Katsuhiro Suzuki 2458adb8f9 SoC: simple-card-utils: set 0Hz to sysclk when shutdown ... This patch set 0Hz to sysclk when shutdown the card. Some codecs set rate constraints that derives from sysclk. This mechanism works correctly if machine drivers give fixed frequency. But simple-audio and audio-graph card set variable clock rate if 'mclk-fs' property exists. In this case, rate constraints will go bad scenario. For example a codec accepts three limited rates (mclk / 256, mclk / 384, mclk / 512). Bad scenario as follows (mclk-fs = 256): - Initialize sysclk by correct value (Ex. 12.288MHz) - Codec set constraints of PCM rate by sysclk 48kHz (1/256), 32kHz (1/384), 24kHz (1/512) - Play 48kHz sound, it's acceptable - Sysclk is not changed - Play 32kHz sound, it's acceptable - Set sysclk to 8.192MHz (= fs * mclk-fs = 32k * 256) - Codec set constraints of PCM rate by sysclk 32kHz (1/256), 21.33kHz (1/384), 16kHz (1/512) - Play 48kHz again, but it's NOT acceptable because constraints do not allow 48kHz So codecs treat 0Hz sysclk as signal of applying no constraints to avoid this problem. Signed-off-by: Katsuhiro Suzuki <katsuhiro@katsuster.net> Link: https://lore.kernel.org/r/20190907174501.19833-1-katsuhiro@katsuster.net Signed-off-by: Mark Brown <broonie@kernel.org>		2019-09-09 10:51:21 +01:00
..
audio-graph-card.c	ASoC: audio-graph: indicate rebind issue	2019-09-03 12:36:24 +01:00
Kconfig	treewide: Add SPDX license identifier - Makefile/Kconfig	2019-05-21 10:50:46 +02:00
Makefile	ASoC: simple-scu-card: remove simple-scu-card	2019-01-03 16:34:19 +00:00
simple-card-utils.c	SoC: simple-card-utils: set 0Hz to sysclk when shutdown	2019-09-09 10:51:21 +01:00
simple-card.c	ASoC: simple-card: indicate rebind issue	2019-09-03 12:36:06 +01:00