summaryrefslogtreecommitdiffstats
path: root/sound/soc/cirrus/Kconfig
diff options
context:
space:
mode:
authorAlexander Sverdlin <alexander.sverdlin@gmail.com>2018-04-28 22:51:42 +0200
committerMark Brown <broonie@kernel.org>2018-05-11 04:27:33 +0200
commit98e1241c357b82e070294f486cef91a1263874fa (patch)
tree5761b94e4ab565df45ebd0e2031837b8580eb128 /sound/soc/cirrus/Kconfig
parentARM: ep93xx: i2s: Add IRQ to platform device resources (diff)
downloadlinux-98e1241c357b82e070294f486cef91a1263874fa.tar.xz
linux-98e1241c357b82e070294f486cef91a1263874fa.zip
ASoC: cirrus: i2s: IRQ-based stream watchdog
I2S controller on EP93xx seems to have undocumented HW issue. According to "EP93xx User’s Guide", controller can handle underflow and either transmit last sample or zeroes in such case until FIFO is filled again. In reality undeflow conditions seem to confuse internal state machine from time to time and the whole stream gets shifted by one byte (as captured by logic analyser on the I2S outputs). One could only hear noise instead of original stream and this continues until the FIFO is disabled and enabled again. Work this around by watching underflow interrupt and resetting I2S TX channel + fill FIFO with zero samples until DMA catches up again. This is a nasty workaround, but it works. Hence, Kconfig option to disable it in case of problems. Signed-off-by: Alexander Sverdlin <alexander.sverdlin@gmail.com> Signed-off-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'sound/soc/cirrus/Kconfig')
-rw-r--r--sound/soc/cirrus/Kconfig17
1 files changed, 17 insertions, 0 deletions
diff --git a/sound/soc/cirrus/Kconfig b/sound/soc/cirrus/Kconfig
index c7cd60f009e9..e09199124c36 100644
--- a/sound/soc/cirrus/Kconfig
+++ b/sound/soc/cirrus/Kconfig
@@ -9,6 +9,23 @@ config SND_EP93XX_SOC
config SND_EP93XX_SOC_I2S
tristate
+if SND_EP93XX_SOC_I2S
+
+config SND_EP93XX_SOC_I2S_WATCHDOG
+ bool "IRQ based underflow watchdog workaround"
+ default y
+ help
+ I2S controller on EP93xx seems to have undocumented HW issue.
+ Underflow of internal I2S controller FIFO could confuse the
+ state machine and the whole stream can be shifted by one byte
+ until I2S is disabled. This option enables IRQ based watchdog
+ which disables and re-enables I2S in case of underflow and
+ fills FIFO with zeroes.
+
+ If you are unsure how to answer this question, answer Y.
+
+endif # if SND_EP93XX_SOC_I2S
+
config SND_EP93XX_SOC_AC97
tristate
select AC97_BUS