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

[Eric Nelson]

On 05/09/2013 05:15 PM, Fabio Estevam wrote:
> From: Fabio Estevam <fabio.estevam at freescale.com>
>
> After a 'reboot' command in Linux or after pressing the system's reset button
> the sgtl5000 driver fails to probe:
>
> 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)
>
> sgtl5000 codec does not have a reset line, nor a reset command in software, so
> after a system reset the codec does not contain the default register values
> from sgtl5000_reg_defaults[] anymore, as these are only valid after a
> power-on-reset cycle.
>
> Fix this issue by explicitly reading all the reset register values from
> sgtl5000_reg_defaults[] and writing them back into sgtl5000 to ensure a sane
> state.
>
> Signed-off-by: Fabio Estevam <fabio.estevam at freescale.com>
> ---
> Changes since v4:
> - Only call sgtl5000_fill_defaults if we know we have a sgtl5000
> Changes since v3:
> - Read sgtl5000_reg_defaults and write these values into sgtl5000
> Changes since v2:
> - Do not use reg_defaults_raw as it is not the correct purpose
> - Manually build sgtl5000_reg_default
> - Improve commitlog
> Changes since v1:
> - Remove sgtl5000_reg_defaults array
> - Do not use num_reg_defaults_raw
>   sound/soc/codecs/sgtl5000.c |   30 ++++++++++++++++++++++++++++++
>   1 file changed, 30 insertions(+)
>

Tested-by: Eric Nelson <eric.nelson at boundarydevices.com>