Skrabec <jernej.skrabec@siol.net>
Cc: Maxime Ripard <maxime.ripard@bootlin.com>
Cc: Jonas Karlman <jonas@kwiboo.se>
Cc: Heiko Stuebner <heiko@sntech.de>
Cc: Jerome Brunet <jbrunet@baylibre.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Tested-by: Jernej Skrabec <jernej.skrabec@siol.net>
Reviewed-by: Jernej Skrabec <jernej.skrabec@siol.net>
Tested-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190612085147.26971-1-narmstrong@baylibre.com
2019-07-01 12:33:19 +02:00
..
Kconfig treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
Makefile treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
dw-hdmi-ahb-audio.c drm: bridge: dw-hdmi: Remove superfluous snd_pcm_suspend*() calls 2019-01-15 17:48:10 +01:00
dw-hdmi-audio.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
dw-hdmi-cec.c drm/bridge: dw-hdmi: add cec driver 2017-08-07 16:18:53 +05:30
dw-hdmi-cec.h drm/bridge: dw-hdmi: add cec driver 2017-08-07 16:18:53 +05:30
dw-hdmi-i2s-audio.c drm: remove include of drmP.h from bridge/dw_hdmi.h 2019-01-09 22:27:44 +01:00
dw-hdmi.c drm/bridge: dw-hdmi: Use automatic CTS generation mode when using non-AHB audio 2019-07-01 12:33:19 +02:00
dw-hdmi.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
dw-mipi-dsi.c drm/bridge/synopsys: dsi: Allow VPG to be enabled via debugfs 2019-06-24 13:41:07 +02:00