i.MX8M + adv7535 HDMI bridge Audio Question

* i.MX8M + adv7535 HDMI bridge Audio Question
@ 2020-08-06 14:27 Adam Ford
  2020-08-06 18:05 ` Adam Ford
  0 siblings, 1 reply; 2+ messages in thread
From: Adam Ford @ 2020-08-06 14:27 UTC (permalink / raw)
  To: NXP Linux Team, arm-soc, Sam Ravnborg

I have an i.MX8M Mini, and I am trying to route audio over the adv7535
HDMI bridge chip.

I have the HDMI video working, but I want to add audio.

The physical connection is using SAI5 interface, and it is being
routed with the following:

SAI5_MCLK -> adv7535 SCLK/MCLK pin
SAI5_TXD0 - > adv7535  I2S pin
SAI5_TX_SYNC -> adv7535 LRCLK pin

I hope this is correct.

I have configured the sai5 node as follows:
&sai5 {
     pinctrl-names = "default";
     pinctrl-0 = <&pinctrl_sai5>;
     assigned-clocks = <&clk IMX8MM_CLK_SAI5>;
     assigned-clock-parents = <&clk IMX8MM_AUDIO_PLL1_OUT>;
     assigned-clock-rates = <24576000>;
     fsl,sai-mclk-direction-output;
     #sound-dai-cells = <0>;
     status = "okay";
};

And I have created a simple-audio-card as follows:

hdmi_sound: hdmi-sound {
     compatible = "simple-audio-card";
     simple-audio-card,name = "hdmi-sound";
     simple-audio-card,format = "i2s";
     #sound-dai-cells = <0>;
     simple-audio-card,cpu {
          sound-dai = <&sai5>;
          system-clock-direction-out;
     };
     simple-audio-card,codec {
          sound-dai = <&adv_bridge>;
     };
};

I added the 2nd port on the adv7535 which is required for audio as follows:
ports {
     #address-cells = <1>;
     #size-cells = <0>;

     port@0 {
          reg = <0>;
          adv7535_from_dsim: endpoint {
               remote-endpoint = <&dsim_to_adv7535>;
          };
     };

     port@2 {
          reg = <2>;
          codec_adv7535: endpoint {
               remove-endpoint = <&hdmi_sound>;
          };
     };
};

In theory that should create a sound card linking the HDMI bridge to
the sound card.

When booting, I see:

[    4.162391] asoc-simple-card hdmi-sound: i2s-hifi <-> 30050000.sai mapping ok
[    4.169564] asoc-simple-card hdmi-sound: ASoC: no DMI vendor name!

I do not know if the missing DMI vendor name is an issue.

aplay -l shows:

card 2: hdmisound [hdmi-sound], device 0: 30050000.sai-i2s-hifi i2s-hifi-0 []
  Subdevices: 1/1
  Subdevice #0: subdevice #0

So I can see the audio card is appearing.  When I attempt to run a
test with the following command:

     speaker-test -c2 -t wav -D sysdefault:CARD=hdmisound

It acts as if it's working, but I don't get any sound from the HDMI
TV.  (yes, I checked the volume, and the TV works on other devices)

Playback device is sysdefault:CARD=hdmisound
Stream parameters are 48000Hz, S16_LE, 2 channels
WAV file(s)
Rate set to 48000Hz (requested 48000Hz)
Buffer size range from 64 to 16384
Period size range from 32 to 8192
Using max buffer size 16384
Periods = 4
was set period_size = 4096
was set buffer_size = 16384
 0 - Front Left
 1 - Front Right
Time per period = 2.732281
...

Does anyone have any suggestions on what I may be missing or what I am
doing wrong?

thanks,

adam

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