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ASoC: soc-dai: add shared BCLK clock for cross-DAI rate constraints

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Add a bclk field to struct snd_soc_dai and a helper function
snd_soc_dai_set_bclk_clk() that platform drivers can use to declare
which clock is their BCLK.

Also cache the bclk_ratio in snd_soc_dai_set_bclk_ratio() so that
the framework can use it later in hw_rule evaluation for TDM
configurations where BCLK = rate * slots * slot_width.

When multiple DAIs on the same card share the same physical BCLK
(detected via clk_is_match()), the ASoC core can automatically
constrain their hw_params so that the resulting BCLK rates are
compatible. This commit adds the data structure support; the actual
constraint logic follows in the next patch.

Signed-off-by: Troy Mitchell <troy.mitchell@linux.spacemit.com>
Link: https://patch.msgid.link/20260522-i2s-same-blk-v4-1-a71a86faaa20@linux.spacemit.com
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Troy Mitchell 2026-05-22 21:33:57 +08:00 committed by Mark Brown
parent e7ae89a0c9
commit 94bdfad3a6
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GPG Key ID: 24D68B725D5487D0
2 changed files with 25 additions and 0 deletions
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7
include/sound/soc-dai.h
View File

@ -17,6 +17,7 @@
struct snd_pcm_substream;
struct snd_soc_dapm_widget;
struct snd_compr_stream;
struct clk;
/*
* DAI hardware audio formats.
@ -188,6 +189,8 @@ int snd_soc_dai_set_pll(struct snd_soc_dai *dai,
int snd_soc_dai_set_bclk_ratio(struct snd_soc_dai *dai, unsigned int ratio);
void snd_soc_dai_set_bclk_clk(struct snd_soc_dai *dai, struct clk *bclk);
/* Digital Audio interface formatting */
int snd_soc_dai_get_fmt_max_priority(const struct snd_soc_pcm_runtime *rtd);
u64 snd_soc_dai_get_fmt(const struct snd_soc_dai *dai, int priority);
@ -473,6 +476,10 @@ struct snd_soc_dai {
unsigned int symmetric_channels;
unsigned int symmetric_sample_bits;
/* shared BCLK clock for cross-DAI rate constraints */
struct clk *bclk;
unsigned int bclk_ratio; /* BCLK = rate * bclk_ratio (0 = use channels * sample_bits) */
/* parent platform/codec */
struct snd_soc_component *component;

18
sound/soc/soc-dai.c
View File

@ -116,10 +116,28 @@ int snd_soc_dai_set_bclk_ratio(struct snd_soc_dai *dai, unsigned int ratio)
dai->driver->ops->set_bclk_ratio)
ret = dai->driver->ops->set_bclk_ratio(dai, ratio);
if (!ret)
dai->bclk_ratio = ratio;
return soc_dai_ret(dai, ret);
}
EXPORT_SYMBOL_GPL(snd_soc_dai_set_bclk_ratio);
/**
* snd_soc_dai_set_bclk_clk - set the BCLK clock for shared clock detection
* @dai: DAI
* @bclk: BCLK clock pointer (or NULL to clear)
*
* When multiple DAIs share the same physical BCLK (detected via
* clk_is_match()), the ASoC core will automatically constrain their
* hw_params so that the resulting BCLK rates are compatible.
*/
void snd_soc_dai_set_bclk_clk(struct snd_soc_dai *dai, struct clk *bclk)
{
dai->bclk = bclk;
}
EXPORT_SYMBOL_GPL(snd_soc_dai_set_bclk_clk);
int snd_soc_dai_get_fmt_max_priority(const struct snd_soc_pcm_runtime *rtd)
{
struct snd_soc_dai *dai;