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Message-ID: <20210805161111.10410-1-rf@opensource.cirrus.com>
Date: Thu, 5 Aug 2021 17:11:04 +0100
From: Richard Fitzgerald <rf@...nsource.cirrus.com>
To: <broonie@...nel.org>
CC: <alsa-devel@...a-project.org>, <patches@...nsource.cirrus.com>,
<linux-kernel@...r.kernel.org>,
Richard Fitzgerald <rf@...nsource.cirrus.com>
Subject: [PATCH 1/8] ASoC: cs42l42: PLL must be running when changing MCLK_SRC_SEL
Both SCLK and PLL clocks must be running to drive the glitch-free mux
behind MCLK_SRC_SEL and complete the switchover.
This patch moves the writing of MCLK_SRC_SEL to when the PLL is started
and stopped, so that it only transitions while the PLL is running.
The unconditional write MCLK_SRC_SEL=0 in cs42l42_mute_stream() is safe
because if the PLL is not running MCLK_SRC_SEL is already 0.
Signed-off-by: Richard Fitzgerald <rf@...nsource.cirrus.com>
Fixes: 43fc357199f9 ("ASoC: cs42l42: Set clock source for both ways of stream")
---
sound/soc/codecs/cs42l42.c | 25 ++++++++++++++++++-------
sound/soc/codecs/cs42l42.h | 1 +
2 files changed, 19 insertions(+), 7 deletions(-)
diff --git a/sound/soc/codecs/cs42l42.c b/sound/soc/codecs/cs42l42.c
index a00dc3c65549..c96549fe6ab2 100644
--- a/sound/soc/codecs/cs42l42.c
+++ b/sound/soc/codecs/cs42l42.c
@@ -619,6 +619,8 @@ static int cs42l42_pll_config(struct snd_soc_component *component)
for (i = 0; i < ARRAY_SIZE(pll_ratio_table); i++) {
if (pll_ratio_table[i].sclk == clk) {
+ cs42l42->pll_config = i;
+
/* Configure the internal sample rate */
snd_soc_component_update_bits(component, CS42L42_MCLK_CTL,
CS42L42_INTERNAL_FS_MASK,
@@ -627,14 +629,9 @@ static int cs42l42_pll_config(struct snd_soc_component *component)
(pll_ratio_table[i].mclk_int !=
24000000)) <<
CS42L42_INTERNAL_FS_SHIFT);
- /* Set the MCLK src (PLL or SCLK) and the divide
- * ratio
- */
+
snd_soc_component_update_bits(component, CS42L42_MCLK_SRC_SEL,
- CS42L42_MCLK_SRC_SEL_MASK |
CS42L42_MCLKDIV_MASK,
- (pll_ratio_table[i].mclk_src_sel
- << CS42L42_MCLK_SRC_SEL_SHIFT) |
(pll_ratio_table[i].mclk_div <<
CS42L42_MCLKDIV_SHIFT));
/* Set up the LRCLK */
@@ -892,13 +889,21 @@ static int cs42l42_mute_stream(struct snd_soc_dai *dai, int mute, int stream)
*/
regmap_multi_reg_write(cs42l42->regmap, cs42l42_to_osc_seq,
ARRAY_SIZE(cs42l42_to_osc_seq));
+
+ /* Must disconnect PLL before stopping it */
+ snd_soc_component_update_bits(component,
+ CS42L42_MCLK_SRC_SEL,
+ CS42L42_MCLK_SRC_SEL_MASK,
+ 0);
+ usleep_range(100, 200);
+
snd_soc_component_update_bits(component, CS42L42_PLL_CTL1,
CS42L42_PLL_START_MASK, 0);
}
} else {
if (!cs42l42->stream_use) {
/* SCLK must be running before codec unmute */
- if ((cs42l42->bclk < 11289600) && (cs42l42->sclk < 11289600)) {
+ if (pll_ratio_table[cs42l42->pll_config].mclk_src_sel) {
snd_soc_component_update_bits(component, CS42L42_PLL_CTL1,
CS42L42_PLL_START_MASK, 1);
@@ -919,6 +924,12 @@ static int cs42l42_mute_stream(struct snd_soc_dai *dai, int mute, int stream)
CS42L42_PLL_LOCK_TIMEOUT_US);
if (ret < 0)
dev_warn(component->dev, "PLL failed to lock: %d\n", ret);
+
+ /* PLL must be running to drive glitchless switch logic */
+ snd_soc_component_update_bits(component,
+ CS42L42_MCLK_SRC_SEL,
+ CS42L42_MCLK_SRC_SEL_MASK,
+ CS42L42_MCLK_SRC_SEL_MASK);
}
/* Mark SCLK as present, turn off internal oscillator */
diff --git a/sound/soc/codecs/cs42l42.h b/sound/soc/codecs/cs42l42.h
index 206b3c81d3e0..b92c17be7f58 100644
--- a/sound/soc/codecs/cs42l42.h
+++ b/sound/soc/codecs/cs42l42.h
@@ -775,6 +775,7 @@ struct cs42l42_private {
struct gpio_desc *reset_gpio;
struct completion pdn_done;
struct snd_soc_jack *jack;
+ int pll_config;
int bclk;
u32 sclk;
u32 srate;
--
2.11.0
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