[v4] ASoC: qcom: lpass-cpu: Fix pop noise during audio capture begin
Judy Hsiao
judyhsiao at chromium.org
Wed Jun 2 17:53:12 CEST 2021
From: Srinivasa Rao Mandadapu <srivasam at codeaurora.org>
This patch fixes PoP noise of around 15ms observed during audio
capture begin.
Enables BCLK and LRCLK in snd_soc_dai_ops prepare call for
introducing some delay before capture start and clock enable.
Co-developed-by: Judy Hsiao <judyhsiao at chromium.org>
Signed-off-by: Judy Hsiao <judyhsiao at chromium.org>
Signed-off-by: Srinivasa Rao Mandadapu <srivasam at codeaurora.org>
(am from https://patchwork.kernel.org/patch/12276369/)
(also found at https://lore.kernel.org/r/20210524142114.18676-1-srivasam@codeaurora.org)
---
Chages Since V3:
-- Check BCLK is off before enabling it in lpass_cpu_daiops_prepare as
lpass_cpu_daiops_prepare can be called multiple times.
-- Check BCLK is on before disabling it in lpass_cpu_daiops_shutdown to
fix the WARN. It is because BCLK may not be enabled if
lpass_cpu_daiops_prepare is not called before lpass_cpu_daiops_shutdown.
-- Adds more comments.
Changes Since V2:
-- Updated comments as per linux style
-- Removed unrelated changes.
Changes Since V1:
-- Enableed BCLK and LRCLK in dai ops prepare API instead of startup API
-- Added comments
sound/soc/qcom/lpass-cpu.c | 83 +++++++++++++++++++++++++++++++++++++-
1 file changed, 82 insertions(+), 1 deletion(-)
diff --git a/sound/soc/qcom/lpass-cpu.c b/sound/soc/qcom/lpass-cpu.c
index af8cb64924a0..b572d7874554 100644
--- a/sound/soc/qcom/lpass-cpu.c
+++ b/sound/soc/qcom/lpass-cpu.c
@@ -6,6 +6,7 @@
*/
#include <linux/clk.h>
+#include <linux/clk-provider.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
@@ -93,8 +94,28 @@ static void lpass_cpu_daiops_shutdown(struct snd_pcm_substream *substream,
struct snd_soc_dai *dai)
{
struct lpass_data *drvdata = snd_soc_dai_get_drvdata(dai);
+ struct lpaif_i2sctl *i2sctl = drvdata->i2sctl;
+ unsigned int id = dai->driver->id;
clk_disable_unprepare(drvdata->mi2s_osr_clk[dai->driver->id]);
+ /*
+ * To ensure LRCLK disabled even in device node validation
+ * Will not impact if disabled in lpass_cpu_daiops_trigger()
+ * suspend.
+ */
+ if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
+ regmap_fields_write(i2sctl->spken, id, LPAIF_I2SCTL_SPKEN_DISABLE);
+ else
+ regmap_fields_write(i2sctl->micen, id, LPAIF_I2SCTL_MICEN_DISABLE);
+
+ /*
+ * BCLK may not be enabled if lpass_cpu_daiops_prepare is called before
+ * lpass_cpu_daiops_shutdown. It's paired with the clk_enable in
+ * lpass_cpu_daiops_prepare.
+ */
+ if (__clk_is_enabled(drvdata->mi2s_bit_clk[dai->driver->id]))
+ clk_disable(drvdata->mi2s_bit_clk[dai->driver->id]);
+
clk_unprepare(drvdata->mi2s_bit_clk[dai->driver->id]);
}
@@ -275,6 +296,18 @@ static int lpass_cpu_daiops_trigger(struct snd_pcm_substream *substream,
case SNDRV_PCM_TRIGGER_START:
case SNDRV_PCM_TRIGGER_RESUME:
case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
+ /*
+ * To ensure lpass BCLK/LRCLK is enabled during
+ * device resume as lpass_cpu_daiops_prepare() is not called
+ * after the device resumes. We don't check BCLK status before
+ * enable/disable BCLK in trigger event because:
+ * 1. These trigger events are paired, so the BCLK
+ * enable_count is balanced.
