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

[Lars-Peter Clausen]

On 05/08/2013 07:04 PM, Fabio Estevam wrote:
> From: Fabio Estevam <fabio.estevam at freescale.com>
> 
> sgtl5000 codec does not have a reset line, nor a reset command in software.
> 
> 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)
> 
> As the sgtl5000 codec did not go through a real reset, we cannot rely on the 
> reg_defaults array, since these are only valid after a clean power-on reset.
> 
> To fix this issue, use 'reg_defaults_raw' which tells the regcache driver
> to actually read the codec registers and then fill the cache.

No, that's not what it does. It will only fill the cache from the hardware,
if reg_defaults_raw is NULL and num_reg_defaults_raw is not 0.

> 
> Signed-off-by: Fabio Estevam <fabio.estevam at freescale.com>
> ---
>  sound/soc/codecs/sgtl5000.c |    4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/sound/soc/codecs/sgtl5000.c b/sound/soc/codecs/sgtl5000.c
> index 327b443..c59fae8 100644
> --- a/sound/soc/codecs/sgtl5000.c
> +++ b/sound/soc/codecs/sgtl5000.c
> @@ -1470,8 +1470,8 @@ static const struct regmap_config sgtl5000_regmap = {
>  	.readable_reg = sgtl5000_readable,
>  
>  	.cache_type = REGCACHE_RBTREE,
> -	.reg_defaults = sgtl5000_reg_defaults,
> -	.num_reg_defaults = ARRAY_SIZE(sgtl5000_reg_defaults),
> +	.reg_defaults_raw = sgtl5000_reg_defaults,
> +	.num_reg_defaults_raw = ARRAY_SIZE(sgtl5000_reg_defaults),

This shouldn't even compile without generating a warning.

>  };
>  
>  static int sgtl5000_i2c_probe(struct i2c_client *client,