[alsa-devel] Pop and offsets at start of audio playback/record for SGTL5000 on i.MX28

[Michael Trimarchi]

Hi

Il 17/nov/2014 08:35 "Craig McQueen" <craig.mcqueen at beamcommunications.com>
ha scritto:
>
> On 14/11/14 13:04, Michael Trimarchi wrote:
>>
>> Hi
>>
>> Il 14/nov/2014 09:58 "Craig McQueen" <
craig.mcqueen at beamcommunications.com> ha scritto:
>> >
>> > On 14/11/14 12:45, Michael Trimarchi wrote:
>> >>
>> >> Hi
>> >>
>> >> Il 14/nov/2014 09:44 "Craig McQueen" <
craig.mcqueen at beamcommunications.com> ha scritto:
>> >> >
>> >> > I'm testing the 3.14.19 kernel for i.MX28 EVK, which has an
SGTL5000 CODEC. I've also tested on the 3.18-rc4 kernel and confirmed this
issue still occurs.
>> >> >
>> >>
>> >> Are you using it in master or slave mode?
>> >
>> >
>>
>> Try to change the pin mux of data line in order to be hz in idle mode
and add a small pull down resistor. Can you check if the dataline is up
when clocks go off?
>
>
> Is it the I2S_DIN pin you're referring to?
>
> This is the Freescale i.MX28 EVK we're talking about, so it's best to
have a software fix that works on the stock EVK hardware. I'm checking the
schematics and I don't see a pull-down. The following is in the imx28.dtsi
device tree source:
>
>                 saif0_pins_b: saif0 at 1 {
>                     reg = <1>;
>                     fsl,pinmux-ids = <
>                         MX28_PAD_SAIF0_LRCLK__SAIF0_LRCLK
>                         MX28_PAD_SAIF0_BITCLK__SAIF0_BITCLK
>                         MX28_PAD_SAIF0_SDATA0__SAIF0_SDATA0
>                     >;
>                     fsl,drive-strength = <MXS_DRIVE_12mA>;
>                     fsl,voltage = <MXS_VOLTAGE_HIGH>;
>                     fsl,pull-up = <MXS_PULL_ENABLE>;
>                 };
>
> However on the i.MX28 I don't think the SAIF0_SDATA0 pin actually has a
pull-up (only a few pins do).
>
> Anyway, I will look into that soon.
>

I think that some patch was submitted for this pop last week

Michael

> --
> Craig McQueen
>