Re: [PATCH v3 7/8] ASoC: cs42l42: Don't set idle_bias_on

Pierre-Louis Bossart
2023-01-30T16:46:06Z

On 1/27/23 10:51, Stefan Binding wrote:
> From: Richard Fitzgerald <rf@opensource.cirrus.com>
>
> idle_bias_on was set because cs42l42 has a "VMID" type pseudo-midrail
> supply (named FILT+), and these typically take a long time to charge.
> But the driver never enabled pm_runtime so it would never have powered-
> down the cs42l42 anyway.
>
> In fact, FILT+ can charge to operating voltage within 12.5 milliseconds
> of enabling HP or ADC. This time is already covered by the startup
> delay of the HP/ADC.
>
> The datasheet warning about FILT+ taking up to 1 second to charge only
> applies in the special cases that either the PLL is started or
> DETECT_MODE set to non-zero while both HP and ADC are off. The driver
> never does either of these.
>
> Removing idle_bias_on allows the Soundwire host controller to suspend
> if there isn't a snd_soc_jack handler registered.
>
> Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com>
> Signed-off-by: Stefan Binding <sbinding@opensource.cirrus.com>

Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>

> ---
> sound/soc/codecs/cs42l42.c | 1 -
> 1 file changed, 1 deletion(-)
>
> diff --git a/sound/soc/codecs/cs42l42.c b/sound/soc/codecs/cs42l42.c
> index aa8d724432ab8..e3edaa1a2761e 100644
> --- a/sound/soc/codecs/cs42l42.c
> +++ b/sound/soc/codecs/cs42l42.c
> @@ -597,7 +597,6 @@ const struct snd_soc_component_driver cs42l42_soc_component = {
> .num_dapm_routes = ARRAY_SIZE(cs42l42_audio_map),
> .controls = cs42l42_snd_controls,
> .num_controls = ARRAY_SIZE(cs42l42_snd_controls),
> - .idle_bias_on = 1,
> .endianness = 1,
> };
> EXPORT_SYMBOL_NS_GPL(cs42l42_soc_component, SND_SOC_CS42L42_CORE);