iMX8QXP SPDIF problem "cannot set hw params: Invalid argument"

[Buridan]

Dear NXP experts:

Now I'm using SPDIF as the primary audio card of Android 10 on iMX8QXP mek board. I don't need the codec code and just output the SPDIF signal form SPDIF0_TX pin. The SDK version is imx8_10_2.2.0 .

My DTS config like this:

// imx8x-mek.dtsi
&spdif0 {
	compatible = "fsl,imx8qm-spdif";
	pinctrl-names = "default";
	pinctrl-0 = <&pinctrl_spdif0>;
	assigned-clocks = <&acm IMX_ADMA_ACM_SPDIF0_TX_CLK_SEL>,
			<&clk IMX_SC_R_AUDIO_PLL_0 IMX_SC_PM_CLK_PLL>,
			<&clk IMX_SC_R_AUDIO_PLL_0 IMX_SC_PM_CLK_SLV_BUS>,
			<&clk IMX_SC_R_AUDIO_PLL_0 IMX_SC_PM_CLK_MST_BUS>,
			<&spdif0_lpcg 0>;
	assigned-clock-parents = <&aud_pll_div0_lpcg 0>;
	assigned-clock-rates = <0>, <786432000>, <49152000>, <24576000>, <49152000>;
	status = "okay";
};

pinctrl_spdif0: spdif0grp {
	fsl,pins = <
		IMX8QXP_SPDIF0_TX_ADMA_SPDIF0_TX        0xc6000040
		IMX8QXP_SPDIF0_RX_ADMA_SPDIF0_RX        0xc6000040
	>;
};

// imxqxp-mek.dts
sound-dummy {
	compatible = "fsl,imx-audio-dummy";
	model = "imx-dummy";
	dai-controller = <&sai0>, <&sai1>, <&esai0>, <&spdif0>;
	dai-codec = <&codec_dummy>;
	status = "okay";
};

The driver modified from NXP dummy codec example, and the part of SPDIF copy from kernel/sound/soc/fsl/imx-spdif.c like this:

// imx-dummy.c
static int imx_dummy_spdif_hw_params(struct snd_pcm_substream *substream,
									 struct snd_pcm_hw_params *params)
{
	struct snd_soc_pcm_runtime *rtd = substream->private_data;
	struct device *dev = rtd->card->dev;
	int ret = 0;
	unsigned int freq;

	printk("run in %s\n", __func__);

	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
		u64 rate = params_rate(params);

		freq = do_div(rate, 8000) ? CLK_11K_FREQ : CLK_8K_FREQ;
		ret = snd_soc_dai_set_sysclk(rtd->cpu_dai, STC_TXCLK_SPDIF_ROOT,
									 freq, SND_SOC_CLOCK_OUT);
		if (ret)
			dev_err(dev, "failed to set cpu sysclk: %d\n", ret);
	}

	return ret;
}
static struct snd_soc_ops imx_aif_spdif_ops = {
	.hw_params = imx_dummy_spdif_hw_params,
};

static int imx_dummy_probe(struct platform_device *pdev)
{
	...
	for (i = 0; i < num_dai; i++) {
		...
		priv->dai[i].stream_name = "SAI S/PDIF PCM";
		priv->dai[i].codecs->dai_name = "snd-soc-dummy-dai";
		priv->dai[i].codecs->name = "snd-soc-dummy";
		...
		if (strstr(cpu_np->name, "spdif")) {
			priv->dai[i].ops = &imx_aif_spdif_ops;
		} else {
		...
	...
}

But it seems not work when I use tinyplay to play wav files:

mek_8q:/sdcard/Music # cat /proc/asound/cards
 0 [imxdummy       ]: imx-dummy - imx-dummy
                      imx-dummy
mek_8q:/sdcard/Music # ls /dev/snd/
controlC0 pcmC0D0p pcmC0D1p pcmC0D2p pcmC0D3p
pcmC0D0c  pcmC0D1c pcmC0D2c pcmC0D3c timer
mek_8q:/sdcard/Music # tinyplay ./1khz-16000-16-1.wav -D 0 -d 3 -p 1024 -n 3
Sample is 1 channels, device only supports >= 2 channels
Bitrate is 16 bits, device only supports >= 32 bits
mek_8q:/sdcard/Music # tinyplay ./1khz-16000-32-2.wav -D 0 -d 3 -p 1024 -n 3
Sample rate is 16000Hz, device only supports >= 32000Hz
mek_8q:/sdcard/Music # tinyplay ./1khz-48000-32-2.wav -D 0 -d 3 -p 1024 -n 3
Unable to open PCM device 3 (cannot set hw params: Invalid argument)
mek_8q:/sdcard/Music # tinymix
Mixer name: 'imx-dummy'
Number of controls: 9
ctl     type    num     name                                     value

0       IEC958  1       IEC958 Playback Default                  unknown
1       IEC958  1       IEC958 Capture Default                   unknown
2       IEC958  1       IEC958 Subcode Capture Default           unknown
Failed to mixer_ctl_get_array
3       BYTE    12      IEC958 Q-subcode Capture Default         4      BOOL    1       IEC958 Rx V-Bit Errors                   Off
5       BOOL    1       IEC958 Tx V-Bit                          Off
6       INT     1       RX Sample Rate                           0
7       BOOL    1       IEC958 USyncMode CDText                  Off
8       BOOL    1       IEC958 Rx Raw Capture Mode Bit           Off