+ * 2. the BCLK can be shared (ex: headset and headset mic),
+ * we need to increase the enable_count so that we don't
+ * turn off the shared BCLK while other devices are using
+ * it.
+ */
if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
ret = regmap_fields_write(i2sctl->spken, id,
LPAIF_I2SCTL_SPKEN_ENABLE);
@@ -288,7 +321,8 @@ static int lpass_cpu_daiops_trigger(struct snd_pcm_substream *substream,
ret = clk_enable(drvdata->mi2s_bit_clk[id]);
if (ret) {
- dev_err(dai->dev, "error in enabling mi2s bit clk: %d\n", ret);
+ dev_err(dai->dev,
+ "error in enabling mi2s bit clk: %d\n", ret);
clk_disable(drvdata->mi2s_osr_clk[id]);
return ret;
}
@@ -296,6 +330,10 @@ static int lpass_cpu_daiops_trigger(struct snd_pcm_substream *substream,
case SNDRV_PCM_TRIGGER_STOP:
case SNDRV_PCM_TRIGGER_SUSPEND:
case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
+ /*
+ * To ensure lpass BCLK/LRCLK is disabled during
+ * device suspend.
+ */
if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
ret = regmap_fields_write(i2sctl->spken, id,
LPAIF_I2SCTL_SPKEN_DISABLE);
@@ -315,12 +353,55 @@ static int lpass_cpu_daiops_trigger(struct snd_pcm_substream *substream,
return ret;
}
+static int lpass_cpu_daiops_prepare(struct snd_pcm_substream *substream,
+ struct snd_soc_dai *dai)
+{
+ struct lpass_data *drvdata = snd_soc_dai_get_drvdata(dai);
+ struct lpaif_i2sctl *i2sctl = drvdata->i2sctl;
+ unsigned int id = dai->driver->id;
+ int ret;
+ /*
+ * To ensure lpass BCLK/LRCLK is enabled bit before playback/capture
+ * data flow starts. This allows other codec to have some delay before
+ * the data flow.
+ * (ex: to drop start up pop noise before capture starts).
+ */
+ if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
+ ret = regmap_fields_write(i2sctl->spken, id,
+ LPAIF_I2SCTL_SPKEN_ENABLE);
+ else
+ ret = regmap_fields_write(i2sctl->micen, id,
+ LPAIF_I2SCTL_MICEN_ENABLE);
+
+ if (ret) {
+ dev_err(dai->dev, "error writing to i2sctl reg: %d\n", ret);
+ return ret;
+ }
+
+ /*
+ * Check BCLK is off before enabling it as lpass_cpu_daiops_prepare can
+ * be called multiple times. It's paired with the clk_disable in
+ * lpass_cpu_daiops_shutdown.
+ */
+ if (!__clk_is_enabled(drvdata->mi2s_bit_clk[dai->driver->id])) {
+ ret = clk_enable(drvdata->mi2s_bit_clk[id]);
+ if (ret) {
+ dev_err(dai->dev,
+ "error in enabling mi2s bit clk: %d\n", ret);
+ clk_disable(drvdata->mi2s_osr_clk[id]);
+ return ret;
+ }
+ }
+ return 0;
+}
+
const struct snd_soc_dai_ops asoc_qcom_lpass_cpu_dai_ops = {
.set_sysclk = lpass_cpu_daiops_set_sysclk,
.startup = lpass_cpu_daiops_startup,
.shutdown = lpass_cpu_daiops_shutdown,
.hw_params = lpass_cpu_daiops_hw_params,
.trigger = lpass_cpu_daiops_trigger,
+ .prepare = lpass_cpu_daiops_prepare,
};
EXPORT_SYMBOL_GPL(asoc_qcom_lpass_cpu_dai_ops);
--
2.31.0
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