The amplifier is started from the PRE_PMU event of its AIF widget, that
is from DAPM in prepare. aw88261_dev_start() waits up to 20 ms there for
the PLL to lock to the bit clock and powers the amplifier down again if
it does not.
The Qualcomm AudioReach backends only start their graph, and with it
the I2S/TDM clocks, in trigger since commit b54a38af7138 ("ASoC: qcom:
q6apm-lpass-dai: move graph start to trigger"). There every start fails
with "start failure (-1)" and the speaker stays silent for the whole
stream, as seen with six AW88261 on a TDM link of SM8750.
Split the start at the first step that needs the bit clock, the PLL
lock check, whatever the host does:
- PRE_PMU clears power down (PWDN), configures the I2S interface and
the PLL and writes the boost settings of aw88261_reg_force_set().
The amplifier stays powered down (AMPPD) and muted.
- The unmute, called after the trigger of the CPU DAI with
.mute_unmute_on_trigger, does the rest: it checks the PLL lock,
clears AMPPD, checks SYSST, enables the feedback and unmutes. If the
PLL does not lock, "start failure" is logged, the amplifier is left
as PRE_PMU left it and the next trigger start tries again.
- The mute in trigger undoes the unmute (mute, feedback off, AMPPD),
and POST_PMD sets PWDN as before.
So only the steps that need the clock run in trigger: 14 register
accesses and 1 ms per amplifier for the unmute when the PLL has locked,
12 and 1 ms for the mute. The same steps run there on hosts that have
the clock running from prepare. aw88261_reg_force_set() only writes
boost settings and now runs before AMPPD is cleared rather than right
after.
wsa883x and wsa884x split their start the same way, with the
configuration in DAPM and GLOBAL_PA_EN in the trigger-time mute. The
vendor driver of this amplifier family (aw882xx) also starts the
amplifier from .mute_stream, with the same sequence.
The register accesses go over I2C and sleep, so they need a nonatomic
trigger, which the Qualcomm DPCM links using this codec have. On an
atomic PCM, as seen from substream->pcm->nonatomic in .startup, PRE_PMU
does the whole start as before and the mute callback does nothing.
POST_PMD can also run for an amplifier that was never powered up, as
seen when the card is registered, so make "already power off" a debug
message.
Assisted-by: LLM
Signed-off-by: Vladyslav Tymoshchuk <[email protected]>
---
[..]
+/*
+ * First part of the start, which does not need the bit clock: power
up and
+ * configure the I2S interface and the PLL. The amplifier stays
powered down
+ * (AMPPD) and muted.
+ */
+static int aw88261_dev_power_up(struct aw88261 *aw88261)
[..]
+/*
+ * Second part of the start, which needs the bit clock as the PLL
locks to
+ * it: check the lock, enable the amplifier and the feedback, and
unmute.
+ * On failure the device is left as aw88261_dev_power_up() left it.
+ */
+static int aw88261_dev_enable(struct aw88261 *aw88261)
[..]
+/* Undo aw88261_dev_enable() */
+static void aw88261_dev_disable(struct aw_device *aw_dev)
[..]
+static int aw88261_dev_start(struct aw88261 *aw88261, bool enable)
[..]
--- a/sound/soc/codecs/aw88261.h
+++ b/sound/soc/codecs/aw88261.h
@@ -564,6 +564,8 @@ enum {
enum {
AW88261_DEV_PW_OFF = 0,
AW88261_DEV_PW_ON,
+ /* powered up and configured, amplifier off: waits for the bit
clock */
+ AW88261_DEV_PW_READY,
