sound/soc/codecs/lochnagar-sc.c

Source file repositories/reference/linux-study-clean/sound/soc/codecs/lochnagar-sc.c

File Facts

System
Linux kernel
Corpus path
sound/soc/codecs/lochnagar-sc.c
Extension
.c
Size
7032 bytes
Lines
267
Domain
Driver Families
Bucket
sound/soc
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

struct lochnagar_sc_priv {
	struct clk *mclk;
};

static const struct snd_soc_dapm_widget lochnagar_sc_widgets[] = {
	SND_SOC_DAPM_LINE("Line Jack", NULL),
	SND_SOC_DAPM_LINE("USB Audio", NULL),
};

static const struct snd_soc_dapm_route lochnagar_sc_routes[] = {
	{ "Line Jack", NULL, "AIF1 Playback" },
	{ "AIF1 Capture", NULL, "Line Jack" },

	{ "USB Audio", NULL, "USB1 Playback" },
	{ "USB Audio", NULL, "USB2 Playback" },
	{ "USB1 Capture", NULL, "USB Audio" },
	{ "USB2 Capture", NULL, "USB Audio" },
};

static const unsigned int lochnagar_sc_chan_vals[] = {
	4, 8,
};

static const struct snd_pcm_hw_constraint_list lochnagar_sc_chan_constraint = {
	.count = ARRAY_SIZE(lochnagar_sc_chan_vals),
	.list = lochnagar_sc_chan_vals,
};

static const unsigned int lochnagar_sc_rate_vals[] = {
	8000, 16000, 24000, 32000, 48000, 96000, 192000,
	22050, 44100, 88200, 176400,
};

static const struct snd_pcm_hw_constraint_list lochnagar_sc_rate_constraint = {
	.count = ARRAY_SIZE(lochnagar_sc_rate_vals),
	.list = lochnagar_sc_rate_vals,
};

static int lochnagar_sc_hw_rule_rate(struct snd_pcm_hw_params *params,
				     struct snd_pcm_hw_rule *rule)
{
	struct snd_interval range = {
		.min = 8000,
		.max = 24576000 / hw_param_interval(params, rule->deps[0])->max,
	};

	return snd_interval_refine(hw_param_interval(params, rule->var),
				   &range);
}

static int lochnagar_sc_startup(struct snd_pcm_substream *substream,
				struct snd_soc_dai *dai)
{
	struct snd_soc_component *comp = dai->component;
	struct lochnagar_sc_priv *priv = snd_soc_component_get_drvdata(comp);
	int ret;

	ret = snd_pcm_hw_constraint_list(substream->runtime, 0,
					 SNDRV_PCM_HW_PARAM_RATE,
					 &lochnagar_sc_rate_constraint);
	if (ret)
		return ret;

	return snd_pcm_hw_rule_add(substream->runtime, 0,
				   SNDRV_PCM_HW_PARAM_RATE,
				   lochnagar_sc_hw_rule_rate, priv,
				   SNDRV_PCM_HW_PARAM_FRAME_BITS, -1);
}

static int lochnagar_sc_line_startup(struct snd_pcm_substream *substream,
				     struct snd_soc_dai *dai)
{
	struct snd_soc_component *comp = dai->component;
	struct lochnagar_sc_priv *priv = snd_soc_component_get_drvdata(comp);
	int ret;

	ret = clk_prepare_enable(priv->mclk);
	if (ret < 0) {
		dev_err(dai->dev, "Failed to enable MCLK: %d\n", ret);
		return ret;
	}

	ret = lochnagar_sc_startup(substream, dai);
	if (ret)
		return ret;

	return snd_pcm_hw_constraint_list(substream->runtime, 0,
					  SNDRV_PCM_HW_PARAM_CHANNELS,
					  &lochnagar_sc_chan_constraint);
}

Annotation

Implementation Notes