From: Andrejs Cainikovs <andrejs.cainikovs@xxxxxxxxxxx> In current configuration, nau8822 codec on development carrier board provides distorted audio output. This happens due to reference clock is fixed to 25MHz and no PLL is enabled. Following is the calculation of deviation error for different frequencies: 44100Hz: fs = 256 (fixed) prescaler = 2 target frequency = 44100 * 256 * 2 = 22579200 deviation = 22579200 vs 25000000 = 9.6832% 48000Hz: fs = 256 (fixed) prescaler = 2 target frequency = 48000 * 256 * 2 = 24576000 deviation = 24576000 vs 25000000 = 1.696% Enabling nau822 PLL via providing mclk-fs property to simple-audio-card configures clocks properly, but also adjusts audio reference clock (mclk), which in case of TI AM62 should be avoided, as it only supports 25MHz output [1][2]. This change enables PLL on nau8822 by providing mclk-fs, and moves away audio reference clock from DAI configuration, which prevents simple-audio-card to adjust it before every playback [3]. [1]: https://e2e.ti.com/support/processors-group/processors/f/processors-forum/1175479/processor-sdk-am62x-output-audio_ext_refclk0-as-mclk-for-codec-and-mcbsp/4444986#4444986 [2]: https://e2e.ti.com/support/processors-group/processors/f/processors-forum/1188051/am625-audio_ext_refclk1-clock-output---dts-support/4476322#4476322 [3]: sound/soc/generic/simple-card-utils.c#L441 Signed-off-by: Andrejs Cainikovs <andrejs.cainikovs@xxxxxxxxxxx> --- This patch requires https://lore.kernel.org/all/20240409121719.337709-1-andrejs.cainikovs@xxxxxxxxx/ to be applied, if not the audio will just stop working because no code will ever enable the required clock to the codec. --- arch/arm64/boot/dts/ti/k3-am62-verdin-dev.dtsi | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/arch/arm64/boot/dts/ti/k3-am62-verdin-dev.dtsi b/arch/arm64/boot/dts/ti/k3-am62-verdin-dev.dtsi index 74eec1a1abca..5c1284b802ad 100644 --- a/arch/arm64/boot/dts/ti/k3-am62-verdin-dev.dtsi +++ b/arch/arm64/boot/dts/ti/k3-am62-verdin-dev.dtsi @@ -14,6 +14,7 @@ sound { simple-audio-card,bitclock-master = <&codec_dai>; simple-audio-card,format = "i2s"; simple-audio-card,frame-master = <&codec_dai>; + simple-audio-card,mclk-fs = <256>; simple-audio-card,name = "verdin-nau8822"; simple-audio-card,routing = "Headphones", "LHP", @@ -34,7 +35,6 @@ sound { "Line", "Line In"; codec_dai: simple-audio-card,codec { - clocks = <&audio_refclk1>; sound-dai = <&nau8822_1a>; }; @@ -107,6 +107,8 @@ nau8822_1a: audio-codec@1a { reg = <0x1a>; pinctrl-names = "default"; pinctrl-0 = <&pinctrl_i2s1_mclk>; + clock-names = "mclk"; + clocks = <&audio_refclk1>; #sound-dai-cells = <0>; }; -- 2.34.1
