ASoC: Add helper functions bias level management

Currently drivers are responsible for managing the bias_level field of
their DAPM context. The DAPM state itself is managed by the DAPM core
though and the core has certain expectations on how and when the bias_level
field should be updated. If drivers don't adhere to these undefined
behavior can occur.

This patch adds a few helper functions for manipulating the DAPM context
state, each function with a description on when it should be used and what
its effects are. This will also help us to move more of the bias_level
management from drivers to the DAPM core.

For convenience also add snd_soc_codec_* wrappers around these helpers.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@kernel.org>

2 files changed, 74 insertions, 0 deletions

diff --git a/include/sound/soc-dapm.h b/include/sound/soc-dapm.h
index 0bc8364..70216d2 100644
--- a/include/sound/soc-dapm.h
+++ b/include/sound/soc-dapm.h
@@ -444,6 +444,9 @@ int snd_soc_dapm_dai_get_connected_widgets(struct snd_soc_dai *dai, int stream,
 struct snd_soc_dapm_context *snd_soc_dapm_kcontrol_dapm(
 	struct snd_kcontrol *kcontrol);
 
+int snd_soc_dapm_force_bias_level(struct snd_soc_dapm_context *dapm,
+	enum snd_soc_bias_level level);
+
 /* dapm widget types */
 enum snd_soc_dapm_type {
 	snd_soc_dapm_input = 0,		/* input pin */
@@ -623,4 +626,35 @@ struct snd_soc_dapm_stats {
 	int neighbour_checks;
 };
 
+/**
+ * snd_soc_dapm_init_bias_level() - Initialize DAPM bias level
+ * @dapm: The DAPM context to initialize
+ * @level: The DAPM level to initialize to
+ *
+ * This function only sets the driver internal state of the DAPM level and will
+ * not modify the state of the device. Hence it should not be used during normal
+ * operation, but only to synchronize the internal state to the device state.
+ * E.g. during driver probe to set the DAPM level to the one corresponding with
+ * the power-on reset state of the device.
+ *
+ * To change the DAPM state of the device use snd_soc_dapm_set_bias_level().
+ */
+static inline void snd_soc_dapm_init_bias_level(
+	struct snd_soc_dapm_context *dapm, enum snd_soc_bias_level level)
+{
+	dapm->bias_level = level;
+}
+
+/**
+ * snd_soc_dapm_get_bias_level() - Get current DAPM bias level
+ * @dapm: The context for which to get the bias level
+ *
+ * Returns: The current bias level of the passed DAPM context.
+ */
+static inline enum snd_soc_bias_level snd_soc_dapm_get_bias_level(
+	struct snd_soc_dapm_context *dapm)
+{
+	return dapm->bias_level;
+}
+
 #endif
diff --git a/include/sound/soc.h b/include/sound/soc.h
index 2f74200..7781bfe 100644
--- a/include/sound/soc.h
+++ b/include/sound/soc.h
@@ -1282,6 +1282,46 @@ static inline struct snd_soc_dapm_context *snd_soc_codec_get_dapm(
 }
 
 /**
+ * snd_soc_dapm_init_bias_level() - Initialize CODEC DAPM bias level
+ * @dapm: The CODEC for which to initialize the DAPM bias level
+ * @level: The DAPM level to initialize to
+ *
+ * Initializes the CODEC DAPM bias level. See snd_soc_dapm_init_bias_level().
+ */
+static inline void snd_soc_codec_init_bias_level(struct snd_soc_codec *codec,
+	enum snd_soc_bias_level level)
+{
+	snd_soc_dapm_init_bias_level(snd_soc_codec_get_dapm(codec), level);
+}
+
+/**
+ * snd_soc_dapm_get_bias_level() - Get current CODEC DAPM bias level
+ * @codec: The CODEC for which to get the DAPM bias level
+ *
+ * Returns: The current DAPM bias level of the CODEC.
+ */
+static inline enum snd_soc_bias_level snd_soc_codec_get_bias_level(
+	struct snd_soc_codec *codec)
+{
+	return snd_soc_dapm_get_bias_level(snd_soc_codec_get_dapm(codec));
+}
+
+/**
+ * snd_soc_codec_force_bias_level() - Set the CODEC DAPM bias level
+ * @codec: The CODEC for which to set the level
+ * @level: The level to set to
+ *
+ * Forces the CODEC bias level to a specific state. See
+ * snd_soc_dapm_force_bias_level().
+ */
+static inline int snd_soc_codec_force_bias_level(struct snd_soc_codec *codec,
+	enum snd_soc_bias_level level)
+{
+	return snd_soc_dapm_force_bias_level(snd_soc_codec_get_dapm(codec),
+		level);
+}
+
+/**
  * snd_soc_dapm_kcontrol_codec() - Returns the codec associated to a kcontrol
  * @kcontrol: The kcontrol
  *