[alsa-devel] [PATCH v3] ASoC: sgtl5000: Fix driver probe after reset

[Lars-Peter Clausen]

On 05/09/2013 07:20 PM, Fabio Estevam wrote:
> 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 
> sgtl5000_reg_defaults table, since these are only valid after a clean power-on 
> reset.
> 
> Fix this issue by explicitly reading all the sgtl5000 registers and filling
> sgtl5000_reg_defaults with such values.
> 
> Signed-off-by: Fabio Estevam <fabio.estevam at freescale.com>

I don't see how this is different from v2, except that it is now opencoding
the register reading and is sharing a driver global variable between
multiple instances (which is kind of a no-go).

> ---
> 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 |   58 ++++++++++++++++++++++++-------------------
>  1 file changed, 33 insertions(+), 25 deletions(-)
> 
> diff --git a/sound/soc/codecs/sgtl5000.c b/sound/soc/codecs/sgtl5000.c
> index 327b443..311dfb5 100644
> --- a/sound/soc/codecs/sgtl5000.c
> +++ b/sound/soc/codecs/sgtl5000.c
> @@ -35,31 +35,7 @@
>  #define SGTL5000_MAX_REG_OFFSET	0x013A
>  
>  /* default value of sgtl5000 registers */
> -static const struct reg_default sgtl5000_reg_defaults[] = {
> -	{ SGTL5000_CHIP_CLK_CTRL,		0x0008 },
> -	{ SGTL5000_CHIP_I2S_CTRL,		0x0010 },
> -	{ SGTL5000_CHIP_SSS_CTRL,		0x0008 },
> -	{ SGTL5000_CHIP_DAC_VOL,		0x3c3c },
> -	{ SGTL5000_CHIP_PAD_STRENGTH,		0x015f },
> -	{ SGTL5000_CHIP_ANA_HP_CTRL,		0x1818 },
> -	{ SGTL5000_CHIP_ANA_CTRL,		0x0111 },
> -	{ SGTL5000_CHIP_LINE_OUT_VOL,		0x0404 },
> -	{ SGTL5000_CHIP_ANA_POWER,		0x7060 },
> -	{ SGTL5000_CHIP_PLL_CTRL,		0x5000 },
> -	{ SGTL5000_DAP_BASS_ENHANCE,		0x0040 },
> -	{ SGTL5000_DAP_BASS_ENHANCE_CTRL,	0x051f },
> -	{ SGTL5000_DAP_SURROUND,		0x0040 },
> -	{ SGTL5000_DAP_EQ_BASS_BAND0,		0x002f },
> -	{ SGTL5000_DAP_EQ_BASS_BAND1,		0x002f },
> -	{ SGTL5000_DAP_EQ_BASS_BAND2,		0x002f },
> -	{ SGTL5000_DAP_EQ_BASS_BAND3,		0x002f },
> -	{ SGTL5000_DAP_EQ_BASS_BAND4,		0x002f },
> -	{ SGTL5000_DAP_MAIN_CHAN,		0x8000 },
> -	{ SGTL5000_DAP_AVC_CTRL,		0x0510 },
> -	{ SGTL5000_DAP_AVC_THRESHOLD,		0x1473 },
> -	{ SGTL5000_DAP_AVC_ATTACK,		0x0028 },
> -	{ SGTL5000_DAP_AVC_DECAY,		0x0050 },
> -};
> +static struct reg_default sgtl5000_reg_defaults[SGTL5000_MAX_REG_OFFSET + 1];
>  
>  /* regulator supplies for sgtl5000, VDDD is an optional external supply */
>  enum sgtl5000_regulator_supplies {
> @@ -1355,6 +1331,33 @@ err_regulator_free:
>  
>  }
>  
> +/*
> + * Read all the sgtl5000 registers to fill the cache, as
> + * we cannot rely on a pre-defined table containing the
> + * power-on reset values of the registers as done in most
> + * of the other codec drivers.
> + *
> + * We follow this approach here because sgtl5000 does not have
> + * a reset line, nor a reset command in software, and this way
> + * we can guarantee that we always have sane register values
> + * stored in the reg_defaults table after a reset
> + */
> +static int sgtl5000_fill_cache(struct snd_soc_codec *codec)
> +{
> +	int i, reg, ret;
> +	struct sgtl5000_priv *sgtl5000 = snd_soc_codec_get_drvdata(codec);
> +
> +	for (i = 0; i < SGTL5000_MAX_REG_OFFSET; i += 2) {
> +		ret = regmap_read(sgtl5000->regmap, i, &reg);
> +		if (ret < 0)
> +			return ret;
> +		sgtl5000_reg_defaults[i].reg = i;
> +		sgtl5000_reg_defaults[i].def = reg;
> +	}
> +
> +	return 0;
> +}
> +
>  static int sgtl5000_probe(struct snd_soc_codec *codec)
>  {
>  	int ret;
> @@ -1377,6 +1380,11 @@ static int sgtl5000_probe(struct snd_soc_codec *codec)
>  	if (ret)
>  		goto err;
>  
> +	/* Build the reg_defaults manually by reading the registers */
> +	ret = sgtl5000_fill_cache(codec);
> +	if (ret)
> +		goto err;
> +
>  	/* enable small pop, introduce 400ms delay in turning off */
>  	snd_soc_update_bits(codec, SGTL5000_CHIP_REF_CTRL,
>  				SGTL5000_SMALL_POP,