Having sgtl5000_clk defines as "fixed-clock" is not enough to prevent
the dai subsystem from overwriting the frequency via sgtl5000_set_dai_sysclk.
Setting system-clock-fixed does the job, and now a 1kHz sine wave
comes out as actually 1kHz, no matter the sample rate of the source.
Testcase: These should sound the same:
speaker-test -r 48000 -t sine -f 1000
speaker-test -r 24000 -t sine -f 1000
Also remove the clock link here as having it in sgtl5000 and
sgtl5000_codec causes duplicate clock unprepares with associated
backtrace.
Signed-off-by: Jakob Unterwurzacher <jakob.unterwurzacher@xxxxxxxxxxxxxxxxxxxxx>
---
arch/arm64/boot/dts/rockchip/px30-ringneck-haikou.dts | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/arch/arm64/boot/dts/rockchip/px30-ringneck-haikou.dts b/arch/arm64/boot/dts/rockchip/px30-ringneck-haikou.dts
index dafeef0c2dab..2cad02096271 100644
--- a/arch/arm64/boot/dts/rockchip/px30-ringneck-haikou.dts
+++ b/arch/arm64/boot/dts/rockchip/px30-ringneck-haikou.dts
@@ -72,8 +72,10 @@ i2s0-sound {
simple-audio-card,bitclock-master = <&sgtl5000_codec>;
sgtl5000_codec: simple-audio-card,codec {
- clocks = <&sgtl5000_clk>;
sound-dai = <&sgtl5000>;
+ // Prevent the dai subsystem from overwriting the clock
+ // frequency. We are using a fixed-frequency oscillator.
+ system-clock-fixed;
};
simple-audio-card,cpu {
--
2.39.2
