ASoC: Do DAPM control updates in the middle of DAPM sequences

Attempt to minimise audible effects from mixer and mux updates by
implementing the actual register changes between powering down widgets
that have become unused and powering up widgets that are newly used.

This means that we're making the change with the minimum set of widgets
powered, that the input path is connected when we're powering up widgets
(so things like DC offset correction can run with their signal active)
and that we bring things down to cold before switching away.  Since
hardware tends to be designed for the power on/off case more than for
dynamic reconfiguration this should minimise pops and clicks during
reconfiguration while active.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Peter Ujfalusi <peter.ujfalusi@nokia.com>
Tested-by: Peter Ujfalusi <peter.ujfalusi@nokia.com>
Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>

1 files changed, 10 insertions, 0 deletions

diff --git a/include/sound/soc-dapm.h b/include/sound/soc-dapm.h
index 98783510d2f1..540872fc1390 100644
--- a/include/sound/soc-dapm.h
+++ b/include/sound/soc-dapm.h
@@ -460,6 +460,14 @@ struct snd_soc_dapm_widget {
         struct list_head power_list;
 };
 
+struct snd_soc_dapm_update {
+        struct snd_soc_dapm_widget *widget;
+        struct snd_kcontrol *kcontrol;
+        int reg;
+        int mask;
+        int val;
+};
+
 /* DAPM context */
 struct snd_soc_dapm_context {
         int n_widgets; /* number of widgets in this context */
@@ -468,6 +476,8 @@ struct snd_soc_dapm_context {
         struct delayed_work delayed_work;
         unsigned int idle_bias_off:1; /* Use BIAS_OFF instead of STANDBY */
 
+        struct snd_soc_dapm_update *update;
+
         struct device *dev; /* from parent - for debug */
         struct snd_soc_codec *codec; /* parent codec */
         struct snd_soc_card *card; /* parent card */