diff mbox series

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

Message ID 20230127165111.3010960-8-sbinding@opensource.cirrus.com
State New
Headers
Series ASoC: cs42l42: Add SoundWire support |

Commit Message

Stefan Binding Jan. 27, 2023, 4:51 p.m. UTC 
  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>
---
 sound/soc/codecs/cs42l42.c | 1 -
 1 file changed, 1 deletion(-)

Comments

Pierre-Louis Bossart Jan. 30, 2023, 4:40 p.m. UTC | #1 
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);
diff mbox series

Patch

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);