[alsa-devel] [PATCH v5 2/2] ASoC: sgtl5000: Fix driver probe after reset

[Troy Kisky]

On 5/9/2013 7:12 PM, Fabio Estevam wrote:
> On Thu, May 9, 2013 at 10:17 PM, Troy Kisky
> <troy.kisky at boundarydevices.com> wrote:
>
>> Did you test a reset/reboot ?  Since the fill_defaults now happens after the
>> read of the device id,
>> how does this fix the mentioned problem ?
> Yes, tested several times :-)
>
> The chip ID has to be read from the register and it always read
> correctly. In patch 1/2, I  just moved the reading to a more standard
> location (in i2c_probe function), just like many other codecs do.
>
> Patch 2/2 fixes the issue by ensuring that we start from sane values
> from power-on reset.
>
> Let's look at the original error:
>
> sgtl5000 0-000a: Device with ID register ffff is not a sgtl5000
> sgtl5000 0-000a: ASoC: failed to probe CODEC -19
> imx-sgtl5000 sound.12: ASoC: failed to instantiate card -19
> imx-sgtl5000 sound.12: snd_soc_register_card failed (-19)
>
> If I move the chip ID reading to i2c_probe (ie, only apply patch 1/2),
> the device ID would be read correctly, but the fail would happen at a
> later point:
>
> sgtl5000 0-000a: sgtl5000 revision 0x11
> sgtl5000 0-000a: Failed to get supply 'VDDD': -517
>   mmcblk0: p1
> 0-000a: 1200 mV normal
> sgtl5000 0-000a: Using internal LDO instead of VDDD
> usb 2-1: new high-speed USB device number 2 using ci_hdrc
> hub 2-1:1.0: USB hub found
> hub 2-1:1.0: 3 ports detected
> sgtl5000 0-000a: ASoC: failed to probe CODEC -110
> imx-sgtl5000 sound.12: ASoC: failed to instantiate card -110
> imx-sgtl5000 sound.12: snd_soc_register_card failed (-110)
> imx-sgtl5000: probe of sound.12 failed with error -110

Shouldn't you update your commit log with this then ?
>
> So the original issue was not about reading the chip ID correctly.
>
> The power related registers change from POR to reset (among others)
>
> If the chip is not properly powered, then we are not able to read its
> ID and we get that original error.
>

Thanks for fixing, I guess I don't need to understand how the fix works.

Troy