[PATCH 5.13 054/151] ASoC: cs42l42: PLL must be running when changing MCLK_SRC_SEL

Greg Kroah-Hartman
2021-08-16T13:22:40Z

From: Richard Fitzgerald <rf@opensource.cirrus.com>

[ Upstream commit f1040e86f83b0f7d5f45724500a6a441731ff4b7 ]

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@opensource.cirrus.com>
Fixes: 43fc357199f9 ("ASoC: cs42l42: Set clock source for both ways of stream")
Link: https://lore.kernel.org/r/20210805161111.10410-1-rf@opensource.cirrus.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
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 22d8c8d03308..7b102a05a1b6 100644
--- a/sound/soc/codecs/cs42l42.c
+++ b/sound/soc/codecs/cs42l42.c
@@ -609,6 +609,8 @@ 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,
@@ -617,14 +619,9 @@ 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 */
@@ -882,13 +879,21 @@ 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);

@@ -909,6 +914,12 @@ 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 5384105afe50..38fd91a168ae 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;
--
2.30.2