topic Re: iMX6Q+SGTL5000 have pop noise in suspend/resume and shutdown processes in i.MX Processors

iMX6Q+SGTL5000 have pop noise in suspend/resume and shutdown processes

bakbad — Tue, 08 Jan 2019 07:36:12 GMT

Hello, NXP

I have a custom board with imx6q and sgtl5000, but when the machine get into suspend or wake up or shutdown, the speaker had a "pop" noise. I had tried this: setting the DAC_MUTE_LEFT and DAC_MUTE_RIGHT bit in suspend function, and clear them in resume function, but it didn't works. Any advices? Thanks.

Best Regards,

bo xu

Re: iMX6Q+SGTL5000 have pop noise in suspend/resume and shutdown processes

igorpadykov — Tue, 08 Jan 2019 10:34:33 GMT

Hi bo

additionally one can consider decreasing volume as described in

sect.2.2.6 Volume Control AN3663 SGTL5000 Initialization and Programming

http://cache.freescale.com/files/analog/doc/app_note/AN3663.pdf

Best regards
igor
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Re: iMX6Q+SGTL5000 have pop noise in suspend/resume and shutdown processes

bakbad — Wed, 09 Jan 2019 14:02:17 GMT

Hi igorpadykov,

Thanks for your advice.I tried as section 2.2.6 told.but when i put the code in sgtl5000_suspend() like this:

static int sgtl5000_suspend(struct snd_soc_codec *codec)

{

// Configure ADC left and right analog volume to desired default.

snd_soc_write(codec, SGTL5000_CHIP_ANA_ADC_CTRL, 0x0000);

// LINEOUT and DAC volume control

snd_soc_update_bits(codec, SGTL5000_CHIP_ANA_CTRL, 8, 0);

snd_soc_write(codec, SGTL5000_CHIP_DAC_VOL, 0x3c3c);

snd_soc_update_bits(codec, SGTL5000_CHIP_ADCDAC_CTRL, 2, 0);

snd_soc_update_bits(codec, SGTL5000_CHIP_ADCDAC_CTRL, 3, 0);

// Unmute ADC

snd_soc_update_bits(code, SGTL5000_CHIP_ANA_CTRL, 0, 0);

sgtl5000_set_bias_level(codec, SND_SOC_BIAS_OFF);

return 0;

}

and rebuild the kernel for the machine. But the machine had no sound before i set it to suspend and when the machine got into suspend status, it can't wake up.Did i missed something?

Best Regards,

bo xu

Re: iMX6Q+SGTL5000 have pop noise in suspend/resume and shutdown processes

bakbad — Thu, 31 Jan 2019 08:05:06 GMT

Hello, everyone

I solved this problem by closing the amplifier（TS4962）'s STBY pin before the system get into suspend, for letting the machine get into suspend we use commands like this "echo 'mem' > /sys/power/state" in the application layer.

The processes just like this:

echo 0 > /sys/class/gpio/gpio204/value (num 204 is the pin number of TS4962's STBY, before get into suspend)

echo "mem" > /sys/power/state (getting into suspend)

echo 1 > /sys/class/gpio/gpio204/value (in wakeup process)

And the pop-click noise has gone.