After configured the SPDIF(/dev/snd/pcmC0D3x, port = 3) as the primary card in vendor/nxp-opensource/imx/alsa/tinyalsa_hal.cpp, the logcat like this when playing audio in app:

02-01 07:15:14.972   371  2137 I audio_hw_primary: start_output_stream: out: 0xe8f47600, device: 2, address: , mode: 0, flags 0x2
02-01 07:15:14.972   371  2137 I audio_hw_primary: select_output_device(), headphone 0 ,headset 0 ,speaker 2
02-01 07:15:14.972   371  2137 I audio_hw_primary: start_output_stream: set to pcm_config_mm_out, rate 48000, chn 2, format 0x0
02-01 07:15:14.972   371  2137 D audio_hw_primary: start_output_stream: pcm_open: card: 0, rate: 48000, channel: 2, format: 0, period_size: 0x400, flag: 8
02-01 07:15:14.980   371  2137 E audio_hw_primary: start_output_stream: pcm_open error: cannot set hw params: Invalid argument
02-01 07:15:14.981   371  2137 V audio_hw_primary: write error, sleep few ms

Is there anything else I need to do for this problem? Thank you!

[igorpadykov]

Hi Buridan

such configuration (without codec) is not supported in nxp bsps, in general one

can try to follow similar example with "simple-audio-card "

https://source.codeaurora.org/external/imx/linux-imx/tree/arch/arm64/boot/dts/freescale/imx8qxp-mek-...

https://source.codeaurora.org/external/imx/linux-imx/tree/Documentation/devicetree/bindings/sound/si...

Use Chapter 7 Audio   i.MX Linux Reference Manual​   describing all linux ALSA software layers

Best regards
igor

[Buridan]

Dear igor:

Do you mean the S/PDIF can only be used in "simple-audio-card" framework? Currently I am using the custom machine driver to create audio card.

I may posted the wrong information that the codec of the sound card is dummy audio codec which is refer to the Dummy audio codec - play & record on i.MX8MM.

And if I just use the S/PDIF driver at kernel/sound/soc/fsl/imx-spdif.c (block the imx-dummy.c) refer to the i.MX Linux Reference Manual in capter 7.4.2~7.4.5, the dts:

sound-spdif {
	compatible = "fsl,imx-audio-spdif";
	model = "imx-spdif";
	spdif-controller = <&spdif0>;
	spdif-in;
	spdif-out;
};

Then I will get the same problem in the main post. Except the S/PDIF, the SAI/ESAI has already worked with dummy codec.

[Buridan]

I opend the DEBUG macro and the printf output:

mek_8q:/ # dmesg | grep dai
[    5.169054] fsl-spdif-dai 59020000.spdif: use rxtx1 as tx clock source for 32000Hz sample rate
[    5.169066] fsl-spdif-dai 59020000.spdif: use txclk df 24 for 32000Hz sample rate
[    5.169072] fsl-spdif-dai 59020000.spdif: the best rate for 32000Hz sample rate is 32000Hz
[    5.176404] fsl-spdif-dai 59020000.spdif: use rxtx5 as tx clock source for 44100Hz sample rate
[    5.176411] fsl-spdif-dai 59020000.spdif: use txclk df 19 for 44100Hz sample rate
[    5.176419] fsl-spdif-dai 59020000.spdif: use sysclk df 3 for 44100Hz sample rate
[    5.176426] fsl-spdif-dai 59020000.spdif: the best rate for 44100Hz sample rate is 43859Hz
[    5.176438] fsl-spdif-dai 59020000.spdif: use rxtx1 as tx clock source for 48000Hz sample rate
[    5.176444] fsl-spdif-dai 59020000.spdif: use txclk df 16 for 48000Hz sample rate
[    5.176451] fsl-spdif-dai 59020000.spdif: the best rate for 48000Hz sample rate is 48000Hz
[    5.176460] fsl-spdif-dai 59020000.spdif: use rxtx1 as tx clock source for 96000Hz sample rate
[    5.176466] fsl-spdif-dai 59020000.spdif: use txclk df 8 for 96000Hz sample rate
[    5.176474] fsl-spdif-dai 59020000.spdif: the best rate for 96000Hz sample rate is 96000Hz
[    5.176482] fsl-spdif-dai 59020000.spdif: use rxtx1 as tx clock source for 192000Hz sample rate
[    5.176489] fsl-spdif-dai 59020000.spdif: use txclk df 4 for 192000Hz sample rate
[    5.176497] fsl-spdif-dai 59020000.spdif: the best rate for 192000Hz sample rate is 192000Hz
[    5.188105] imx-dummy sound-dummy: snd-soc-dummy-dai <-> 59040000.sai mapping ok
[    5.198172] imx-dummy sound-dummy: snd-soc-dummy-dai <-> 59050000.sai mapping ok
[    5.208096] imx-dummy sound-dummy: snd-soc-dummy-dai <-> 59010000.esai mapping ok
[    5.222350] imx-dummy sound-dummy: snd-soc-dummy-dai <-> 59020000.spdif mapping ok
mek_8q:/ # tinyplay /sdcard/Music/1
1khz-16000-16-1.wav       1khz-32000-32-2.wav       1khz-8000-8-2.wav
1khz-16000-32-2.wav       1khz-48000-32-2.wav
mek_8q:/ # tinyplay /sdcard/Music/1khz-48000-32-2.wav -D 0 -d 3 -p 1024 -n 3
Unable to open PCM device 3 (cannot set hw params: Invalid argument)