[PATCH v2 13/20] ASoC: tegra20: i2s: Filter out unsupported rates
From: Dmitry Osipenko <digetx@gmail.com>
Date: 2021-11-26 16:36:45
Also in:
alsa-devel, dri-devel, linux-tegra, lkml
Subsystem:
sound, sound - soc layer / dynamic audio power management (asoc), the rest · Maintainers:
Jaroslav Kysela, Takashi Iwai, Liam Girdwood, Mark Brown, Linus Torvalds
Support new nvidia,fixed-parent-rate device-tree property which instructs I2S that board wants parent clock rate to stay at a fixed rate. This allows to play audio over S/PDIF and I2S simultaneously. The root of the problem is that audio components on Tegra share the same audio PLL, and thus, only a subset of rates can be supported if we want to play audio simultaneously. Filter out audio rates that don't match parent clock rate if device-tree has the nvidia,fixed-parent-rate property. Signed-off-by: Dmitry Osipenko <digetx@gmail.com> --- sound/soc/tegra/tegra20_i2s.c | 49 +++++++++++++++++++++++++++++++++++ 1 file changed, 49 insertions(+)
diff --git a/sound/soc/tegra/tegra20_i2s.c b/sound/soc/tegra/tegra20_i2s.c
index 266d2cab9f49..27365a877e47 100644
--- a/sound/soc/tegra/tegra20_i2s.c
+++ b/sound/soc/tegra/tegra20_i2s.c@@ -262,10 +262,59 @@ static int tegra20_i2s_probe(struct snd_soc_dai *dai) return 0; } +static const unsigned int tegra20_i2s_rates[] = { + 8000, 11025, 16000, 22050, 32000, 44100, 48000, 64000, 88200, 96000 +}; + +static int tegra20_i2s_filter_rates(struct snd_pcm_hw_params *params, + struct snd_pcm_hw_rule *rule) +{ + struct snd_interval *r = hw_param_interval(params, rule->var); + struct snd_soc_dai *dai = rule->private; + struct tegra20_i2s *i2s = dev_get_drvdata(dai->dev); + struct clk *parent = clk_get_parent(i2s->clk_i2s); + long i, parent_rate, valid_rates = 0; + + parent_rate = clk_get_rate(parent); + if (parent_rate <= 0) { + dev_err(dai->dev, "Can't get parent clock rate: %ld\n", + parent_rate); + return parent_rate ?: -EINVAL; + } + + for (i = 0; i < ARRAY_SIZE(tegra20_i2s_rates); i++) { + if (parent_rate % (tegra20_i2s_rates[i] * 128) == 0) + valid_rates |= BIT(i); + } + + /* + * At least one rate must be valid, otherwise the parent clock isn't + * audio PLL. Nothing should be filtered in this case. + */ + if (!valid_rates) + valid_rates = BIT(ARRAY_SIZE(tegra20_i2s_rates)) - 1; + + return snd_interval_list(r, ARRAY_SIZE(tegra20_i2s_rates), + tegra20_i2s_rates, valid_rates); +} + +static int tegra20_i2s_startup(struct snd_pcm_substream *substream, + struct snd_soc_dai *dai) +{ + if (!device_property_read_bool(dai->dev, "nvidia,fixed-parent-rate")) + return 0; + + return snd_pcm_hw_rule_add(substream->runtime, 0, + SNDRV_PCM_HW_PARAM_RATE, + tegra20_i2s_filter_rates, dai, + SNDRV_PCM_HW_PARAM_RATE, -1); +} + static const struct snd_soc_dai_ops tegra20_i2s_dai_ops = { .set_fmt = tegra20_i2s_set_fmt, .hw_params = tegra20_i2s_hw_params, .trigger = tegra20_i2s_trigger, + .startup = tegra20_i2s_startup, }; static const struct snd_soc_dai_driver tegra20_i2s_dai_template = {
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2.33.1